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Wastewater Treatment Plant Master Plan Vol. 1 - 2000I ' r di _'IF CF; I ' i.� carOLLO . e n G i n e e r s a City of Pismo Beach • WASTEWATER TREATMENT PLANT od�94�. COLLECTION SYSTEM MASTER PLANS OF CAILA Final Report, February 2000 H:\Fina11PismoBch_FN014838AOO1Rpticvrtoc.wpd J{ 2700 YGNAGIO VALLEY ROAD, SUITE 300 WALNUT GREEK, CALIFORNIA 94598 (51.0) 932-1110 + FAX (510) 930-0208 it City of Pismo Beach WASTEWATER TREATMENT PLANT AND COLLECTION SYSTEM FACILITY PLAN TABLE OF CONTENTS C�1Jff2t;t:9M=rA;rAlltPl�711V,I,,ElXA 1.1 INTRODUCTION..................................................... 1-1 1.2 BACKGROUND...................................................... 1-1 1.3 PURPOSE AND SCOPE OF WASTEWATER TREATMENT PLANT AND COLLECTION SYSTEM MASTER PLANS ............................................. 1-2 1.4 DESIGN FLOWS AND WASTEWATER CHARACTERISTICS .................. 1-2 1.5 FINDINGS OF WASTEWATER TREATMENT PLANT MASTER PLAN ............ 1-3 Waste Discharge Requirements .......................................... 1-3 Analysis of Existing Treatment Facility ..................................... 1-3 Maximum Utilization of Existing Plant ...................................... 1-6 Immediate Improvements to Existing Plant .................................. 1-6 1.6 WASTEWATER TREATMENT PLANT UPGRADE ALTERNATIVES ............. 1-7 1.7 CONSOLIDATION WITH SOUTH SAN LUIS OBISPO COUNTY SANITATION DISTRIIM 1.8 FINDINGS OF COLLECTION SYSTEM MASTER PLAN ...................... 1-11 Infiltration lInflow Analysis ............................................. 1-11 Gravity Collection System 1-11 Sewer Lift Stations ................................................... 1-11 1.9 COLLECTION SYSTEM UPGRADE RECOMMENDATIONS ................... 1-12 CHAPTER 2 - CURRENT PROJECTED WASTEWATER CHARACTERISTICS 2.1 INTRODUCTION..................................................... 2-1 j 2.2 CURRENT WASTEWATER FLOWS AND POLLUTANT LOADS ................ 2-1 J Wastewater Flows 2-1 J Pollutant Loads ....................................................... 2-2 _1 CHAPTER 3 - CURRENT WASTE DISCHARGE REQUIREMENTS 3.1 INTRODUCTION..................................................... 3-1 3.2 CURRENT WASTE DISCHARGE REQUIREMENTS .......................... 3-1 JH:1FinallPismoBch_FNO' 4836AOO1Rpticvrtoo.wpd i City of Pismo Beach WASTEWATER TREATMENT PLANT AND COLLECTION SYSTEM FACILITY PLAN 3.3 REGIONAL WATER QUALITY CONTROL BOARD (RWQCB) CONCERNS ....... 3-2 3.4 REUSE CRITERIA .................................................... 3-2 3.5 ABILITY TO COMPLY WITH NPDES REQUIREMENTS ... _ ................... 3-3 CHAPTER 4 - ANALYSIS OF EXISTING TREATMENT FACILITY 4.1 INTRODUCTION..................................................... 4-1 4.2 PHYSICAL CONDITION ..................... I .......................... 4-1 4.3 PLANT HYDRAULICS ................................................. 4-4 4.4 UNIT PROCESS CAPACITIES .......................................... 4-4 Headworks.......................................................... 4-4 FlowMetering........................................................ 4-5 BarScreens......................................................... 4-5 Aerated Grit Chamber ................................................. 4-5 .} Primary Treatment .................................................... 4-5 } Secondary Treatment . 4-6 Secondary Clarifiers.................................................... 4-6 Primary and Secondary Sludge Pumps .................................... 4-7 Secondary Effluent Pump Station 4-7 Effluent Disinfection Facilities ............................................ 4-7 Hypochlorite/Bisulfite Feed System .......... . ............................ 4-8 Solids Handling 4-8 Dissolved Air Flotation Thickner (DAFT) .................................... 4-8 Anaerobic Digesters ................................................... 4-8 J Belt Filter Press ...................................................... 4-8 1 Sludge Storage and Drying Area ......................................... 4-8 Support Systems ..................................................... 4-8 Operations Center/Laboratory ........................................... 4-8 1 Plant Maintenance Facilities ............................................. 4-9 Plant Utilities........................................................ 4-9 Plant Instrumentation and Control :::..................................... 4-9 Plant Electrical Equipment 4-10 4.5 SUMMARY OF EXISTING PLANT CAPACITY ............................. 4-10 4.6 COMPONENTS RECOMMENDED FOR REPLACEMENT OR UPGRADE ........ 4-10 1 H:\FinallPiSmoBch_FNOA836A001Rptkcvrtoc.wpd ii City of Pismo Beach WASTEWATER TREATMENT PLANT AND r COLLECTION SYSTEM FACILITY PLAN CHAPTER 5 - TREATMENT UPGRADE ALTERNATIVES ANALYSIS 5.1 INTRODUCTION..................................................... 5-1 Consolidation with South San Luis Obispo County Sanitation District ............. 5-1 Los Osos Advanced Integrated Pond System ............................... 5-2 Trickling Filter/Solids Contact (TFISC) Process ........................ _ ..... 5-2 -7 5.2 ALTERNATIVES EVALUATION CRITERIA ................................. 5-2 5.3 DEVELOPMENT OF VIABLE TREATMENT UPGRADE ALTERNATIVES ......... 5-3 Alternative A - Activated Sludge .......................................... 5-4 Alternatives B and C - Oxidation Ditch ..................................... 5-9 Alternative B - Oxidation Ditch with Primary Clarifiers ......................... 5-9 Alternative C - Oxidation Ditch without Primary Clarifiers ...................... 5-10 Alternative A-1 - Maximum Use of Existing Plant ............................ 5-10 5.4 COMPARISON OF VIABLE TREATMENT UPGRADE ALTERNATIVES .......... 5-14 Cost Criteria Comparison .............................................. 5-14 O&M Cost Comparison ................................................ 5-14 Total Project Cost Comparison .......................................... 5-16 Life Cycle Cost Comparison ............................................ 5-16 Practical and Institutional Criteria Comparison .............................. 5-17 CHAPTER 6 - IMPLEMENTATION PLAN 6.1 RECOMMENDED ALTERNATIVE FOR BUILDOUT .......................... 6-1 6.2 IMPLEMENTATION SCHEDULE ......................................... 6-1 6.3 STATE REVOLVING FUND LOANS ...................................... 6-6 LIST OF TABLES 1.1 Design Flows and Wastewater Characteristics ............................... 1-2 1.2 Immediate Improvements ............................................... 1-6 1.3 Annualized Life Cycle WWTP Cost Comparison ............................. 1-7 1.4 Comparison of Advantages and Disadvantages Associated with each WWTP Alternative ................................................. 1-8 1.5 Priority 1 Capital Improvements.......... 1-12 1.6 Priority 2 Capital Improvements ............................... 1-13 1.7 Priority 3 Capital Improvements ......................................... 1-13 2.1 Summary of Existing and Projected Flows and Peaking Factors ................. 2-2 2.2 Design Flows and Wastewater Characteristics . 2-3 3.1 Summary of Current and Proposed Conventional Pollutant WDRs ............... 3-1 :l H:1FinahPismoBch_FNO44836A001Rp6cvrloc.wpd ill City of Pismo Beach WASTEWATER TREATMENT PLANT AND COLLECTION SYSTEM FACILITY PLAN 4.1 Facility Condition Evaluation Summary ..................... I .............. 4-2 4.2 Summary of Components Recommended for Replacement or Upgrade .......... 4-10 5.1 Alternative A - Activated Sludge Total Project Cost Estimate .................... 5-5 5.2 Alternatives B and C - Oxidation Ditch Total Project Cost Estimate ............... 5-6 5.3 Alternative A-1 Maximum Use of Existing Plant .............................. 5-7 5.4 Annual O&M Cost Comparison .......................................... 5-16 5.5 Annualized Total Capital Cost Comparison of WWTP Alternatives .............. 5-17 5.6 Annualized Life Cycle Cost Comparison ................................... 5-17 5.7 Comparison of Advantages and Disadvantages Associated with each WWTP Alternative ................................................ 5-18 6.1 Recommended WWTP Project Cost Estimate - Oxidation Ditch without Primary Clarifiers ............................................ 6-5 6.2 Estimated Annual Loan Payments of SRF Loans ............................. 6-6 LIST OF FIGURES 1.1 July Flow Projections Maximum Dry Weather Flow ........................... 1-4 1.2 Site Layout of Recommended Wastewater Treatment Plant for Buildout ........... 1-9 1.3 Alternative A-1 - Maximum Use of Existing Plant ............................ 1-10 4.1 Site Layout of Existing WWTP........................................... 4-3 5.1 Alternative A - Layout .................................................. 5-8 5.2. Alternative B - Layout ................................................. 5-11 5.3 Alternative C - Layout ................................................. 5-12 5.4 Site Layout Alternative A-1 Maximum Use of Existing Plant .................... 5-13 6.1 Recommended Alternative Layout ........................................ 6-2 6.2 Preliminary Schematic Profile of Recommended Alternative .................... 6-3 6.3 Implementation Schedule ............................................... 6-4 LIST OF APPENDICES A - COMPLIANCE DOCUMENTS FROM REGIONAL WATER QUALITY CONTROL BOARD B - TECHNICAL MEMORANDUM NO. 1 - WASTEWATER FLOWS AND CHARACTERISTICS C - EXISTING WASTEWATER TREATMENT PLANT DESIGN CRITERIA D - ALTERNATIVES - DESIGN CRITERIA E - TECHNICAL MEMORANDUM NO. 2 - ELECTRICAL EVALUATION F- KENNEDYIJENKS CONSULTANTS' DRAFT WASTEWATER TREATMENT CAPACITY STUDY G- CAROLLO'S REVIEW COMMENTS ON KENNEDYIJENKS' STUDY H- ALTERNATIVE A-1 DESIGN CRITERIA - MAXIMUM USE OF EXISTING PLANT I- CONSOLIDATION WITH SOUTH SAN LUIS OBISPO COUNTY SANITATION DISTRICT ` H:Tinal\PismoBch FNOW838Ao41Rpttvrtoc.wpd iv r Chapter 1 3� EXECUTIVE SUMMARY 1.1 INTRODUCTION The Master Plan is provided in two volumes. Volume No. 1 includes the Wastewater Treatment Master Plan and Volume No. 2 includes the Collection System Master Plan. Chapter 1 of the wastewater treatment master plan is in the Executive Summary for both volumes. The Pismo Beach Wastewater Treatment Plant (WWTP) was designed to provide secondary treated effluent which is pumped via a pipeline to the joint ocean outfall with the South San Luis Obispo County Sanitation District Wastewater Facility into the Pacific Ocean. The need to maintain a high quality effluent and provide a facility with adequate reliability is critical to protecting the beneficial uses of this receiving water. Many components of the wastewater treatment plant are in excess of 44 years old. The treatment facility has experienced periodic violations of National Pollution Discharge Elimination System (NPDES) permit criteria of disinfection standards for coliform due to equipment malfunctions and sewer system overflows. The WWTP has not violated discharge requirements for Biochemical Oxygen Demand (BOD) or suspended solid (SS). A copy of compliance documents associated with Pismo Beach's WWTP is included in Appendix A. The Pismo Beach Wastewater Collection System consists of gravity sewers, nine lift stations, and force mains which convey raw wastewater to the WWTP. Due to the entry of extraneous storm water into the collection system and the lack of adequate capacity, overflows have occurred at several lift stations during periods of intense rainfall. The majority of the overflows have occurred at the Addie Street lift station, which conveys approximately two-thirds of the City's total wastewater flow. In addition, recent flow records indicate that the existing 12-inch diameter interceptor sewer which conveys wastewater from the Shell Beach area flows nearly full under existing peak summer conditions. Because of this the City has already initiated the design of the Shell Beach Force Main Relocation Project which will divert wastewater flows away from the Addie Street Pump Station directly to the WWTP. The City has also purchased new generators for some lift stations to assume proper operation during a power outage. 1.2 BACKGROUND The Pismo Beach WWTP was originally constructed in 1955. WWTP process modifications and additions were constructed in 1973 and 1984, bringing the plant to its current capacity. As explained in Chapter 4, the current capacity is estimated at 1.5 mgd, average day maximum month dry weather flow (ADMMDWF). The WWTP's permitted capacity is 1.75 mgd ADMMDWF. This would be equal to the peak day dry weather flow (PDF) of :i J H:1FinaINPismoBch_FN014836AOO\Rpt\01.wpd 1-1 1.75 mgd on July 4, 1998 occurring everyday of the month. The existing WWTP is not capable of sustaining treatment of 1.75 mgd for an entire month. Unit processes at the plant include grit removal, primary sedimentation, conventional activated sludge, secondary clarification, chlorination, and dechlorination. Treatment of wastewater biosolids includes dissolved air flotation thickening, anaerobic digestion, and belt filter press dewatering. 1.3 PURPOSE AND SCOPE OF WASTEWATER TREATMENT PLANT AND COLLECTION SYSTEM MASTER PLANS The primary purpose of the Wastewater Treatment Master Plan (Master Plan) is to provide a comprehensive plan which identifies upgrades required to provide reliable long term compliance with NPDES requirements. The purpose of the Wastewater Collection System Master Plan is to furnish a comprehensive program of prioritized capital improvements which will address existing .� deficiencies and provide adequate collection system capacity and redundancy consistent with the ultimate needs of the City. 1.4 DESIGN FLOWS AND WASTEWATER CHARACTERISTICS 4 Table 1.1 presents design flows and wastewater characteristics. In the year 2006 it is projected that the design capacity of 1.5 mgd Average Day Maximum Month Dry Weather flow will be reached. Table 1.1 Design Flows and Wastewater Characteristics City of Pismo Beach Design Year 1998 1999(4) 2006 2016 Population, persons 8,528 -- -- 14,438 Hotel Rooms 1,831 -- -- 3,119 Commercial, sq ft 953,600 -- -- 1,602,000 RV Park, spaces 811 -- -- 821 Flow, mgd Average Annual (AAF) 1.18 1.08 1.4 2.0 Peals Day Dry Weather 1.76 1.60 2.2 3.0 (PDF) Average Day Maximum 1.26 1.20 1.5 2.4 Month Dry Weather Flow (ADMMDWF)(3) H:1FinalhPismoBch_FNO\4636A001RpNI.wpd' 1-2 Table 1.1 Design Flows and Wastewater Characteristics City of Pismo Beach Design Year 1998 1999t4f 2006 2016 Peak Hour Wet Weather 3.14 3.00 3.9 6.0 (PHWWF) Influent Concentration BOD (1) 248 263 -- 250 TSS (2) 297 278 -- 330 Influent Loading, Ibs/day BOD 2,480 2,369 -- 4,170 TSS 2,970 2,504 -- 5,500 Notes: 1) Five day Biochemical Oxygen Demand, Average Annual Values 2) Total Suspended Solids, Average Annual Values 3) NPDES Permit Requirement is 1.75 mgd ADMMDWF 4) Based on January to September 1999 Flows Figure 1.1 presents a graph of wastewater flow projections versus the design years for a 3, 2, and 1 percent growth rate. Based on the 3 percent growth rate shown in Figure 1.1, the ADMMDWF treatment capacity (permit condition) of 1.5 mgd may be reached in year 2006. The plant may reach 90 percent of the 1.5 mgd capacity or 1.36 mgd in year 2004, based on a 3 percent growth rate which is the worst case growth rate. This gives the City of Pismo Beach four or more years to plan, design, and construct a treatment plant expansion in Pismo Beach or consolidation of treatment facilities with the South San Luis Obispo County Sanitation District (SSLOCSD). 1.5 FINDINGS OF WASTEWATER TREATMENT PLANT MASTER PLAN Waste Discharge Requirements It is anticipated that the future waste discharge requirements for standard conventional pollutants will remain as currently indicated in the existing NPDES permit. J Analysis of Existing Treatment Facility Many of the existing treatment processes and structures were constructed in the 1950s and are over 44 years old. The condition of many mechanical and electrical components is poor or marginal at best. The City of Pismo Beach retained Kennedy/Jenks Consultants' (K/J) to review the July 1999 Draft Master Plan prepared by Carollo. K/J's draft Wastewater Treatment Capacity Study is included in Appendix F. Carollo's review comments on the K/J study are H:1Final\PismoBch FNOA83BAOOIRpt101.wpd 1-3 co ti T �o T Z W r 0 � Z W m r M T V CL LU O cm o �cm C(nF a� � y V a IL w O =aw C07 CMt o W ai Z IX Z cn o = o_ Z R LL gt�07� T 1 a °D r W V mLU o N W FLLL o 0 LJL M Q � o 0 uL O c U y a� � ao aN _Cb m s a UJ woo CA0 Z V c �E M Q! v M Y7 N N IA r IA C C (aJW),kVC b3d SNOTTVE) NOITIIW included in Appendix G. Based on K/J's recommendations, Carollo has revised the assessment of structural conditions of the existing plant from that presented in the July 1999 draft. In addition, Carollo's chief structural engineer visited the WWTP in November 1999 to perform a visual inspection of structures. A facility condition assessment which was performed indicates the need to replace the following components in marginal to poor condition. Headworks • Aerated Grit Chamber Primary Treatment • Primary Sludge and Scum pumps • Primary Clarifier No. 2 Scraper Mechanism Secondary Treatment Secondary Clarifier No. 3 Bridge and Scraper Mechanism • Secondary Sludge Pumps ] An evaluation of unit process capacities was performed which indicates the need to replace } or modify the following components due to treatment and/or hydraulic capacity limitations. Headworks • Aerated Grit Chamber • Add Mechanical Bar Screen with Compactor • Add Separate Manual Bar Screen • Add Parshall Flume for Influent Flow Measuring Primary Treatment • Replace Primary Sludge and Scum Pumps Secondary Treatment • Replace Secondary Clarifier Mechanisms • Replace SecondarySludge-Pump-Station 0 Construct Additional Chlorine Contact Basin(s) • Upgrade Secondary Effluent Pump Station I H:1FinaKPismoBch_FNOWB36AU01Rpl1Di.wpd 1-5 Maximum Utilization of Existing Plant After reviewing KIJ draft study contained in Appendix F, the City authorized Carollo to develop an alternative to maximize the use of existing structures, particularly the existing clarifier complex in order to reduce capital costs of the project. Therefore Alternative A-1 - �. Maximum Use of Existing Plant has been added to the final report. Immediate improvements to Existing Plant The planning, design, and construction of a major wastewater treatment plant expansion takes a number of years. Chapter 6 of the Master Plan presents -a-possible implementation schedule. If design begins in late year 2000, the upgraded plant could be operational in four to five years. There are immediate improvements which should be implemented in the short term and assure that the treatment facilities can provide compliance with the NPDES permit between now and the date when the new plant or consolidation at the South County Sanitary District is completed. Table 1.2 lists recommended immediate improvements for the City's consideration to be phased in the next few years. Table 1.2 Immediate Improvements City of Pismo Beach Immediate Plant Improvements Five Year Life Items Estimated Cost New Secondary Clarifier No. 3 Mechanism (40') $140,000 New Secondary Clarifier No. 2 Mechanism (30) $80,000 Clean/Repair Digester No. 1(1) $120,000 Replace Primary Sludge Pumps(')K $60,000 Install second RAS Pump with VFDX $25,000 Replace corroded Steel Splitter Box $20,000 Seismic Bracing of Sludge Piping(') $10,000 Seismic Bracing of Air Blowers(') $15,000 Rehabilitate Belt Filter PressMy $50,000 Rehabilitate DAFT and Pumps(') $25,000 Provide Locker Room, Shower, and Toilet in Existing MCC $25,000 Building(') � Improvements for Electrical Facilities (see TM 2 in Appendix E)(') 4 $30,000 Total Immediate Improvements $600,000 (1) Immediate improvements applicable to Alternative A-1 H:1FinallPismoBch_FN014836A00%Rpt1Ol.wpd 1-6 1.6 WASTEWATER TREATMENT PLANT UPGRADE ALTERNATIVES y The configuration and sizing of facilities required to provide long term compliance with the NPDES permit at a future maximum average annual flow of 2.0 mgd and 2.4 mgd ADMMDWF (permit condition) were developed. Upgrade alternatives centered around the ability to provide secondary treatment under all conditions. The viable alternatives were compared based upon cost criteria, practical criteria and institutional criteria. Alternative A-1 was developed after submittal of -the Draft Master Plan to show the maximum reuse of the existing activated sludge plant. Based on this comparison of alternatives, it is recommended that the City of Pismo Beach proceed with the plant upgrade based upon Alternative C - oxidation ditch process without primary clarifiers. Table 1.3 presents a summary of life cycle cost comparison of the three alternatives for buildout and Table 1.4 presents a comparison of advantages and disadvantages. The marginal 2 percent cost difference between Alternative A-1 and Alternative C is not significant to warrant upgrading the existing 44 year old plant to the maximum extent. As noted in Table 1.4, there are more advantages for the City of Pismo Beach with Alternative C, especially lower anticipated O&M costs. The site layout of the Alternative C treatment plant for buildout is presented in Figure 1.1. The site layout for alternative A-1 is shown in Figure 1.2. Table 1.3 Annualized Life Cycle WWTP Cost Comparison ($/year) City of Pismo Beach Alt. C Alt. A-1 Oxidation Maximum Alt. A Ditch without Used Existing Activated Primary Item I Plant I Sludge I Clarifiers Total Project Cost $6,470,000 $7,090,000 $7,570,000 Annualized Total Capital Cost(') $470,000 $515,000 $550,000 Annual O&M Cost $665,000 $665,000 $607,000 Total Annual Life Cycle Cost $1,135,000 $1,180,000 $1,157,000 Difference in Cost Low Cost + 4% +2% (1) Annualized costs based on 6% - i over 30 years. (P/A=13.765) (Actual funding interest rate maybe less.) IH:1FinaklPismoBch_PNOA836AOOIRptWl .wpd 1-7 Table 1.4 Comparison of Advantages and Disadvantages Associated with each 1NVIITP Alternative City of Pismo Beach Alt. C Alt, A-1 Oxidation Maximum Alt. A Ditch without Used Existing Activated Primary Evaluation Criteria Plant Sludge Clarifiers A I NJ D AlNJ D A NJ D Cost Criteria O&M Cost Sludge Disposal Cost Total Annual Cost Capital Cost Practical Criteria Ease of Operations'_`a Constructability�_ Age of Facilities Institutional Criteria Low Odor Potential. Minimize Visual Impacts N D': A D A N> D Total Score 2 3 4= 1 4 2 6 3 A = Advantage N = Neutral D = Disadvantage H:1FinallPismoBch_FNd14836A001Rpt101.wo - 1 "8 "'JON j.4 SCALE 1 50' Uoo&r M2 Idued in 1999. or Fill in Equetlj7gfion Basinll-' f01- Sledge Storage Area CAN Imp. if. > r 40 VD. LEGEND ir r 0 New Treatment Units Existing Treatment Units to be Demolished Existing Forcemains Forcemain Sections to be Abandoned Connect Forcemains to New Headworks -Floure- 1.2 SITE LAYOUT OF RECOMMENDE6 ..oft WASTEWATER TREATMENT PLANT FOR BUILDOUT CITY OF PISMO BEACH I WASTEWATER MASTER PLAN PROCESS LEGEND 10 Headworks with Grit Removal ( 65'0 Secondary Clarifiers ' ' ! ,x • # � _f ` - ^; y, 0 Primary Influent Weir Splitter Box 4.1 ®Gonvert Existing Secondary a Clarifier to Chlorine Contact ' ' SCALE 1 _ 50 Convert Existing Two 3D's� � �• ' SecondaryClarifiers to Primary CBasin No. 1 larifiers 10 Existing Chlorine Contact ' Ae7lP�rdtogragh r " Fdr#edu!. 1 99. Q New Primary Effluent Lift Station Basin No. 2 r. , „, _ � - w L New (Fourth) Aeration Basin tt Relocated Location for s_ _,'. r - Chlorination and Cechlorination - *1 — © ML Weir Splitter Box * r ,� •� _ 0 RAS/WAS Pump Station 12 RehariiMate Existing Electrical Room F ' and Fourth Blower47 oht- 1 +r 1 x Fi�l infaua[ztion-B`�11 #, for Mudge Storage AresS! vp ECGr1C13r+ �'' 1 _". �, C;ar�fiier }W � k * � fi ec:or7dtry Clarifier fi J _ W ?131299M1.-UR,2 `r lJ OPerations eliterr' Lab Y }Vaa for 1 Grit Classifier I A.- LEGEND �I [ 0 New Treatment Units Existing Treatment Units to be Demolished , j Existing Treatment Units to be Changed to Other Process Existing Forcemains � Connect Forcemains to New Headworks �= Figure 1.3 SITE LAYOUT ALTERNATIVE A-1 , MAXIMUM USE OF EXISTING PLANT CITY OF PISMO BEACH � WASTEWATER MASTER PLAN = 1.7 CONSOLIDATION WITH SOUTH SAN LUIS OBISPO COUNTY SANITATION DISTRICT The City of Pismo Beach contracted with Kennedy/Jenks Consultants to perform a preliminary analysis of the alternative of wastewater treatment consolidation with SSLOCSD. This analysis is included as Appendix I. The City may consider an addendum to the Wastewater Treatment Master Plan to include more detailed analysis of consolidation with the SSLOCSD. 1.8 FINDINGS OF COLLECTION SYSTEM -MASTER PLAN Infiltration / Inflow Analysis During periods of intense rainfall, wastewater flows at the WWTP have periodically tripled due to the entry of extraneous storm water into the system. Collection system overflows have also resulted from the high storm -related peak flows. During the period of January through March, 1999, the City maintained a system of flow meters with the intent of isolating the infiltration / inflow (Ill) problem to smaller sub -areas of the system. Rainfall during the monitoring period was light by historical standards. The largest storm occurred on March 15, when approximately 1.2 inches of rain was recorded at the WWTP. System- wide III was small during this event, and flow remained at average levels at the WWTP. Even with the light rainfall, the metering program was successful in identifying a major contributor to the 1/1 problem - the Pismo Heights area. During the period analyzed, the y Pismo Heights area contributed more than 80 percent of the total estimated III reaching the WWTP. In addition, it is anticipated that subsequent attempts to eliminate III from the Pismo Heights will be cost effective when compared with the capital expense of upgrading the downstream facilities to adequately convey extraneous storm flows. L ' Gravity Collection System 41 A hydraulic computer model was prepared for the gravity collection system to analyze system performance under existing and future conditions. Based on the results of this analysis, several existing and future gravity system deficiencies were noted. The existing interceptor which conveys wastewater more than two miles from the Shell Beach area to the Addie Street lift station is undersized for both existing and future peak flows. It is recommended that the City bypass the interceptor with a 12-inch diameter force main from Shell Beach to the WWTP. Future flow deficiencies were also noted upstream of the Pismo Oaks and Vista Del Mar lift stations. 'Replacement of gravity sewers is recommended for i these locations. Sewer Lift Stations A separate computer model was developed to analyze the nine lift stations and associated force mains. Each station was analyzed for deficiencies, and improvements of varying priority were recommended for all nine stations. The Addie Street lift station has been in ` ` H:1FinallPismoBch_FNOW836AOOIRpWi.wpd 1-11 operation for 44 years, and replacement of the station is warranted due to capacity, redundancy, odor, and age -related deficiencies. Due to its critical role in the collection system and historical overflow problems, the Addie Street lift station replacement project was given a higher priority than the other lift station improvements. For the remaining eight lift stations, various upgrades to existing infrastructure are recommended. In accordance with the Facilities Element of the City General Plan, all lift stations should ultimately have standby power. In addition, connection facilities to accommodate a trailer -mounted pump station, such as the unit recently purchased by the City, should be added to each lift station. The Sunset Palisades lift station is the only exception to this recommendation, where discharge pressures exceed the capacity of the trailer -mounted unit. 1.9 COLLECTION SYSTEM UPGRADE RECOMMENDATIONS The Collection System Master Plan consists of staged capital improvements to correct existing deficiencies and provide for the ultimate City needs. The following tables summarize a three stage capital improvement program which reflects the relative importance and recommended timing of the projects. Priority 1 improvements should be constructed in the next few years. Priority 2 improvements should be completed in the next 5 to 10 years, and Priority 3 improvements should be implemented in 10 to 15 years. The total cost of the recommended collection system improvements is $2,915,000. Table 1.5 Priority 1 Capital Improvements City of Pismo Beach Budget No. Project Name Description Cost Estimate 1-1 Shell Beach force main Bypass the existing interceptor with a (1) relocation new 12 inch force main to the Addie Street L.S. force main. 1-2 Pismo Heights III Reduce Ill in the Pismo Heights area by $50,000 Elimination contacting residents and repairing leaks. 1-3 Addie Street lift station Construct a new submersible lift station $800,000 replacement facility at Addie Street. 1-4 Pismo Oaks lift station Upgrade the Pismo Oaks L.S. to $300,000 upgrade -correct structural; capacity, and operational problems. 1-5 Interceptor manhole Coat interceptor manholes with a $140,000 rehabilitation sulfide -resistant product. 1-6 Five Cities lift station Upgrade the Five Cities L.S. with new $310,000 upgrade pumps and stand by power. Replace the existing 6 inch force main with an 8 inch. J H:1FinallPismoBch_FNO\483eA001RpWl.wpd 1-12 Table 1.5 Priority 1 Capital Improvements City of Pismo Beach Budget No. Project Name Description Cost Estimate 1-7 Park/Cypress gravity Combine the three existing lines into a $355,000 sewer improvements common 18 inch sewer with additional depth. Divert flows as summarized in .Chapter 6. TOTAL OF PRIORITY 1 IMPROVEMENTS (ENR-CCI = 7000) $1,956,000 (1) In progress, not included in Budget Cost Estimate. Table 1.6 Priority 2 Capital Improvements City of Pismo Beach Budget Cost No. Project Name Description Estimate 2-1 Vista Del Mar lift station Upgrade the Vista Del Mar L.S. to $220,000 and force main upgrade correct capacity and operational problems. Upgrade the existing 6 inch force main to 8 inch 2-2 Freeway Foothills lift Upgrade the Foothill Freeway lift $80,000 station upgrade station to correct operational problems and add stand by power. 2-3 St. Andrews lift station Add stand by power and upgrade $50,000 stand by generator & electrical system electrical upgrades TOTAL OF PRIORITY 2 IMPROVEMENTS (ENR-CCI = 7000) $3509D00 Table 1.7 Priority 3 Capital Improvements City of Pismo No. I Project Name 3-1 Sewer sag repair adjacent to Pismo Pier 3-2 Spyglass lift station upgrade 3-3 PG& E lift station stand by generator Budget Cost Description Estimate Correct existing sag with new 8 inch $62,000 sewer. Upgrade the Spyglass lift station to $110,000 add stand by power and correct operational deficiencies Add stand by power $24,000 H:1Final%PismoBch_FNOWSWA001Rpt1Dl .%vo 1-13 I Table 1.7 Priority 3 Capital Improvements City of Pismo Budget Cost No. Project Name Description Estimate 3-4 Sunset Palisades lift Add stand by power (1) station stand by generator 3-5 Vista Del Mar gravity Replace existing 8 inch sewer with a $114,000 system upgrade 10 inch sewer to prevent system surcharging 3-6 Pismo Oaks gravity Replace the existing 10 inch sewer $300,000 system upgrade with a 12 inch sewer to meet future capacity requirements TOTAL OF PRIORITY 3 IMPROVEMENTS (ENR-CCI = 7000) $610,000 TOTAL OF ALL IMPROVEMENTS (PRIORITY 1, 2 & 3) $2,915,000 (1) In progress, not included in Budget Cost Estimate. H:hFinar%PismoBeh_FNOW83MOOIRpt101.vvo 1-14 IChapter 2 CURRENT AND PROJECTED WASTEWATER CHARACTERISTICS 2.1 INTRODUCTION This chapter summarizes the findings of the evaluation of the existing wastewater flows and loads at the City of Pismo Beach Wastewater Treatment Plant (WWTP) and identities projected future capacity requirements. Wastewater flow represents the rate at which wastewater enters the WWTP from the wastewater collection system. Flows are expressed in million gallons per day (mgd). Evaluation of wastewater flow includes a review of flows received in dry weather and wet weather under average and peak hour conditions. Wastewater load represents the daily quantity of conventional pollutants, expressed in pounds per day (lbs per day) which enter the WWTP. The biochemical oxygen demand (BOD), and total suspended solids (TSS), together with flow, control the sizing of the unit treatment processes at the WWTP. This chapter also summarizes projected flow, BOD and TSS load conditions under which the WWTP is anticipated to operate in the future. Future flows and loads are projected based upon future growth projection contained in Appendix B. 2.2 CURRENT WASTEWATER FLOWS AND POLLUTANT LOADS Wastewater Flows Plant operating data for the period January 1998 through December 1998 and January 1999 to September 1999 were analyzed to determine the current wastewater flow. The 1998 average annual flow (AAF) was 1.18 mgd. The 1998 average day maximum month dry weather flow was 1.26 mgd. The 1998 peak day dry weather flow (PDF) which typically occurs on July 4 was at 1.76 mgd. As with any WWTP, the flow to the Pismo Beach WWTP varies throughout the day in response to the diurnal water use of the population within the service area. Peak flows typically occur in the mornings (8 to 10 a.m.) and evenings (6 to 8 p.m.). The daily diurnal peaking factors were evaluated under both dry weather and wet weather conditions. This analysis indicates a 1998 peak hour wet weather flow (PHWWF) of approximately 3.14 mgd. Table 2.1 summarizes the 1998, 1999, and buildout flow conditions and flow peaking - factors. ` H:\FinaHPismoBch—FNO14836AOO1RptH02.WOD 2-1 1 Table 2.1 Summary of Existing and Projected Flows and Peaking Factors City of Pismo Flow (mgd) Flow Condition Peaking 1998 1999 Build -Out Factors Flows Flows(�) Flows Average Annual Flow (AAF) 1.18 1.08 2.00 NIA Peak Day Dry Weather Flow (PDF) 1.76 1.60 3.00 1.5 Peak Hour Wet Weather Flow 3.14 3.0 6.0(1) 3.0 (PHWWF) Average Day Maximum Month Dry 1.26 1.20 2.4 1.2 Weather Flow (ADMMDWF) Average Day Maximum Month Wet 1.59 1.09 2.7 1.35 Weather Flow (ADMMWWF) Notes: 1) The future .estimate of 6.0 mgd includes 2.0 mgd of storm water inflow. 2) Based on January to September 1999 flows. 3) Permit will include this flow value. Pollutant Loads Pollutant Loads represent the amount of pollutants received at the WWTP in the raw wastewater. The raw wastewater pollutants must be reduced through treatment in order to meet discharge criteria established by the Regional Water Quality Control Board (RWQCB). The conventional pollutant loads dictate sizing and configuration of the plant. Pollutant load is a function of the quantity of wastewater (flow) and the strength of pollutants (concentration). The conventional pollutants considered in evaluating the WWTP include BOD and TSS. Five years (1994 to 1999) of data from the WWTP annual reports were evaluated. As presented in Appendix B, the design pollutant concentration for BOD and TSS is 250 and 330 mg/L, respectively. Table 2.2 presents the recommended design flows and wastewater characteristics for the year 1998 and the future design year at buildout, 2016. As noted in Appendix B, Technical Memorandum No. 1 Wastewater Flows and Characteristics, the Year 2016-buildout flows -estimatesinclude approximately 1,438 future population from possible changes in the sphere of influence. The Year 2016 flow estimate is predicated on a maximum allowable growth rate of 3 percent per year. `� H:1FinaWismoi3ch__FN04483SAoo1Rpm2.wpb 2-2 Table 2.2 Design Flows and Wastewater Characteristics City of Pismo Beach Design Year 1998 1999(3) 2006 2016 Population, persons 8,528 -- -- 14,438 Hotel Rooms 1,831 -- -- 3,119 Commercial, sq ft 963,600 -- -- 1,602,000 RV Park, spaces 811 -- -- 821 Flow, mgd Average Annual 1.18 1.08 1.4 2.0 Peak Day Dry Weather 1.76 1.60 2.2 3.0 (PDF) Average Day Maximum 1.26 1.20 1.5 2.4 Month Dry Weather Flow (ADMMDWF) Peak Hour Wet Weather 3.14 3.0 3.9 6.0 (PHWWF) Influent Concentration BOD (1) 248 263 250 TSS (2) 297 248 -- 330 Influent Loading, Ibs/day BOD 2,480 2,369 -- 4,170 TSS 2,970 2,504 -- 5,500 Notes: 1) Five day Biochemical Oxygen Demand, Average Annual Values 2) Total Suspended Solids, Average Annual Values 3) Based on January to September Flows IH:%FinahPismo8ch_FNOW836A001Rpt102.WPb 2-3 Chapter 3 WASTE DISCHARGE REQUIREMENTS 3.1 INTRODUCTION �1 This chapter provides a summary of the current and anticipated future waste discharge } requirements. The plants ability to comply with key waste discharge requirements (WDRs) is evaluated. Potential future plant upgrades which may be required to comply with future regulations are identified. 3.2 CURRENT WASTE DISCHARGE REQUIREMENTS The facility currently operates under NPDES permit No. CA0048151, Order No. 94-52. A summary of effluent requirements for conventional pollutants contained within the permit is presented in Table 3.1. Table 3.1 Summary of Current and Proposed Conventional Pollutant WDRs City of Pismo Beach Monthly Weekly Constituent Units Average Average Daily Peak BOD, 5-day mg/L 30 45 90 TSS mg/L 30 45 90 Fecal Coliform MPN1100 ml — 200 2,000 Acute Toxicity TUa 1.5 2.0 2.5 The existing NPDES permit and WDR expires on June 3, 1999 and are scheduled for renewal in the year 1999, The proposed Order 99-31 will be the reissued permit. A draft of this reissued permit is included in Appendix A. Both the draft Order 99-31 and the current Order 94-52 state that "effluent daily dry weather flow shall not exceed a monthly average 1.75 mgd." The key words in the above sentence are dry, weather, and monthly average. This flow is termed "average day maximum month dry weather flow (ADMMDWF). The ADMMDWF in 1998 was 1.26 mgd and in 1999 it was 1.20 mgd which is less than 1.75 mgd. The corresponding value for the design ADMMDWF for the huildout flows is 2.4-mgd. The plant treated 1.76 mgd on July 4, 1998; however the plant could not consistently treat 1.75 mgd for each of the 31 days of July. The actual capacity of the plant for the ADMMDWF is approximately 1.5 mgd as explained in Chapter 4. Per the permit, the 30 day monthly average flow in wet weather months of January, February, and March can exceed 1.75 mgd. . ] H:1Final\PismoBch_FNOW836A001Rpho3.WPO 3-1 3.3 REGIONAL WATER QUALITY CONTROL BOARD (RWQCB) CONCERNS The City of Pismo Beach has worked with the RWQCB to identify and resolve problems with the wastewater collection and treatment system. The RWQCB cited the following issues as significant concerns with the existing facilities. • Collection System Spills Complete Infiltration/Inflow Analysis • Submit Draft Complete Draft Wastewater Master Plans • Investigate Reuse of Reclaimed Wastewater The Regional Water Quality Control Board (RWQCB) has verbally requested the City to evaluate reuse of reclaimed wastewater. Reclaimed water applied to golf courses and Caltrans medians will require Title 22 water quality suitable for golf course application. It is recommended that reclaimed wastewater used for golf course irrigation must be filtered to a turbidity of 2 NTU and disinfected to achieve 2.2 MPN/100 ml total coliform. This analysis assumes that the new golf course will have residential units in close proximity and therefore require tertiary filtered wastewater with 2.2 MPN. :) 3.4 REUSE CRITERIA 4 Title 22 of the California Administration Code requires that "unrestricted use" recycled waters meet a 2 NTU turbidity and a 2.2 MPN total coliform. Filters would need to be installed to consistently achieve a 2 NTU turbidity during the reclamation season. In addition to the Title 22 criteria, additional criteria to protect the soils, trees, ornamental shrubs, and turf grass with reclaimed wastewater are applicable. If the reclaimed j wastewater is not within the following acceptable ranges for constituents, it may not be j feasible to use without additional treatment. Criterion Total Dissolved Solids Electrical Conductivity Boron Chloride Sodium Adjusted Sodium Adsorption Ration (ASAR) Bicarbonate H:WinallPiamoBct_FNOW836AOO\Rpt103.WPfl 3-2 Acceptable Range not to exceed 700 mg1L not to exceed 1.1 dSm'' not to exceed 1.0 mg/L not to exceed 100 mg/L not to exceed 70 mg/L not to exceed 3.0 not to exceed 300 mg/L 3.5 ABILITY TO COMPLY WITH NPDES REQUIREMENTS The current plant operating data indicates that the existing wastewater treatment facility has complied with BOD and TSS discharge criteria. Although BOD and TSS removal is not ' a problem at the WWTP the current treatment plant will be unable to reliably provide treatment for increased wastewater flows. The existing treatment facility cannot meet Title 22 unrestricted reuse criteria without tertiary filters. If a golf course wants to use reclaimed wastewater from the City of Pismo Beach's WWTP, the golf course, not the City, would construct the filters. Turf grass is sensitive to other wastewater constituents which are not removed with secondary treatment and tertiary filters as noted above. ._J tiH:%FinailPismoBctL FNObA836A001Rpt103.WPD 3-3 IChapter 4 ANALYSIS OF EXISTING TREATMENT FACILITY 4.1 INTRODUCTION This chapter presents the findings of the evaluation of the existing capacity of the City of Pismo Beach Wastewater Treatment Plant (WWTP). The evaluation is broken into two categories: 1) physical condition and 2) unit process capacities. The hydraulic capacity of the plant is also evaluated. The discussion is organized to follow the wastewater flow through the plant. An existing plant site layout is presented in Figure 4.1. Detailed design criteria for the existing plant are included in Appendix C. 4.2 PHYSICAL CONDITION Many of the unit processes and structures were constructed in the 1950's which represents a current age of over 44 years. In general, most concrete structures at wastewater treatment facilities are anticipated to have a useful life of about 50 years before corrosion, spalling and other damage requires replacement of the structure. Some concrete and steel structures, exposed to extremely corrosive environments, such as those in headworks and 1 primary clarifier area will exhibit dramatically shorter life spans. In addition, structures constructed in the 1950's may not comply with the current Uniform Building Code (UBC) for seismic stability. Mechanical and electrical components typically have a useful service life of 20 to 25 years if properly maintained. In order to evaluate the need to replace or repair existing structures and facilities, the condition of each unit process was evaluated. Carollo Engineers, P.C. (Carollo) performed independent evaluations of the structural, mechanical and electrical condition of the unit processes. The City contracted with Kennedy Jenks Consultants (KIJ) to review the July 1999 Draft Master Plan. KIJ's draft wastewater capacity study is included in Appendix F. Carollo's review comments on the KIJ study are included in Appendix G. Based on KIJ's recommendations, Carollo revised the assessment of structural conditions of the existing plant from that presented in the July 1999 draft. Carollo's chief structural engineer visited the WWTP in November 1999 to perform a visual inspection of structures. Carollo concurs with KIJ's recommendations and we offer the following additional structural recommendations. If -the existing clarifiers are to. be continued in use for the upgraded project, the inside walls should be sand blasted and coated with polyurethane. Although the Jstructures appear to be adequately designed for seismic forces, seismic bracing is required for pumps, equipment, pipelines, and electrical facilities. Seismic bracing has been added as an immediate improvement as noted in Table 1.2 of the Executive Summary. The revised results are summarized in Table 4.1. It is recommended that the unit processes and equipment which have been determined to be in marginal or poor condition and are beyond normal service life, be replaced to provide f M:%Final\PismoBch—FNO0 4836A00%RIM04.WPd 4-1 adequate and reliable future service. Facilities recommended for replacement based upon physical condition include: • Grit Chamber • Primary Sludge Pumps • Secondary Sludge Pumps Table 4.1 Faciiity Condition Evaluation Summary City of Pismo Beach Structural Mechanical Electrical No. of Unit Condition Condition Condition Units Age Unit Process (ea) (rs) A I M P A I M P A I M P 1. HEADWORKS a. Manual Bar Screen 1 15 Ili, b. Aerated Grit Chamber 1 26 f♦ 2. PRIMARY TREATMENT a. Primary Clarifiers 2 44 Structure(l) b. Primary Clarifier 2 5 • '' Equipment c. Primary Sludge Pumps 2 20 • , 3. SECONDARY TREATMENT a. Aeration Tank Nos. 1 &2 2 26: b. Aeration Tank No. 3 1 15 a. Secondary Clarifiers 2 44 (W) (Nos. 1 & 2) d. Secondary Clarifier (4U) 1 20 • • No. 3 e. Secondary Sludge 2 20 Pumps f. Secondary Clarifier 1 44120 •_ Nos. 2 & 3 Mechanism 4. SOLIDS HANDLING a. Anaerobic Digester 1 44 • i No. 1 b. Anaerobic Digester 1 1� No. 2 c. DAFT 1 15 b. Belt Filter Press 1 15; 5. DISINFECTION a. Chlorine Contact Basin 1 26 ;rr 40 6. EFFLUENT DISCHARGE PUMPS a. Pumps 2 16 i A=Adequate M=Marginal P=Poor (1) Marginal structural condition, require coating and patolhing for 20 year additional life. H:1FinailPismoEch_FN014836AWkRpV4.WPD 4-2 LEGEND Q Headworks r` ® Equalization Basin * *•' " — ® Two 30 R. Diameter Primary Clarifiers - � ' -,;- SCALE 1I}i ® Aeration Tanks qL=Y fto&,r 1992 , ® Metal Splitter Box for MLSS :� 1� A e(+af Photograph © 40 Ft Diameter Secondary Clarifier . 4 CREEV- ,. = Y Edited in 1999. Two 30 Ft Diameter Secondary Clarifiers �. � � .. r - _ � T • ©Q Lab and Sludge Pumps in Basement `` ' i+ f M e Chlorine Contact sank - ; '' { �,, owl ' - Q Outfall Booster Pump Station -bpi' _ " ' ® Digester No. 2 MCC Building for Digester No. 2 ■ t0 DigesterNo.1 and y +� J PP " Boiler and Generator Building 11 Dissolved Air Flotation (DAF) Unit s .. = X „�■..�+. `� iz Belt Filter Press Building i ' x rr I r►�•I+ 18 Corporation Yard Garage and Offices is Blower Building, Control Building, Shop and Storage 15 Sludge Storage Site Stormwater Pumps q:'�-, # 17 Storage Tanks for Chlorination/Declorination Chemicals t 18 Storage Tanks for Ferric Chloride 'I R 19 Above Ground Fuel Storage Tank Qo Digester Flare h 't4'.,. 14 , 9 �r i g @ BALL Fin Figure 4.1 _ '' - - �'"' �, ='� *,�' SITE LAYOUT OF EXISTING WWTP -j '"" JV. „'.- + •' CITY OF PISMO BEACH ! :: �' ' I r�•�' WASTEWATER MASTER PLAN ' P6489M!.CDR y...�r 1..-'� 4.3 PLANT HYDRAULICS Wastewater flows by gravity through the existing treatment processes. All raw wastewater enters the WWTP at the headworks through force mains which include: an 18-inch polyethylene lined force main with an internal diameter of 16-inches from the Addie Street Pump Station, a 12-inch diameter force main from the Addie Street Pump Station and three 8-inch pressure sewers from Pismo Oaks. The wastewater moves by gravity through the aerated grit chamber. The three 8-inch diameter pressure sewers discharge into a steel compartment which has a flow flume and a manual bar rack. Following the headworks the wastewater flows by gravity via a 24-inch diameter pipeline to two primary clarifiers. A 24-inch primary effluent pipeline carries the wastewater by gravity from the primary clarifiers to the aeration tanks. The plant staff stated that there is a second pipeline which was constructed from the 1 primary clarifiers to the aeration basins. The City does not have record drawings of this 1 second pipeline. From both calculations and visual inspection, these pipelines are the major hydraulic problem with the existing WWTP. During normal daily flows, the primary effluent weirs are submerged. There are water marks on the inside of each primary clarifier showing that water levels have been within 6-inches of the top of the clarifier walls for extended periods of time. If the existing clarifiers are to remain in service for the long term, a new primary effluent lift station should be constructed. Aeration tank effluent flows by gravity to two 30-foot diameter and one 40-foot diameter secondary clarifiers. Secondary effluent flows to the chlorine contact basin for disinfection. From the chlorine contact basin the final effluent is conveyed to effluent pumps where it is pumped to the outfall. The existing facilities' hydraulic profile indicates inadequate hydraulic capacity at flows above 3.0 mgd. The elevation drop through the existing plant is only four feet. This is significantly less elevation drop than desirable. A well designed plant of this size has double the elevation loss through the plant - 8 feet instead of 4 feet. 4.4 UNIT PROCESS CAPACITIES Headworks The existing WWTP headworks consists of an aerated grit chamber. The headworks was constructed in the early 1970's and is approximately 26 years old. Due to corrosion related to hydrogen sulfide exposure and other severe duty conditions, the headworks structure has experienced accelerated deterioration and is considered to be in very poor condition as shown in photographs 1, 2, and 3 (Photographs are included at the end of this Chapter). It is recommended that the headworks be completely replaced for the long term due to physical conditions. The new headworks should also include a stainless steel mechanical screen, a manual stainless steel bar screen and a plastic Parshall flume for the flow measurement. The capacity of each headworks component is summarized below. H:1FinallPismo6ch— FNO\4836AOOLRpt104.WPD 4-4 r Flow Metering A new Parshall flume with an ultrasonic flow transmitter would be located upstream of the j screens. The Parshall flume would measure flow entering the WWTP. The capacity of the J flume would be approximately 6.0 mgd when running at a depth of 2.0 feet. The flume would provide adequate capacity to meter average dry weather and peak wet weather 7 flows. Bar Screens A mechanical screen would be used to remove rags and large debris entering the plant. A manual bar rack would be installed in a bypass channel and used in the event that the mechanical screen is out of service. The manual bar rack would have a one -inch bar spacing. The mechanical screen would have 1/2 inch bar spacing. The mechanical and bypass bar screens would be both rated for a capacity of 6.0 mgd, PHWWF. Aerated Grit Chamber A new aerated grit chamber could be located downstream of the Parshall flume and screens. The aerated grit chamber is used to remove grit and inorganic material from the wastewater while allowing organics to pass through to the downstream treatment processes. The existing aerated grit chamber is 7 feet long by 12 feet wide by 10 feet deep and currently provides a 2.9 minutes detention time at flows of 3.12 mgd; a detention time of 30 minutes is recommended. The grit chamber is therefore adequately sized for current but not adequately sized for the future flow conditions. The grit chamber and equipment is also approximately 26 year old. Due to corrosion related to hydrogen sulfide exposure and other severe duty conditions at the headworks, the mechanical and electrical equipment for the aerated grit chamber have experienced accelerated deterioration and are in very poor condition. Replacement of the grit chamber and grit handling equipment is therefore recommended for the long term. For the next five to six years, the existing grit channel could be operated at greater than 3 minutes detention until a new grit channel is constructed. Primary Treatment Two 30 foot diameter primary clarifiers provide initial removal of suspended solids and BOD. The primary clarifiers are in marginal structural condition and are over 44 years old. The existing primary and secondary clarifiers are shown in Photograph 4. The electrical facilities are in marginal condition and have surpassed their useful life. The primary clarifiers are marginally sized to provide treatment of AAF (1.40 mgd) at an average surface overflow rate (SOR) of 972 gpd/sf. The corresponding SOR at the PHWWF is approximately 2,708 gpolsf. K/J recommended that the existing two 30 feet diameter primary clarifiers are acceptable to treat an AAF of 1.4 mgd and a ADMMDWF of 1.5 mgd. Carollo has revised Table C.1 of Appendix C to reflect year 2006 flows in addition to year 1998 flows. Although the primary clarifier overflow rates at year 2006 flows are high, the WWTP should be able to meet effluent permit requirements. Higher flows between years H:IFinallPisrno6ch— FN014836AOO\RO04.WPD 4-5 2000 and 2006 will increase water levels in the existing primary clarifiers such that weirs will be surcharged more often. Sludge from the primary clarifiers is pumped to anaerobic digestion using one of two pumps (250 gpm each). Primary scum pumped to the digester by a 45 gpm pump. If primary clarification is used, it is recommended that a new primary sludge and scum handling systems be provided as part of the primary treatment system. The existing facilities are old and would not be properly located for the new clarifiers. For process reliability, primary sludge pumping facilities should be designed to provide a dedicated positive displacement pump for two primary clarifiers plus a dedicated pump for primary scum. A single standby pump is recommended to provide reliable backup for both the sludge and scum pumping systems. Secondary Treatment Three aeration tanks, two 30-foot diameter secondary clarifiers and one 40-foot diameter secondary clarifier, provide secondary treatment at the WWTP. During normal plant operation all three aeration tanks operate in series to provide Biochemical Oxygen Demand (BOD) removal. The three tanks will be operating at capacity with the year 2006 flows and loads. Additional aeration basins would be required to treat additional flows. The aeration basins are in adequate structural condition but would require diffuser upgrading for the long term. Secondary Clarifiers Aeration tank effluent is distributed to three secondary clarifiers through a metal weir box which is in very poor condition. The 40 foot diameter secondary clarifier and the metal weir box are shown in Photograph 5. The existing secondary clarifiers use scraper type mechanisms for sludge removal. Secondary Clarifier Nos. 1 and 2 are over 44 years old and are in marginal structural condition. Secondary Clarifier No. 3 is 20 years old and is in poor mechanical condition. The mechanical components of the Secondary Clarifiers Nos. 2 and 3 are very poor condition and replacement of the sludge collection mechanism and associated electrical components with new equipment would be necessary. The mechanism and bridge deck for Clarifier No. 3 are in extremely poor condition and are unsafe for plant staff. The mechanism and bridge deck for Clarifier No. 3 should be replaced as an immediate improvement. Clarifier No. 2 mechanism is also in poor condition and should be replaced as an immediate improvement. The clarifiers lack a means of draining for routine .or-amergency maintenance. The weirs of the secondary clarifiers have been surcharged during peak wastewater flows. This happens because there is not adequate hydraulic head between the secondary clarifiers, and the chlorine contact basin. The main process problem with the Secondary Clarifiers is that they have shallow side water depths (9.5 ft and 10.75 ft). The current standard is to design clarifiers with 14 ft side water depth. The secondary clarifiers have a total rated AAF capacity of 1.4 mgd when H:1Fina14PismoBch_FNOW83MOO\RpW4.WF D 4-6 operated at overflow rates of approximately 1,460 gpolsf. This overflow rate is a high value for clarification of activated sludge mixed liquor required for projected design flows, but is acceptable for the existing plant up to the Year 2006. Carollo recommends new secondary clarifiers and secondary sludge pump station for all upgrade alternatives. Primary and Secondary Sludge Pumps The existing primary and secondary sludge pumps are in a small basement area between the clarifiers. The sludge pumps and piping are crammed into a small space and are very difficult to maintain (Photograph 6 shows the secondary sludge pumps). New sludge pumps in a larger station should be included in all upgrade alternatives. Secondary Effluent Pump Station Secondary effluent is pumped out the outfall using an effluent pump station. This pump station is approximately sixteen years old. The pump station includes two pumps with VFD drives. Only one VFD can operate at a time. The second pump has to be manually throttled. The existing reliable pump station capacity with one pump reserved for standby is approximately 3.0 mgd. With both pumps in service the capacity is approximately 4.0 mgd. This capacity is inadequate for anticipated future peals flows of 6.0 mgd. It is recommended that new pumps with adequate capacity including a spare pump for reliability be provided. The pumps should be sized at approximately 3.0 mgd to convey peak hour flows of 6.0 mgd with one unit reserved as a standby. It is also recommended that variable frequency (VFD) drives be replaced for these pumps in order to allow improved process performance. New VFD drives and motors will also result in more efficient energy use. Photograph 7 shows the effluent pump station on the left and chlorine contact basin at the right. Effluent Disinfection Facilities Secondary effluent is disinfected in one chlorine contact basin. Liquid sodium hypochlorite solution is fed at the head of chlorine contact basin. The chlorine contact basin is approximately 44 years old. The basin is in adequate structural condition. The chlorine contact basin is 37 feet long by 18 feet wide by 8 feet deep and provides an 18 minute contact time at 3.12 mgd which was the peak hour flow in 1998. However, a 30 minute contact time is required at peak hour flows. Therefore the existing chlorine contact basin is currently hydraulically inadequate. The chlorine -contact basin.provides.,only..30-minutes . of -contact time up to only 2.0 mgd. j Additional chlorine contact basin capacity should be provided to meet contact times at j projected flows. For the short term before the WWTP upgrade is operational, the plant staff will use more chlorine to disinfect wastewater due to the lower contact time. H:%Final\PismoBch FNOW836AOOIRpt104.WPD 4-7 Hypochlorite/Bisulfite Feed System The hypochlorite and bisultete feed systems are currently provided by a service contract. The City could install more permanent modifications to the chemical feed, pumping and control equipment to improve the reliability of the critical elements of these systems. Solids Handling Carollo's preliminary evaluation is that the existing sludge handling process units have adequate capacity for the year 2016 design flows and loads. Dissolved Air Flotation Thickner (DAFT) A 20 foot diameter dissolved air flotation thickner (DAFT) was constructed in 1983. This unit thickens waste activated sludge before flowing to the digester. Anaerobic Digesters The facility includes two anaerobic digesters. Digester No.2, which is 47 feet in diameter, was constructed in 1998 (shown in Photograph No. 8). It is heated and properly mixed. Digester No.1, which is 40 feet in diameter, was constructed in the 1950's and is unheated and not mixed. Digester No.1 essentially serves as a sludge storage tank where a limited amount of biological activity occurs. Belt Filter Press A one meter belt filter press was constructed in 1983. The purpose of the belt filter press system is to dewater digested sludge from 3 percent solids concentration to approximately 1 18.5 percent concentration. The dewatered sludge is stockpiled at the site. Dewatered sludge is picked of up one or two times a week under a service contract and trucked to a composting facility in Lost Hills. Sludge Storage and Drying Area The existing plant has inadequate storage area for belt filter press sludge. A paved area should be used to store sludge instead of the dirt area now used. The City should consider constructing a paved sludge storage area. The existing equalization basin could be filled in and paved for this purpose as part of the plant upgrade. Support Systems Operations Center/Laboratory The existing operations center, -shower,- sanitary #acuities and laboratory are not adequate to support the process upgrades associated with current and future anticipated capacities. The operation center is located in the electrical room of the existing blower building. Under current design standards the electrical equipment should be in a dedicated room with no other facilities. The current use of the electrical room as an office and a "make -shift" locker room is not considered acceptable (see Photograph 9). Current electrical equipment criteria requires a 3 foot open space in front of electrical panels. The existing 344 sq ft electrical control room should be converted to an electrical room only for the upgraded H:%Fina[NPismoBdt_FNO\4836AOO\Rpt104.WF D 4-8 plant. The Wastewater System Supervisor shares a second floor office with the Water Department in Corporation Yard Garage. There are no other offices. WWTP personnel share bathroom facilities with Corporation Yard personnel. The small laboratory in the building between the clarifiers was last upgraded in 1973 and is deficient in space and equipment to maintain a wastewater treatment plant in the 1990's (see Photograph 10). w A 2,000 sq. ft. new operation center and laboratory should be included with the upgraded facilities. During final design phase, the building should be programmed for the City's specific requirements. Recommended square foot of space is noted below. 5 Laboratory 575 Office No. 1/Operations Center 270 Office No. 2 168 Halls 275 Men and Women Locker Room 336 Training Room/Lunch Room 168 Storage and Miscellaneous 208 Total 2,000 Plant Maintenance Facilities The existing plant maintenance areas are inadequate for proper maintenance of a WWTP of this size. It is recommended that the maintenance/storage facility be upgraded by providing dedicated maintenance areas which contain an additional 1,000 sf of working area. Finalization of the location of new maintenance space at the plant site will be performed as part of the preliminary design phase. It may be possible to rehabilitate the former 500 sq ft of the gas chlorination rooms as maintenance areas. In addition, the Public Works Department has had plans to construct a new storage facility. Plant Utilities Plant utilities such as plant service water, plant air and electrical power supply will require improvement as part of the facility upgrades. Plant Instrumentation and Control A plant wide Supervisory Control and Data Acquisition (SCADA) system is recommended as part of all facility upgrades. The SCADA system will include a distributed programmable logic controller (PLC) network used to operate and monitor various equipment within each process area around the plant. The distributed PLC system will be tied to a central operator interface computer station to be located in the new operations center. This will replace the f out dated control panel shown in Photograph 9 JH:1FinalTismoBch_FN044133 OD%RptW4.WPD 4-•9 Plant Electrical Equipment Refer to Technical Memorandum No. 2 in Appendix E. 4.5 SUMMARY OF EXISTING PLANT CAPACITY A summary of the existing capacity of all major unit processes is presented in Appendix C. Hydraulic features such as grit channel, bar screens, flow meters, clarifiers and plant hydraulics must be capable of passing anticipated future PHWWF of 6.0 mgd. All other unit processes must be adequately sized to provide secondary treatment of anticipated future AAF of 2.0 mgd and ADMMDWF of 2.4.mgd including. adequate reliability and redundancy. As indicated in Appendix C, the most significant capacity limitations in the plants overall capacity rating are the grit channel, primary clarifiers, and secondary clarifiers, other capacity limiting processes include; secondary effluent pump station and chlorine contact basin. The remaining unit processes are of adequate size to properly treat the year 1998 and year 2006 flows and loading but not the anticipated future flows and loadings. The capacity of the existing treatment plant is rated as follows: Average Annual Flow (AFF) .............................. 1.40 mgd Average Day Maximum Month Dry Weather Flow (ADMMDWF) ... 1.50 mgd 4.6 COMPONENTS RECOMMENDED FOR REPLACEMENT OR UPGRADE Several components of the WWTP are recommended for replacement or upgrade. Recommendations are based on condition and limited capacity. A summary of the components recommended for replacement or modification and the reason for that recommendation is presented in Table 4.2. In some cases, a component may be scheduled for replacement based upon both criteria. Table 4.2 Summary of Components Recommended for Replacement: or Upgrade City of Pismo Beach Replacement Upgrade Condition Capacity Condition Capacity Aerated Grit Chamber Aerated Grit Chamber Chemical Feed Aeration Basins Facilities Primary Sludge Effluent Pump Station Pumps Secondary Clarifiers Primary Sludge Pumps Chlorine Contact Basin Secondary Sludge Secondary Clarifiers Pumps Secondary Sledge Pumps ` H:1FinallPismoBdt_FNOW83GA001R004.WPD 4-10 li - • h A �y - 7� I ; �. F�11 ire Equali.z'ation Basirk .. , ■ram fae:.:luck'.torage Area l OWN 4 .i5' ryT i' y b- y ' 'A ; �� ' r. f Two New Aeration Tanks 5 4 IP New % Chlorine - lro,}riii n e Co Ia Basins . Wt 1Ju . k �'ror x r l SCALE f" _ 50' i Odobsr *9 ,4arial Rotogra,91r 9dite0in 1999. ,63 f + L IL t41s- A LEGEND 0 New Treatment Units Existing Treatment Units to be Demolished Existing Forcemains Forcemain Sections to be Abandoned Connect Forcemains to New Headworks I + Figure 5.1 1 ,4 b ` SITE LAYOUT ALTERNATIVE A ACTIVATED SLUDGE - CITY OF PISMO BEACH _.- WASTEWATER MASTER PLAN ' r PBOOM3 Wri 4- N Photograph 1 - Existing Headworks is in very poor condition. I Photograph 2 - Shows corrosion related to hydrogen sulfide exposure. H:7inalVPismo5ch_FNO14836AOO1Rpt104PIC.WPD 4-11 Photograph 3 - Headwork shows corrosion related to hydrogen sulfide exposure. Photograph 4 - Existing clarifier complex. M:%Fln;RI\Pismo5ch-FNOW836AOO1Ro04PIC.WPD 4-12 Photograph 5 - 40-foot diameter secondary clarifier and metal weir box (at right). Photograph 6 - Existing secondary sludge pump in small basement space. H:IFinallPismoBch_FNO1483GA004Rpt104PICAPD 4-13 Photograph 7 - Existing effluent pump station and chlorine contact basin. Photograph 8 - Existing Digester No. 2. `} H:IFina[1PismoBch_Fmowa36A001Rpt104PIC.WPD 4-14 E QD rx W & MUIR # R L Photograph 9 - Existing electrical room should not be used as an office or a "make -shift' locker room. Photograph 10 - Existing plant laboratory is deficient in space and equipment H:\'inalWismoBch_FNo14SWA001Rpt104PIC.WPO 4-15 I Chapter 5 TREATMENT UPGRADE ALTERNATIVES ANALYSIS 5.1 INTRODUCTION This chapter provides a summary and comparison of the viable treatment alternatives for reliable long term compliance with the current and anticipated future City of Pismo Beach x-� Wastewater Treatment Plant (WWTP) waste discharge requirements stipulated by the Regional Water Quality Control Board (RWQCB). Analysis of alternatives is based upon the projected future flows and pollutant loads presented in Chapter 2. In order to comply with the RWQCB National Pollution Discharge Elimination System (NPDES) permit requirements, viable alternatives must provide reliable secondary treatment. In Section 5.3 of this chapter four viable alternatives are evaluated and compared in detail for the Pismo Beach Wastewater Treatment Plant. The following other alternatives we considered in less detail. Consolidation with South San Luis Obispo County Sanitation District The City of Pismo Beach pumps secondary treated effluent through an 18-inch, approximately 17,500 feet long outfall pipeline to the South San Luis Obispo County Sanitation District's (SSLOCSD) wastewater treatment plant site. The City of Pismo Beach's Outfall connects with the SSLOCSD outfall and then discharges into the Pacific Ocean. It may be possible to construct a new raw wastewater pump station at the Pismo Beach WWTP site and pump untreated wastewater through the 18-inch outfall line to the SSLOCSD's WWTP. Under this alternative the existing Pismo Beach WWTP could be demolished and used for other land uses. The scope of work for this wastewater treatment master plan did not include an analysis of Regionalization with the SSLOCSD. There may be some operating cost advantages to this alternative due to economies of scale. The existing SSLOCSD's WWTP may have some excess treatment capacity but probably not enough to serve the City of Pismo Beach for buildout wastewater flows. The SSLOCSD's WWTP is a trickling filter plant and has less restrictive discharge_BOD and TSS -requirements .(40 BOD/40 TSS for SSLOCSD versus 30 BOD/30 TSS for Pismo Beach's WWTP). Before the City implements an expansion project at the Pismo Beach WWTP, this alternative will be evaluated in more detail. i The City of Pismo Beach contracted with Kennedy/Jenks Consultants to perform a preliminary analysis of the alternative of wastewater treatment consolidation with SSLOCSD. This analysis is included in Appendix I. The City may consider an addendum to :.S ` i H:IFinal\PiSMOBch_FNOW83BAOO\RpM6.WPD 5-1 the Wastewater Treatment Master Plan to include more detailed analysis of consolidation with the SSLOCSD. ILos Osos Advanced Integrated Pond System The Los Osos Community Service District is planning to construct an Advanced Integrated Pond System. This will be a totally new treatment facility. This facility is in the planning stage; however, this land intensive process will require approximately 15 to 20 acres of ponds. The advanced integrated pond system is a proprietary design. Carollo does not consider the advance integrated pond system viable for the City of Pismo Beach because of extensive land requirements. There is not 15 to 20 acres of land available at the City of Pismo Beach's WWTP without considering using the adjacent Pismo Beach ball fields. Trickling Filter/Solids Contact (TFISC) Process Both the SSLOCSD and the City of San Luis Obispo use trickling filters for secondary treatment. This type of treatment plant was not included as a viable alternative for the following reasons. • Trickling filters are normally 20 feet high and have a visual disadvantages at the Pismo Beach WWTP. • Trickling filters provide less BOD and TSS removal than the current activated sludge process at the Pismo Beach WWTP. • Based on previous experience, trickling filters are marginally cost effective compared with oxidation ditches which are included in two of the viable alternatives. • Trickling filters are less resistant to the variable flows and wastewater characteristics of typical tourist communities than is the oxidation ditch treatment process included in two of the three viable alternatives. 5.2 ALTERNATIVES EVALUATION CRITERIA Criteria used to compare viable alternatives and select the best alternative were determined by Carollo Engineers, P.C. (Carollo). Selection criteria with respect to cost, practical implementation and institutional issues are listed below in order of importance. Cost Criteria - Operations and Maintenance (O&M) Cost - Cost for replacement of structures and components which are beyond normal service life or in poor physical condition - Life cycle cost - Capital cost • Practical Implementation Criteria - Ease of operations `� H:1FinallPismoBch_FNO\4836AOO1RpWS.WPD 5-2 - Constructability and reliable operation during construction • Institutional Criteria Low odor generation - Minimize visual impacts This chapter presents conceptual project capital costs for alternatives. Conceptual costs do not reflect every component required to implement the recommended improvements. Conceptual costs have contingency factors to accommodate unknowns to be identified in final detailed design. The cost included in this report were estimated in the second quarter of 1999. Since the recommended improvements will occur some time in the future, the costs are indexed to allow adjustment of the estimated costs for fluctuations in construction costs over time. The index used in the wastewater master plan is the Engineering News Record (ENR), Construction Cost Index (CCI) for Los Angeles. The ENR-CCI for Los Angeles for March 1999 was 6832. The cost estimates have been indexed a projected ENR-CCI for Los Angeles of 7000 in Year 2002 which is the estimated beginning of construction. This projection is based on an approximate 1 percent increase per year in construction costs. 5.3 DEVELOPMENT OF VIABLE TREATMENT UPGRADE ALTERNATIVES As shown in Figure 1.1 and as indicated in Chapter 4, the existing plant may reach 90 percent of its capacity by the year 2004 based on a 3 percent growth rate. For this reason, a "no project" alternative, which simply repairs the existing facilities as currently designed is not adequate to provide reliable long term NPDES permit compliance. Four viable liquid treatment upgrade alternatives were identified based upon proven performance at other similar facilities, adequate site space availability and standard industry practice for WWTPs design. The four viable treatment alternatives evaluated herein are: Alternative A-1 - Maximum Use of Existing Plant ;. Alternative A - Activated Sludge Alternative B - Oxidation Ditch with Primary Clarifiers Alternative C - Oxidation Ditch without Primary Clarifiers HAFinallPismoBh FN0W836A00\RptW.WP.D 5-3 Due to the need to replace certain components and keep the existing plant operational during construction, where possible, new facilities would be constructed off-line in the area -, of the existing sludge storage or to the west of the existing aeration basin. Continued use of existing anaerobic digestion facilities is included for solids stabilization where appropriate. Sludge thickening in the existing DAFT prior to anaerobic digestion is required for activated sludge and oxidation ditch alternatives using primary clarifiers. Alternative A - Activated Sludge The process for Alternative A is based upon continued use of the activated sludge type i. treatment process similar to that currently used at the existing plant. This alternative uses new primary clarifiers, new activated sludge basins and new secondary clarifiers. The Anaerobic Digester No. 2, recently constructed, will be utilized for solids stabilization under this alternative. In order to provide reliable performance, Anaerobic Digester No. 1 will be used for sludge storage before being pumped to the belt filter press. A complete set of design criteria for each alternative is presented in Appendix D. Table D.1 in Appendix D indicates the design criteria for facilities associated with the activated sludge alternative. Figure 5.1 presents the preliminary layout of Alternative A. An estimated total project cost of $7,090,000 for the activated sludge alternative is presented in Table 5.1. Costs for mobilization, site demolition, site paving and grading, yard piping, electrical components and plant instrumentation have been estimated based upon typical percentages required to construct these components. Percentages used are based upon Carollo Engineers facility cost data base. A 30 percent factor to cover the cost of contingencies engineering, legal and administrative services has been added to the estimated bid cost of all alternatives. The entire plant can be constructed and made operational without disruption to the existing plant. Because there is minimal rehabilitation, the risk of cost overruns is less than Alternative A-1. H:1FinallPismoBch FNOW836A001RpW6.WPD 54 I Table 5.1 Alternative A - Activated Sludge Total Project Cost Estimate City of Pismo Beach Estimated Cost Item (ENR-CCI = 7000)(1) Mobilization/Demobilization (5%) $165,500 Flood Protection Wall/Steel Sheeting(z) $350,000 Construction Sequence Site Constraints (1 %) $66,200 Site Work (5%) $165,500 Yard Piping (8%) $264,800 Storage/Maintenance Facilities $75,000 Operations Center/Laboratory $330,000 Headworks $350,000 Grit Chamber $220,000 Primary Clarifiers $450,000 Primary Sludge Pump Station $350,000 One New Activated Sludge Tanks $450,000 Upgrade Existing Activated Sludge Tanks $60,000 Additional Aeration Air Blowers $50,000 Secondary Clarifiers $900,000 At Grade Primary and Secondary Sludge Pump Station $380,000 Chlorine Contact Basin No. 2 $250,000 Effluent Pump Station Upgrade $200,000 Distribution Structures and Miscellaneous Facilities (5%) $165,500 Electrical (12%) $397,200 Instrumentation (5%) (Rounded) $165,500 Estimated Bid Cost $5,455,200 Contingency, Engineering, Legal, and Administrative (30%) $1,634,800 Total Project Cost $7,090,000 (1) Estimated costs are indexed to an ENR-CCI of 7000 projected for the midpoint of construction in January 2002. 2 City to discuss with FEMA, if required. H:IFInaiNPISMOBch_FN014836AOO1Rpt105. WPD 5-5 1 Table 5.2 Alternatives B and C - Oxidation Ditch Total Project Cost Estimates City of Pismo Beach Estimated Cost Estimated Cost Alt. B Alt. C - with Primary without Primary Clarifiers Clarifiers Item (ENR-CCI=7000)(') (ENR-CCI=7000)t'I Mobilization/Demobilization (5%) $216,500 $184,500 Flood Protection/Steel Sheeting(`? $350,000 $350,000 Construction Sequence/Site Constraints (1 %) $43,300 $36,900 Site Work (5%) $216,500 $184,500 Yard Piping (8%) $346,400 $295,200 Storage/Maintenance Facilities $75,000 $75,000 Operations Center/Laboratory $330,000 $330,000 Headworks(2) $350,000 $350,000 Grit Chamber(2) $220,000 $0 Primary Clarifiers() $450,000 $0 Oxidation Ditches $1,400,000 $1,850,000 Secondary Clarifiers $900,000 $900,000 At Grade Primary and Secondary Sludge $380,000 $160,000 Pump Station Convert Aeration Tanks to Chlorine Contact $100,000 $100,000 Basin Effluent Pump Station Upgrade $200,000 $200,000 Distribution Structures and Miscellaneous $216,500 $184,500 Facilities Electrical (12%) $519,600 $442,800 Instrumentation (5%) $216,500 184 500 Estimated Bid Cost $6,530,300 $5,827,900 Contingency, Engineering, Legal, and $1,959,700 $1,742,100 Administration (30%) Total Project Cost $8,490,000 $7,570,000 Notes: (1) Estimated costs are indexed to an ENR-CCI of 7000 projected for the midpoint of construction in January 2002. (2) Alternative C does not have a grit chamber. (3) Alternative C does not have primary clarifiers and sludge pump station. 4 City to discuss with FEMA, if required. l H:1Finat\PismoBch FNOWSWA00%RptM,WPD 55-6 J Table 6.3 Alternative A-1 Maximum Use of Existing Plant City of Pismo Beach Estimated Cost Items (ENR-CCI = 7000)") Mobilization/Demobilization (5%) $153,250 Flood Protection Wail/Steel Sheeting(2) $350,000 Fill in Existing Grit Chamber $20,000 Construction Sequence Site Constraints (2%) $59,300 Site Work (5%) $153,250 Yard Piping (8%) $245,200 Storage/Maintenance Facility $75,000 Operations Center/Laboratory $330,000 Headworks $350,000 New Grit Chamber $220,000 Primary Influent Weir Splitter Box $40,000 Convert Two Existing 30 ft Diam. Secondary Clarifiers to $30,000 Primary Sandblast and Coat Inside of Four Existing 30 ft Clarifiers $85,000 Upgrade Existing Primary Sludge Pump Station $120,000 New Primary Effluent Lift Station (Screw Pumps) $260,000 One New Activated Sludge Basin $450,000 Upgrade Existing Activated Sludge Tanks $60,000 Additional Aeration Blower $50,000 ML Weir Splitter Box $40,000 Secondary Clarifiers $900,000 At Grade Secondary Sludge Pump Station No. Building $160,000 Convert Existing 40 ft Clarifier to Chlorine Contact Basin $100,000 Effluent Pump Station Upgrade $200,000 Electrical (12%) $367,800 Instrumentation (5%) $153,250 Estimated Bid Cost $4,974,050 Contingency, Engineering, Legal, and Administration (30%) $1,496,950 -Total-Project Cost $6,470,000 (1) Estimated costs are indexed to an ENR-CCI of 7000 projected for the midpoint of construction in January 2002. (2) Ci to discuss with FEMA, if required. H:1Final%PismoBoh_FNOM836A001Rpt105. WPD 5-7 + i yam�d .o ondary Purnp oLI`sQ7t2rairlr� �1 Stat�orjSi Secondary FhiS pipe will be r 1oC'6k6 Ditch with Primafios Ditch +n+ith Pr'iinaries y PBns9M4;CDF �r �t �.�- ; 1141 .JT "• : �' �' �. •V4 " SCALE 1" _ 0' * F rOctober 1992 t . lolkdi17 199D. .. t4' r FiEI in E ;I hastn + A F Sludge SLOrc cue Area � CD � w rr ' C + 10 > "FM Y v iirQ=mow + xl lie ,�' { . y, LEGEND i 0 New Treatment Units i f Existing Treatment Units to be demolished Existing Forcemains ■ Forcemain Sections to be Abandoned Connect Forcemains to New Headworks Figure 5.2 SITE LAYOUT ALTERNATIVE B OXIDATION DITCHES WITH PRIMARY CLARIFIERS CITY OF PISMO BEACH .. 3 WASTEWATER MASTER PLAN I r{ 4 7T i AV n + P6434Mz.cDr. -i i - ,• r SCALE r Oct?b8v 1992 JT -.- , , Aerial �hctor�raph .. edited in 1999, .I Fill in =qualization Basin tqr iijd e' torage Area i l A rA AI .7.1 `Jti *� LEGEND Q New Treatment Units �+ ,Q Existing Treatment Units to be Demolished •� Existing Forcemains Forcemain Sections to be Abandoned *a �, Connect Forcemain to New Headworks Figure 5.3 " SITE LAYOUT ALTERNATIVE C OXIDATION DITCHES WITHOUT PRIMARY CLARIFIERS �,- CITY OF PISMO BEACH i ! WASTEWATER MASTER PLAN q hi PROCESS LEGEND #•. 1Q Headworks with Grit Removal sQ 65'0 Secondary Clarifiers Primary Influent Weir Splitter Box (9) Convert Existing Secondary - Q Convert Existing Two 30'{� Clarifier to Chlorine Contact SCALE j r'' Secondary Clarifiers to Basin No. 1 f �' li 1992 Phmar Clarifiers io Existin Chlorine Contact 4C[obnr Y O Basin No. 2 f.� } . Aefial Ptotopph ® New Primary Effluent Lift Station *► "dried n 1999. 0 New (Fourth) Aeration Basin 5 Relocated Location for Chlorination and Dechlorination 4 r wy © ML Weir Splitter Box i2 Rehabilitate Existing 7Q RAS/WAS Pump Station Electrical Room w } and Fourth Blower .' = r _ - rAr, -lip 1 - �i Fill in EgUaf?�tition Basin IL - y ip Tt rMl 'IL r r JM Ll w its, I j�I � W, , aerations Center/ Lab rW P67299idi.CDR11 i TI ; .1 � r 0, , r LEGEND Q New Treatment Units Existing Treatment Units to be Demolished i. Existing Treatment Units to be Changed to Other Process i Existing Forcemains I Connect Forcemains to New Headworks Figure 5.4 � SITE LAYOUT ALTERNATIVE A-1 I MAXIMUM USE OF EXISTING PLANT C[TY OF PISMO BEACH WASTEWATER MASTER PLAN = JTable H.1 of Appendix H presents the design criteria for Alternative A-1 - Maximum Use of Existing Plant. An estimated total project cost of $6,470,000 for Alternative A-1 is presented in Table 5.3. 5.4 COMPARISON OF VIABLE TREATMENT UPGRADE ` ALTERNATIVES Viable alternative treatment process upgrades have been compared based upon the alternative evaluation criteria described in Section 5.2. Cost Criteria Comparison The cost criteria include O&M cost, and cost to replace facilities due to age and condition, which is reflected in a capital cost and life cycle cost. The City's staff has emphasized the importance of providing treatment system upgrades which are easy and cost effective to operate. O&M Cost Comparison The comparative costs to operate and maintain the systems proposed under each alternative was evaluated. JO&M costs include the following components: • Labor Cost • Power Cost • Sludge Disposal Cost • Equipment Replacement Cost Labor Cost. Labor cost estimates reflect the number of operations and maintenance (O&M) personnel required for each alternative. Alternative A Activated Sludge, is anticipated to require the largest number of O&M personnel due to the complexity of the treatment process which uses a suspended growth activated sludge system. Conversely, Alternative No. C - Oxidation Ditch without Primary Clarifiers, requires the fewest O&M personnel due to the elimination of primary clarification, anaerobic digestion and grit channels. Alternatives A and B both include primary treatment and anaerobic digestion which is -anticipated to increase- OG&ill- staffing -needs -by -one additional operator as compared to that of Alternative C. Power Cost. The power cost is based upon power use for aeration. J Sludge Disposal Cost. The City of Pismo Beach current) contracts with San Joaquin g P Y Y q Valley Composting in Lost Hills for sludge disposal. Current sludge disposal costs are IH:1FinaRPismoSch—FN044836AOD1Rpt105.WFD 5-14 rl $30/ton and were approximately $54,000/year in 1999. Sludge disposal costs are II anticipated to range from $90,000/yr to $112,000/yr in the year 2016 based on 1998 costs per ton. The sludge is generated primarily from domestic wastewater and is considered non -hazardous. The smallest amount of sludge production is anticipated when using the activated sludge. The largest amount of sludge production is anticipated when using a oxidation ditch without primary clarifiers. The oxidation ditch sludge production is greatest due to the lack of anaerobic digestion. Item No. 1 of the RWQCB's review comments on the July 1999 draft Master Plan is copied below. 1. Minimization of sludge disposal costs may be achieved by finding or establishing a local disposal option. Careful consideration should be given to the final disposal of the biosolids from this facility. As regulations and public scrutiny continue to focus on sludge spreading sites, all but the highest quality (Class A) sludge will be increasingly difficult and costly to dispose of." The City currently produces a Class B sludge, which is anaerobically digested. The City stores digested sludge on site for a short time period. San Joaquin Valley Composting picks up sludge approximately twice per week and composts the sludge at a facility in Lost Hills. If Pismo Beach stored Class B sludge for 18 months it could become Class A sludge. Under EPA Regulations 503 Class A sludge can be applied to land without significant restrictions. The City has investigated local disposal options with no solution, because of the difficulties of siting sludge management facilities. Like numerous other communities in areas without significant farm land the City of Pismo Beach will have to rely on the services of San Joaquin Valley Composting or other similar service companies. Sludge disposal is the major disadvantage of Alternative C - Oxidation Ditches without primary clarifiers. Alternative C sludge is not Class B and must be removed for this plant site every other day in wet weather periods or odors will be excessive. Equipment Replacement Cost. Equipment replacement costs were estimated based upon the need to replace one half of all mechanical components over the anticipated 20 year life cycle of these components. Therefore, those processes with the greatest degree of mechanical components will require the highest annual equipment replacement cost. The oxidation ditch processes is anticipated to have the lowest annual equipment cost because it uses fewer mechanical components than the other alternatives evaluated and has the most new equipment. Alternative A-1 has the highest annual equipment cost because it uses the most mechanical components. Also Alternative A-1 has the most existing older equipment which will require more replacement funds in the next 20 years. Table 5.4 provides a summary of the estimated comparative O&M costs for each alternative. O&M costs common to each alternative are not included in Table 5.4. H:1FinalTismoBch FN04483eA001RpMS.WPD 5-15 The overall annual O&M cost comparison indicates that Alternative C - Oxidation Ditch without Primary Clarifiers is anticipated to result in the least annual O&M cost. This reflects the relative ease of operation of a conventional oxidation ditch when compared to the other alternatives evaluated. Total Project Cost Comparison Total project costs developed in Section 5.3 are summarized and compared here. Table 5.5 presents a comparison of the estimated total project cost and annualized capital cost for each alternative. The total project costs for both oxidation ditch Alternatives B and C can be considered equal based on the accuracy of a planning level estimate. In the case of the oxidation ditch alternatives, the additional cost for primary treatment, sludge thickening and anaerobic digestion associated with Alternative B appears to offset the benefits associated with a reduction in oxidation ditch size. Life Cycle Cost Comparison A comparison of the annualized life cycle cost of each alternative when capital and O&M costs are considered together is summarized in Table 5.6. Table 5.6 indicates that the lowest annual life cycle cost alternative is anticipated to be Alternative A-1 - Maximum Use of Existing Plant. Table 5.4 Annual O&M Cost Comparison of WWTP Alternatives ($/year) City of Pismo Beach Alt. A-1 Alt. C Alt. A Maximum Use Oxidation Ditch Activated of Existing without Primary Cost Factor Sludge Plant Clarifier Labor4')(2) $330,000 (6) $330,000 (6) $275,000 (5) Power�3) $135,000 $135,000 $170,000 Sludge Disposal(4) $90,000 $90,000 $112,000 Equipment Replacement 1110,000 11$ 0,000 5$0,000 Comparative Total Annual $665,000 $665,000 $607,000 O&M Cost Difference in -cost +10% +10% lowest cost (1) Anticipated number of O&M personnel shown in parenthesis (2) Based upon $55,000/yr annual salary and benefits. (3) Based upon average of $0.085 (KWh). (4) Based upon $ 30/ton hauling and disposal, 1998 price for year 2016 sludge quantity. ` H:1FinalkP9smoBch_FNOA836AOG\RptW5.WPD 5-16 Table 5.6 Annualized Total Capital Cost Comparison of WWTP Alternatives City of Pismo Beach Alt. C Alt. A Alt. A-1 Oxidation Ditch Activated Maximum Use of without Primary Process Area Sludge Existing Plant Clarifier Estimated Bid Cost $5,455,200 $4,974,050 $5,827,900 Contingency, Engineering, Legal, and Administrative (30%) $634,800 $1,495,950 $1,742,100 Total Project Cost $7,090,000 $6,470,000 $7,570,000 Annualized Total Capital Cost') $/year $515,000 $470,000 $650,000 Difference in Cost +9% lowest +17% (1) Annualized costs based on 6% = i over 30 years. (PIA=13.765) (Actual funding interest rate may be less.) Table 5.6 Annualized Life Cycle Cost Comparison of WWTP Alternate ($/year) City of Pismo Beach Alt. C Alt. A-1 Oxidation Alt A. Maximum Ditch without Activated Use of Primary Item I Sludge Existing Plant Clarifier Annualized Total Capital Costs') $515,000 $470,000 $550,000 Annual O&M Cost $665,000 $665,000 60$ 7. 000 Total Annual Life Cycle Cost $1,180,000 $1,135,000 $1,157,000 (1) Annualized costs based on 6% = i over 30 years. (PIA = 13.765) (Actual funding interest rate may be less. Practical and Institutional Criteria Comparison A comparison of practical and institutional criteria was performed to determine if overriding considerations would result in selection of an alternative other than an oxidation ditch. Each alternative received one of three rankings in each evaluation criteria category. Rankings were as follows. A = Offers relative advantages when compared to the other alternatives. N = Offers no advantages or disadvantages when compared to the other alternatives. D = Offers relative disadvantages when compared to the other alternatives Using this system, alternatives with the highest A score and lowest D score would be favorable. H:\FinailPismoBch—FNO'4836AOOIRpt105.WPD 5-17 The results of the comparison of advantages and disadvantages related to practical criteria, institutional criteria combined with cost criteria are presented in Table 5.7. The total score of advantages and disadvantages in these categories indicates that Alternative C - Oxidation Ditch Without Primary Clarifiers is considered the apparent best alternative based on cost and other practical and institutional criteria. Table 5.7 Comparison of Advantages and Disadvantages Associated with each WWTP Alternative City of Pismo Beach Alt. C Oxidation Ditch Alt. A-1 Alt. A without Maximum Used Activated Primary Evaluation Criteria Existing Plant Sludge Clarifiers A N D A N I D AT N I D Cost Criteria O&M Cost Sludge Disposal Cost` Total Annual Cost .r. Capital Cost Practical Criteria Ease of Operations` Constructability #; Age of Facilities. Institutional Criteria Low Odor Potential Minimize Visual Impacts' N A D :` N Q` Total Score '` 3 1 .4 2 S 3 .0 A = Advantage N = Neutral D = Disadvantage H:Tinal%PismoBch_FNOW836AOO RpWS.WPD 5-18 Cha ter 6 IMPLEMENTATION PLAN 6.1 RECOMMENDED ALTERNATIVE FOR BUILDOUT Based upon the development and evaluation of alternatives presented in Chapter 5 the apparent best plant upgrade alternative which provides reliable long term compliance with NPDES permit requirements is Alternative C oxidation ditch process without primary clarifiers. The site layout for the recommended WWTP for buildout is presented in Figure 6.1. The overall total project cost associated with the recommended project is $7,570,000. A summary of the estimated total project cost is presented in Table 6.1. A preliminary schematic hydraulic profile of recommended alternatives is presented in Figure 6.2. 6.2 IMPLEMENTATION SCHEDULE A possible project implementation schedule is presented in Figure 6.3. The City of Pismo Beach may revise the schedule according to actual flow data. It is suggested that the design and construction of the collection system and the WWTP improvements be uncoupled such that both components of the project can proceed independently. Uncoupling the two project components will expedite correction of the current sewer overflows. Because the specialty contractors who typically perform sewer rehabilitation work are different from those who construct wastewater treatment plants, cost savings due to economies of scale associated with construction of both project components together will not be significant. IH:1FinallPismoBch_FNOW836A001RptM.wpd 6-1 rl. 4 �' ��..•,L.� .;, fib*: 11 IF,? I I 4' VYILI Lj4, r lIZ?U Ifo Ir R 4 1 i L %: SCALE I ` 50 I • °fir{ .. - ... _� � - . � October l99 - A-V fdrted in 1999_ i Fill in Eclualizat;on Basin - 1 r flu d 's t IF y 2 µ — 5 Id . I LEGEND f� 0 New Treatment Units Existing Treatment knits to be Demolished ® Existing Forcemains kt 4 Forcemain Sections to be Abandoned Connect Forcemains to New Headworks Figure 6.1 SITE LAYOUT OF RECOMMENDED WASTEWATER TREATMENT PLANT FOR BU[LDOUT , CITY OF PISMO BEACH WASTEWATER MASTER PLAN °_ 4] E cz L c X N LLJ J o w Ln Q- cFS a N �a+vl c J E Luo q� Li I II CO cC C m m Q Q C j C r c II C) 0 ,- O � a � U L � L 'L p cry O J O LL Z2 V M.. J W 00 coWp0 a)= W � .cm enZa w O ZUU �w mm W LL M p a 0 0 N m i O cc CD M d c a- � cn C N i a= Z Q O w cl 00 ? 4)ZLL.LU pMMJ0- li LU D LL J NC) - � I c� A I- N C y a Ps, Table 6.1 Recommended WWTP Project Cost Estimate - Oxidation Ditch without Primary Clarifiers City of Pismo Beach Estimated Cost Alt. B - with Primary Clarifiers Item (CCCI=7000) Mobilization/Demobilization (5%) $184,500 Flood Protection/Steel Sheeting(4) $350,000 Construction Sequence/Site Constraints (1%) $369,000 Site Work (5%) $184,500 Yard Piping (8%) $295,200 Storage/Maintenance Facilities $75,000 Operations Center/Laboratory $330,000 Headworks(Z) $350,000 Grit Chamber(2) $0 Primary Clarifiers(3) $0 Oxidation Ditches $1,850,000 Secondary Clarifiers $900,000 At Grade Primary and Secondary Sludge Pump Station $160,000 Convert Aeration Tanks to Chlorine Contact Basin $100,000 Effluent Pump Station Upgrade $200,000 Distribution Structures and Miscellaneous Facilities $184,500 Electrical (12%) $442,800 Instrumentation (5%) $184,500 Estimated Bid Cost $5,827,900 Contingency, Engineering, Legal, and Administration (30%) $L742,100 Total Project Cost $7,570,000 JH:1FinalTismoBeh_FNO\ 4836ADD1Rpt1D6.wpd 6-5 6.3 STATE REVOLVING FUND LOANS The State Water Resources Control Board (SWRCB) administers the State Revolving Fund (SRF) for Construction of Wastewater Treatment Facilities. The interest rates and terms for SRF loans to communities are as follows. Interest Rate 2.8 percent (July 1999) Term 20 years Currently the SWRCB has $300 to $400 million dollars of funds which have not been committed. If the City of Pismo Beach decides to apply for a SRF loan, the Regional Water Quality Control Board (RWQCB) could place the City on the priority list after the City decides what project they.want to construct. The estimated annual payment for SRF Loan are presented in Table 6.2. Table 6.2 Estimated Annual Loan Payments of SRF Loans City of Pismo Beach Total Project Estimated Annual Project Cosa) SRF Loan Payment 12� Collection System Priority 1 Improvements $1,955,000 $130,000 Alternative C WWTP $7,570,000 $500,000 Subtotal $9,525,000 $630,000 (1) ENR-CCI = 7000 (2) 20 year term SRF loan rate of 2.8 percent The City of Pismo Beach should determine the impact of these loan payments on the current sewer rates as part of the SRF loan application process. JW:1FinailPismoBch—FNO44836AOOIRpt106.wpd 6-6 APPENDIX A COMPLIANCE DOCUMENTS FROM REGIONAL WATER QUALITY CONTROL BOARD `1 H:1FhaKPismoBch_FN014838Aoo1FtpMPP.WPD STATE OF CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD CENTRAL COAST REGION 81 Higuera Street, Suite 200 San Luis Obispo, CA 93401-5427 CLEANUP OR ABATEMENT ORDER NO. 98-83 Concerning CITY OF PISMO BEACH, SAN LUIS OBISPO COUNTY The California Regional Water Quality Control Board, Central Coast Region (hereafter Board), finds: 1. The City of Pismo Beach (hereafter Discharger) threaten compliance with this order is operates wastewater collection, treatment, and prohibited. disposal facilities to provide sewerage service within the City limits. Treated municipal "8. Collection, treatment, and discharge of wastewater is discharged to the Pacific Ocean waste shall not create a nuisance or through an outfall located off Pismo State pollution, as defined by Section 13050 of Beach (35006'09" N. Latitude, 12003829" W. the California Water Code. Longitude). "I1.Operation of collection, treatment, and 2. The discharge is subject to Waste Discharge disposal systems shall be in a manner that Requirements Order No. 94-52, NPDES Permit precludes public contact with wastewater. No. CA0048151, adopted by the Board on June 3, 1994. Order No. 94-52 implements state and 4. The Discharger has reported 18 sewage spills in federal regulations and specifies in part: the past 3 years. Spills have been primarily due to inadequate capacity in the collection system "D. PROVISIONS and power failures. During the past 3 years, approximately 140,250 gallons of sewage have "5. The Discharger shall comply with all items overflowed the sewer system resulting in of the attached "Standard Provisions and approximately 60,930 gallons of sewage Reporting Requirements for National discharged to surface waters (combined total Po1lutart D-scha.be Elimination System from all incidents). Permits," dated January 1985. Paragraph (a) of item E.I. shall apply only if the 5. Section 13304 of the California Water Code bypass is for essential maintenance to provides that the Board may order any person ` assure efficient operation.D" discharging waste in violation of waste discharge requirements to cleanup or abate the 3. Standard Provisions referenced in Provision effects thereof; or in the case of threatened ` D.S. above specify in part: pollution or nuisance, to take other necessary remedial action. "A. GENERAL PERMIT CONDITIONS 6. This enforcement action is taken for the - "4. "Bypass" and "overflow" of untreated and protection of the environment and as such is partially treated waste is prohibited. exempt from the provisions of the Califomia i Environmental Quality Act (Public Resources "7. Introduction of "pollutant free" Code Section 21100 et seq.) in accordance with wastewater to the collection, treatment, Section 15321, Chapter 3, Title 14, California and disposal system in amounts that Code of Regulations. ACL Complaint No. 98-83 -2- IT IS HEREBY ORDERED, pursuant to Sections 13267 and 13304 of the California Water Code, the City of Pismo Beach shall: As soon as possible but no later than December• 31. 1998, complete emergency connection to increase capacity of Addie Street lift station to accommodate wet whether flows. 2. As soon as possible but no later than July 30, 1999, complete draft wastewater system master plan identifying deficiencics and proposed corrective' actions. The master plan shall include, but not be limited to evaluation and correction of deficiencies in collection system capacity, standby power sources, staffing levels, operations and maintenance, and any other areas impacting the City's ability to comply with Order No. 94-52. December 8, 1998 3. As soon as possible but no later than June 30, 1999, complete Infiltration/Inflow Analysis to identify sources of storm water intrusion. 4. As soon as possible but no later than June 30, 1999, complete upgrade of Sunset Palisades lift station to increase capacity to accommodate build -out of the Palisades area. 5. As soon as possible but no later than December 31, 1999, complete final wastewater system master plan. 6. Submit monthly status reports indicating progress and compliance with scheduled corrective actions, such reports may be combined with monthly self -monitoring reports if the discharger so chooses. All technical and monitoring reports required in conjunction with this Order are required pursuant to Section 13267 and 13304 of the California Water Code. All such reports shall include a statement by the Discharger or an authorized representative, certifying under penalty of perjury under laws of the State of California, that the report is true, complete and accurate. Engineering reports and plans shall be prepared, signed, and stamped by a qualified licensed/registered professional. It is expected that completion of the wastewater master plan (item 5 above) will identify deficiencies and long - and short-term convective measures not addressed in this Order. When such information is available, this Order may be reviewed and amended as needed or replaced by an updated Order. If, in the opinion of the Executive Officer, the Discharger fails to comply with the provisions of this Order, including compliance with the above meationed schedule, the Executive Officer m2y seek authoriation to request the Attorney General to tape appropriate enforcement action against the Discharger, including injunction and civil remedies, if appropriate; the Executive Officer is authorized to issue an Administrative Civil Liabilities Complaint; or refer the City of Pismo Beach back to the Board for further enforcement action. I, ROGER W. BRIGGS, Executive Officer, of the California Regional Water Quality Control Board, Central Coast Region, do hereby certify that the foregoing is a full, true, and correct copy of an Order issued by the iRegional Water Quality Control Board on December 8, 1998. /ry Executiv Officer SJM\H:lenforcelpismo.cao 4 Task: 112-01 File: City of Pismo Beach 10 STATE OF CALIFORNIA CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD CENTRAL COAST REGION 81 Higuera Street, Suite 200 San Luis Obispo, CA 93401-5427 WASTE DISCHARGE REQUIREMENTS ORDER NO. 99-31 NPDES PERMIT NO CA 0048151 Waste Discharger Identification No. 3 400106001 Second Draft March 22, 1999 Proposed for Consideration at the duly 9, 1999, Meeting 1,11� I I-JR For CITY OF PISMO BEACH 4pr WASTEWATER FACILITY San Luis Obispo County The California Regional Water Quality Control Board, Central Coast Region, (hereafter Board), finds that: 1. The City of Pismo Beach (hereafter Discharger) operates a wastewater collection, treatment, and disposal system to provide sewerage service to ithe City of Pismo Beach. Treated municipal wastewater is discharged directly to an ocean outfall jointly owned by the Discharger and South San Luis Obispo County Sanitation District. South San Luis Obispo County Sanitation District f is regulated by NPDES Permit No. CA0048003. } 2. These Waste Discharge Requirements are being updated to replace Order No. 94-52, adopted by the Board on June 3,1994. 3. The Pismo Beach Wastewater Facility is located on property owned by the Discharger in San Luis Obispo County at 550 Frady Lane, Pismo Beach, as shown on Attachment "A" of this Order. 4. The treatment system consists of primary sedimentation, activated sludge, secondary sedimentation chlorination and dechlorination. A I Biosolids are anaerobically digested, dewatered, J and disposed of by land application. The treatment facility's average dry weather flow design capacity is 1.75 MGD. A diagram of the treatment facility processes is shown on Attachment "B" of this Order. ..1 J 5. Treated municipal wastewater is discharged to the Pacific Ocean through a 4,400 foot (1,340 m) outfall/diffuser system. The outfall terminates in the Pacific Ocean (35' 05' 85" N. Latitude, 12(° 38' 75" W. Longitude) in approximately 55 feet (16.8 m) of water. The minimum initial dilution (seawater:effluent) of the outfall is 165:1 based on a flow of 6.75 MGD (I.75 MOD from the Discharger and 5.0 MGD from South San Luis Obispo County Sanitation District). The outfall location is shown on Attachment "A". 6. The Environmental Protection Agency and Board . classify this discharge as a major discharge (51.0 MGD). 7. The State Water Resources Control Board (State Board) adopted the "Water Quality Control Plan, Ocean Waters of California -California Ocean Plan" (California Ocean Plan) on duly 23, 1997. The Ocean Plan contains water quality objectives and other requirements goveming discharge to the Pacific Ocean. 8. The most recent version of the Water Quality (Basin Plan), was adopted by the Board on September 8, 1994. The Basin Plan incorporates statewide plans and Attachment #1 July 9,1999, Meeting Proposed WDR Order No. 99-31 WDR Order No. 99-31 -2- Draft for Meeting of July 9; 1999 1 i policies by reference and contains a strategy for protecting beneficial uses ofthe Pacific Ocean. 9. Existing and anticipated beneficial uses in the vicinity of the discharge include: a. Water contact recreation; b. Non -contact water recreation, including aesthetic enjoyment; c. Industrial water supply; d. Navigation; e. Marine habitat; f: Shellfish harvesting; g. Rare, threatened, and Endangered Species; h. Ocean commercial and sport fishing; and i. Wildlife habitat. 10. The shellfish harvesting beneficial use (Finding 91) exists wherever mussels, clams, or oysters may be harvested for human consumption. To the knowledge of this Regional Board: 1) Mussels are present at shoreline locations near the discharge; 2) clamming activity is present in this area; but, 3) oyster harvesting is not practiced nearby. ' The shellfish harvesting beneficial use and the shellfish harvesting bacterial limits specified in paragraph C.2. of this Order apply at all shoreline monitoring stations. 11. Federal Regulations for stormwater discharges were promulgated by the U.S. Environmental Protection Agency on November 19, 1990. the regulations [40 Code of Federal Regulations (CFR) Parts 122, 123, and 124] require specific categories of industrial activities including Publicly Owned Treatment Works (POTWs) which discharge stormwater to obtain a NPDES permit and to implement Best Available Technology Economically Achievable (BAT) and Best Conventional Pollutant Control Technology (BCT) to control pollutants in industrial stormwater discharges. 12. The stormwater flows from the wastewater treatment facility process areas are directed to the headworks and discharged with treated wastewater. These stormwater flows constitute all industrial stormwater at this facility and consequently this permit regulates all industrial stormwater discharge at this facility along with wastewater discharge. If the City proposes to discharge stormwater flows from the treatment facility directly to surface waters (instead of processing through treatment facility), it must submit 'a permit application for separate stormwater discharge permit. 13. Waste discharge requirements for this discharge are exempt from the provisions of the California Environmental Quality Act (Public Resources Code, Section 21100, et seq.) in accordance with Section 13389 of the California Water Code. 14. A permit, and the privilege to discharge waste into waters of the State, is conditional upon the discharge complying with provisions of Division 7 of the California Water Code and of the Clean Water Act (as amended or as supplemented by implementing guidelines and regulations), and with any more stringent effluent limitations necessary to implement water quality control plans, to protect beneficial uses, and to prevent nuisance. This Order shall serve as a National Pollutant Discharge Elimination System Permit pursuant to Section 402 of the Clean Water Act. Compliance with this Order should assure conditions are met and mitigate any potential changes in water quality due to the discharge. IS. On March 30, 1999, the Board notified the Discharger and interested agencies and persons of its intent to reissue waste discharge requirements for the discharge and has provided them with a copy of the proposed Order and an opportunity to submit written comments, and scheduled a public hearing. 16. In a public hearing on July 9, 1999, the Board heard and considered all comments pertaining to the discharge and found this Order consistent with the above findings. IT IS HEREBY ORDERED, pursuant to authority in Section 13377 of the California Water Code, that the City of Pismo Beach, its agents, successors, and assigns, may discharge waste from the Wastewater Facility providing compliance is maintained with the following: (Note: General permit conditions, definitions, and the method of determining compliance are contained in the attached "Standard Provisions and Reporting WDR Order No. 99-31 -3- Draft for Meeting of July 9, 1999 Requirements for National Pollutant Discharge Elimination System Permits," dated January, 1985, included as part of this Order). Throughout these requirements footnotes are listed to indicate the source of requirements specified. Requirement footnotes are as follows: A=Caiifornia Ocean Plan B=Basin Plan C=Thermal Plan D=Code of Federal Regulations Title 40 Sections 122, 133 and 403 Requirements not referenced are based on staffs professional judgement. A. DISCHARGE PROHIBITIONS 1. Discharge of treated wastewater at a location other than 350 05' 85" N. Latitude, 1201 38' 75" W. Longitude, is prohibited. B. EFFLUENT LIMITATIONS 1. "Removal Efficiencies" for Total Suspended Solids and Biochemical Oxygen Demand (BOD) shall not be less than 80% °. In addition, effluent shall not exceed the following limitations: Monthly Weekly (30-Day) (7-Day) Daily Constituent Units Average Average Maximum BOD, 5-dayo mg/1 30 45 90 lbs/day 438* 657* 1314* kg/day 199* 298* 596* ` Total Suspendedp mg/1 30 45 90 Solids lbs/day 438* 657* 3753* j f kg/day 199* 298* 1702* Grease and Oil" mg/1 25 40 75 lbs/day 365* 584* 1095* kg/day 166* 265* 497* Settleable Solids" mL1l 1.0 1.5 3.0 TurbidityA NTU 75 100 225 Monthly Weekly (30-Day) (7-Day) Daily Constituent Units Average Average Maximum JpH Within limits of 6.0 to 9.0 at all times. Acute Toxicity" TUa 1.5 2.0 2.5 (Median) Fecal Coltform ' MPN/100 ml 200 2000 *For FIows less than 1.75 MGD, mass emission rates shall not exceed the "Maximum Allowable Mass Emission hate". **1f information is received which d=onsuates that the Fecal Coliform limitations are inappropriate, this Order may be revised and the limitations modified. 7 WDR Order No. 99-31 -4- Draft for Meeting of July 9,1999 2. Effluent shall not exceed the following Limits:*" 6-Month Daily Instantaneous Constituent Units Median Maximum maximum 1 PROTECTION OF MARINE AQUATIC LIFE Arsenic mg/l 0.83 4.82 12.79 Cadmium mg/l 0.17 0.66 1.66 Chromium (Hex) mg/l 0.33 1.33 3.32 Copper mg/l 0.17 1.66 4.65 Lead mg/l 033 1.33 3.32 Mercury ugh 6.56 26.48 66.32 Nickel mg/l 0.83 3.32 8.30 Selenium mg/l 2A9 9.96 24.90 Silver mg/l 0.09 0.44 1.14 Zinc mgll 2.00 11.96 31.88 Cyanide mg/l 0.17 0.66 1.66 Total Chlorine Residual mg/l 0.33 1.33 9.96 lk Ammonia (as N) mg/1 99.60 398.40 996.00 Chronic Toxicity TUc -- 166.00 - Phenolic Compounds (non -chlorinated) mg/1 4.98 19.92 49.80 Chlorinated - Phenolics mg/l 0.17 0.66 1.66 Endosulfan ug/l I A9 2.99 4.48 Endrin ugh 0.33 0.66 1.00 HCH ugh 0.66 1.33 1.99 Radioactivity Not to exceed limits specified in Title 17, Division 1, Chapter 5, Subchapter 4, Group 3, Article 3, Section 30269, of the California Code of Regulations. Constituent Units 30 Day Average PROTECTION OF HUMAN HEALTH - NONCARCINOGENS AcroIein mg/l 36.52 N-J Antimony 9/1 0.20 Bis(2-chloroethoxy) Methane mg/l 0.73 Bis(2-chloroisopropyl) Ether 9/1 0.20 Chlorobenzene 9/1 0.09 Chromium (IIn 9/1 31.54 Di-n-butyl Phthalate 9/1 0.58 Dichlorobenzenes 9/1 0.85 1,1-dichloroethylene 9/1 1.18 Diehtyl Phthalate 9j1 5.48 Dimethyl Phthalate kg/ll 0.14 4,6-dinitro-2-methylphenol mg/l 36.52 2,4-ftitrophenol mg/l 0.66 Ethylbenzene 9/1 0.68 Fluoranthene mg/l 2A9 Hexachlorocyclopentadiene mg/l 9.63 Isophorone 911 24•90 Nitrobenzene mg/l 0.81 WDR Order No. 99-31 .5- Draft for Meeting of July 9, 1999 PROTECTION OF HUMAN HEALTH - CARCINOGENS . j Thallium mg/1 2.32 Toluene 9/1 14.11 1,1,2,2-tetrachloroethane 9/1 020 Tributyltin ug/1 013 1, 1, 1 -trichloroethane kg/1 0.09 1,1,2-trichloroethane 9/1 7.14 s Acrylonitrile ug/1 16.60 Aldrin ng/1 3.65 Benzene mg/l 0.98 1 Benzidine ng/1 11.45 Beryllium ug/1 5.48 Bis(2-chloroethyl) Ether ug/l 7.47 Bis(2-ethylhexyl) Phthalate mg/l 0.58 Carbon Tetrachloride mg/1 0.15 Chlordane ng/1 3.82 Chloroform mg/l 21.58 DDT' ng/l 28.22 1,4-dichlorbenxene mg/l 2.99 Constituent Units 30-Day Average PROTECTION OF HUMAN HEALTH -- CARCINOGENS 3,3-dichlorobenzidine ug/l 1.34 1,2-dichloroethane mg/1 21.58 Dichloromethane mg/l 74.70 1,34chloropropene mg/1 I A8 Dieldrin ng/1 6.64 2,44initrotoluene m9/1 0.43 1,2-dipheny1hydrazine ug/l 26.56 Halomethanes mg/l 21.58 Heptachlor ug/1 0.12 Hexachlorobenzene ng/l 34.86 Hexachlorobutadiene mg/1 2.32 Hexachloroethane mg/l 0.42 N-nitrasodimethylamine mg/1 1.21 N-nitrosodiphenylamine mgll 0.42 pAHs ug/1 I A6 PCBs ng/l 3.15 TCDD equivalents' pg/1 0.65 Tetrachloroethylene mg/l 16A3 Toxaphene ng/1 34.86 Trichloroethylene mg/l 4AS 2,4,6-tdchlorophenol ug/1 48.14 Vinyl Chloride mg/1 5.98 i The sum of 4XDDT; 2,41)DT; 4,4'DDE; 2,4DDE; 4,49DDD and 2,41)DD. 2 The sum of the concentrations -of chlorinated dibenzodioxins and chlorinated dibenzof =u multiplied by their respective toxicity factors. WDR Order No. 99-31 -6- Draft for Meeting of July 9,1999 1 b. During any 24-hour period, the effluent mass emission rate shall not exceed the "Maximum Allowable Daily Mass Emission Rate". c. Violation of the "Instantaneous Maximum" or "Maximum Allowable Daily Emission Rate" must be reported to the Board within 24 hours. d. During any six-month period, the effluent mass emission rate shall not exceed the "Maximum Allowable Six -Month Median Mass Emission Rate". Based on California Ocean Plan criteria using a minimum initial dilution of 165:1. If actual dilution is found to be less than this value, it will be recalculated and the Order revised. The chromium limit may be met as total chromium if the Discharger chooses. The cyanide limit may be met by the combined measurements of free cyanide, simple alkali metal cyanides, and weakly complexed organometallic complexes upon approval by the Regional Board and EPA. 3. Effluent daily dry weather flow shall not exceed a monthly average of 1.75 MGD (6624 m3/day). 4. Effluent shall be essentially free of materials and substances that:" a. float or become floatable upon discharge. b. may form sediments which degrade benthic communities or other aquatic life. c. accumulate -to toxic levels in marine waters, sediments or biota. d. decrease the natural light to benthic communities and other marine life. e. materials that result in aesthetically undesirable discoloration of the ocean surface. C. RECEIVING WATER LIMITATIONS (Receiving water duality is a result of many factors, some unrelated to the discharge. This permit considers these factors and is designed to minimize the influence of the discharge to the receiving water.) Thr., discha= shall not cause: J 1. The following bacteriological limits to be exceeded in the water column (a) within a zone bounded by the shoreline and 30-foot depth contour/a distance of 1,000 feet from the l shoreline; (b) within areas where there are kelp beds; and (c) within areas used for body contact recreation:" (MPN/I00 ml) Parameter ' Total Coliform Fecal Coliform Log Mean (30-day) - - - 200 90% of Samples (60-day) - - - 400 80% of Samples (30-day) 1,000 --- in nnn - - - *Verified by a repeat sample taken within 48 hours. 1. The following bacteriological limits to be exceeded in the water column in areas where shellfish are harvested" Total Coliform Parameter Applicable Organisms to any 30-day period (MPN/I00 ml) Median 70 900/6 of Samples 230 2. Floating particulates and grease and oil to be visible on the ocean surface." 3. Aesthetically undesirable discoloration of the ocean surface." 4. Significant reduction of transmittance of natural light in ocean waters outside the "zone of initial dilution." 5. Change in the rate of deposition of inert solids and the characteristics of inert solids in ocean sediments such that benthic communities are degraded A WDR Order No. 99-31 -7- Draft for Meeting of July 9, 1999 6. The dissolved oxygen concentration outside the "zone of initial dilution" to fall below 5.0 mg/l or to be depressed more than 10 percent from that which occurs naturally 7. The pH outside the "zone of initial dilution" to be depressed below 7.0, raised above 8.3, or changed more than 0.2 units from that which occurs naturally." 8. Dissolved sulfide concentrations of waters in and near sediments to significantly increase above that present under natural conditions." 9. Concentrations of the same substances listed in Effluent limitation No. B.2. to increase in marine sediments to levels which would degrade indigenous biota" 10. Objectionable aquatic growth or degradation of indigenous biota" 11. Concentrations of organic materials in marine sediments to increase to a level which would degrade marine life.^ 12. Degradation of marine communities, including vertebrate, invertebrate, and plant species ' 13. Alteration in natural taste, odor, and color of fish, shellfish, or other marine resources used for human consumption A 307(b) and (c) of the Clean Water Act. This permit implements General Pretreatment Regulations of Codified Federal Regulation, 40 CFR Part 403, as reference. The objective of the pretreatment program is to prevent the introduction of pollutants into the POTW (publicly owned treatment works) which will interfere with the operation of the treatment works, pass through the treatment facility, reduce opportunities to recycle and reuse municipal wastewater and sludge, or expose POTW employees to hazardous chemicals. In order to provide adequate legal authority for the Discharger to protect its POTW, and to evaluate sources of industrial discharges, the Discharger must perform the following pretreatment activities: 1. Develop a sewer use ordinance to provide all of the legal authorities described in 40 CFR 403.8(f)(1). 2. By July 9, 2000, submit to this office the results of an industrial waste survey as described in 40 CFR 403.8 (f)(2xi)-(ii), and a report summarizing potential impacts of industrial discharges upon the POTW. The report must include an evaluation of the need for regulation of industrial discharges to implement the objectives of the federal pretreatment program. 14. Concentrations of organic materials in fish, 3. shellfish or other marine resources used for human consumption to bioaccumulate to levels that are harmful to human health. 15. Degradation of marine life due to radioactive waste. A B 16. Temperature of the receiving water to adversely affect beneficial uses D. PRETREATMENT SPECIFICATIONS A Pretreatment Program is a regulatory program administered by the Discharger that implements National Pretreatment Standards. These standards are promulgated by the Environmental Protection Agency in accordance with Section It in the evaluation of D.2. and. above, the Executive Officer determines that a formal pretreatment program is necessary to adequately meet program objectives, then the Discharger shall develop such a program in accordance with 40 CFR 403.9..E 4. The Discharger shall comply, and ensure affected "indirect dischargers" comply, with Paragraph D.1. of "Standard Provisions and Reporting Requirements." E. BIOSOLIDS SPECIFICATIONS (Note: "Biosolids" refers to non -hazardous sewage sludge as defined in 40 CFR 503.9. Sewage sludge that is hazardous as defined in 40 CFR 261 must be disposed in accordance with rf WDR Order No. 99-31 -a- Draft for Meeting of July 9, 1999 -RCRA. Sludge with PCB levels > 50 mg/kg must possibly result in overflow or exceed pump be disposed in accordance with 40 CFR 761. station capacity; and I. Al! biosolids; generated by the permittee shall be b. identify, assign., and implement spill used or disposed of in compliance with the prevention measures and collection system applicable portions of management practices to ensure overflows and contribution of pollutants or a. 40 CFR 503: for biosolids that are land incompatible wastes to Discharger's applied, placed in surface disposal sites treatment system are minimized. (dedicated land disposal sites or monofills), or incinerated; 2. Each sewering entity shall make a copy of the • . Program available upon request to a r b. 40 CFR 258: for biosolids disposed in representative of the Regional Board. municipal solid waste landfills; 3. The Program shall provtde a description of the c. 40 dFR 257: for all biosolids use and collection and transport system, measures used to disposar practices not covered under 40 ensure proper operation, and other information CFR 258 or 503. necessary to determine compliance with these requirements. The Program shall include, at a 40 CFR 503 Subpart B (land application) . minimum, the following items: applies to biosolids applied for the purpose of enhancing plant growth or for land reclamation. a. A map showing: collection system lines 503 Subpart C (surface disposal) applies to greater than 12 inches, pump stations, biosolids placed on the land for the purpose of standby power facilities, surface water bodies disposal. (including discharge point(s) where pump station overflows may occur), storm drain The permittee is responsible for assuring that all inlets, and date of last revision. biosolids produced at its facility are used or disposed of in accordance with these rules, b. A narrative description of the following: whether the permittee uses or disposes of the biosolids; itself or transfers them to another i. Line flushing and Cleaning: Describe party for further treatment, use, or disposal. The available equipment and projected permittee is responsible for informing schedule necessary to clean and flush subsequent preparers, appliers, and disposers of entire system every two -years, and the requirements that they must meet under assigned staff. Describe coordination these rules. with area plumbers to address introduction of incompatible wastes (root F. INFILTRATIONIINFLOW balls) during lateral cleaning and efforts to abate introduction of construction ` Each entity shall develop and implement an debris into the system. Infiltration/Inflow and Spill PreventionProgram (Program). The Program shall be reviewed and ii. Visual System Inspection: Describe updated as necessary by September 1, of every visual inspeciton methods (e.g., yea television lines), replacement schedules, frequency, collection system length and 1. The Program shall be developed in accordance detail problem areas found. Inspection with engineering practices and shall address the records shall be retained for five years. following objectives: iii. Inflow & Infiltration: Describe current a. identify infiltration and inflow sources that and five year projected investigation may affect treatment facility operation or methods (e.g., smoke testing), frequency, 7 WDR Order No. 99-31 -9- Draft for Meeting of July 9,1999 rresults, and efforts to reduce storm water all stag position, duties, and training inflows and sewer line ex -filtration. received during the past year. Identify Inspection records shall be retained for managers and -provide a list of contacts with five years. associated phone numbers. iv. Preventative Repair and Replacement: b. Training: List the frequency of training, Describe a projected schedule to qualification of each employee, and eliminate sewage conveyance systems coordination with the Discharger and other determined or projected to be structurally member entities. Periodic dates for training compromised. List each project or reach shall be identified. of conveyance to be replaced separately along with proposed start and estimated 6. Planning and Reporting: The Program shall completion dates. provide a description of planning efforts and reporting a system operation. The Program shall v. Pump Station Maintenance: Describe include, at a minimum, the following items: each pump station, location, flow monitoring (wet and dry weather), and a. Spill Response: Describe a plan, identify the previous year's operational problems employees responsible and duties necessary and overflows. to implement your response to spills. vi. Alternate Power Supply for Pump Identify posting, notification, and spill Station Operation: Describe alternate estimation efforts used. power supply for each pump station within the member entity's system. b. Annual Reporting: List spills or system problems during the previous year, cleanups, 4. Fiscal Resources: The Program shall provide a amounts, location, and efforts to ensure A description of fiscal resources necessary to ensure similar spills or problems do not reoccur. tracking or follow-up procedure shall be used system operation The Program shall include, at a to ensure appropriate response has been minimum, the following hems: taken. Inspections and maintenance activities a. Fee Structure: Quantification of current and shall be documented and recorded. five year projected sewer assessment fees c. Offsite and Onsite Spill Alarms: Describe necessary to implement the Program, the current or proposed alarm system (or why 1 including a comparision of fees collected by ��3'}, central information location, the Discharger as well as those collected by staffing and response times for detecting all other member sewering entities. spills from the system. ` b. Available Fiscal Resources: Actual and five d. Wet Season Manhole Inspections: Describe year projected budget expenses for staffing, or propose frequency to conduct inspections operation and replacement of the collection to detect line blockage during wet season :.� system, including a description of a capital flows to avoid system overflows, staffing, improvement or sinking fund to provide and available and projected equipment to funding for item 6.e., below. `^ ensure safe and effective inspections. 5. Personnel and Training: The Program shall a Capital Improvement: Describe a current provide a description of staffing available to and projected work plan. ensure system operation. The Program shall include, at a minimum, the following items: f. Five Year Planning: Describe projected a. Personnel: Identify specific individual (and planning efforts. job titles) who are responsible for g. Twenty (20) Year Planning: Describe long developing, implementing, and revising the tern ping efforts. Program. Provide an organizational chart of WDR Order No. 99-31 -10- Draft for Meeting of July 9, 1999 7. Each member entity shall provide a semi-annual 3. Discharger shall comply with all items of the report describing program development and "Standard Provisions and Reporting permit compliance over the previous six months. Requirements for National Pollutant Discharge Reports shall be of sufficient content as to enable Elimination System Permits," dated January the Regional Board to determine compliance with 1985. Paragraph (a) of item E.1. shall apply only requirements. if the bypass is for essential maintenance to assure efficient operation. G. PROVISIONS 4. Discharger shall implement a toxicity reduction 1. The requirements prescribed by this Order evaluation and take appropriate remedial action to supersede requirements prescribed by Order No. reduce toxicity to its required level, if the effluent 94-52, adopted by the Board on June 3, 1994.. Chronic or Acute Toxicity limit is consistently `.. Order No. 94-52, "Waste Discharge exceeded. A Requirements for City of Pismo Beach Wastewater Facility," is hereby rescinded. 5. This Order expires July 9, 2004, and the Discharger must file a Report of Waste Discharge 2. Discharger shall comply with "Monitoring and in accordance with Title 23, Division 3, Chapter 9, of the California Code of Regulations, not later Reporting Program No. 99-31," as ordered by the than Jan 9, 2004, if -it wishes to continue the -) Executive Officer.A discharge." I, Roger W. Briggs, Executive Officer, do hereby certify the foregoing is a full, true, and correct copy of an Order adopted by the California Regional Water Quality Control Board, Central Coast Region, on July 9, 1999. Executive Officer Date s.\Prog mm\NPDF,S1Pismo199-03 I .wdr.doc r� APPENDIX B TECHNICAL MEMORANDUM NO. 1 - WASTEWATER FLOWS AND CHARACTERISTICS 1 _1 H:14836AOOIRpt1APP.WPD I City of Pismo Beach TECHNICAL MEMORANDUM NO. 1 WASTEWATER FLOWS AND CHARACTERISTICS May 1999 H:1Final\PismoI3ch FN014836AOO1TMITMol.wpd i� 7580 NORTH INGRAM AVENUE, SUITE 112 FRESNO, CALIFORNIA 93711 (559) 436-6616 FAX (559) 436-1191 City. of Pismo Beach TECHNICAL MEMORANDUM NO. 1 WASTEWATER FLOWS AND CHARACTERISTICS TABLE OF CONTENTS 1.0 PURPOSE............................................................. 1-1 2.0 LAND USE AND POPULATION ............................................. 1-1 3.0 GROWTH RATE ANALYSIS ................................................ 1-2 4.0 EXISTING AND FUTURE WASTEWATER FLOWS .............................. 1-2 Peaking Factor Analysis .................................................. 1-5 5.0 EXISTING AND FUTURE WASTEWATER CHARACTERISTICS .................... 1-6 6.0 DESIGN FLOWS AND WASTEWATER CHARACTERISTICS 1-7 LIST OF TABLES 1 Existing and Future Land Use and Population ................................. 1-2 2 Existing Average Flows by Land Uses ....................................... 1-4 3 Build -Out Average Annual Flows by Land Uses ................................ 1-4 4 Summary of Existing and Projected Flows and Peaking Factors .................. 1-5 5 Existing and Future Wastewater Characteristics ............................... 1-6 6 Design Flows and Wastewater Characteristics ................................. 1-7 LIST OF FIGURES 1 Residential Growth Rates...................................................1-3 H:\FinagPismoBch_FNO�483BAOO\TM\TMOt.wpd i December S, 1999 1 . -. - Technical Memorandum No. 1 WASTEWATER FLOWS AND CHARACTERISTICS 1.0 PURPOSE ,1 This Technical Memorandum No. 1 (TM No. 1) has been prepared by Carollo Engineers, P.C. l (Carollo) and by John L. Wallace and Associates (JLWA) for the City of Pismo Beach. Carollo is the prime consultant and is responsible for both the wastewater treatment facility (WWTF) master plan and the collection system master plan. JLWA is responsible to Carollo to prepare the collection system master plan. In coordination with a separate agreement with the City for the Infiltration/inflow Study, JLWA developed land use and population projections and existing and future wastewater flows for the collection system which discharges into the headworks at the wastewater treatment facility. Carollo will use the flows projected by JLWA to the evaluate the wastewater treatment facilities. 2.0 LAND USE AND POPULATION Land use zoning within the City of Pismo Beach is governed by the Land Use Element of the General Plan & Local Coastal Plan adopted in November, 1992. The General Plan predicts a build -out population for the City of 13,000 persons and establishes a maximum allowable growth rate of 3 percent per year. This ultimate population includes the annexation of areas within the Sphere of Influence, or probable future City limits. In addition to review of the General Plan, JLWA met with City planning staff to determine the following: • Pending or proposed changes to the Sphere of Influence. • Status of proposed annexations within the existing Sphere of Influence. • Growth patterns and residential development occurring after the 1992 General Plan Update. When the proposed changes to the Sphere of Influence are included within the future population J estimate, the bulid-out population increases to 14,438 persons. Table 1 summarizes the existing and future land use patterns within the City by development type. More detailed zoning designations are available for each type of land use. However, the general categories identified } below were used for the estimation of future wastewater flows. j H:1FinallPiamoBch_FNO\4836ADO\TM\TMOl.wpd 1-1 December 8, 1999 Table 1 Existing .and Future Land_ Use and Pmpulati.on . City of Pismo Beach = Future Uses Development Description Existing Uses (1998) (within current Sphere) Residential Dwelling Units 5,448 units 6,896 units Residential Population (Used 8,528 persons 13,000 persons for flow estimates) Commercial 953,600 sq ft 1,602,000 sq ft Hotel Rooms 1,631 rooms 3,039 rooms RV Parks 811 spaces 821 spaces Proposed Sphere of Influence Modifications Residential Dwelling Units -- 575 units Residential Population -- 1,438 persons Hotel Rooms -- 80 rooms 3.0 GROWTH RATE ANALYSIS The Growth Management Element of the General Plan stipulates a maximum growth rate of 3 percent for the City. Since the preparation of the General Plan in 1992, growth has been at a slower rate, with an average value of 1 percent. However, given the current economic conditions in the area, higher growth rates are expected to persist in the near future. As an example, more building permits were issued in 1998 than in any year since 1991. For the purpose of the master plans it will be assumed that the growth rate will approach 3 percent. Therefore, the City will be assumed to be completely built -out by the year 2013 within the existing Sphere of Influence. If the proposed modifications to the Sphere of Influence are included, the City will be completely built - out by the year 2016. Figure 1 summarizes residential development within the City in terms of growth rate. 4.0 EXISTING AND FUTURE WASTEWATER FLOWS Historical wastewater flows were examined throughout the City collection and treatment system by utilizing the following sources of data: • Wastewater Treatment Facility (WTF) flow records • Lift station flow data • Flow meter data associated with the current infiltration/inflow study being performed by JLWA. I H:\Final\PiamoBch—FNO\4836AOO\TMkTMOI.wpd 1-2 December 8, 1999 N Z ~ U 0- = r m N J is 1- �L 4 L.L W CM Q QQ 3 L U ce) Lu sQ Scn N CL O N000 O) Co O N ti O O N O N M O N T CD m CD o o c o o g o S T w 4� p� O N C Ci3 C�0 T T T T T T T uopIndod 1eituapisaa \ \ n \ m \ � s \ CA N � LL � .a C7 � � m r N � W O � C1 � 4J _ 1 � M ' 1 1 1 1 1 1 11 Table 2 summarizes the estimated wastewater quantification characteristics of various existing development types within the City. The flow factors employed in Table 2 were derived from a variety of sources including the Facilities Element of the General Plan, corresponding data from l similar communities, and water use information. Table 2 Existing Average Flows by Land Uses City of Pismo Beach Average Annual Flow Factor Flow Source of Flow Quantity (gal/day/unit) (gal/day) Residential 8,528 Persons 95 810,160 Hotel Rooms 1,831 rooms 100 183,100 Commercial 953,600 sq ft 0.10 95,360 RV Park 811 50 40,550 Public Facility N/A 20,000 20,000 #nfiltration/Inflow N/A 35,000 35,000 1,184,170 1998 Average Annual Flow =1.2 mgd Table 3 extrapolates the future wastewater flows tributary to the City WWTF using the factors from Table 2. Table 3 Build -Out Average Annual Flows by Land Uses City of Pismo Average Annual Flow Factor Flow Source of Flow Quantity (gal/day/unit) (gal/day) Residential 14,438 persons 95 1,371,610 Hotel Rooms 3,119 rooms 100 311,900 Commercial 1,602,000 sq ft 0.10 160,200 RV Park 821 spaces 50 41,050 Institutional N/A 30,000 30,000 Infiltration/inflow N/A 35,000 35,000 1,949,760 Average Annual Flow at Build -Out = 2.0 mgd l H:\Finanpismoscn FNO\483►aa\TM\TMOI.wpa 1-4 December 8, 1999 Peaking Factor Analysis To appropriately design wastewater treatment and collection facilities, peak flow conditions must be quantified. These conditions are often determined through the use of a multiplication factor, commonly termed a peaking factor, that is applied to the Average Annual Flow. To determine the appropriate peaking factors, historical City flow records were examined for maximum month, day, and hour flows. Table 4 summarizes the existing and future flows and peaking factors. Table 4 Summary of Existing and Projected Flows and Peaking Factors City of Pismo Flow (mgd) Flow Condition Peaking Factors 1998 Build -Out Flows Flows Average Annual Flow (AAF) 1.20 2.00 NIA Peak Day Dry Weather Flow (PDF) 1.76 3.00 1.5 Peak Hour Wet Weather Flow (PHWWF) 3.14 6.0(1) 3.0 Average Day Maximum Month Dry Weather Flow 1.26 2.4 1.2 Average Day Maximum Month Wet Weather Flow 1.59 2.7 1.35 Notes: 1) The future estimate of 6.0 mgd includes 2.0 mgd of storm water inflow. H:1FinallPismoBch_FNO14836A001TM\TM01.wpd 1-5 December 8, 1999 5.0 EXISTING AND FUTURE WASTEWATER CHARACTERISTICS Table 5 presents the historical wastewater flows and characteristics for the past five years. The data presented was obtained from the City of Pismo Beach Treatment Facility Annual reports. Table 5 Existing and Future Wastewater Characteristics City of Pismo Beach Average Daily Maximum Average Month Dry Maximum Daily Annual Weather Wet Weather BODE') TSS(2) Year Flow, mgd Flow, mgd Flow, mgd mg/L mg/L 1994 0.95 1.07 1.53 288 357 1995 1.04 1.11 3.01 278 368 1996 1.06 1.12 2.21 255 319 1997 1.08 1.14 2.48 220 302 1998 1.18 1.26 3.06 248 297 1999(3) 1.08 1.20 2.48 263 278 5 Year Average — --- — 257 330 1994 to 1998 Use for Future — --- — 250 330 Projections Notes: (1) Five day biochemical oxygen demand. Average Annual Values (2) Total suspended solids. Average Annual Values (3) Average of January to September 1999. IH:1FinallPismoBch_FNO\4836A501TMITMOi.wpd 1-6 December 8, 1999 6.0 DESIGN FLOWS AND WASTEWATER CHARACTERISTICS Table 6 presents the recommended design flows and wastewater characteristics. The flows are also presented in Tables 2,3 and 4. For evaluating existing facilities and planning future facilities, the design criteria for influent BOD and TSS average annual values are set at 250 mg/L and 330 mg/L, respectively. Table 6 Design Flows and Wastewater Characteristics City of Pismo Beach Design Year 1998 1999(3) 2016 Population, persons 8,528 --- 14,438 Hotel Rooms 1,831 --- 3,119 Commercial, sq ft 953,600 --- 1,602,000 RV Park, spaces 811 --- 821 Flow, mgd Average Annual 1.20 1.0813) 2.0 Peak Day Dry Weather 1.76 1.60 3.0 (PDF) Peak Hour Wet Weather 3.14 3.00 6.0 (PHWWF) Influent Concentration BOD (1) 248 263 250 TSS (2) 297 278 330 Influent Loading, Ibslday BOD 2,480 2,369 4,170 TSS 2,970 2,504 5,500 Notes: 1) Five day Biochemical Oxygen Demand, Average Annual Values 2) Total Suspended Solids, Average Annual Values 3) Average of January to September 1999 H:%FinallPismoBch_FNO\4838A061TM1TMO1.wPd 1-7 December 8, 1999 APPENDIX C EXISTING WASTEWATER TREATMENT PLANT DESIGN CRITERIA a H:1Fina]\PismoBch FNO\4836AOD\Rpt\APP.WPD Table CA Existing Wastewater Treatment Plant Design Criteria City of Pismo Beach Values/Comments 1998 2006 Parameter Design Flow, mgd Average Annual (AAF) 1.18 1.4 Average Day Maximum Month Dry 1.26 1.5 Weather Flow (ADMMDWF) Peak Hour Wet Weather (PHWWF) 3.14 3.9 Design Loadings, Average Annual BOD$, mg/L 248 250 BOD$ Ibs/day 2,480 2,920 TSS, mg/L 297 330 TSS, Ibs/ day 2,970 3,853 Influent Force Mains, Diameter, inches Addie Street Pump Station 12 and16 12 and16 Pismo Oaks Siphons 3 at 8 3 at 8 Aerated Grit Channel Number of Units 1 1 Dimensions L x W x SWD, ft 7 x 12 x 10 7 x 12 x 10 Total Volume, gallons 6,283 6,283 Detention time at PHWWF, minutes 2.9/At Capacity 2.3 Primary Clarifiers Number and Diameter, ft 2 at 30 2 at 30 Total Surface Area, sq ft 1,414 1,414 Side Water Depth, ft 8/11.5 8/11.5 Total Volume, gallons 121,630 121,630 Detention Time, hours at Average Flow 2.43 2.09 Surface Overflow Rate at AAF, gpd/sq ft 848 972 PHWWF, gpd/sq ft 2,220 2,708 H:1FinallPlsmo6ch_FNO148$BAOO\Table\Parametr.wpd Table C.1 Existing Wastewater Treatment Plant Design Criteria City of Pismo Beach Values/Comments 1998 2006 Parameter Flow Equalization Basin Volume, gallons 365,000 365,000 Storage time Hours at Average Flow 7.3 e.3 Aeration Tanks Number 3 3 Width x Length, ft 20 x 60 20 x 60 Side Water Depth, ft 15 15 Total Volume, cu ft 54,000 54,000 Influent BODb, mg/L Average 248 250 BOD5 Loading Ib/BOD,/day/1,000 cu ft 32 39.3 Detention Time At Average Flow, hours 8.07 9.23 With 25 Percent Return, hours 6.46 5.53 Secondary Clarifiers Number and Diameter, ft 2 at 30/1 at 40 Total Surface Area, sq ft 2,671 2,671 Side Water Depth, ft 9.5/10.75/Current Standard is 14 ft Total Volume, gallons 201,554 201,554 Detention Time, hours at Average Flow 4.00 3.45 Surface Overflow Rates at Average Flow, gpd/sq ft 449 524 Peak Hour Flow, gpd/sq ft 1,176 1,460 Aeration Blowers Number (2,000 cfm each) 3 3 Horsepower, horsepower, each 60 60 H:1Finef PismoBch_FNQI483B►001TableNParametr.wpd Table CA Existing Wastewater Treatment Plant Design Criteria City of Pismo Beach Values/Comments Parameter 1998 F 2006 Chlorine Contact Chamber Number 1 1 Size LxWxSWD 37x18x8 37x18x8 Volume, cu ft 5,328 5,328 Volume, gallons 39,850 39,850 Detention Time at Average Flow, minutes 48 41 at Peak Flow, minutes 181Should be 30 15 Plant Effluent Pumping Number of Pumps, with VFD's 2 2 Reported Operating Capacity, mgd 3.0 3.0 Operating Head, ft 28 --- Capacity with two Pumps, mgd 6.0/Requires 2 to Pump peak flow with no standby. Outfall Diameter, inches 18 --- Outfall Pipe Length, feet 17,500 --- Digester No. 2 Diameter, ft 47 --- Volume, gal 307,000 --- Digester feed, gpd 15,350 --- Detention Time, days 20 --- Digester No. 1 (holding digester) Diameter, ft 40 --- Volume, gal 187,750 --- Detention Time, days ¢ 15 --- Dissolved Flotation Thickener (DAF) H:1Final PismoBch_FNO\4836AOOITable\Pammetr.wpd Table CA Existing Wastewater Treatment Plant Design Criteria City of Pismo Beach Values/Comments Parameter 1998 2006 Number of Units 1 --- Diameter, ft 20 --- Side Water Depth, It 6.4 --- Surface Area, sq ft 314 --- Capacity, gpm at 5,000 mg/L TSS 120 --- Belt Filter Press Number 1 --- Size, meters belt width 1 --- Capacity, gpm at 3.5 percent feed solids 43 --- Average Solids Concentration, percent 18.5-19 --- by weight Wet Cake Quantity at18.5 percent solids, 6.5 --- tons/day H:1FinallPiamoBch FNO14B36AOO1Table\Parametr.wpd APPENDIX D ALTERNATIVES - DESIGN CRITERIA J H:14836AOM1 tIAPP.WPD Table D.1 Alternative B - Rehabilitation of Existing Activated Sludge Plant Design Criteria City of Pismo Beach - Design Year 2016 Parameter Design Flow, mgd Average Annual (AAF) 2.0 Average Day Maximum Month Dry 2.4 weather Flow (ADMMDWF) Permit Condition Peak Hour Wet Weather (PHWWF) 6.0 Design Loadings, Average Annual BOD5, mg/L 250 BOD5 lbs/day 4,170 TSS, mg/L 330 TSS, Ibs/ day 5,500 Headworks Existing New Parshall Flume Width, Inches — 12 Parshall Flume Capacity, mgd — 6 Number of Mechanical Bar Screens ---- 1 Type of Screen — Climber or Continuous Bar Screen Spacing, inches — 1/2 Bar Screen Capacity, mgd — 6 Number Manual Bar Screen — 1 Influent Force Mains, Diameter, inches Addie Street Pump Station 12 & 16 --- Pismo Oaks Siphons 3 at S --- New Shell Beach Force Main — 12 Aerated Grit Channel Type --- Aerated Number of Units — 1 H:\Final\PismoBch—FNOk4836AGD\TableNParamW.wpd 1 Table D.1 Alternative B - Rehabilitation of Existing Activated Sludge Plant Design Criteria City of Pismo Beach Design Year 2016 Parameter Existing New Dimensions L x W x SWD, ft --- 10 x 14 x 12 Total Volume, gallons — 12,570 Detention time at PHWWF, minutes --- 3 Number of Blowers --- 1 +1 Blower Capacity, each — 150 Primary Clarifiers Number and Diameter, ft -- 2 at 45 Total Surface Area, sq ft — 3,179 Side Water Depth, ft -- 10 Total Volume, gallons — 237,800 Detention Time, hours at Average Flow — 2.85 Surface Overflow Rate at AAF, gpd/sq ft — 629 PHWWF, gpd/sq ft — 1,887 Aeration Tanks Number 3 2 Width x Length, ft 20 x 60 20 x 60 Side Water Depth, ft 15 15 Total Volume, cu ft 544,000 36,000 Influent BODS, mg/L Average 248 250 BOD., Loading ib/BOD,/day/1,000 cu ft 32 32 Detention Time at AAF, hours At Average Flow, hours 8.1 8.1 With 25 Percent Return, hours 6.5 6.5 H:1Fina1\PismoBch FNO\4836AOO\Table%Parametr.wpd 2 Table D.1 Alternative B - Rehabilitation of Existing Activated Sludge Plant Design Criteria City of Pismo Beach Parameter Design Year 2016 Existing New Secondary Clarifiers Number and Diameter, ft — 2 at 65 Total Surface Area, sq ft -- 6,633 Side Water Depth, ft — 14 Total Volume, gallons ---- 694,630 Detention Time, hours at Average Flow — 8.3 Surface Overflow Rates at Average Flow, gpd/sq ft — 302 Peak Hour Flow, gpolsq ft — 905 Aeration Blowers Number (2,000 cfm, each) 3 2 Horsepower, horsepower, each 60 60 Chlorine Contact Chamber Number (Reuse Aeration Basin) Size L x W x SWD 1 2 Volume, cuft 37x18x8 37x18x9 Volume, gallons 5,328 11,988 Detention Time at Average Flow, minutes — 93 at Peak Flow, minutes — 31 Plant Effluent Pumping Number of Pumps, with VFD 2 1 Reported Operating Capacity, mgd 3.0 3.0 Operating Head, ft 28 >28 Capacity with two Pumps, mgd 6.0 H:1FinallPismoBch_FNO\4836AOD\Table\PwameV.wpd 3 Table DA Alternative B - Rehabilitation of Existing Activated Sludge Plant Design Criteria City of Pismo Beach Parameter Design Year 2016 Existing New Outfall Diameter, inches 18 --- Outfall Pipe Length, feet 17,600 — Digester No. 2 Diameter, ft 47 --- Volume, gal 307,000 --- Digester feed, gpd 15,350 — Detention Time, days 20 --- Digester No. 1 (holding digester) Diameter, ft 40 --- Volume, gal 187,750 --- Detention Time, days <15 --- Dissolved Air Flotation Thickener (DAFT) Number of Units 1 --- Diameter, ft 20 --- Side Water Depth, ft 6.4 --- Surface Area, sq ft 314 --- Capacity, gpm at 5,000 mg/L TSS 120 --- Belt Filter Press Number 1 --- Size, meters belt width 1 --- Capacity, gpm at 3.5 percent feed solids 43 --- Average Solids Concentration, percent by 18.5 to 19.0 --- weight Wet Cake Quantity at 18.5 percent solids, 6.5 — tons/day H:\Final\PismoBch FNO\48WAODITablelParametr.wpd 4 Table D.2 Alternative B - Oxidation Ditch with Primary Clarifiers Design Criteria City of Pismo Beach Design Year 2016 Parameter Design Flow, mgd Average Annual (AAF) 2.0 Average Day Maximum Month Dry 2.4 Weather Flow (ADMMDWF) Peak Hour Wet Weather (PHWWF) 6.0 Design Loadings, Average Annual BODS, mg/L 250 BOD5 Ibs/day 4,170 TSS, mg/L 330 TSS, Ibs/ day 5,500 Headworks Existing New Parshall Flume Width, inches — 12 Parshall Flume Capacity, mgd — 6 Number of Mechanical Bar Screens — 1 Type of Screen — Climber or Continuous Bar Screen Spacing, inches — 1 /2 Bar Screen Capacity, mgd — 6 Number Manual Bar Screen — 1 Influent Force Mains, Diameter, inches Addie Street Pump Station 12 & 16 --- Pismo Oaks Siphons 3 at S --- New Shell Beach Force Main — 12 Aerated Grit Channel Type --- Aerated Number of Units --- 1 Dimensions L x W x SWD, ft --- 10 x 14 x 12 H:%FinallPismoBch_FNOW36AOD\Table\Parami&.wpd 5 Table D.2 Alternative B - Oxidation Ditch with Primary Clarifiers Design Criteria City of Pismo Beach Design Year 2016 Parameter Existing New Total Volume, gallons — 12,570 Detention time at PHWWF, minutes — 3 Number of Blowers --- 1 +1 Blower Capacity, each — 150 Primary Clarifiers Number and Diameter, ft -- 2 at 45 Total Surface Area, sq ft — 3,179 Side Water Depth, ft — 10 Total Volume, gallons — 237,800 Detention Time, hours at Average Flow — 2.85 Surface Overflow Rate at AAF, gpd/sq ft — 629 PHWWF, gpd/sq ft — 1,887 Oxidation Ditch Number — 2 Width x Length, ft — 52 X 167 Side Water Depth, ft — 12 Volume each, mg — 1.5 SOD, Loading Ib/BODdday/1,000 cu ft — 15 Detention Time at AAF, hours — 17.5 Number of Aerators — 4 Estimated Horsepower of Aerators, Hp — 60/40 (two -speed) Secondary Clarifiers Number and Diameter, ft — 2 at 65 Total Surface Area, sq ft — 6,633 H:1FinallPismoBch_FNO\4836AOOITable\Pararnetr.wpd 6 Table D.2 Alternative B - Oxidation Ditch with Primary Clarifiers Design Criteria City of Pismo Beach Design Year Parameter 2016 Existing New Side Water Depth, ft — 14 Total Volume, gallons ---- 694,630 Detention Time, hours at Average Flow — 8.3 Surface Overflow Rates at Average Flow, gpolsq ft — 302 Peak Hour Flow, gpolsq ft -- 905 Chlorine Contact Chamber Number (Reuse Aeration Basin) — 2 Size LxWxSWD --- 20x60x15 Volume, cu ft — 36,000 Volume, gallons — 269,280 Detention Time at Average Flow, minutes — 193 at Peak Flow, minutes — 65 Plant Effluent Pumping Number of Pumps, with VFD 2 1 Reported Operating Capacity, mgd 3.0 3.0 Operating Head, ft 28 >28 Capacity with two Pumps, mgd 6.0 Outfall Diameter, inches 18 --- Outfall Pipe Length, feet 17,500 — Digester No. 2 Diameter, ft 47 --- Volume, gal 307,000 --- Digester feed, gpd 15,350 --- H:\Final�PismoBch_FNO\483a&M%Table\ParamW.wpd 7 Table D.2 Alternative B - Oxidation Ditch with Primary Clarifiers Design Criteria City of Pismo Beach Parameter Design Year 2016 Existing New Detention Time, days 20 --- Digester No. 1 (holding digester) Diameter, ft 40 --- Volume, gal 187,750 --- Detention Time, days < 15 --- Dissolved Air Flotation Thickener (DAFT) Number of Units 1 --- Diameter, ft 20 --- Side Water Depth, ft 6.4 --- Surface Area, sq ft 314 --- Capacity, gpm at 5,000 mg/L TSS 120 --- Belt Filter Press Number 1 --- Size, meters belt width 1 --- Capacity, gpm at 3.5 percent feed solids 43 --- Average Solids Concentration, percent by 18.5 to 19.0 --- weight Wet Cake Quantity at 18.5 percent solids, 6.5 — tons/day H:\Final PismoBch_FNO\4836AMTabie\Paramev.wpd 8 Table D.3 Alternative C - Oxidation Ditch without Primaries Design Criteria City of Pismo Beach Design Year 2016 Parameter Design Flow, mgd Average Annual (AAF) 2.0 Average Day Maximum Month Dry 2.4 Weather Flow (ADMMDWF) Peak Hour Wet Weather (PHWWF) 6.0 Design Loadings, Average Annual BOD5, mg/L 250 BOD5 Ibslday 4,170 TSS, mg/L 330 TSS, Ibs/ day 5,500 Headworks Existing New Parshall Flume Width, inches — 12 Parshall Flume Capacity, mgd — 6 Number of Mechanical Bar Screens — 1 Type of Screen — Climber or Continuous Bar Screen Spacing, inches — 1/2 Bar Screen Capacity, mgd — 6 Number Manual Bar Screen — 1 Influent Force Mains, Diameter, inches Addie Street Pump Station 12 & 16 --- Pismo Oaks Siphons 3 at 8 --- New Shell Beach Force Main — 12 Oxidation Ditch Number — 2 Width x Length, ft --- 52 x 234 Side Water Depth, ft — 12 H:\FinaRPismoBch_FNO\4BMA=Table\Pammetr.wpd 9 Table D.3 Alternative C - Oxidation Ditch without Primaries Design Criteria City of Pismo Beach Design Year 2016 Parameter Existing New Volume, each, mg — 2.0 BOD5 Loading Ib/BODdday/1,000 cu ft — 15 Detention Time at AAF, hours — 25.0 Number of Aerators — 4 Estimated Horsepower of Aerators, Hp — 75/45 (two -speed) Secondary Clarifiers Number and Diameter, ft — 2 at 65 Total Surface Area, sq ft — 6,633 Side Water Depth, ft — 14 Total Volume, gallons ---- 694,630 Detention Time, hours at Average Flow — 8.3 Surface Overflow Rates at Average Flow, gpd/sq ft — 302 Peak Hour Flow, gpd/sq ft — 905 Chlorine Contact Chamber Number (Reuse Aeration Basin) 2 Size LxWxSWD --- 20x60x15 Volume, cu ft — 36,000 Volume, gallons — 269,280 Detention Time at Average Flow, minutes -- 193 at Peak Flow, minutes — 65 Plant Effluent Pumping Number of Pumps, with VFD 2 1 Reported Operating Capacity, mgd 3.0 3.0 H:1Fna%PismoSch_FNO\4838AOOITabie\Pammetr.wpd 10 Table D.3 Alternative C - Oxidation Ditch without Primaries Design Criteria City of Pismo Beach - -- Parameter Operating Head, ft Capacity with two Pumps, mgd Outfall Diameter, inches Outfall Pipe Length, feet Digester No. 2 Diameter, ft Volume, gal Digester feed, gpd Detention Time, days Digester No. 1 (holding digester) Diameter, ft Volume, gal Detention Time, days Dissolved Air Flotation Thickener (DAFT) Number of Units Diameter, ft Side Water Depth, ft Surface Area, sq ft Capacity, gpm at 5,000 mg/L TSS Belt Filter Press Number Size, meters belt width Capacity, gpm at 3.5 percent feed solids Average Solids Concentration, percent by weight Wet Cake Quantity at 18.5 percent solids, tons/day Existing 28 18 17,500 47 307,000 15,350 20 40 187,750 c15 1 20 6.4 314 120 1 i 43 18.5 to 19.0 6.5 Design Year _ -- 2016 New > 28 6.0 H:1Final\PIsmOBch_FNON48WA=Table\Parametr.vrpd 11 1 APPENDIX E TECHNICAL MEMORANDUM NO. 2 - ELECTRICAL EVALUATION HA4836AOO1RptWP.WPD J City of Pismo Beach TECHNICAL MEMORANDUM NO.2 ELECTRICAL EVALUATION June1999 REVISED: December 1999 F:IFina1\Pismo6ch FN014636AOOITN\TMO2.wpd 7580 NORTH INGRAM AVENUE, SUITE 112 FRESNO, CALIFORNIA 93711 • (559) 436-6616 FAX (559) 436-1191 City of Pismo Beach TECHNICAL MEMORANDUM NO.2 - ELECTRICAL EVALUATION 1.0 ELECTRICAL SCOPE OF WORK ......................................... 2-1 2.0 SUMMARY OF FINDINGS AND RECOMMENDATIONS ........................ 2-1 Immediate Improvements ............................................... 2-1 Long Term Improvements ............................................... 2-3 3.0 EVALUATION OF EXISTING POWER DISTRIBUTION SYSTEM ................. 2-4 4.0 STANDBY POWER GENERATORS ........................................ 2-4 5.0 PROPOSED POWER DISTRIBUTION SYSTEM .............................. 2-5 6.0 POWER MONITORING AND METERING DEVICES ........................... 2-6 7.0 ELECTRICAL DESIGN STANDARDS ...................................... 2-7 Application of Conduit and Wiring Materials . ................................ 2-7 Enclosures for Corrosive and Hazardous Locations .......................... 2-7 Underground Duct banks ............................................... 2-8 LIST OF TABLES 2.1 Immediate Improvements for Electrical Facilities ................. . ........... 2-1 H:1Final\PismoBch—FNOI4835AOOITM\TM02.wpd Technical Memorandum No. 2 ELECTRICAL EVALUATION 1.0 ELECTRICAL SCOPE OF WORK The existing electrical power distribution facilities was evaluated to determine the system capacity to supply power to new additional loads, to observe the existing electrical equipment condition for continuos operation during a future number of years, and to access the field conditions for new facilities associated with the plant expansion. Carollo's electrical engineer has identified the major elements of electrical equipment and has documented his findings during field observations. Basic recommendations for the proposed plant upgrade are as follows. 2.0 SUMMARY OF FINDINGS AND RECOMMENDATIONS Immediate Improvements Table 2.1 presents immediate improvements to electrical facilities and the Pismo Beach Wastewater Treatment Plant (WWTP). On December 16, 1999, Carollo's Electrical Engineer visited the WWTP and compiled a list of electrical items to be included in immediate improvements to electrical facilities. The items within Table 2.1 are necessary for electrical systems to function reliably from the year 2000 to 2006 when the upgraded WWTP may be operational. Table 2.1 Immediate Improvements for Electrical Facilities Technical Memorandum No. 2 Area 1 Item Description Observations(') Recommendation(2) Cost PG&E 1 Transformer(T340) Fair Condition. OK for next 5 years Continue using it NIA Main Electrical Poor working space around electrical Remove non -electrical 2 Room equipment furniture $5,000 Additional non -electrical items appliances, lockers and violates the Code. files. Add seismic restraints. $2,000 Fair Condition and limited spare 3 Main Switchboard capacity Continue using it NIA Fair Condition and limited spare 4 Transfer Switch capacity Continue using it NIA `Vf F:1FnAPiamoBch_FNO\4838AOONTM\TMO2.wpd 2-1 Table 2.1 Immediate Improvements for Electrical Facilities Technical Memorandum No. 2 Area / Item Description Observations(') Recommendation12) Cost Annunciator & Clean Up, replace light 5 Controls Poor maintenance condition bulbs $500 Add fillers to panel knockouts Lighting fixtures in non -working Replace 8 lighting 6 Room adjacent to condition fixtures $2,000 electrical room Generator No.1; 7 250KW Fair Condition with no spare capacity Continue using it NIA (and with 418 running hours) Generator No.2; Poor Condition with corrosion on Continue using it; 8 60KW enclosure. sand -blast $2,000 (and with 154 running hours) enclosure and paint. RAS I WAS Pump Defective lighting and no seismic Replace lighting 9 Room restraints fixtures; $2,000 Install cover on pull box next to VFD. add conduit's restraints $2,500 10 Laboratory Room Defective lighting lamps Replace lighting bulbs $100 No lighting for night observations or Add about 6 ten feet 11 Aeration Basins operations light poles $7,000 Appears in satisfactory average 12 Effluent Pumps Pit condition No action NIA I Chlorine Contact No lighting for night observations or Add about 2 ten feet 13 Basin operations light poles $3,000 Grit Chamber Motor, pull boxes and conduits 14 Equipment w/severe corrosion Replace entire structure $(3) Storm Water Lift Provide conduit for 15 Station Float switch wiring exposed protection $1 Lighting Pole near No handhole cover and partial 16 PG&E damage Add cover F:\Finat�PismoSch_FN014636AOO1tM1TMO2.wpd 2-2 '1 Table 2.1 Immediate Improvements for Electrical Facilities Technical Memorandum No. 2 Area / Item Description Observations') Recommendationm Cost Belt Filter Press Fair working condition. Defective 17 MCC lamps Replace lighting bulbs $100 Belt Filter Press Polymer Feed Pump wlsevere 18 Room corrosion Replace entire unit $(3) Some lighting fixtures not working Replace lighting fixtures $1,500 Additional electrical New motor starters and wiring 19 loads required New work as needed $(3) Relocation of Office Additional non -electrical items 20 from violates the Code. Construct new Office $(3) Electrical Room 21 Miscellaneous Miscellaneous Improvements Miscellaneous Electrical $1,250 Improvements Subtotal Improvements $30,000 to Electrical Facilities Notes: 1. The recommendations are based on understanding that the maximum additional load will not exceed 100 HP, during next five to six years 2. Assessment of existing electrical systems for reliable functionality from year 2000 to year 2006. 3. See Table 1.2 of Wastewater Treatment Master Plan for other immediate improvement recommendations. Long Term Improvements • The main utility service for the proposed facilities will remain at 480 volt level, and the existing transformer capacity shall be evaluated in the design phase after further analysis of the new additional electrical loads. The construction budget shall include the charges for the Electrical Utility (PG&E) to provide a new electrical service to the plant. The existing main service switchboard does not have spare capacity to supply additional power to numerous electrical equipment associated with the plant upgrade. • A new 480 volt power distribution system will be required and it will consist of a new service switchboard, to feed the existing motor control center (MCC) as well as additional MCCs. i The existing standby 480 volt diesel engine -generators do not have substantial spare capacity to power additional electrical loads. Y F:\Final\PjsmoBch-FNO1483aAM\TKTMM.vjpd 2-3 1 T Voltage Metal Enclosed Switchboard r Low voltage switchboard with insulated case circuit breakers (Cutler -Hammer type SPB and GE type Power Break) are available for low voltage distribution system. Each switchboard will consist of the required number of vertical sections bolted together to form a rigid assembly. All bus bars will be tin-plated copper and sizing will be based on ANSI standard temperature rise criteria of 65 deg.0 over a 40 deg.0 ambient outside the enclosure. A copper ground bus will be specified firmly secured to each vertical section structure and will be extended entire length of the switchboard. All hardware used will be high tensile strength and zinc plated. Each low -voltage power air circuit breaker will be specified with a solid state tripping system. The trip unit shall use microprocessor based technology to provide the basic adjustable time - current protection functions. Motor Control Centers Motor control centers provide the best method for grouping motor control, associated control, and the distribution equipment. Motor control centers will be specified according to the type of starters used ( electro mechanical or solid-state). All motor control centers will be indoor, NEMA type 1 gasketed or type 12. Adequate space for conduit and wiring to enter the top or bottom will be provided without structure interference. IJ Draw -out units will be secure by a spring -loaded quarter turn indicating type fastening device located at the top front of the unit. Wiring will be NEMA Class II, Type B to simplify the connection of field wiring and reduce the construction cost. Each motor control center will contain a main horizontal copper tin-plated bus and each vertical section shall contain a vertical bus of minimum rating of 300 amperes for front mounted units and 600 amperes for back to back mounted units. Each vertical bus will be copper and shall be securely bolted to the horizontal main bus. Low Voltage Panelboards • } Two types of panelboards will be specified: lighting -and appliances panelboards and distribution power panelboards. Panelboards cabinets will be of code gauge galvanized steel, with hinged doors that will allow complete access to wiring without the removal of large bolts and heavy covers. All panelboards will have copper bus with bolt -on molded case circuit breakers. Also, the panels will be fully rated to withstand potential short circuit currents. ` H;%4836AOO\1U'rMO2.wpd 2-3 A new standby 480 volt diesel engine -generator will be required to power substantial new l loads, as well as the existing larger generator should remain supplying standby power to existing equipment. • The existing MCCs do not have ample spaces or substantial spare capacity to install j additional motor starters. However, these MCCs are in good condition to remain supplying power to existing equipment. Additional new motor control centers will be required for areas of substantial new process l loads. k • The existing process equipment is monitored by a lamp type annunciator panel with chart t recorders located in existing main electrical room of the aeration blower building. This panel is not in working condition and it is obsolete. It should be replaced with a new modern type of automation system that provides better means for staff to monitor and 1 control the plant. a • The electrical switchboards, MCCs and generators should be connected to a new Plant Supervisory Control and Data Acquisition (SCADA) system for the purpose of monitoring J energy consumption, status of equipment and process control. • A new Plant Control Room should be constructed to facilitate a clean and noise free space, 1 for the installation of proposed new modern Control and Data Acquisition (SCADA) system. l 3.0 EVALUATION OF EXISTING POWER DISTRIBUTION SYSTEM The existing main switchboard was manufactured by Square D Company and it is rated 3 phase, 480 volt, and with 600 amperes main circuit breaker. Also, two existing MCCs are located adjacent to the main switchboard and they are rated 480 volt, 600 amperes. The switchboard and MCCs do not have available substantial spare capacity or adequate space for additional circuit breakers. However, this existing equipment is in fair condition to remain supplying power to existing equipment. The electrical utility meter section should be disconnected and provided in new proposed switchboard. JAn existing automatic transfer switch is located within the main switchboard for the operation of standby generator power. The transfer switch appears in fair condition and it may be acceptable for future use. However, the estimated electrical new loads associated with the plant expansion will required a second automatic transfer switch. • An existing control panel for the effluent pumps contains two variable speed drives, which are old technology. The entire control panel has inconvenient and obsolete controls which should be replaced with up-to-date equipment. • At the Belt Filter Press Building, there is an existing MCC which appears in fair condition and it would be acceptable to continue being used. • For the Digester No. 2 Project, a motor control center was provided in 1998 and it is in excellent condition for future use. 4.0 STANDBY POWER GENERATORS • There are two existing standby generators that supply power to different loads. The larger generator is rated for 250 KW, 480 volt, 375 amperes and it is interconnected with the main F;\Final\PismoBch_FNO\4836A401TKTMO2.wpd 2-4 switchboard via an automatic 600 amperes transfer switch. This generator appears in fair condition and it has approximately 410 hours of operation. The second smaller generator is rated 60 KW, 480 volt and it supplies standby power only to the effluent pumps. This smaller generator will not have sufficient capacity for the size of the new effluent pumps i and additional new loads, hence it should be removed. • A new standby power generator will be required for the numerous additional new loads. The exact size will be determine upon further definition of the new process loads during the j design phase. 5.0 PROPOSED POWER DISTRIBUTION SYSTEM The design of the new facilities should include an approach that best fits the following overall goals: safety, minimum initial investment, maximum flexibility, equipment efficiency, minimum maintenance and maximum power reliability. The subsequent subsections identify alternate options and provide recommendations for the power distribution system. Voltage Metal Enclosed Switchboard Low voltage switchboard with insulated case circuit breakers (Cutler -Hammer type SPB and GE type Power Break) are available for low voltage distribution system. Each switchboard will consist of the required number of vertical sections bolted together to form a rigid assembly. All bus bars will be tin-plated copper and sizing will be based on ANSI standard temperature rise criteria of 65 deg.0 over a 40 deg.0 ambient outside the enclosure. A copper ground bus will be specified firmly secured to each vertical section structure and will be extended entire length of the switchboard. All hardware used will be high tensile strength and zinc plated. Each low -voltage power air circuit breaker will be specified with a solid state tripping system. The trip unit shall use microprocessor based technology to provide the basic adjustable time - current protection functions. Motor Control Centers Motor control centers provide the best method for grouping motor control, associated control, and the distribution equipment. Motor control centers will be specified according to the type of starters used ( electro mechanical or solid-state ). All motor control centers will be indoor, NEMA type 1 gasketed or type 12. Adequate space for conduit and wiring to enter the top or bottom will be provided without structure interference. Draw -out units will be secure by a spring -loaded quarter turn indicating type fastening device I located at the top front of the unit. Wiring will be NEMA Class 11, Type B to simplify the J connection of field wiring and reduce the construction cost. } F:1FinallPismoBch_FNO\4836AOOITM\TMO2.wpd 2-5 Each motor control center will contain a main horizontal copper tin-plated bus and each vertical section shall contain a vertical bus of minimum rating of 300 amperes for front mounted units and 600 amperes for back to back mounted units. Each vertical bus will be copper and shall be securely bolted to the horizontal main bus. Low Voltage Panelboards Two types of panelboards will be specified: fighting and appliances panelboards and distribution power panelboards. Panelboards cabinets will be of code gauge galvanized steel, with hinged doors that will allow complete access to wiring without the removal of large bolts and heavy covers. All panelboards will have copper bus with bolt -on molded case circuit breakers. Also, the panels will be fully rated to withstand potential short circuit currents. Variable Speed Control Devices The most convenient and efficient equipment specified for speed control of motors is the variable frequency drive (VFD). However, there are some inconveniences with the use of this equipment, because the rectifier section of this equipment switches or pulses the power supply, causing the current to vary widely from a sinusoidal wave shape. These type of currents are high in harmonics and their rms value is not easy to calculate. Additionally, there will be electrical devices within the plant that measure time on the basis of wave shape, such as the standby generators. Other numerous problems with harmonics is that the internal timing clocks of electronic instruments or computers may fail and potentially these could cause instruments or computers failures, plus power distribution transformers may overheat. There are a few VFD manufactures producing equipment with 18 pulse technology which produces very small amounts of harmonics; unfortunately this equipment is only economically feasible for ratings larger than 75 HP. VFD equipment rated less than 75 HP is manufactured with 6 pulse technology and the operation of multiple small VFD units produce a combined substantial quantity of harmonics. To minimize the current distortion and voltage distortion caused by VFDs, the optimum design approach is to select VFD equipment that produce minimum harmonics. Therefore, 18 pulse technology will be specified for VFDs larger than 75 HP and standard small VFDs will be specified for smaller equipment. 6.0 POWER MONITORING AND METERING DEVICES The reliability of the power distribution system depends of many operating factors as well as maintenance requirements. Additionally, the rising cost of energy and the need to operate and JF:IFinailPismo9ch_FNO\4836AOO1TMXTMO2.wpd 2-6 maintain more equipment with less staff creates the requirement for quick information available in real time to the plant staff. The 480 volt switchboard and motor control centers will be specified with an electronic monitoring and metering device, which has graphic display of real and reactive power, current, voltage, frequency, power factor, percentage of total harmonics distortion, minimum and maximum trend analysis. It will also include communications capability to interface with PLCs of the SCADA or DCS system. 7.0 ELECTRICAL DESIGN STANDARDS Electrical design documents will conform to the latest editions of the national and local codes. Where the requirements of more than one code or standard are applicable, the more restrictive will govern. Application of Conduit and Wiring Materials. • Galvanized rigid steel: exposed In indoor dry locations and no -corrosive areas. • PVC coated rigid steel: exposed outdoor locations, wet indoor locations, entering and exiting concrete slabs, in corrosive areas designated Nema 4X. PVC rigid non-metallic schedule 40: encased in concrete ductbanks. • Liquid tight flexible conduit: for termination of motorized equipment. • Electrical metallic tubing: In drop ceilings and partitions of administrative buildings. Conductors will be copper only and material application will be as follows: • Power 600 volt cables will be type XHHW, cross -linked (vulcanized) polyethylene insulation, resistant to weather and most chemicals. • Lighting, Receptacles and control cables for less than 600 volts will be type THWN. • Multiconductor power and control cables will be type THWN with overall PVC jacket. • Instrumentation conductors will be minimum size 18 AWG, copper with PVC insulation, shielded and flame-retardant PVC external jacket. • Communication conductors will copper or fiber optic type with adequate insulation, shielding and jackets for the application. Enclosures for Corrosive and Hazardous Locations Electrical equipments, enclosures, and wiring materials installed in corrosive locations shall be NEMA Type 4X and in hazardous locations shall be suitable for the specific type of hazardous atmosphere present. Special considerations shall be given to locating equipments indoors and away from hazardous areas. Apparatus for outdoor mounting shall be weatherproof, preferable NEMA Type 4X. Most small boxes for conduits located outdoor and in corrosive locations will be specified with PVC coatings. Metallic pull or terminal boxes will be specified of 316 stainless steel material. F:\Final�PismoBch_FNOk48WAOOUMITMO2.wpd 2-7 Underground Duct banks All 480 volts main feeders will be installed in duct banks. Special consideration will be given for future growth during final design. Duct banks and manholes will have specifications requirements for water stops, grouting, automatic sump pumps and extra sealing to prevent water entry. Common duct banks in joint trench with separate manholes will be design to separate power and communication wiring systems. ;-1 F:\FinagPismoBch_FNO14836AOC\TM\TMO2.wpd 2-8 IAPPENDIX F KENNEDYNENKS CONSULTANTS' DRAFT WASTEWATER r� TREATMENT CAPACITY STUDY H:\FinagPismoBch_FNO\4836AODIRpt1APP,WPD Kennedy/Jenks Consultants 8 October 1999 Mr. David L. Stringfield, P.E. Principal Carollo Engineers 7580 North Ingram Ave., Suite 112 Fresno, CA 93711 Subject: Pismo Beach Wastewater Treatment Plant Capacity Study K/J 995037.00 Dear Dave: Engineers & Scientists 2191 East Bayshore Road Suite 200 Palo Alto, California 94303 650-852.2800 FAX 650-856-8527 As discussed during our recent telephone conversation, 1 am finishing up our Pismo Beach work related to wastewater treatment plant capacity. As you know, this has involved a "Peer Review' of your draft of July 1999. Basically, our review has focused on the issue of current treatment plant capacity. As agreed with Dennis ❑elzeit, we felt there would not be reason for us to review the subject of projections and alternatives for meeting wastewater treatment needs associated with these projections. I am enclosing a copy of the draft of our review which I believe contains an elaboration of essentially the same information which I discussed by phone. While we can agree to disagree on some of the matters reviewed, I feel it would be most helpful for you to review the enclosed and if you care to provide us with comments to the end of making our work as factual as we can prior to submitting to the City in final form. I have sent to the City a copy of the same material and with the same request for comment and any suggested changes. Thanks for the information you previously sent to me Dave and your time spent during telephone conversations. This effort has been helpful and anything more you can do by way of further comments will be appreciated. Very truly yours, KENNEDY/JENKS CONSULTANTS Jo H. Jenks Senior Consultant enc. cc: City of Pismo Beach, Mr. Delzeit DRAFT REVIEW OF (DRAFT) MASTER PLAN FOR WASTEWATER TREATMENT AND DISPOSAL 1 November 1999 K/J 995037.00 REVIEW OF JULY 1999 DRAFT REPORT —WASTEWATER TREATMENT PLANT ;. City of Pismo Beach CA Background The City of Pismo Beach received a draft Report, dated July 1999, "Wastewater Treatment Plant and Collection System Master Plans." This report was prepared by Carollo Engineers with John L. Wallace & Associates assisting in preparation of that portion of the studies and report relating to collection system analysis. It is important to note it was appropriate for the City to take initiative in having a study done in order to anticipate wastewater collection, treatment and disposal needs associated with increased City development consistent with the City's General Plan. In fact, the General Conditions which are part of the State and Federal waste discharge requirements specifically mandates that a wastewater discharger anticipate well in advance of actual needs to accommodate increased wastewater volume so that meeting of requirements are uninterrupted. The Carollo draft report summarized their studies related to the City's existing wastewater treatment plant for the purpose of determining plant needs in respect to current and projected wastewater flows. The studies investigated alternatives for meeting of projected City "build -out" needs defined as treatment plant flow capacity for 2.0 million gallons per day (mgd). In addition, the Carollo draft report identifies existing treatment plant capacity as being for 1.3 mgd whereas the waste discharge requirements from the Regional Water Quality Control Board identify the Pismo Beach wastewater treatment plant capacity as being 1.75 mgd. The Carollo recommendations for meeting of projected treatment plant "build -out" flow capacity needs of 2.0 mgd is for the City essentially to abandon the existing wastewater treatment plant and to construct a new plant to at the same site at an estimated cost of $ 8.33 million. Carollo also offers a series of interim steps which could be taken as a means to increase current capacity from 1.3 mgd to 1.4 mgd. After presentation of the Carollo draft report during July of 1999, the City staff along with City Council understandably became concerned regarding both the stated wastewater flow capacity limitations of the existing wastewater treatment plant and costs estimated for providing needed increased "build -out" capacity. This concern as to current flow capacity limitation in particular was of near term major significance since existing wastewater flows are approaching the 1.3 mgd assumed limiting figure. It was understood that continuing to accept additional connections to the sewer system as a result of planned growth could soon result in flows in excess of the 1.3 mgd amount. To further complicate this matter, it is recognized that any major expansion to provide additional wastewater treatment capacity will take at least three years to accomplish. The foregoing factors led to a desire on the part of the City to, 1) review the basis and validity for concluding that existing capacity of the City's wastewater treatment plant is actually 1.3 mgd and 2) determine if an alternative which would involve some form of consolidation with use of South San Luis Obispo County Sanitation District's wastewater treatment plant should be considered further? To assist in this review of current wastewater treatment plant capacity and study of a consolidation alternative, the City engaged the independent services of Kennedy/Jenks Consultants. Kennedy/Jenks Consultants were the design engineers on the original Pismo Beach wastewater treatment plant in 1953 and since 1919 has had a major focus on the c.5 hj d=%pismo5.doc - 1 - r� planning and design of water and wastewater treatment facilities including those for South San Luis Obispo County Sanitation District. Carollo Engineers agreed to having a "peer review" of their draft report referenced above and specifically limited to the two areas of City interest noted j above. Again it is noted that the K/J review and studies have not included evaluation of the j Carollo alternatives and recommendations for meeting of "build -out" needs. CAPACITY ISSUE In this review, it is important to make the distinction between "existing plant capacity" and "projected capacity needs." The Corollo study and draft report is centered on identifying and evaluating alternatives for meeting of projected future capacity needs (2.0 mgd). In reviewing the Carollo report and discussing the matter with Carollo staff, it is apparent that the identified 1.3 mgd existing plant capacity assessment is based both on Carollo experience and on past assessments by one of two other engineering firms. Information in this regard was obtained through two prior studies summarized in available documents: • "Final Report— Recommendations for Pismo Beach Wastewater Treatment Plant Upgrade and Expansion" dated August 1984 and prepared by ES Environmental Services. • Letter report to Mr. James Ashcraft DPW City of Pismo Beach under the date March 20, 1991 by Brown and Caldwell Consultants, "City of Pismo Beach Wastewater Treatment Plant Liquid Stream Hydraulic Capacity Evaluation." The ES report was written ahead of and served as the basis for the mid-1980s major plant expansion. This 1984 study and report identified then plant design capacity as being 1.2-1.3 mgd. It was suggested that this capacity could be increased to 1.45 mgd in the event that use of chemicals was initiated. The ES report recommended two successive phases of plant expansion. The first phase expansion was subsequently constructed including a third aeration tank, dissolved air flotation for sludge thickening ahead of digestion and a belt filter press for digested sludge dewatering. With completion of these enlargements, the stated overall plant flow capacity was shown as 1.75 mgd on a peak flow basis. The ES report is unclear as to what assumptions were made as to average dry -weather flow capacity with completion of the enlargements, but it appears that the ES assumption was in the range of 1.5-1.65 mgd. It would be assumed then that the Pismo Beach wastewater treatment plant as it is today, incorporating the enlargements recommended by ES in 1984 as it does, the ES assessment is that plant capacity is for at least 1.5 mgd average dry -weather flow and 1.75 mgd on a wet - weather flow basis. Additional capacity apparently was conditioned upon also providing for more digester capacity which in 1998 was provided. The Brown & Caldwell study concluded that the existing wastewater treatment plant capacity was 1.3 mgd based primarily on an analysis of hydraulic limitations, particularly of the primary clarifiers and organic loading capacity of the aeration tanks. The Carollo report reflects results of the Brown and Caldwell study assigning a plant flow capacity of 1.3 mgd based primarily on evaluation against typical design criteria for each individual process element as well as assessment of physical condition. It is significant to observe that neither the Brown & Caldwell or Carollo studies used actual } results of operation as a means of verifying ability of the treatment plant to meet requirements as against "textbook" and internal company criteria evaluations. Ii c:l hj dom%pismo$, doc - 2 - Waste Discharge Requirements Results of the City's wastewater treatment plant operations are regulated by waste discharge requirements promulgated by the State of California and Federal EPA. Current requirements for the Pismo Beach treated wastewater discharge are contained in Order No 99-31 of the rl California Regional Water Quality Control Board (RWQCB), Central Coast Region which also I serves as Federal EPA requirements, NPDES Permit No, CA 0048151. Thus the requirements have the authority of both State and Federal law. In respect to wastewater flow capacity limitation, Order No. 99-31 lists in the "Findings" section, "The treatment facility's average dry weather flow design capacity is 1.75 mgd." Then, under the heading of "Effluent Limitations," there is the statement, "Effluent daily dry weather flow shall not exceed a monthly average of 1.75 mgd " Discussion with staff of the RWQCB, indicates that it is unclear as to where this capacity figure originated. It seems probable that the 1.75 mgd figure came from the 1984 ES engineering study which identified this number as a peak flow limitation. In any case, the only significance which this figure may have in respect to current studies would be that as long as other requirements are being met, such as for residual constituent concentrations in plant effluent as being discharged to the receiving waters, the RWQCB would have no clear regulatory authority to use a lower capacity figure than 1.75 mgd as the basis for enforcement actions such as limiting further connections to the City's sewerage system. The requirements set forth in RWQCB Order No. 99-31 are extensive and cover a long list of effluent constituent limitations directed towards protection of both the marine aquatic life and human health within the affected receiving waters of the Pacific Ocean. Those constituent requirements, which relate to basic ability of the wastewater treatment plant to provide that needed level of treatment prior to discharge, are to be seen primarily in the limitations on biochemical oxygen demand (BOD), and suspended solids (30/30 mg/1). Other indicators of plant performance, grease and oil, settleable solids, turbidity, acute toxicity and fecal coliform are generally seen to follow the meeting of BOD and suspended solids limitations. In viewing reported results of operation of the Pismo Beach treatment plant, this conclusion is validated. Thus, for purposes of present studies, the capacity evaluation is based primarily on ability of existing plant to consistently meet waste discharge requirement limitations for suspended solids as being the best single indicator of treatment effectiveness. In further regard to waste discharge limitations, it is helpful to understand that for the key factors of BOD and suspended solids, as well as for other constituents, the limitations are identified in respect to segments of time. That is, the requirement for BOD and suspended solids is for "Monthly (30-Day) average not to exceed 30 mgll." Similarly, the BOD and suspended solids identify a figure of 45 mg/1 to be achieved on a weekly, 7-day average basis and a daily maximum of 90 mg/I. The significance of the foregoing is that no violation of requirements exist unless any one of the three limitations related to time are violated. For any seven day period the BOD and suspended solids can reach 45 mg1I as long as the 30-day average of 30 mg/I and daily maximum of 90 mg/I are met during the same period of 30-days. The primary reason for waste discharge requirements having this varying scale is in recognition of the fact that circumstances, such as a very high flow condition related to heavy storms can exist for short periods and impair treatment plant operation for a limited time while over 30-days, plant c 5jhj d=Xpismo5.doc - 3 - performance may be entirely acceptable and reflected by a 30-day average constituent concentration within the 30-day limits. 71 The foregoing is the basis for understanding that responsible engineering practice normally is to design on the basis of "average dry -weather flow" needs as long as there is expectation that higher flow conditions are typical of that which would be expected . This is reflected further in most waste discharge requirements which, as in the case of Pismo Beach, are identified on the basis of "average dry -weather flow' (ADWF). ADWF is usually assumed to cover the months (in California) of between May and October. In the case of Pismo Beach however, it is seen that other than typical wastewater flow conditions exist as a result of, 1) influx of non-resident r population during summer months (July and August) and, 2) peak flow conditions occasioned during winter months by high rainfall precipitation. It is prudent therefore to judge adequacy of the Pismo Beach wastewater treatment plant to meet design objectives as defined by those conditions existing during the peak dry -weather flow months of July and August with usual consideration of hydraulic needs associated with peak flow conditions occurring during winter months. Actual Results Vs. Waste Discharge Requirements Limitations As observed above, the Carollo and earlier Brown & Caldwell studies relating to an assessment of flow capacity of the Pismo Beach wastewater treatment plant are based primarily on evidence other than actual results obtained during different loading conditions. In this regard then, it is of particular significance to further observe that during recent years there is essentially no history of non-compliance with waste discharge requirements of the State and EPA. The City is required to submit monthly and annual reports to the Regional Water Quality Control Board, which reports serve to document results of operation, particularly concentrations of specific constituents against requirements. As noted above, for purposes of present studies, it has been appropriate to view historical records of actual plant operation during the months of July and August even though the waste discharge requirements are based on "average dry -weather flows" which could be considered to include the months of from April through October. Again, it is appropriate to base any evaluation of performance or needs on conditions of wastewater flows during these two months separately as representing "worst case." To further demonstrate the significance of evaluating existing plant capacity from actual results as against computed results, the following summary of monthly averages during ""worst case" dry -weather months of July and August for the past three years is presented: Dates Julyl97 Aug.197 July198 Aug.198 Jul.199 Augl99 Avg. Flows, m d 1.14 1.17 1.26 1.24 1.20 1.15 Effl. SS, m 11 13 8 9 8 14 12 Similarly, the following summary of monthly averages during "worst case" wet -weather months of January and February for the past three years is presented: Dates JanJ97 Feb.197 Jan.I98 Feb.198 Jan.199 F'eb.199 Avg. Flows, mgd 1.35 1.06 1.11 1.60 1.00 1.04 Eff1. SS, mgll 16 15 13. 21 12 10 c l hi domkpismo5. doc - 4 - In viewing the treatment plant effluent results summarized above it is observed again that the waste discharge requirements are to have a residual suspended solids (SS) concentration of less than 30 mg/l. r In addition to the foregoing documentation of results seen during two full month segments of winter and "worst condition" summer flows are results obtained during a peak full month period of February 1998. Presumably as a result of exceptionally high flows occasioned by El Nino rains, average wastewater flow for the entire month was 1.60 mgd, some 23% higher flows than the 1.3 mgd limiting capacity shown through prior studies. Along with the 1.60 mgd sustained peak flow for the month ias shown that effluent suspended solids averaged 21 mg/1, again well below the 30 mg/l limit. From the foregoing summaries, certain observations can be made: • Actual results clearly show that the existing wastewater treatment plant is providing excellent results and well within waste discharge requirements for suspended solids of not more than 30 mgll. • The existing Pismo Beach wastewater treatment plant clearly has a firm capacity to meet waste discharge requirements of more than 1.3 mgd. • Plant operation and management may be more significant to results within limits of flow rates experienced through the treatment plant. In further regard to the matter of actual results in comparison with waste discharge requirement it is appropriate to review the second basic parameter indicating plant effectiveness, biochemical oxygen demand (BOD). With the exception of one month during 1998 and two lmonths during 1999, the BOD results reported were all within the 30 mgll waste discharge limit. J However, in the K/J review of reported results, it became immediately apparent that reported BOD results were suspect. This was obvious from the fact that essentially all BOD concentrations were shown as being higher, sometimes two or three times higher, than suspended solids concentrations. Typically it is seen with results from a standard activated sludge process such as at Pismo Beach, suspended solids are most often about the same, or higher than BOD concentrations found in plant effluent. A second observable condition was the reported presence of nitrite and low ammonia residuals in plant effluent, are sure indicators of nitrification occurring as part of the activated sludge process. To verify this condition, parallel samples were tested for BOD, one sample for total BOD (TBOD) and the other for carbonaceous BOD (CBOD). Results of this testing during a limited four weeks showed an average TBOD of 14 mg/I and CBOD of 4 mg/l, typical of a partially nitrified effluent. The significance of the foregoing is that the BOD test is basically for the determining biochemical degradation of carbonaceous material during a 5-day period of incubation. However, if a sample contains forms of nitrogen along with presence of nitrifying bacteria, a TBOD test will not differentiate between carbonaceous and nitrogenous demand, but will include both thus precluding a true assessment of the oxygen demand associated with organic material, the basic objective for evaluating secondary treatment plant performance and meeting of requirements. To obtain the CBOD from a nitrifying treatment plant effluent, it is necessary to utilize inhibiting reagents in the test. Recognizing this, when a treatment plant operation results in a partially nitrified plant effluent as is seen to be the case at Pismo Beach, regulating authorities will accept CBOD (sometimes with a lower limit of 25 mg/1) rather than TBOD results as part of the monitoring program requirements. As an alternative, nitrification and its potential consequences in respect to BOD determination, can be controlled through operating techniques. Reducing the amount of solids under aeration along with reduction of available C 5jhi domkpismo5.doe - 5 - oxygen can assist in inhibiting nitrification which is not called for or needed with the Pismo i Beach treated wastewater discharge to the ocean.. It is further noted that the disparity between TBOD and CBOD results will vary during the year as nitrification varies depending upon loading, available oxygen and temperature in particular. One of the interesting observations which can be made in respect to the Pismo Beach plant operation is the fact that nitrification is occurring serves to demonstrate an excess in capacity of the aeration tanks as well as adequacy of air being supplied. This is further seen from the knowledge that under current flow conditions, aeration tank detention time is some 8 hours, about double that which would be considered necessary for obtaining plant effluents to meet a requirement for BOD of less than 30 mg/I. In any case, the above is presented by way of explanation as to wily the present studies as to effectiveness of treatment plant operation has been centered upon removal of suspended solids and concentrations in plant effluent. It may be assumed that actual CBOD, if tested for in the past, would be seen by concentrations of about, or somewhat less than suspended 4 solids concentrations and well within requirements. This conclusion can and should be verified through testing of parallel samples over a period of time. Alternative Approaches to Capacity Determination As noted hereinbefore, the prior studies summarized in the report and letter referenced above each provided an evaluation of wastewater flow capacity primarily utilizing the approach of identifying a list of textbook criteria (or in the case of Carollo, "Carollo utilized criteria") and then compared each process element of the treatment plant against these criteria. Essentially this approach supposes that whatever process unit is shown by textbook design criteria to have the least capacity, this figure then becomes the overall treatment plant limiting capacity. This is inherently a very conservative approach although in the case of an entirely new wastewater treatment plant is an approach which may be appropriate. However, for the case of an existing treatment plant which has had a series of improvements added over the years, the "textbook" basis for evaluation can lead to an unrealistic assessment, This is particularly true when there are historic records of actual results available for use as verification, as is the case of the Pismo Beach wastewater treatment plant results as discussed above. Also, it should be understood that textbook design criteria usually covers a range of values. For instance in the case of primary clarifier overflow rates, listed values are generally between 800 gpd/sf and 1,200 gpd/sf (gallons per day per square foot of surface area). In the case of conventional activated sludge aeration basins (as at Pismo Beach plant), food to y microorganism ratios (f:m) are generally shown in the textbooks as being from 0.2 to 0.4 and BOD loading suggested to be between 20 — 40 Ibs BOD/day/1,000 cf. In giving these ranges, it is expected that the design engineer will give appropriate consideration to other factors surrounding the particular process unit being considered and in particular relating to waste discharge objectives and requirements. If waste discharge requirements call for a limiting residual BOD of 20 mg/l, a f:m ratio of 0.2 and a BOD loading of 20 lbs BOD/day/1,000 cf might. be utilized for aeration tanks design. On the other hand, if the requirement is for a BOD residual of 30 mg/l, an f:m ratio of 0.4 might be utilized for design and aeration tank loading of 40 Ibs BOD/day/1,000 cf. In the case of primary clarifiers, higher loadings can be tolerated if accounted for in the design of downstream units. Similarly, in the case of aeration tanks, detention time and BOD loading per unit of volume can be tempered by use of higher mixed E liquor solids concentration and more air volume. An example of this is to be found in the case J of so called "high purity oxygen" systems where the detention time for aeration can be one-half that of conventional activated sludge basins. c l hi doWpwnoS.doc -6- �4 :1 In any case, for purposes of the studies summarized herein, it has been appropriate to undertake the capacity of the Pismo Beach wastewater treatment plant on the basis of, 1) evaluating capacities of each process unit against reasonably accepted textbook criteria and then, 2) testing the conclusions of this evaluation against the record of actual plant performance. UNIT PROCESS CAPACITIES In reviewing the Carollo assessment of unit process capacities, again a distinction needs to be made in respect to "current and near term" and "projected future" needs. This distinction is not clearly made in the Carollo draft report. Basically, the K/J assessment of unit process capacities has been centered on current and near term capacities assuming that there will be a need to satisfactorily accommodate normal increases in near -term wastewater flows during the next, say three years before any major plant improvements can be made to meet "build out" capacity needs. Headworks This facility was constructed during the 1970's and includes the aerated grit chamber and manuallly cleaned bar screen. The Carollo study called for replacement of this unit on the basis of poor condition of the structure, mechanical and electrical work. In addition, the grit chamber was judged to be inadequate in size on the basis of providing insufficient detention time, defined as less than 3 minutes, under peak flow conditions. This same conclusion in respect to flow capacity was reported in the Brown and Caldwell 1991 letter. K/J Assessment Our site inspection of the headworks facilities did not reveal major structural deterioration, except in isolated locations around the air piping, but did confirm some poor condition of mechanical equipment, pipework etc.. It is to be understood that the primary function of the existing headworks is for grit removal and capacity is basically related to detention time. It is to be remembered however, that the Pismo Beach wastewater treatment plant operated for more than 20 years with no grit removal unit. The primary purpose of removing a portion of grit at the head -end of the treatment plant is to delay cleaning of the digester(s) of accumulated grit and to reduce excessive wear on sludge pumps and pipework. It is concluded that existing headworks facilities are currently in some need of equipment and minor concrete rehabilitation. Actual flow capacity of the headworks cannot be really ascertained in the absence of incoming flow metering. Empirically it is seen that, with whatever limitations, the headworks does not cause an inability of the treatment plant to meet waste discharge requirements. In any case, effectiveness of the existing headworks does not affect the current or near term overall flow capacity of existing plant to meet waste discharge requirements. Primary Clarifiers There are two primary clarifiers. One of these clarifiers was included in the original treatment plant while the other was constructed within an original mixing tank as part of a subsequent plant enlargement. As part of this same enlargement, the second mixing tank was converted to a secondary clarifier. It is apparent that when this plant enlargement was undertaken and the c yhj d=%p,vno5 doc - 7 - first two aeration tanks were constructed downstream from the primary clarifiers, available static head was limited by the water level elevation of the then existing secondary clarifiers downstream from the primaries. This condition accounts for a significant hydraulic capacity limitation which is evidenced by submergence of primary clarifier weirs when flow rates exceed about 1.3 mgd flow rate, a condition which occurs regularly each day during times of peak flows. The Carollo study called for abandonment of the two primary clarifiers on the basis of, 1) surface overflow rates (SORB) being "much higher than desired and not acceptable," (Carollo proposed to utilize an SOR of 420 gpd/sf, a figure well below the lowest textbook value of 800 gpolsf as the design basis for primary clarifiers as part of their Alternative A expansion project), 2) being in "marginal structural condition and over 44 years old," and 3) poor mechanical and electrical condition. K/J Assessment On site inspection of the primary clarifiers did not reveal major structure deterioration. A separate structural analysis was made using the original plans for the 1953 project. This analysis revealed sufficient reinforcing steel which probably would meet today's Code for seismic regulations for new structures. K/J's experience indicates that even in the presence of some corrosive environment it would not be expected that structures such as the Pismo Beach primary clarifiers would call for abandonment in the near future because of age. Numerous wastewater treatment plants designed by K/J located in the San Francisco Bay area were constructed during the 1930's, survived without difficulty several earthquakes (including the 1989 Loma Pierta quake) and process units from that time period are still in service today as part of expanded wastewater treatment facilities. Aside from the needs relating to mechanical and electrical equipment condition, K/J does not believe that it would be justified to abandon the primary clarifiers simply because of an assumed structural deficiency based on age. In respect to higher than textbook values for surface overflow rate (Carollo recommends 420 gallons per square foot per day (gpd/sf) while Brown and Caldwell recommend 1,000 gpd/sf), it should be understood that textbook criteria are based on obtaining most efficient operation, but do not account for subsequent, downstream process elements. And, in fact, Carollo demonstrates this understanding when noting that their recommended oxidation ditch project for meeting of "build out' needs does not include any primary clarifiers, the added solids and biochemical oxygen demand in the feed being accounted for in the sizing of the oxidation ditch and following secondary clarifiers. This is further demonstrated when reviewing actual results of plant operation. Going back to the very high wintertime flows experienced during February of 1998 it is shown that the average daily wastewater flows during this month was 1.60 mgd. The corresponding average day primary clarifier overflow rates (SOR) during these two months then was 1,133 gpd/sf and peak day SOR of over 2,000 gpd/sf. Of particular significance to the point is that the average residual suspended solids in the treatment plant effluent during this high flow period was 21 mg/1 (requirement is for less than 30 mg/1). And in fact, further 4_ review of the operating results of the Pismo Beach wastewater treatment plant does not reveal any particular relationship with hydraulic loading of any process unit, including the primary clarifiers in relationship to final, actual results. Of course, this observation is limited in its application to wastewater flows within the range being experienced. In any case, given the conditions surrounding the existing primary clarifiers, it would not be unreasonable to assume a flow capacity, based on an SOR of 1,100 gpd/sf resulting in a primary clarifier element capacity of at least 1.5 mgd. Given the foregoing, while concluding that the primary clarifiers are in need of some rehabilitation and repair as well as improved hydraulics. It is further concluded that the primary clarifiers element of the treatment plant, based on both textbook analysis and c ljhj d=V sma5.doc - 8 - validated through actual results, do not impact the current, or near term overall capacity of the existing treatment plant to meet waste discharge requirements. Equalization Basin There is an equalization basin which apparently was constructed as part of a treatment plant improvement prior to 1986. This basin has a reported capacity for 365,000 gallons. The purpose for this basin may have been to equalize the flow to the aeration tanks, or to relieve some of the diurnal hydraulic overload seen in the primary clarifier launders. Current operation of this basin is to manually divert a portion of primary clarifier effluent to the basin and then pump basin contents directly to the aeration tanks, or back to the primary clarifiers during periods of lower flow. Carollo did not asses the equalization basin in the context of plant capacity. Brown and Caldwell did assign value of the equalization basin to equalize flows to the aeration tanks. KIJ Assessment It appears that the equalization basin serves an important purpose and possibly could be utilized to even better advantage, most particularly to mitigate the daily diurnal overloading of the primary clarifiers. This would require means of conveying primary clarifier effluent just below the elevation of weir flooding, directly to the basin. Another alternative would be to have the entire primary clarifier effluent go to the equalization basin on a continuous basis and then pump on a equalized flow basis to the aeration tanks consistent with maintaining a maximum - and minimum water level in the basin. The alternative of equalizing incoming flow to the plant ahead of the primary clarifier while feasible, would incur additional risk of solids deposition and consequent increased odor potential in the basin and increase the need for some form of continuous mixing. It is concluded that the existing equalization basin does and could continue to serve a significant role in the operation and effectiveness of existing plant if improved. The form of improvements should be reviewed against benefits which could be of both near term and long range. However, the effectiveness of the existing equalization pond does not directly affect the current or near term flow capacity of existing plant to meet waste discharge requirements. Aeration Tanks There are three existing aeration tanks located immediately downstream from the primary clarifiers. Plant operators have made wise use of the aeration tanks through adopting a strategy providing for a partially anoxic zone at the head end of the aeration tanks to assist in developing an activated sludge with good settling characteristics and controlling excessive build-up of biologic scum.. The Carollo study concluded that, the three existing aeration tanks "are operating at capacity with the 1998 flows and loads" The ES studies assigned aeration tank capacity at 1.5 mgd based on their mathematical modeling. The Brown & Caldwell study also assigned aeration tank capacity at 1.3 mgd based on an assumed organic loading criteria of 40 Ibslday BOD/1,000 cf. KIJ Assessment Utilizing the 1.2 mgd flow figure shown in the Carollo study draft report as the existing treatment plant design capacity, the aeration tank detention time at this flow would be some 8 hours. Then, taking the current operating condition of mixed liquor suspended solids concentration (MLSS) of 2,200 mgll and design incoming BOD of 248 mgll (174 mgll to J c yhj d=1p'SMGS.doe - 9 - aeration), the f:m ratio is about 0.2. This f:rn figures is at the bottom of textbook given criteria which shows typical aeration tank detention time criteria as being from 4 - 8 hours and f:m as being from 0.2 -- 0.4 in the design of conventional activated sludge. As previously observed, the bottom of the ranges can be assumed as typical for insuring a final effluent BOD residual in the range of 20 mg/l. In the case of Pismo Beach, the requirement for discharge is not 20 mg/l, but 30 mg/i, a significantly less rigorous design objective. Even after adding an additional - degree of conservatism, general experience would suggest that 6 hours of detention time and f:m ratio of 0.3 would be more than adequate along with appropriately sized secondary clarifiers reliably to meet a requirement of 30 mg/I BOD residual. This conclusion assumes an ._ adequate supply of air to support biologic oxidation with a higher than present loading, but supplying additional oxygen would be a relatively easy accomplishment either by simply providing added air supply if the diffusers can accept an increase, or providing more air with additional or modified diffusers and blower. A still further alternative would be to operate at a r lower MLSS which, while increasing the f:m value somewhat, would also serve to reduce the amount of oxygen currently being consumed in the process of unneeded nitrification. As verification of aeration tank capacity, appeal is made to actual high loading results during the peak 1998 wastewater flows. As indicated previously, during the months of February 1998, average flow for these month was 1.60 mgd. This flow rate resulted in an average detention time within the aeration tanks of 6 hours. To calculate the actual f:m ratio shown to be sustainable, reference is made to the highest loading during July and August of 1998 when average incoming BOD was highest averaging 383 mg/I with presumably about 287 mg/l SOD strength going to the aeration tanks at an average flow rate of 1.25 mgd. These loading conditions resulted in an f:m ratio of about 0.36. From the foregoing K/J textbook evaluation with verification by actual results, it is believed that the aeration tanks have a reliable capacity of at least 1.5 mgd. This figure also is consistent with the ES estimate based on their computer j analysis. It is concluded that the existing aeration tanks process element of the treatment plant, based on both textbook analysis and validated through actual results, do not directly affect the current, or near term overall capacity of the existing treatment plant to meet waste discharge requirements. - Secondary Clarifiers There are three secondary clarifiers, One of these clarifiers was part of the original treatment plant; one was later constructed within what was originally a mixing tank; the third as part of a subsequent plant enlargement. The Carollo study calls attention to, "The secondary clarifiers use scraper type mechanisms for sludge removal. A scraper mechanism is now considered inadequate for use with activated sludge processes," and "The main problem with the secondary clarifiers is that they have shallow water depths." Carollo also calls attention to poor flow distribution through the existing metal weir box. Finally, Carollo concludes that, "'Based on the age, depth and condition of the secondary clarifiers, it is recommended that they be demolished." K/J Assessment On site inspection of the secondary clarifiers did not reveal any significant structure deterioration. Also, the same comments regarding structural integrity of the primary clarifiers apply to the secondaries. K/J does not agree with the Carollo observations concerning distribution, scraper mechanisms and clarifier depths ion respect to these particular clarifiers.. The flow distribution could be improved without major expense. In respect to scraper vh, doca�.Gamo5.doc - 10 - I mechanisms for smaller sized secondary clarifiers the continuous sludge removal type of more recent mechanisms are of questionable value in respect to improved performance. A different type of spiral scraper mechanism might be considered if designed today. Also, in respect to depth, again significance is lessened with smaller clarifiers such as seen at the Pismo Beach plant. In any case, it is to be observed that these existing clarifiers, with whatever limitations there might be in respect to current design practices, nevertheless provide more than satisfactory results as have many other older secondary clarifiers elsewhere throughout the country. The Carollo design analyses of existing secondary clarifiers indicates that at the 1.2 mgd incoming flow figure used for capacity analyses, secondary clarifier surface overflow rates (SOR) are 450 gpd/sf. This figure compares with textbook design criteria for SOR of secondary clarifiers when operating downstream from an aeration tank in an activated sludge process in a range of from 400 — 800 gpd/sf. The proposed Carollo design basis for their Alternative A is seen as having an SOR of 302 gpolsf. Because of the existing secondary clarifier mechanisms and somewhat shallow depth, it would be justified to assess capacity on the basis of a lower textbook figure of SOR, say about 550 gpolsf. Looking for verification of this figure from actual results, appeal can be made again to the highest continuous flows occurring during February of 1998, namely a daily average during the entire month of 1.60 mgd. This continuous flow resulted in an average SOR of 600 gpolsf. At this SOR, average suspended solids in plant effluent was still 21 mg1I against the required less than 30 mg/l.. Based on the foregoing it would be reasonable to assume a flow capacity based on an SOR of 550 gpolsf resulting in a secondary clarifier capacity of 1.5 mgd, the same as for the primary clarifiers and the aeration tanks. Again, the 1.5 mgd secondary clarifier capacity also agrees with the ES assessment. It is concluded that the existing secondary clarifiers element of the treatment plant, based on both textbook analysis and validated through actual results, does not directly affect the current, or near term overall capacity of the existing treatment plant to meet waste discharge requirements. Chlorine Contact Basin There is a single chlorine contact basin downstream from the secondary clarifiers. Hypochlorite is used for disinfectant and bisuffite used for de -chlorination. The Carollo study concluded that the existing basin "provides an 18 minute contact time at 3.12 mgd which was the peak hour flow in 1998. However, a 30-minute contact time is required at peak hour flows. Therefore the existing chlorine contact basin is currently hydraulically inadequate." K/J Assessment While it would be desirable to have additional chlorine contact time, within obvious limits, it is accepted that higher doses of chlorine can compensate for a lesser contact time. Again, it is instructive to observe actual results against textbook based analysis. It is difficult to assess what flow capacity existing chlorine contact basin has in respect to meeting of disinfection requirements since peak flow rates are buffered by use of the equalization basin. Use of this this basin on an equalized flow basis serves to make more effective use of the chlorine contact basin and should be continued. As Carollo noted, at the highest peak hour flows recorded through the treatment plant during 1998, the reported flow rate was 3.12 mgd resulting in a calculated chlorine contact time of 18 minutes. Actual results of disinfection during both peak flow months of February and March 1998 showed compliance with coliform limitations (fecal) of 200 MPN/100 ml, with actual median values being at 2 MPN/100 ml, well within limits. Whatever else can be said concerning existing chlorine contact basin, it appears justified in concluding yh; doc3'ryno$.doc that capacity to meet requirements is at some varying figure above 3.12 mgd and possibly significantly more depending on amount of hypochlorite addition under high flow conditions. It is concluded that the existing chlorine contact basin element of the treatment plant, based on both textbook analysis and validated by actual results, ,does not directly . affect the current, or near term overall capacity of the existing treatment plant to meet waste discharge requirements. Solids Handling The solids handling facilities consist primarily of: 0 Dissolved air flotation thickener for thickening of waste activated sludge ahead of the anaerobic digesters, Two anaerobic digesters, one which was part of the original 1953 plant project, the other constructed in 1998 to handle combined raw sludge from the primary clarifiers and thickened waste activated sludge, One belt press constructed as part of the 1983 project for the purpose of dewatering F digested sludge for storage ahead of transport to land disposal in the central valley. The Carollo assessment of the solids handling facilities elements of the treatment plant is stated, "Carollo's preliminary evaluation is that the existing sludge handling process units are } adequate for the year 2018 design flows and loads." 1 KIJ Assessment JK1J concurs with the Carollo. assessment. Specifically to the focus of present studies KIJ i concludes that both by textbook analysis and actual results, the solids handling elements of the existing treatment plant do not impact the current, or near term overall capacity to meet waste discharge requirements. SUMMARY The review and studies summarized hereinbefore, were directed primarily towards the question of what can be considered to be the firm flow capacity of the City's wastewater treatment plant reliably to meet State and Federal waste discharge requirements? This capacity was identified in the recently submitted draft report prepared by Carollo Engineers to be 1.3 mgd. The Carollo studies also identified poor physical condition of structures and equipment as a further basis for limiting current capacity and emphasizing the need for abandoning existing plant. It was found that there were two prior engineering studies conducted by two other engineering firms, one by Brown & Caldwell in 1991 and the other by Engineering Science (ES) in 1984. The Brown & Caldwell study concluded that the capacity of the Pismo Beach wastewater treatment plant was 1.3 mgd. The ES study concluded that plant capacity in 1984 was 1.2 mgd and that with recommended improvements, capacity would then be for 1.5 mgd capacity with peak capacity for 1.75 mgd. The ES recommended improvements were constructed and are included in the ` plant facilities as they exist today. In reviewing the Carollo and Brown & Caldwell engineering studies, K/J observed that the assessment of treatment plant capacity was essentially determined on the basis of applying very conservative textbook criteria in an analysis of each individual process element of the treatment plant. Much of the criteria used in prior capacity studies were those which might be utilized if the treatment plant was intended to obtain better than an effluent with residual BOD and suspended solids of less than 20 mg/I rather that the c 0i d=kpam05.doc - 1 2 - J actual requirement of 30 mg/l. In any case, neither the Carollo or Brown & Caldwell studies validated the assessment of 1.3 mgd flow capacity on the basis of actual results against meeting of State and Federal waste discharge requirements. The K/J assessment summarized herein, combined a textbook analysis of each individual process element, but utilizing mid -point textbook criteria, then validating the textbook capacity assessment against actual results of plant operation as shown from the plant monitoring program results. In particular, operating results were utilized which were found during times of maximum flows and loadings with the further distinction of maximum flows and loading during the winter months and summer months of July and August. It was shown that during the highest flow month of February 1998, average flow during this month was 1.60 mgd. During this high flow month, average effluent suspended solids was 21 mg1I against the requirement for less than 30 mg/l. During the peak summertime loading months of July and August 1998, average wastewater flow during these two months was 1.25 mgd and average effluent suspended solids during this time was 9 mg/l. Mid -point criteria analysis suggested that the aeration tanks and secondary clarifiers may limit plant flow capacity to about 1.5 mgd, which figure also corresponds to the ES study assessment. There clearly are evident needs at the Pismo Beach wastewater treatment plant in respect to maintenance and rehabilitation. These needs should be addressed regardless of other considerations in order to insure reliable, consistent operation and meeting of waste discharge requirements. Other immediate improvements which could be considered to enhance treatment plant effectiveness and reliability would be to improve use of the equalization basin and to empty and clean the original digester which then could be utilized to advantage for sludge storage and solids separation. 1 K/J concurs that the City of Pismo Beach should embark upon an expansion program which will J result in ability to treat projected future increased wastewater flows defined in the Carollo report as being 2.0 mgd on an average day maximum month dry weather flow basis. The needed ' expansion program might take the form of some form of consolidation for combined wastewater treatment and disposal through the South San Luis Obispo County Sanitation District's wastewater treatment plant and existing joint use ocean outfall line. The alternative would be to expand the existing Pismo Beach wastewater treatment plant. K/J believes that there is another local option for meeting increased flow capacity needs which would make use of existing tankage and be less costly than the Carollo proposed oxidation ditch Alternative C. Regardless of how increased wastewater treatment capacity is best achieved, there will be an interim period of at least three years needed for the planning, design, financing and construction of new facilities. It is important that the Pismo Beach wastewater treatment plant be capable of - meeting waste discharge requirements during this interim period. Based on the study summarized herein, KIJ believes that the existing Pismo Beach wastewater treatment plant with adequate maintenance, some rehabilitation and minor improvements is fully capable of meeting waste discharge requirements while accepting relatively small incremental increases in wastewater flows which will occur as a result of the normal, planned growth of the community. H is understood that the General Plan allows for such growth to proceed at a 3% rate per annum. ` 1 Confidence in these conclusions is supported by the fine history of results being obtained J through excellent plant operation. Also, given that the results being obtained are well within requirement limits it may be assumed any deterioration of results portending failure to meet requirements would be clearly evident well in advance, in which case further remedial steps could then be taken such as those recommended as part of the Carollo studies. c yh3 docstpws o5.doc - 1 3 - APPENDIX G CAROLLO'S REVIEW COMMENTS ON KENNEDY/JENKS' STUDY _J { H:\Final\PismoBch_FNOI483SAOOIRptVAPP.WPD V-WcorOLLO October 25, 1999 4836A.00 Mr. R. Dennis Delzeit, P.E. Director of Public Services/City Engineer City of Pismo Beach 760 Mattie Beach Pismo Beach, CA 93449 Dedicated to treatise, responsive, quality sohition.s for those we serm. Subject: Review of Kennedy/Jenks Consultants' Draft Pismo Beach Wastewater Treatment Plant Capacity Study Dear Mr. Delzeit: We received a copy of Kennedy/Jenks Consultant's (K/J) above noted study on October Y1 12, 1999. This letter provides Carollo Engineers P.C. (Carollo) review comments and 1 analysis. We reviewed K/J's study, and they did an excellent review of Carolio's draft July 1999 Master Plan. The good news for the City is that the Wastewater Treatment Plant (WWTP) can be expanded or rehabilitated in an orderly manner over the next three to four years without jeopardizing the issuance of building permits. The City now has a fourth consultant's opinion of the capacity of the existing wastewater treatment plant (WWT*P). K/J rates the WWTP at 1.5 mgd whereas Carollo (1999), Brown and Caldwell (1992) and ES Environmental Services (1984) rated the WWTP at 1.3 mgd as reported in K/J' study. Carollo did not review the ES Environmental Services' Report until after we submitted the draft Master Plan. Carollo had reviewed a September 1982 report to the City prepared by PRC Toups which was not referenced in K/J's Study. The Executive Summary of ES Environmental Services' 1984 report has the following statement: "When plant flows approach 1.20 mgd, an expansion will be required. One additional aeration basin, a dissolved air flotation sludge thickener, a belt filter for sludge dewatering, and minor process modifications will be required. This expansion will increase l the maximum capacity of the plant to 1.75 mgd." The text of the rest of the report does not J substantiate the 1.75 mgd capacity. Although the report contained inconsistencies, the 1.75 mgd capacity in the Executive Summary was considered by the City as the capacity of the WWTP. ` Carollo recommended a rating of 1.4 mgd with short term contingency measures as noted in our letter to you dated July 29, 1999. The 1.4 mgd is only 0.10 mgd or seven percent less than K/J's rating of 1.5 mgd. H:IFinoPismofth FN0N4836A0 Lb1 Delze08.wpd 7580 NORTH INGRAM AVENUE, SUITE 112• - FRESNO, CALIFORNIA 93711 - (559) 436-6616 - FAX (559) 436-1191 1_E Mr. Dennis Delzeit Public Services Director City of Pismo Beach October 25, 1999 Page No. 2 After submitting our Draft Master Plan, City staff provided Carollo with additional documentation of the 1.75 mgd capacity figure as indicated in the NPDES Permit approved by the Regional Board as Order No. 87-90. In a January 5, 1987 memorandum from the then City Engineer to the then Director of Public Services, the 1982 PRC Toups' report was T� referenced not the ES Environmental Services' 1984. report. The memorandum states "The present expansion that is now under construction will increase the plant capacity to 1.75 mgd which should handle the flow expected in the year 2004". The 1986 expansion -� did not included the following process additions recommended in the PRC Toups report which may have increased the capacity to 1.75 mgd. Two new rectangular primary clarifiers were not constructed. Conversion of the existing primary clarifiers to secondary clarifiers i with new sludge collection mechanisms was not constructed, miscellaneous piping and J pumps to accommodate the new primary clarifiers and the conversion of the existing primary clarifiers to secondary clarifiers were not constructed. The 1.75 mgd capacity was based on the 1982 PRC Toups report's text but not based on the actual implementation of their recommendations. Both Carollo and K/J agree that the WWTP requires upgrading, rehabilitation and expansion within a three to four year period. This upgrading could occur at the existing facilities or involve some form of consolidation with the South San Luis Obispo County Sanitation District's (SSLOCSD) wastewater treatment plant. Carollo appreciates K/J's review comments in regard to the overflow rates for the primary clarifiers. In the final report, Carollo will adjust the overflow.rates to higher values. Carollo's main concerns with rehabilitating the existing clarifier complex are hydraulics and redundancy. It is difficult to maintain treatment criteria if there is no redundancy available. Plant hydraulics may not allow reliable treatment if one of the existing clarifiers has to be removed from service for an extended period of time. Carollo reviewed the actual operations data of the WWTP during the preparation of the draft July 1999 Master Plan. Carollo agrees that plant operations and management is very significant in the ability of the existing plant to treat wastewater below permitted levels. The questions is how long does the City want to have the operations staff keep stretching �J resources to meet effluent criteria. Based on K/J's experience, they envision a more extensive rehabilitation of the existing WWTP than recommended by Carollo. Carollo did provide for short term rehabilitation of the existing plant in the draft report under Alternative D Staged Wastewater Treatment Plant Construction Option. Implementation of Alternative D would give the City time to reevaluate the rehabilitation of the existing plant to continue for long term service. K/J and Carollo both agree that equalization basins can cause odors. Carollo differs with K/J on the continued use of the equalization basin in the upgraded plant. Carollo recommends that the equalization basin be eventually filled and the area used for storage HftF1nel\PIsmo8ch FN014636AOO\WDeIze06,wpd `1 7580 NORTH INGRAM AVENUE, SUITE 112 . • FRESNO, CALIFORNIA 93711 - (559) 436-6616, - FAX (559) 436-1191 Mr. Dennis Delzeit Public Services Director City of Pismo Beach October 25, 1999 Page No. 3 of dewatered sludge. Equalization basins create unnecessary odors and are difficult for operators to maintain. The City should make administrative decisions before Carollo finalizes the draft WWTP Master Plan. if the City decides not to join with the SSLOCSD, the City must decide whether to rehabilitate the existing WWTP for long term service or to proceed with Alterative C or D as recommended by Carollo. There are numerous unknowns in rehabilitating existing facilities for long term service. Carollo's 1999 Master Plan has a limited budget of $40,000 which was not sufficient to perform a detailed analysis for long term rehabilitation of the existing plant. A subsequent pre -design report should be performed to provide more detailed analysis of the existing plant. Carollo will submit a proposal under separate cover letter for a pre -design report on maximizing the use of the existing plant. This detailed analysis should consider sequence of construction to maintain reliable treatment while the plant is being rehabilitated. Under Alternative D, the construction of a new 1.0 mgd oxidation ditch plant would precede the rehabilitation of the existing plant. With the 1.0 mgd oxidation ditch in place, redundancy issues with the existing plant would be eliminated. Carollo appreciates providing engineering services to the City of Pismo Beach and looks forward to meeting with you and the City Council on November 2, 1999. Carollo appreciates KIJ review and are pleased with the results. If you have questions or comments, please call us. Sincerely, CAROLLO ENGINEERS, P.C. .i David L. Stringfield,;e.E.xj�— BEHIDLS:cjp H:1F+naI\P1smoBch FN0\4836Aoo\LtrlD9jzeO6.wpd `� 7580 NORTH W RAM AVENUE, SUITE 112 - FRESNO. CALIFORNIA 93711 • (559) 436-6616. • FAX (559) 436-1191 I APPENDIX H ALTERNATIVE A-1 DESIGN CRITERIA - MAXIMUM USE OF EXISTING PLANT ` { H:1FinailPismoBch_FNO�4&%AOO1Rpt1APP.WPD Table H.1 Alternative A-1 - Design Criteria - Maximum Use of Existing Plant City of Pismo Beach Design Year 2016 Parameter Design Flow, mgd Average Annual (AAF) 2.0 Average Day Maximum Month Dry 2.4 Weather Flow (ADMMDWF) - Permit Condition Peak Hour Wet Weather (PHWWF) 6.0 Design Loadings, Average Annual BOD5, mg/L 250 BODS lbs/day 4,170 TSS, mg/L 330 TSS, Ibs/ day 5,500 Headworks Existing New Parshall Flume Width, inches — 12 Parshall Flume Capacity, mgd — 6 Number of Mechanical Bar Screens — 1 Type of Screen — Climber or Continuous Bar Screen Spacing, inches — 1/2 Bar Screen Capacity, mgd — 6 Number Manual Bar Screen — 1 Influent Force Mains, Diameter, inches Addie Street Pump Station 12 & 16 --- Pismo Oaks Siphons 3 at 8 --- New Shell Beach Force Main — 12 Aerated Grit Channel Type --- Aerated Number of Units -- 1 Dimensions L x W x SWD, ft --- 10 x 14 x 12 H:\Final\PismoBch—FNOk4BWAOO\Table\Pammetr.wpd 1 Table H.1 Alternative A-1 - Design Criteria - Maximum Use of Existing Plant City of Pismo Beach Design Year Parameter 2016 Existing New Total Volume, gallons — 12,570 Detention time at PHWWF, minutes — 3 Number of Blowers --- 1 + 1 Blower Capacity, each — 150 Primary Clarifiers Number and Diameter, ft 4 at 30(') --- Total Surface Area, sq ft 2,828 --- Side Water Depth, ft 8, 11.5, 9.5 --- Total Volume,, gallons 222,000 --- Detention Time, hours at Average Flow 2.66 --- Surface Overflow Rate at AAF, gpd/sq ft 707 --- PHWWF, gpd/sq ft 2,120 --- Aeration Tanks Number 3 1 Width x Length, ft 20 x 60 20 x 60 Side Water Depth, ft 15 15 Total Volume, cu ft 54,000 72,000 Influent BODb, mg/L Average 248 250 BOD, Loading Ib/BODdday/1,000 cu ft --- 40.5 Detention Time At Average Flow, hours --- 6.46 With 25 Percent Return, hours --- 5.17 Secondary Clarifiers Number and Diameter, ft — 2 at 65 H:\FinagPismoBch_FN014836AOO\Teble\Parametr.wpd 2 Table H.1 Alternative A-1 - Design Criteria - Maximum Use of Existing Plant City of Pismo Beach Design Year Parameter 2016 Existing New Total Surface Area, sq ft — 6,633 Side Water Depth, ft — 14 Total Volume, gallons ---- 694,630 Detention Time, hours at Average Flow — 8.3 Surface Overflow Rates at Average Flow, gpolsq ft — 302 Peak Hour Flow, gpd/sq ft — 905 Aeration Blowers Number (2,000 cfm, each) 3 1 Horsepower, horsepower, each 60 60 Chlorine Contact Chamber Number 1 1 Size L x W x SWD 37 x 18 x 8 —(2) Volume, cu ft 5,328 10,130 Volume, gallons 39,850 75,800 Detention Time at Average Flow, minutes — 76 at Peak Flow, minutes ----- 25 Plant Effluent Pumping Number of Pumps, with VFD 2 1 Reported Operating Capacity, mgd 3.0 3.0 Operating Head, ft 28 >28 Capacity with two Pumps, mgd 6.0 Outfall Diameter, inches 18 --- Outfall Pipe Length, feet 17,500 — H:\Final PismoBch_FN014836AOOITnhle\Psrametr.wpd 3 Table H.1 Alternative A-1 - Design Criteria - Maximum Use of Existing Plant City of Pismo Beach Parameter Existing Design Year 2016 New Digester No. 2 Diameter, ft 47 --- Volume, gal 307,000 --- Digester feed, gpd 15,350 --- Detention Time, days 20 --- Digester No. 1 (holding digester) Diameter, ft 40 --- Volume, gal 187,750 --- Detention Time, days <15 --- Dissolved Air Flotation Thickener (DAFT) Number of Units 1 --- I Diameter, ft 20 --- Side Water Depth, ft 6.4 --- Surface Area, sq ft 314 --- Capacity, gpm at 5,000 mg/L TSS 120 --- Belt Filter Press Number 1 --- Size, meters belt width 1 --- Capacity, gpm at 3.5 percent feed solids 43 --- Average Solids Concentration, percent by 18.5 to 19.0 --- weight Wet Cake Quantity at 18.5 percent solids, 6.5 --- tons/day (1) Convert two existing 30 ft secondary clarifiers to primary clarifiers. (2) Convert existing 40 ft diameter secondary clarifier to a second chlorine contact basin. H:\Final PismoBch_FNO\4836AOOITable\Pwametr.wpd 4 1 APPENDIX 1 CONSOLIDATION WITH SOUTH SAN LUIS OBISPO COUNTY SANITATION DISTRICT I H:IFinaRPismoBch_FNO\48WAOO\Rpt1APP.WPD ALTERNATIVE OF WASTEWATER TREATMENT CONSO WITH SOUTH SAN LUIS OBISPO COUNTY SANITATION RICT D JAN 31 2000 Background CAROLLO ENGINEERS During the past, it has been suggested that combining wastewater treatment as well as disposal for both Pismo Beach and South San Luis Obispo County Sanitation District (SSLOCSD) should be considered. Most logically, this consideration would be given at such time as either agency is investigating alternatives for meeting increased capacity needs, alternatives which would involve expenditures of significant sums of public monies. This is the case presently for Pismo Beach which shortly will need to commence the planning, design and construction of facilities estimated to cost some $ 6.47 million, as seen in the Carollo draft report in order to provide means of meeting projected increased capacity needs. These needs will be occasioned by increasing wastewater flows approaching the capacity of the existing wastewater treatment plant. The projected needs are those associated with orderly increases in city development consistent with the city's General Plan and recently shown to be for a capacity of 2.0 million gallons per day (mgd) on an annual average basis, 2.4 mgd on a peak month flow basis. In any study of consolidation for combined wastewater treatment the basic study elements usually will be, 1) economics and, 2) other factors unique to the particular circumstances. f In respect to economics, the elements usually seen as significant are: • Identifying capital and continuing operating costs for facilities needed to transport wastewater to the consolidated plant for treatment and disposal along with capital and operating costs of added facilities needed to accommodate the increased flows. That there should be economies of scale, both capital costs and operation and maintenance costs are accepted. For instance, in K/J's experience typically a 3 mgd secondary wastewater treatment plant will cost about $ 3.5/gallon of capacity. On the other hand, a 6 mgd capacity secondary wastewater treatment plant will cost about $ 2.5/gallon. Similarly, the unit cost for treatment plant operation and maintenance will be correspondingly less when operating a higher capacity plant than smaller. Comparison of capital and operating costs for participating in construction and operation of new local facilities to meet combined wastewater treatment needs against costs for independent, local facilities. Again, it would be expected that construction costs and continuing operation and maintenance costs for a local, smaller capacity wastewater treatment plant will be more. However, these higher costs over time, may be overcome by important factors other than economic. In respect to other factors, included in this particular case would be at least: • Issues having to do with governance and loss of local control. • Water reclamation, market and value of local reuse. • Value of existing Pismo Beach wastewater treatment plant site. c:14 doesWwnc7.doc - 14 - 1 . Other The basic purpose of the studies summarized hereinafter has been to give a preliminary, 1 overview of the alternative for transporting the City's wastewater through the existing effluent line to the SSLOCSD site. Wastewater treatment would be combined ahead of continued discharge of treated wastewater through the already joint -use outfall to offshore ocean waters. It is to be understood that the studies at this point are at a reconnaissance level only with the objective of determining if a more in-depth, detailed study on the part of both SSLOCSD and Pismo Beach is warranted. It is important to understand that the study summarized hereinafter is not intended to provide definitive answers to the "other factors" such as those identified above. The study has been undertaken primarily to establish a general economic framework on the basis of which a decision can be made as to whether giving further, comprehensive study of all important factors, including verification of economic assumptions should be given. Presumably, such further study would also involve active participation of SSLOCSD to insure their independent long-range needs are accounted for. Transporting of Wastewater to SSLOCSD There is an existing pipeline between the sites of the Pismo Beach and SSLOCSD's wastewater treatment plant. This pipeline is for the purpose of conveying treated Pismo Beach wastewater to a junction with SSLOCSD's treatment plant outfall for disposal in a joint use ocean outfall discharging both SSLOCSD and Pismo Beach treated wastewater nearly a mile offshore into some 60 feet of water depth. This existing pipeline between the two existing treatment plant sites immediately sets aside what otherwise could be a major cost factor in respect to consolidation. That is, this same pipeline currently conveying treated Pismo Beach wastewater, could be utilized to convey untreated wastewater for treatment at the SSLOCSD site. Currently, wastewater generated within the City's service area arrives at the treatment plant site from two pumping plants, the Addle Street lift station and the Pismo Oaks lift station. Also, there is a small area being served by gravity to the treatment plant site. The City's (draft) Master Plan calls for $ 800,000 of improvements to Addle Street and $ 300,000 of improvements to the Pismo Oaks lift stations. It has been assumed that these improvements at those costs could include pumping units with capacities consistent with pumping needs directly to the existing pipeline to the SSLOCSD treatment plant site The remaining small area could be served by a new small local lift station similarly pumping directly to the existing pipeline to the SSLOCSD plant site. Connection would then be made to the existing SSLOCSD influent headworks and pumping plant. These facilities were designed originally to handle average dry -weather flows of 12 mgd with corresponding peaks so would continue to be more than adequate to accommodate a combined 7 mgd of flow. Treatment at SSLOCSD The existing SSLOCSD wastewater treatment plant was first placed into operation during 1966 with a designated average annual capacity for 2.0 mgd and certain portions of the plant such as the pumping plant designed in anticipation of meeting these projected ultimate capacity needs associated with the regional area of 12 mgd. Since that time there has been a succession of enlargements with current plant capacity designated as 5 mgd against current wastewater flows to the plant of about 3.0 mgd. It is roughly estimated that the combined costs for original plant plus enlargements was about $10 million. As presently configured, the biologic secondary treatment is provided through use of a fixed film reactor (FFR), sometimes referred to as a c4hi e—VWM7A- - 15 - ,trickling filter." Use of an FFR has made possible somewhat less stringent waste discharge requirements as seen in limits of 40 mg/l for residual suspended solids and BOD rather than the 30 mg/l prescribed for the Pismo Beach treated wastewater discharge. Development within the j SSLOCSD service area has been considerably less than predicted through the 1963 original l planning studies ahead of District formation. In respect to actual future District capacity needs it does not appear that a wastewater treatment plant enlargement will be required to meet District needs alone for some time into the future. The exception to this conclusion might be in the case of changed waste discharge requirements of greater stringency or needs in respect to water reclamation. As to the possibilities of providing a 2.4 mgd (two month peak summer flow) additional capacity to serve the needs of Pismo Beach as part of a consolidation, it appears that for preliminary consideration, it is appropriate to identify those needs on the basis of simply increasing the existing capacity from the current 5 mgd to 7.4 mgd. One reason to approach the matter in this way is avoiding the questions surrounding past State and Federal grant participation in the financing of existing plant and enlargement construction. The principle established as part of Federal and State Clean water grant regulations is that grants were provided for the benefit of the development within the service area of the grantee, in this case, SSLOCSD. The principle goes to the point that SSLOCSD is not at liberty to sell capacity to dischargers outside of the service area for which existing treatment plant was designed to accommodate. On the other hand concession can be made when it is shown that whatever form the improvements take, the future wastewater treatment interests of planned for development within the existing plant service area are not affected. In reviewing the design basis and current operating experience, it appears that in consideration of providing means whereby an additional 2.4 mgd of Pismo Beach wastewater could be accommodated by the existing SSLOCSD treatment plant without prejudice to the existing District service area, each basic process element could be considered separately. The existing headworks and Pumping plant has more than adequate capacity into the foreseeable future to meet the needs of an additional 2.4 mgd of Pismo Beach flow. A Pismo Beach contribution to this element of the treatment facility might take the form of providing a new higher capacity raw sewage pumping unit. Also, a metering vault would need to be constructed to meter wastewater flows from Pismo Beach ahead of discharge to the pumping plant headworks. With an additional 2.4 mgd, existing primary clarifiers would be inadequate. It would be appropriate to construct a third primary clarifier of the same size as the existing two primary clarifiers and at the expense of Pismo Beach. A third primary clarifier would be of some benefit to the District in respect to providing additional redundancy and somewhat more detention time and reduced overflow rates. The benefit to the District could be seen as a partial offset for Pismo Beach use of other process units. With an additional 2.4 mgd, the existing FFR would be loaded at higher hydraulic and organic loading than design with corresponding reduction in effectiveness. However, this reduction in effectiveness could be accounted for by providing a downstream process element for additional biologic oxidation, in this case an entirely new activated sludge aeration system together with new secondary clarifier, again at Pismo Beach expense. The needed increase of 2.4 mgd, additional means of biologic oxidation to achieve secondary treatment could be obtained most conveniently through installation of aeration tanks providing short -period aeration following the fixed film reactor as part of a dual biologic process. This improvement is seen as a benefit to c.V11 do=\9W o7.d= . 16 - I the District as well as Pismo Beach inasmuch as installation of aeration tanks would provide I some redundancy not currently existing as well as to insure a higher quality of combined plant effluent than now achieved, looking forward to meeting higher standards for reclamation. The benefits to SSLOCSD could be seen as a partial offset for Pismo Beach use of other existing process units. The existing two digesters would be capable of handling the projected solids loading from the added 2 mgd (annual average) of wastewater flows, but would require more adequate pre - thickening of solids ahead of digestion. This improvement is also seen as a benefit to the District as well as meeting Pismo Beach needs. There is an existing gravity sludge thickener unit which currently is not utilized. This thickener was installed to handle combined primary and secondary sludges. However, it was determined that primary sludge unexpectedly thickens to 5 — 6% in the primary clarifiers, which sludge includes return of underflow from the secondary l clarifier. The separate thickener then is not needed to meet current design needs. On the other 1 hand, in the event that Pismo Beach additional flows would be accommodated, the existing sludge thickener conveniently could be converted for use as a dissolved air flotation thickener l handling exclusively waste activated sludge as is the current practice at the Pismo Beach J treatment plant. In respect to digested solids handling, the existing centrifuge and. drying. beds could not be considered as being adequate for the handling of solids from an additional 2 mgd (average annual) of Pismo Beach wastewater flow. However, the centrifuge structure was designed to have space to accommodate a new, second centrifuge unit which could meet the additional Pismo Beach solids loading needs. At the same time the additional centrifuge could be seen as an added benefit to the District by providing dewatering redundancy not currently available. By having Pismo Beach pay the costs for converting the existing thickener to a DAF unit and installing a second centrifuge, the benefits to SSLOCSD could be seen as a partial offset for Pismo Beach use of other existing facilities. The existing secondary clarifier would not be adequate to handle an additional 2.4 mgd of Pismo Beach wastewater while still meeting the design needs of the District. It would be necessary therefore to construct a new secondary clarifier which would be sized so as to accommodate secondary/activated sludge together with the existing secondary clarifier. This improvement is also seen as an added benefit to the District by providing secondary clarifier redundancy which does not now exist With Pismo Beach assuming the entire costs for this new secondary clarifier, the benefits to SSLOCSD could be seen as a partial offset for Pismo Beach use of other existing facilities. ` Currently detention time after introduction of hypochlorite for disinfection is provided through strategic use of the existing secondary clarifier.. With introduction of the aeration system this expedient would no longer be practical. Also, the District has determined that there is a J secondary effect resulting from the current practice of adding hypochlodte to secondary clarifier influent. This practice appears to break down residual cells within the wastewater with a consequent increase of residual biochemical oxygen demand (BOD). It is evident then that the District is in need of providing an entirely new, separate chlorine contact tank. This tank would l have sufficient capacity for the total 7.4 mgd of flow, meeting the combined needs of the District J and Pismo Beach. This improvement would benefit both the District and Pismo Beach and by Pismo Beach paying the cost of this improvement, the benefits to SSLOCSD could be seen as a partial offset for Pismo Beach use of other existing process units. mjt j ao=*kmo7.doe - 17 - The foregoing additions and improvements to the SSLOCSD wastewater treatment plant could be seen as satisfying the need for providing an additional 2.4 mgd to the existing 5 mgd plant capacity. For purposes of present study and evaluation, it has been assumed that the additions suggested above would be financed by the City of Pismo Beach. However, it is also assumed for preliminary discussion purposes, that there would be significant benefits from these additions accruing to the District, particularly in respect to redundancy of facilities for primary clarifiers, secondary treatment, aeration tanks and final clarifier, secondary waste sludge thickener, digested sludge dewatering and chlorine contact tank. Again, for preliminary purposes of study Ll and evaluation, it has been assumed that these benefits to the District would serve to account for a Pismo Beach "buy -in" to those elements of existing plant to be jointly used. Also to be noted is an understanding that SSLOCSD currently does not have a "Master Plan" for means to achieve flow capacity beyond the current 5 mgd. If any expansion would be considered to meet Pismo Beach needs as discussed herein, it would be necessary before going further in the evaluations to identify long-range needs of SSLOCSD so as to insure that whatever is constructed is consistent with meeting needs of both agencies. l Preliminary Cost Estimates J Estimated capital costs associated with the improvements identified above might be seen as the l costs to Pismo Beach for wastewater pumping and treatment which, based on the foregoing l assumptions, would be in the range of: Pismo Beach Pump Station improvements $ 300,000 lMetering vault 200,000 Connections to existing works 200,000 Primary clarifier 450,000 Aeration tanks 1,100,000 Dissolved Air Flotation 300,000 Additional centrifuge 200,000 Secondary clarifier 1,200,000 Chlorine contact tank 450,000 Sub -total $ 4,400,000 Incidentals 1,300,000 Total costs $ 5,700,000 In respect to continuing operation and maintenance costs (O & M), reference is made to the current SSLOCSD operating budget. The 1999-2000 FY budget totals $1,812,689. This figure however includes $ 250,000 assigned to Contingency & Reserve as well as an additional over $ l 200,000 set aside for anticipated and unanticipated maintenance, repair and replacement of plant. These reserve and contingency budget items represent about 30% of the total budget a major amount much of which is judged to be non -recurring, but adds to an already significant reserve of nearly $ 8 million. Through further discussions with SSLOCSD staff, it is their L judgement that taking the non -recurring items from the current budget that the more appropriate year 1999/2000 budget figure to utilize for projections would be $1,400,000. It is thought that additional costs for the SSLOCSD treatment plant operations up to present capacity for 5 mgd would be limited primarily to those costs associated with pumping of flows and chemicals for disinfection along with some additional labor. To arrive at an estimate of cost for operating a 7.0 mgd capacity facility (including 2.4 mgd two month summer peak) from _J Pismo Beach) it has been assumed that there would be proportional increases in costs (3 mgd current flows vs 7.4 mgd projected future combined annual flows) for solids handling, electrical :J energy and chemicals for disinfection. In addition, there would be some increase in costs for two more operators and other items of materials and supplies. A preliminary estimate of total costs when operating with combined flows is suggested as being about $ 1,820,000, or a 30% j increase above the current budget. In respect,to operating cost sharing however, it is assumed J that the Pismo Beach annual flow figure of 2.0 mgd should be utilized. Thus, the average annual flow from SSLOCSD of 5.0 mgd is compared with the average annual flow projected -1 from Pismo Beach of 2.0 mgd, or a total annual flow of 7.0 mgd. At the 7.0 mgd annual flow II figure, the proportionate costs for the 2.0 mgd Pismo Beach contribution based on relative flows would be 217 x $1,820,000 = $ 520,000 per year. It should be noted that these figures are based on assumed wastewater flows resulting from °buildour of both District and City, which condition presumably will not actually occur for some time into the future. Treatment at Pismo Beach Using the Carollo recommended least cost project as defined in the Carollo draft report to meet the 2.4 mgd projected capacity needs (Alternative A-1 Maximum Use of Existing Plant), capital costs are estimated to be $ 6,470,000. In respect to continuing operation and maintenance costs, Carollo showed estimated O & M annual costs of $ 665,000 for the recommended project, but with acknowledgement that this figure does not include those costs which were common to all three of the alternatives evaluated. To gain understanding of what additional costs would be attributable to continuing i} operation of a Pismo Beach 2 mgd wastewater treatment plant, review of the current 1999-2000 1 budget was made. This current budget for the Pismo Beach wastewater treatment operations is shown to be $ 1,031,594 which includes all those items of overhead and administration comparable to the SSLOCSD budget. However, in the case of Pismo Beach, a portion of the total budget includes costs for maintaining the City's sewer system. This distinction is not made in the Pismo Beach budget so it is not possible to gain a precise understanding of actual costs associated for wastewater treatment alone. For preliminary purposes of present study it has ` 1 been assumed that costs associated with the City's sewer system represents about 35% of the total budget with the remaining 65% going to wastewater treatment operations. On this basis then, current budget for wastewater treatment might be about 0.65 x 1,031,594 = $ 670,500. This figure however may be low as it is understood that there may be current staff vacancies as well as significant needs in respect to ongoing rehabilitation and equipment replacement. As shown above when estimated future SSLOCSD treatment plant O & M costs, increases in those items directly related to flow, electrical energy, chemicals for disinfection, solids disposal have been increased proportionally to 2.0 mgd average annual flow from the current 1.3 mgd suggesting a total treatment plant operating budget of some $ 870 000 r year. Also to 9g g p p g 9 � per Y account for special needs for equipment replacement and rehabilitation not currently accounted for, but needed for the alternative involving continuing use of existing plant, a figure of $ 30,000 per year is assumed. This results then in an estimated total of $ 900,000 annual O & M costs when operating under full average annual load conditions. of 2.0 mgd. y' It should be noted there is recognition that use of 1999-2000 budget figures at current dollar value does not account for actual increases resulting from future inflation. However, the ` standard approach with engineering economics of altematives being evaluated is to assume that revenues in the future will increase in proportion to expenses. This then allows for a reasonably accurate comparison to be made on the basis of today's dollar value. GYMd0M%pi=7.d= - 19 - Economic Evaluation of Alternatives To obtain an overall economic evaluation of the two alternatives, consolidation vs. independent means of meeting Pismo Beach wastewater treatment needs, combining estimated capital costs with estimated 0 & M costs on a "Present Worth" basis. The use of °Present Worth" for economic comparison can be seen most easily as that sum of money which invested at assumed interest would meet the identified cost needs during the assumed period of time. The Carollo evaluations of alternatives for meeting increased capacity needs locally was done on a Present Worth basis utilizing a 30-year life cycle at 6% interest. The Present Worth number seen for each alternative then represents the amount of money which invested at 6% would furnish sufficient funds to pay all identified capital and annual operating and maintenance costs over a 30-year period. The foregoing has been applied to the cost figures associated with each alternative, Consolidation and Independent as follows: Consolidation Alternative Capital cost for treatment $ 5,700,000 Annual 0 & M costs (PW) 7,150.000 Total Present Worth $12,850,000 Independent Alternative Capital costs $ 6,470,000 Annual 0 & M costs (PW) 12,390,000 Total Present Worth, $ 18,860,000 From the foregoing, it appears that the consolidation alternative has a $ 6,010,000 overall long- term economic advantage over the independent alternative. This advantage is also seen as an initial capital cost saving of $ 770,000 and a savings in annual costs for operation and maintenance (0 & M) of $ 380,000 per year. In connection with the foregoing economic an of alternatives, it should be observed again that estimates of costs for the consolidation alternative have been made in the absence of more detailed engineering and cost studies which would need to be made if this alternative is to be considered further. Other Factors In addition to the question of the economics associated with the alternatives of consolidation with SSLOCSD and continued independent Pismo Beach wastewater treatment plant operation, other factors which would enter into any further consideration of a consolidation alternative would include: Governance Obviously any form of consolidation with SSLOCSD would entail some degree of lost local control. Still further expansion of capacity to serve development beyond the original 2.0 mgd c.,44 d-► -7.d- -20- average annual flow need might be more difficult to achieve when having to account for needs of the District also, which needs might not correspond in respect to timing. Presumably however, control could be provided through whatever form of agreement might be reached between the two agencies. Also in respect to governance, would be alternatives of Pismo Beach possibly becoming a full member agency of the District such as was most recently done in the case of Grover Beach, or contracting with the District for wastewater treatment services as was done originally by Grover Beach. The matter of governance also could be viewed in respect to potential advantages to the City of consolidation where there would be a major reduction in work and administrative load on City staff as a result of the District's assuming these responsibilities on behalf of the City. An additional factor in respect to administration is the establishing and enforcing of waste discharge requirements through one responsible agency rather than two with dealings before the Regional Water Quality Control Board as well as other regulating agencies. To some extent this is already being done as a result of the single discharge of combined District and City's treated wastewater in the joint use ocean outfall line. Water Reclamation i The need of water reclamation for beneficial reuse is becoming increasingly apparent not only in the Central Coast area, but throughout the State. There may be local markets for reclaimed water which most conveniently could be served from a local Pismo Beach wastewater treatment and reclamation plant. Elsewhere the possible reclamation needs are accounted for through agreements which call for entitlement of reclaimed water back to the contributing agency in equal amounts to that contributed. On the other hand, a local Pismo Beach market could be served through strategic use of portions of existing Pismo Beach wastewater treatment plant for purposes of producing sufficient reclaimed water to meet then established needs. Under such circumstances, solids produced through reclamation could be introduced back into the main wastewater flow going to SSLOCSD. This concept of "satellite" reclamation plants is well established, especially in the southern California area. In addition, it is understood that SSLOCSD is currently undertaking a major water reclamation study which will show a potential area -wide program for reclaimed water use including a network of pipelines to points of reuse, which could include areas within Pismo Beach. Existing Pismo Beach Treatment Plant Site In the event of a consolidation program being implemented, presumably the site of the existing Pismo Beach wastewater treatment plant could be made available for some higher form of use. To the extent that this is considered and costs of existing plant demolition do not exceed the land value, the value of this site also could be seen as an additional economic factor to be considered. Undoubtedly there are numerous other factors surrounding the question of consolidation, factors which have to do with administration, procedures and other needs to fully protect the interests in this case of Pismo Beach. However, consolidations such as being reviewed herein are not new, J but have been successfully implemented through agreements at many other locations to mutual advantage of the agencies involved. o:yN doce%pwmo7.aoo - 21 - ISummary In summary of the foregoing, the preliminary analysis reviewed shows a potentially significant economic advantage to Pismo Beach in consolidating wastewater treatment at the site of the South San Luis Obispo County Sanitation District's treatment plant. This economic advantage would be reduced to the extent that there might be a lowering of costs for constructing additional facilities to meet the City's current and projected future needs independently. Also, a more detailed analysis of costs for maintenance and operation of local versus consolidated facilities could serve to increase, or decrease the currently shown economic advantage favoring consolidation with the District. However, there is little uncertainty that there could be a significant cost savings to Pismo Beach, both capital costs and continuing annual operation and maintenance costs if consolidation is accomplished. The question then will be whether cost savings are sufficient to overcome possible negative aspects of other factors which should be j considered in respect to the long-range interests of the City of Pismo Beach. As part of further discussion of this matter, obvious areas of interest would include the issues of governance, control, relationship with regulating agencies, water reclamation and value of the existing Pismo Beach wastewater treatment plant site. ' If on the basis of the foregoing preliminary evaluations consolidation with SSLOCSD is deemed worthy of further investigation, then more detailed study would need to be given through a joint study, participated in by both the City and South San Luis Obispo Country Sanitation District. J �:y�7. - 22 -