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2 7 0 0 Y G N A C I O V A L L E Y R O A D , S U I T E 3 0 0 • W A L N U T C R E E K , C A L I F O R N I A 9 4 5 9 8 • ( 9 2 5 ) 9 3 2 - 1 7 1 0 • F A X ( 9 2 5 ) 9 3 0 - 0 2 0 8 H:\Final\Modesto_WCO\6887L00\Rpt\Masterplansupp\Execsummary\Draft\ES.Doc City of Modesto Wastewater Treatment Master Plan Jennings Road Secondary Treatment Facility WASTEWATER TREATMENT MASTER PLAN SUPPLEMENT EXECUTIVE SUMMARY DRAFT June 2008 ---PAGE BREAK--- DRAFT - June 30, 2008 i H:\Final\Modesto_WCO\6887L00\Rpt\Masterplansupp\Execsummary\Draft\ES.Doc City of Modesto, California WASTEWATER TREATMENT MASTER PLAN SUPPLEMENT EXECUTIVE SUMMARY TABLE OF CONTENTS Page 1.0 INTRODUCTION 2.0 3.0 PROJECTED FLOW AND WASTEWATER CHARACTERISTICS 4.0 EFFLUENT LIMITATIONS AND DISCHARGE 4.1 Ammonia 4.1.1 Seasonal 3 4.1.2 Year Round 9 4.2 Metals 4.3 Salinity (as Electrical 5.0 RECOMMENDED JENNINGS ROAD TREATMENT FACILITIES 5.1 Salinity 6.0 WASTEWATER TREATMENT CAPITAL IMPROVEMENT 6.1 Recommended Project 6.2 PROJECT IMPLEMENTATION LIST OF TABLES Table 1 Projected Flow and Loadings 5 Table 2 Comparison of New (2008) and 2007 Master Plan NPDES Permit Effluent 7 Table 3 Recommended Phasing Capacity 11 Table 4 Estimated Capital Costs for Reverse Osmosis 14 Table 5 Total Revised Wastewater Treatment Capital 16 Table 6 Wastewater Treatment CIP Cost 20 LIST OF FIGURES Figure 1 Projected Population at Buildout of SOI - Mid Density 2 Figure 2 Projected Flows 4 Figure 3 Recommended Jennings Road Treatment Schematic 12 Figure 4 Recommended Jennings Road Conceptual Site Layout 13 Figure 5 Recommended Project Schematic 17 Figure 6 Required Tertiary Treatment Capacity Needs and Phasing 19 Figure 7 Near-Term Project Schedule 22 Figure 8 Long-Term Project 23 ---PAGE BREAK--- DRAFT - June 30, 2008 1 H:\Final\Modesto_WCO\6887L00\Rpt\MasterPlanSupp\ExecSummary\Draft\ES.doc City of Modesto WASTEWATER TREATMENT MASTER PLAN SUPPLEMENT EXECUTIVE SUMMARY 1.0 INTRODUCTION The City of Modesto’s (City) Wastewater Treatment Master Plan (Master Plan) was developed during the 2005 to 2006 timeframe and was formally adopted in March 2007. The plan was prepared using City-furnished population growth rates available at the time. In addition, the plan relied upon anticipated wastewater discharge permit conditions for the Jennings Road Secondary Treatment Facility based on several meetings and discussions with staff of the Regional Water Quality Control Board Housing and resultant near-term population growth has slowed considerably in the last 12 months. In addition, the adopted a new waste discharge order on May 2, 2008. This order contains discharge limits for seasonal secondary effluent discharges to the San Joaquin River which are considerably more restrictive than those currently in effect and as indicated from previous communications with the Consequently, a Master Plan Supplement (Supplement) is required to address changes in population trends as well as the more restrictive waste discharge requirements. Consistent with the premise of the original Master Plan, it is the City’s desire to continue the practice of land application of segregated cannery process water. Detailed specific studies are anticipated to be required to verify appropriate land application rates and methodologies. Accordingly, the analysis presented herein focuses on the treatment and disposal of domestic wastewater flows. 2.0 POPULATION In the 2007 Master Plan, an annual population growth rate of 1.6 percent to 2011 and 1.75 percent thereafter, was used to project future flows. For this Supplement, it was assumed that the annual growth rate will be 0.7 percent for 2008 and 2011, 1.6 percent for 2010 and 2011, and 1.75 percent thereafter. This results in a projected 2030 population of 346,700 compared to 355,000 used in the 2007 Master Plan. Figure 1 is a plot of historic and updated population projections. The near term growth rate of 0.7 percent per year was selected based on growth rates that occurred in the past economic decline in the mid-1990s. As indicated in Figure 1 after recovery from this downturn, historical annual population growth increased to about 2 percent over the next 10 years. Therefore, it appears reasonable that a similar pattern would occur when the housing market returns to more typical conditions. ---PAGE BREAK--- mo708mpf1-6887.ai Figure 1 PROJECTED POPULATION AT BUILDOUT OF SOI – MID-DENSITY WASTEWATER TREATMENT MASTER PLAN SUPPLEMENT EXECUTIVE SUMMARY CITY OF MODESTO 100,000 150,000 200,000 250,000 300,000 350,000 400,000 1986 1996 2006 2016 2026 2036 2046 Year Population Historical Population Data Mid-Density: SOI Build-Out Projected Population - 0.7% (2008-2009), 1.6% (2010-2011), 1.75% thereafter 2 ---PAGE BREAK--- DRAFT - June 30, 2008 H:\Final\Modesto_WCO\6887L00\Rpt\MasterPlanSupp\ExecSummary\Draft\ES.doc 3 3.0 PROJECTED FLOW AND WASTEWATER CHARACTERISTICS Projected wastewater flow has been revised based on the new population projection and applying the same unit flow of 117 gallons per capita per day (gpcd) used in the Master Plan. Figure 2 is a plot of the projected average annual flows presented in the Master Plan and those developed in this Supplement. As indicated, updated population projections result in a year 2030 flow of 40.7 million gallons per day (mgd) compared to the flow of 41.5 mgd used for the 2007 Master Plan. Wastewater biochemical oxygen demand (BOD), total suspended solids (TSS), and ammonia concentrations have been updated as well based on the most recent data provided by the City. It is anticipated that wastewater characteristics in the future will be similar to existing conditions. Table 1 presents a summary of updated projected wastewater flow and loadings. 4.0 EFFLUENT LIMITATIONS AND DISCHARGE SPECIFICATIONS The issued final Waste Discharge Requirements (WDRs) on May 2, 2008. The new WDR has impact on the Master Plan relative to both seasonal and year round river discharge. New limits for ammonia, metals, and electrical conductivity are of key concern. Table 2 presents a comparison of waste discharge requirements anticipated from previous communication with staff and outlined in the 2007 Master Plan to the new requirements. 4.1 Ammonia Existing discharge requirements that were in effect during development of the Master Plan allowed for a “floating” ammonia limit. The limit depended on the temperature and pH of the effluent. The ammonia limit ranged from 32.6 mg/L at a pH of 6.5, to 2.6 mg/L at a pH of 8.5. In contrast, the new discharge order has a fixed average limit of 0.9 mg/L, regardless of pH or temperature. In order to achieve this limit the treatment process must be robust and controllable, especially in the winter months when temperatures are low and it is more difficult to nitrify. 4.1.1 Seasonal Discharge Currently the City does not consistently remove ammonia from storage pond effluent during the discharge season. Ammonia levels typically rise in the winter months when biological activity slows due to low temperatures. Concentrations are also likely increasing in these months because the algae die off and release ammonia. The current pond system can adequately meet the previous pH and temperature-based floating limits for ammonia. However, additional treatment (nitrification) will be required to consistently remove ammonia in the winter. ---PAGE BREAK--- mo708mpf2-6887.ai Figure 2 PROJECTED FLOWS WASTEWATER TREATMENT MASTER PLAN SUPPLEMENT EXECUTIVE SUMMARY CITY OF MODESTO 0 5 10 15 20 25 30 35 40 45 1995 2000 2005 2010 2015 2020 2025 2030 2035 Month-Year Flow (MGD) Actual Average Day Master Plan Projection Supplement Projection 4 ---PAGE BREAK--- DRAFT - June 30, 2008 H:\Final\Modesto_WCO\6887L00\Rpt\MasterPlanSupp\ExecSummary\Draft\ES.doc 5 Table 1 Projected Flow and Loadings Wastewater Master Plan Supplement Executive Summary City of Modesto, California Year 2005-2007 Average 2010 2015 2020 2025 2030 Population 230,900 255,300 283,800 714,200 346,700 Flows, mgd Annual Average Flow (AAF) 26.2 27.1 30 33.3 36.9 40.7 Average Dry Weather Flow (ADWF) Peaking Factor 1.00 1.00 1.00 1.00 1.00 1.00 ADWF 26.2 27.1 30.0 33.3 36.9 40.7 Maximum Month Flow (MMF) Peaking Factor 1.11 1.11 1.11 1.11 1.11 1.11 MMF 29.1 30.1 33.3 37.0 41.0 45.2 Peak Dry Weather Flow (PDWF) Peaking Factor 1.42 1.42 1.42 1.42 1.42 1.42 PDWF 37.2 38.5 42.6 47.3 52.4 57.8 Peak Wet Weather Flow (PWWF) Peaking Factor 2.77 2.70 2.60 2.50 2.40 2.30 PWWF 71.7 73.2 78.0 83.3 88.6 93.6 Influent to Sutter Ave. (Primary Plant) BOD Concentration, mg/L 452 452 452 452 452 452 Average Annual Loading, lbs/day 98,800 102,200 113,100 125,500 139,100 153,400 Peaking Factor 1.23 1.23 1.23 1.23 1.23 1.23 Maximum Month Loading, lbs/day 121,500 125,700 139,100 154,400 171,100 188,700 TSS Concentration, mg/L 366 366 366 366 366 366 Average Annual Loading, lbs/day 80,000 82,700 91,600 101,600 112,600 124,200 Peaking Factor 1.46 1.46 1.46 1.46 1.46 1.46 Maximum Month Loading, lbs/day 116,800 120,700 133,700 148,300 164,400 181,300 Ammonia Concentration, mg/L 28 28 28 28 28 28 Average Annual Loading, lbs/day 6,100 6,300 7,000 7,800 8,600 9,500 Peaking Factor 1.46 1.46 1.46 1.46 1.46 1.46 Maximum Month Loading, lbs/day 8,900 9,200 10,200 11.400 12,600 13,900 ---PAGE BREAK--- DRAFT - June 30, 2008 H:\Final\Modesto_WCO\6887L00\Rpt\MasterPlanSupp\ExecSummary\Draft\ES.doc 6 Table 1 Projected Flow and Loadings (Continued) Wastewater Master Plan Supplement Executive Summary City of Modesto, California Year 2005-2007 Average 2010 2015 2020 2025 2030 Electrical Conductivity, µmhos/cm Average Annual 1,250 1,250 1,250 1,250 1,250 1,250 Peaking Factor 1.19 1.19 1.19 1.19 1.19 1.19 Maximum Month 1,500 1,500 1,500 1,500 1,500 1,500 Primary Effluent (Influent to Jennings Road Facility - Secondary Plant) BOD Concentration, mg/L 272 272 272 272 272 272 Average Annual Loading, lbs/day 59,900 61,500 68,100 75,500 83,700 92,300 Peaking Factor 1.29 1.29 1.29 1.29 1.29 1.29 Maximum Month Loading, lbs/day 77,300 79,300 87,800 97,400 108,000 119,100 TSS Concentration, mg/L 112 112 112 112 112 112 Average Annual Loading, lbs/day 24,500 25,300 28,000 31,100 34,500 38,000 Peaking Factor 1.71 1.71 1.71 1.71 1.71 1.71 Maximum Month Loading, lbs/day 41,900 43,300 47,900 53,200 59,000 65,000 Ammonia Concentration, mg/L 27 27 27 27 27 27 Average Annual Loading, lbs/day 5,900 6,100 6,800 7,500 8,300 9,200 Peaking Factor 1.26 1.26 1.26 1.26 1.26 1.26 Maximum Month Loading, lbs/day 7,400 7,700 8,600 9,500 10,50 11,600 ---PAGE BREAK--- DRAFT - June 30, 2008 7 H:\Final\Modesto_WCO\6887L00\Rpt\MasterPlanSupp\ExecSummary\Draft\ES.doc Table 2 Comparison of New (2008) and 2007 Master Plan NPDES Permit Effluent Limitations Wastewater Treatment Master Plan Supplement Executive Summary City of Modesto, California 2007 Master Plan New 2008 Limits Constituent Averaging Period Units Seasonal Discharge Limits Year Round Discharge Limits Seasonal Discharge Limits Year Round Discharge Limits BOD5 Average mg/L 30 10 30 10 Weekly Average mg/L 45 15 45 15 Daily Maximum mg/L 90 20 90 20 TSS Average mg/L 45 10 45 10 Weekly Average mg/L 60 15 60 15 Daily Maximum mg/L 105 20 105 20 Settleable Solids Average mL/L 0.1 Daily Maximum mL/L 0.2 Ammonia Average mg/L 2.6 to 32.6(1) 0.9 0.9 Daily Maximum mg/L 8.0 2.1 2.1 Chlorine Residual Daily Maximum mg/L 0.02 0 4-Day Average mg/L 0.01 0.01 1-Hour Average mg/L 0.02 0.02 Total Coliform 7-Day Median MPN/100 mL 23 2.2 23 2.2 Daily Maximum MPN/100 mL 500 23 240 23 Selenium (Total) Average µg/L 4.1 4.1 4.1 Daily Maximum µg/L 8.2 8.2 8.2 Copper (Total) Average µg/L 4.5 4.5 Daily Maximum µg/L 8.3 8.3 Molybdenum Average µg/L 10 10 Daily Maximum µg/L 15 15 23 TDS Daily Maximum µg/L 924 924 ---PAGE BREAK--- DRAFT - June 30, 2008 8 H:\Final\Modesto_WCO\6887L00\Rpt\MasterPlanSupp\ExecSummary\Draft\ES.doc Table 2 Comparison of New (2008) and 2007 Master Plan NPDES Permit Effluent Limitations (Continued) Wastewater Treatment Master Plan Supplement Executive Summary City of Modesto, California 2007 Master Plan New 2008 Limits Constituent Averaging Period Units Seasonal Discharge Limits Year Round Discharge Limits Seasonal Discharge Limits Year Round Discharge Limits EC Daily Maximum µmhos/cm 1,689 1,689 Average µmhos/cm - 1,341(2) 1,341(2) Chlorodibromomethane Daily Maximum µg/L 137.5 14.5 Average µg/L 5.0 Dichlorobromomethane Daily Maximum µg/L 70 70 25.7 Average µg/L 9.6 Carbon Tetrachloride Annual Average µg/L 4.5(4) 4.5(4) Daily Maximum µg/L 8.9 Manganese Annual Average µg/L 50 50 Iron Annual Average µg/L 300 300 Nitrate Average mg/L 10 42 10 Nitrite Average mg/L 1 1 pH Instantaneous Std. Units 6.5 - 8.5 6.5 - 8.5 6.5 - 8.5 6.5 - 8.5 Turbidity Instantaneous NTU 2 2 Flow Average Daily MGD 70 4.8 70 4.8 Aluminum Annual Average µg/L 200 200 200 200 Daily Maximum µg/L 750 Average µg/L 373 Notes: Calculated based on pH and temperature. Range is from 32.6 at pH 6.5 to 2.6 at pH 8.5. Interim limits. UV disinfection (which does not produce triholomethanes) will be used for year-round discharge. Calculated value based on 20:1 dilution. ---PAGE BREAK--- DRAFT - June 30, 2008 9 H:\Final\Modesto_WCO\6887L00\Rpt\MasterPlanSupp\ExecSummary\Draft\ES.doc The cost of providing nitrification for the existing seasonal discharge is greater than that required to provide tertiary treatment and year round discharge. In addition, it is uncertain if future permits will continue to allow a seasonal secondary effluent discharge to the San Joaquin River. As a result of the new permit limit for ammonia, it is recommended that all river discharges be upgraded to tertiary treatment prior to the 2013 compliance date. This results in the elimination of seasonal river discharge 3 years earlier than that anticipated in the Master Plan. 4.1.2 Year Round Discharge The Master Plan adopted the concept of utilizing the activated sludge process to provide nitrification and denitrification for year round discharge. The most cost-effective approach was to use the existing recirculation channel as a nitrification and denitrification reactor. However, due to its large volume with limited hydraulic and aeration control, it is unlikely that the recirculation channel will be a reliable process to meet the new, lower fixed ammonia limit, especially during the winter. Accordingly, the aeration basin configuration required to meet the new permit requirements for nitrification has been revised to include a plug-flow type reactor with fine bubble aeration. The reactor would consist of a new concrete tank with dividing walls. 4.2 Metals The biological nutrient removal (BNR)/tertiary treatment required for year round discharge will not incorporate the facultative ponds which are effective in removing metals such as aluminum and iron. Therefore, the BNR/tertiary process must be capable of removing metals without using the facultative ponds. Pilot testing of a membrane bioreactor (MBR) indicate that metals limits can be achieved with the MBR process. Other tertiary processes, such as media filtration, may not be adequate to reduce metals levels to within standards. 4.3 Salinity (as Electrical Conductivity) The interim limits for electrical conductivity (EC) can currently be met without additional treatment. These interim limits will be in effect until 2022 or 2026, depending on whether the year is a critically dry year or a normal year. For critically dry years, compliance is not required until 2026. The City will need to plan for further treatment or develop new waste management practices to reduce salinity in river discharges. The future limits will require a 25 percent reduction in EC from current levels, for September 1 through March 31, and a 48 percent reduction for April 1 through August 31. The new WDRs require that the City submit a workplan and schedule for complying with the new EC limits by June 1, 2009. ---PAGE BREAK--- DRAFT - June 30, 2008 10 H:\Final\Modesto_WCO\6887L00\Rpt\MasterPlanSupp\ExecSummary\Draft\ES.doc Options to reduce EC include: • Source Control. Reduce salinity by changing the potable water source from groundwater to surface water. The City has already converted 40 percent of its supply to surface water and is expected to convert 80 percent by 2010. In addition, the City will need to mandate salt reduction measures by industries and the public (such as banning the use of water softeners). The combined effect of these measures should be evaluated to estimate future effluent EC levels in the effluent. • Water Reuse. The total salinity mass load to the river can be reduced by diverting some of the effluent to water reuse. However, the salinity concentration would not be reduced by this approach. The current WDR requires a concentration-based limit, so using the mass-based emission approach would be a change in policy that would need to be approved by the regulatory agencies. • Additional Treatment. Additional treatment to reduce EC may be required. The most accepted salinity reduction process is reverse osmosis (RO). If the MBR process is utilized for BNR/tertiary treatment, it would be sufficient for pretreatment of the flow before reverse osmosis. Therefore, additional ultra filtration would not be required in subsequent phases if the MBR process is selected. Approximately 50 percent of the river discharge flow would require RO to meet future EC limits. For example, at 2030, the required RO capacity would be approximately 13 mgd, assuming the non- desalinated effluent would be blended with the RO effluent. 5.0 RECOMMENDED JENNINGS ROAD TREATMENT FACILITIES It is recommended that all seasonal secondary effluent discharge to the San Joaquin River be eliminated by the May 2013 compliance date required by the new permit. At that time, effluent quality would be upgraded to a tertiary level of treatment and river discharge would be year round. Secondary effluent and segregated cannery process water would continue to be utilized to irrigate the City’s 3,876 acre ranch. Upgraded treatment for year-round river discharge would consist of BNR with MBR. Treatment facilities would be constructed in three phases (1A, 2, and Table 3 presents the capacity requirements for the various phases. The staging was developed based on a 10th percentile river flow, in accordance with the Master Plan. The treatment process for subsequent phases would be similar to the Phase 1A process train. However, a plug flow type aeration basin would be used instead of the oxidation ditch reactor used for Phase 1A. The aeration basin would be aerated with fine bubble diffusers to provide increased efficiency. A blower building would also be required. Waste solids from the activated sludge process would be discharged to the recirculation channel and facultative ponds. Figures 3 and 4 show a flow schematic and conceptual layout, respectively of the proposed treatment facilities. ---PAGE BREAK--- DRAFT - June 30, 2008 11 H:\Final\Modesto_WCO\6887L00\Rpt\MasterPlanSupp\ExecSummary\Draft\ES.doc Table 3 Recommended Phasing Capacity Requirements Wastewater Treatment Master Plan Supplement Executive Summary City of Modesto, California 1 2 3 4 5=2+4 6=1-5 7 8 9 10=7+8+9 11=4+6+10 12=11-1 BNR/Tertiary Capacity Additions (mgd) Year Population Average Annual Flow (mgd) Secondary Effluent to Land (mgd)(3) Secondary Effluent to River, without DAF mgd(2) Secondary Effluent to River with DAF, mgd(1) Total Disposal Capacity Existing Facilities (mgd) Additional Disposal Capacity Required (mgd) Phase 1A Phase 2 Phase 3 Total BNR/Tertiary Capacity (mgd) Total Disposal Capacity (mgd) Excess Disposal Capacity Available (mgd) 2006 219,900 26.1 14.0 10.2 10.2 24.2 1.9 – – – 0.0 24.2 -1.9 2008 229,500 26.5 14.0 10.2 13.2 27.2 -0.7 – – – 0.0 27.2 0.7 2009 233,200 26.7 14.0 10.2 13.2 27.2 -0.5 2.3 – – 2.3 29.5 2.8 2011 240,500 27.5 14.0 10.2 13.2 27.2 0.3 2.3 – – 2.3 29.5 2.0 2013 267,400 28.7 14.0 10.2 13.2 27.2 1.5 2.3 18.4 – 20.7 34.7 19.2 2013 267,400 28.7 14.0 0 14.0 14.7 2.3 18.4 – 20.7 34.7 6.0 2022 309,100 34.7 14.0 0 14.0 20.7 2.3 18.4 6.0 26.7 40.7 6.0 2026 328,300 37.6 14.0 0 14.0 23.6 2.3 18.4 6.0 26.7 40.7 3.1 2030 355,000 40.7 14.0 0 14.0 26.7 2.3 18.4 6.0 26.7 40.7 0.0 Notes: DAF project adds the annual average equivalent of approximately 3.0 mgd. Assumes secondary effluent discharges to river and discontinued in 2013. DAF would no longer be used for effluent treatment and its use would be reassigned to waste-activated sludge thickening. Based on lowest 10th percentile river flow assumption. Includes evaporation/percolation loss of 5.9 mgd. Net effluent to land = 8.1 mgd. ---PAGE BREAK--- Recirculation Channel FFRs Facultative Ponds Storage Reservoirs Irrigation 14.0 14.0 mgd Figure 3 RECOMMENDED JENNINGS ROAD TREATMENT SCHEMATIC WASTEWATER TREATMENT MASTER PLAN SUPPLEMENT EXECUTIVE SUMMARY CITY OF MODESTO LEGEND 40.7 - Denotes flow in mgd at 2030 40.7 mgd mo708mpf3-6887.ai UV Disinfection (Open Channel) 24.4 mgd 26.7 mgd Return Activated Sludge Waste Activated Sludge BNR Aeration Basins 2.3 mgd 24.4 mgd Phase 2 - 18.4 mgd Phase 3 - 6.0 mgd BNR Oxidation Ditch Membrane Tanks Membrane Tanks UV Disinfection (In-Vessel) 2.3 mgd Return Activated Sludge Waste Activated Sludge S a n J o a q ui n Ri v e r 12 ---PAGE BREAK--- LEGEND Phase 1A Phase 2 Phase 3 PHASE 1A OPERATION CENTER SKID MOUNTED MEMBRANE ELECTRICAL BUILDINGS UV ELECTRICAL DIVERSION VALVES IN VESSEL UV AERATION BASINS PHASE 2 MEMBRANE LAYDOWN AREA MEMBRANE TANKS PHASE 2 MEMBRANE TANKS PHASE 3 RAS PUMP STATION PHASE 2 MEMBRANE SUPPORT EQUIPMENT BUILDING PHASE 2 RAS/WAS PUMP STATION PHASE 2 UV CHANNEL PHASE 2 UV CHANNEL PHASE 3 FINE SCREENS PHASE 2 OPERATIONS CENTER PHASE 2 RAS PUMP STATION PHASE 3 MEMBRANE SUPPORT EQUIPMENT BUILDING PHASE 3 MAIN ELEC BUILDING PHASE 2 PE PUMP STATION PHASE 3 PRIMARY EFFLUENT PUMP STATION PE PUMP STATION PHASE 2 FINE SCREENS PHASE 3 FINE SCREENS BIO FILTERS PHASE 2 BIO FILTERS PHASE 2 AERATION BASINS PHASE 3 UV ELECTRICAL PHASE 2 OXIDATION DITCH PHASE 1A BLOWER BUILDING PHASE 2 BIO FILTER COVER BIO FILTER COVER BIO FILTER COVER Figure 4 RECOMMENDED JENNINGS ROAD CONCEPTUAL SITE LAYOUT WASTEWATER TREATMENT MASTER PLAN SUPPLEMENT EXECUTIVE SUMMARY CITY OF MODESTO mo708mpf4-6887.ai 13 ---PAGE BREAK--- DRAFT - June 30, 2008 14 H:\Final\Modesto_WCO\6887L00\Rpt\MasterPlanSupp\ExecSummary\Draft\ES.doc 5.1 Salinity Reduction As described previously, the new WDRs require compliance with new EC (salinity) levels by the year 2022 for non-critically dry years and the year 2026 for critically dry years. The following describes the likely process, should treatment be required to achieve the new salinity limits. For planning purposes, it was assumed that the salinity removal process would consist of reverse osmosis (RO). RO produces a brine concentrate that requires expensive disposal. Brine can be disposed of by using brine concentrators and evaporation ponds, or deep well injection (if permitted by regulatory agencies). To achieve the new EC limits, the design output flow for the RO system would be about 13 mgd by the year 2030 (at the end of Phase Planning-level capital cost estimates were prepared for the RO system and brine disposal facilities, based on the capacity required for Phase 3. The capital costs are summarized in Table 4. As indicated, the cost for the RO system would be approximately $41.0 M in today’s dollars. The cost for brine disposal would be approximately $17.0 M for deep well injection or $177.5 M for the brine concentration/ evaporation pond system. These costs are very preliminary and would need to be verified in a separate study. Table 4 Estimated Capital Costs for Reverse Osmosis Systems Wastewater Treatment Master Plan Supplement Executive Summary City of Modesto, California June 2006 ENR Alternative Design Flow (mgd) Unit Process Phase 2 2013(1) $M 1 Zero Liquid Discharge 26.7 RO System 41.0 Brine Concentrator 94.2 Brine Ponds 83.3 Total 218.5 2 Deep Well Injection 26.7 RO System 41.0 Deep Well Injection 17.0 Total 58.0 Notes: June 2006 dollars. ENR CCI = 8441. Estimated capital costs include the following: estimating contingency - 30%, general conditions - contractor overhead and profit - engineering, legal and administrative - 20%, change order contingency - ---PAGE BREAK--- DRAFT - June 30, 2008 15 H:\Final\Modesto_WCO\6887L00\Rpt\MasterPlanSupp\ExecSummary\Draft\ES.doc If RO and brine disposal is required in the future, it will have a major impact on the City’s resources. It is likely that all municipal dischargers to the San Joaquin River will have similar limits, which could create a financial hardship for the entire region. Additional studies should be conducted to address the impacts and to possibly develop a regional solution to the salinity problem. Due to unknowns, it is considered too soon to include the RO/brine disposal system in the City’s capital improvements program. However, salinity will continue to be a major issue for the City and for all dischargers to the San Joaquin River. The final approach to meeting the new salinity limits will need to be refined as the overall solution evolves. 6.0 WASTEWATER TREATMENT CAPITAL IMPROVEMENT PROGRAM The overall recommended wastewater treatment capital improvement program (CIP) includes the upgrade of facilities at Jennings Road plus improvements to the Sutter Avenue Primary Treatment plant and Primary Effluent Outfall as described in the Master Plan. The implementation plan includes proposed staging of the project through year 2030. 6.1 Recommended Project The recommended wastewater treatment CIP consists of the following components: • Improvements to the Sutter Avenue Primary Treatment Plant to expand its hydraulic capacity, solids treatment capacity and to provide protection for a 100-year flood event. • Relining the primary effluent outfall (from Sutter Avenue to Jennings Road) to increase its hydraulic capacity and to improve reliability. • Expansion and upgrade of the Jennings Road Secondary Treatment Plant to increase domestic effluent disposal capacity and to comply with projected discharge requirements. • Specific special planning studies required throughout the planning period. These studies include engineering system analysis, periodic Master Plan updates, and detailed scientific studies to verify appropriate loadings and land application methodologies associated with segregated cannery process flows. The project components and estimated costs associated with the updated 2030 population projection are summarized in Table 5. All costs are based on June 2006 data to be consistent with those presented in the Master Plan and include allowances for contingencies, engineering, legal, and administrative expenses. Figure 5 is a schematic diagram for the recommended project. ---PAGE BREAK--- DRAFT - June 30, 2008 16 H:\Final\Modesto_WCO\6887L00\Rpt\MasterPlanSupp\ExecSummary\Draft\ES.doc Table 5 Total Revised Wastewater Treatment Capital Costs Wastewater Treatment Master Plan Supplement Executive Summary City of Modesto, California Costs in $M(1) Sutter Avenue Primary Treatment Plant Influent Flume Hydraulic Improvements 1.5 Bar Screen 0.6 Influent Pump 1.1 Grit Removal Unit 0.3 Primary Effluent Pump Station 9.3 Anaerobic Digester 4.8 Flood Control Improvements 14.0 Stormwater Pump Station 2.0 Sludge Dewatering 7.6 Subtotal Sutter Avenue Primary Plant 41.2 Primary Effluent Pipeline Lining of Existing Pipeline 23.2 Jennings Road Secondary Treatment Plant Dissolved Air Flotation Project 8.0 BNR/Tertiary Improvements Phase 1A Improvements 20.6 Phase 2 and 3 Improvements PE Pump Station 6.9 Fine Screens 5.3 Aeration Basins 30.4 Blower Building 12.3 RAS/WAS pump station 6.7 Membrane Tanks 63.7 UV Disinfection 15.1 Effluent Pipeline from Tertiary Plant to Exist. Outfall 10.5 New WAS inlet 0.2 Standby power 2.7 Reverse Osmosis System (if required) 0(2) Brine Disposal (if required) 0(2) Operations Center 3.5 Subtotal BNR/Tertiary Improvements 177.9 Improvements to Existing Facilities Conversion from Chlorine Gas to Hypochlorite 1.4 Effluent Pump Station Improvements 3.0 Outfall Improvements 4.0 Flood Control Improvements 0.2 Fixed Film Reactor Improvements and Odor Control 7.5 Subtotal Improvements to Existing Facilities 16.1 Subtotal Jennings Road Secondary/Tertiary Plant 202.0 Special Planning Studies 10.6 Total Project 277.0 Note: Conceptual level costs. Based on June 2006 dollars (ENRCCI = 8441). Includes allowances for contingencies, engineering, legal and administrative expenses. These processes may be required to comply with the future salinity TMDL in either 2022 or 2026. Costs range from $58 M to $218 M depending on brine disposal system chosen (see Chapter Costs are not included at this time pending further development of a salinity reduction program. ---PAGE BREAK--- Figure 5 RECOMMENDED PROJECT SCHEMATIC WASTEWATER TREATMENT MASTER PLAN SUPPLEMENT EXECUTIVE SUMMARY CITY OF MODESTO Anaerobic Digesters (add one) Existing Facilities Sutter Avenue Improvements Jennings Road Improvements Facilities to be Discontinued at Phase 2 LEGEND Sludge Drying Beds (line with concrete) Cannery Wastewater (Season: Jul-Sep) Headworks Facility (add 1 pump, bar screen, and grit removal mechanism) 40.7 mgd at Build-Out Domestic Wastewater Sutter Avenue Facility Primary Clarifiers Pumping Plant No. 3 FFRs 14 mgd Facultative Ponds Chlorine Contact Tank Effluent PS S a n J o a q ui n Ri v e r Land Application Site (2,526 Acres) Primary Effluent PS Recirculation Channel 60-inch Primary Effluent Outfall (add plastic liner) 60-inch Cannery Process Water Outfall Primary Effluent PS FFR Influent PS Influent PS Storage Ponds Dissolved Air Flotation Jennings Road Facility mo708mpf5-6887.ai Aeration Basins Membrane Tanks WAS Phase 1A - 2.3 mgd Oxidation Ditch To Recirculation Channel/ Facultative Ponds Permeate RAS WAS Permeate RAS Ultraviolet Disinfection (Open Channel) UV Disinfection (In-Vessel) Rotary Fine Screens Rotary Fine Screens Phase 2 and 3 - 24.4 mgd To Recirculation Channel/ Facultative Ponds 17 ---PAGE BREAK--- DRAFT - June 30, 2008 18 H:\Final\Modesto_WCO\6887L00\Rpt\MasterPlanSupp\ExecSummary\Draft\ES.doc 6.2 PROJECT IMPLEMENTATION PLAN The implementation plan was revised from the Master Plan to reflect the new waste discharge requirements and their compliance schedule, and to account for updated flow and loading projections. Figure 6 shows the required tertiary treatment capacity needs and a phasing plan that would strictly follow the capacity needs for “just in time” phasing. Under this approach the tertiary phasing would be: 1A - 2.3 mgd (2010), Phase 2 - 18.4 mgd (2013), and Phase 3 - 6 mgd (2022). Phase 2A was added to spread out the costs between the Sutter Ave Facility and Jennings Road improvements. Table 6 summarizes the estimated project capital cost for each place. Figure 7 is a near-term, implementation schedule for Phases 1A and 2. Figure 8 presents the estimated long-term schedule for all project phases. ---PAGE BREAK--- mo708mpf6-6887.ai 27.2 29.5 34.7 36.5 40.7 24.2 14.0 5.9 Year Capacity for Land Discharge Capacity for River Discharge Capacity for Tertiary-Treated Effluent Discharge Capacity Deficiencies Domestic Wastewater Flow, mgd 2005 50 40 30 20 10 0 2010 2011 2013 2008 2009 2015 2016 2020 2025 2022 2030 Figure 6 REQUIRED TERTIARY TREATMENT CAPACITY NEEDS AND PHASING PLAN WASTEWATER TREATMENT MASTER PLAN SUPPLEMENT EXECUTIVE SUMMARY CITY OF MODESTO 19 Projected Domestic Wastewater Flow(1) (annual average flow) Domestic secondary effluent to land (8.1 mgd) (2,526 acres) BNR/tertiary river discharge Phase 1A 2.3 mgd Phase 2 18.4 mgd(2) Phase 3 6.0 mgd Seasonal river discharge of secondary effluent (10.2 mgd(3)) DAF (3.0 mgd) Net evaporation loss (5.9 mgd) Notes: 1. Based on 0.7% growth to 2011 and then 1.75% growth to 2030. 2. Assumes discontinuation of secondary effluent discharge to river in 2013 and phase out of DAF. 3. Based on 10th percentile river flow conditions. ---PAGE BREAK--- DRAFT - June 30, 2008 20 H:\Final\Modesto_WCO\6887L00\Rpt\MasterPlanSupp\ExecSummary\Draft\ES.doc Table 6 Wastewater Treatment CIP Cost Phasing Wastewater Treatment Master Plan Supplement Executive Summary City of Modesto, California Conceptual Level Costs - $M(1) Project Phases: DAF Phase 1A Phase 2 Phase 2A Phase 3 Total Approximate Year of Implementation: 2008 2010 2013 2018 2022 Costs Sutter Avenue Primary Treatment Plant Influent Flume Hydraulic Improvements 1.5 1.5 Bar Screen 0.6 0.6 Influent Pump 1.1 1.1 Grit Removal Unit 0.3 0.3 Primary Effluent Pump Station 9.3 9.3 Anaerobic Digester 4.8 4.8 Flood Control Improvements 14.0 14.0 Stormwater Pump Station 2.0 2.0 Sludge Dewatering 7.6 7.6 Subtotal Sutter Avenue Primary Plant 0.0 14.1 27.1 0.0 41.2 Primary Effluent Pipeline Lining of Existing Pipeline 23.2 23.2 Jennings Road Secondary Treatment Plant Dissolved Air Flotation Project 8.0 0.0 0.0 0.0 8.0 BNR/Tertiary Improvements Phase 1A Improvements 20.6 20.6 PE Pump Station 5.2 1.7 6.9 Fine Screens 4.0 1.3 5.3 Aeration Basins 22.9 7.5 30.4 Blower Building 9.3 3.0 12.3 ML/WAS pump station 5.0 1.7 6.7 Membrane Tanks 48.0 15.7 63.7 UV Disinfection 11.4 3.7 15.1 Effluent Pipeline from Tertiary Plant to Exist. Outfall-- 10.5 0.0 10.5 New WAS inlet 0.2 0.2 Standby power 2.0 0.7 2.7 Reverse Osmosis System 0 0 0(2) Brine Disposal 0 0 0(2) Operations Center 3.5 0.0 3.5 Subtotal BNR/Tertiary Improvements 0.0 20.6 122.0 0 35.3 177.9 ---PAGE BREAK--- DRAFT - June 30, 2008 21 H:\Final\Modesto_WCO\6887L00\Rpt\MasterPlanSupp\ExecSummary\Draft\ES.doc Table 6 Wastewater Treatment CIP Cost Phasing (Continued) Wastewater Treatment Master Plan Supplement Executive Summary City of Modesto, California Conceptual Level Costs - $M(1) DAF Phase 1A Phase 2 Phase 2A Phase 3 Total Project Phases: Approximate Year of Implementation: 2008 2009 2013 2018 2022 Costs Improvements to Existing Facilities Conversion from Chlorine Gas to Hypochlorite 1.4 0.0 1.4 Effluent Pump Station Improvements 3.0 0.0 3.0 Outfall Improvements 4.0 0.0 4.0 Flood Control Improvements 0.2 0.0 0.2 Fixed Film Reactor Improvements and Odor Control 7.5 0.0 0.0 7.5 Subtotal Improvements to Existing Facilities 0.0 1.4 11.7 3.0 0.0 16.1 Subtotal Jennings Road Secondary/Tert. Plant 8.0 22.0 133.7 3.0 35.3 202.0 Special Planning Studies Engineering System Analysis 0 0.6 0.8 1.1 1.1 3.6 Master Plan Updates 1.0 2.0 1.0 2.0 6.0 Land Application Studies 1.0 1.0 Subtotal Special Planning Studies 0 2.6 2.8 2.1 3.1 10.6 Total Project 8.0 47.8 150.6 32.2 38.4 277.0 Note: Conceptual level costs. Based on June 2006 dollars (ENR CCI = 8441). Includes allowances for contingencies, engineering, legal and administrative expenses. See note from Table 5. ---PAGE BREAK--- mo708mps1-6887.ai Figure 7 NEAR TERM PROJECT SCHEDULE WASTEWATER TREATMENT MASTER PLAN SUPPLEMENT EXECUTIVE SUMMARY CITY OF MODESTO 2008 2009 2010 2011 2012 2013 M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S Phase 1A - BNR/Tertiary Facilities at Jennings Rd Design Bidding and Award (3 months) Construction (18 months) Startup (6 months) Phase 2 - BNR/Tertiary Facilities at Jennings Rd, Digester and Primary Effluent Pump Station Improvments at Sutter Ave Preliminary Design (6 months) Design (12 months) Bidding and Award (3 months) Construction (30 months) Startup (6 months) Compliance Date per Tentative Order (May 2013) 22 ---PAGE BREAK--- mo708mps2-6887.ai Figure 8 LONG TERM PROJECT SCHEDULE WASTEWATER TREATMENT MASTER PLAN SUPPLEMENT EXECUTIVE SUMMARY CITY OF MODESTO Phase 1A - BNR/Tertiary Facilities at Jennings Rd Phase 2 - BNR/Tertiary Facilities at Jennings Rd. Digester and Primary Effluent Pump Station Improvments at Sutter Ave Phase 2A - Other Sutter Ave. Improvments Phase 3 - BNR/Tertiary Facilities at Jennings Rd Compliance Date per Tentative Order (May 2013) 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Design Bidding and Award (3 months) Construction (18 months) Startup (6 months) Preliminary Design (6 months) Design (12 months) Bidding and Award (3 months) Construction (30 months) Startup (6 months) Startup Construction Design Bidding and Award Startup (6 months) Construction (24 months) Bidding and Award (3 months) Design (12 months) 23