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07.a. Receive information on wastewater supply versus recycled water demand
Page 1 of 74 Item 7.a. Central Contra Costa Sanitary District March 1, 2018 TO: HONORABLE BOARD OF DIRECTORS FROM: DAN FROST, SENIOR ENGINEER MELODY LABELLA, RESOURCE RECOVERY PROGRAM MANAGER REVIEWED BY: DANEA GEMMELL, PLANNING AND DEVELOPMENT SERVICES DIVISION MANAGER JEAN-MARC PETIT, DIRECTOR OF ENGINEERING AND TECHNICAL SERVICES ROGER S. BAILEY, GENERAL MANAGER SUBJECT: RECEIVE INFORMATION ON WASTEWATER SUPPLYVERSUS RECYCLED WATER DEMAND With a growing number of raw wastewater diversion requests and future recycled water commitments and goals, staff would like to review Central San's current and future wastewater supply against upcoming and potential future diversions and recycled water demands to ensure that the Board has the best available information to support its decision-making. Staff provides an overview of this topic in the attached PowerPoint presentation. The attached white paper, endorsed by the California Association of Sanitation Agencies (CASA), Wate Reuse California, California Water Environment Association (CW EA), and the Water Research Foundation, highlights the impacts to wastewater conveyance, treatment systems, and recycled water projects due to declining flows. Staff looks forward to reviewing this information with you at the March 1, 2018 Board meeting. Strategic Plan Tie-In GOAL SIX: Embrace Technology, Innovation and Environmental Sustainability Strategy 1 -Augment the Region's Water Supply ATTACHMENTS: March 1, 2018 Regular Board Meeting Agenda Packet- Page 57 of 225 Page 2 of 74 1. Wastewater Supply vs. Recycled Water Demand Presentation 2. White Paper-Adapting to Change: Utility Systems and Declining Flows March 1, 2018 Regular Board Meeting Agenda Packet- Page 58 of 225 C r WASTEWATER SUPPLY VS . RECYCLED WATER DEMAND s � Jean-Marc Petit, Director of Engineering & Technical Services March 1 , 2018 got .i Board Meeting March 1, 201 rd Meeti - r RECYCLED WATER USES )T77 dMb 01 ,I - Treatment .FAX w_ S - c Plant Suisun Bay Discharge Water Exchange Project Plant Filter Plant Advanced Utility & Treatment ? _ ===- Water Clearwell Facilities Martinez zone 1 Refineries .• Recycled �` ii Water t■■..............., :. :My i1 Concord 7, Contra Costa Water Reuse District/Santa Clara Project Valley Water District Water Exchange — WATER DIVERSIONS Treatment Plant Suisun Bay Discharge co Plant Filter Plant Advanced utility <— & Treatment Water Clearwell Facilities Martinez zone Refineries Recycled 11 Water Diablo Other Country Diversions? Club Diversion Concord Contra Costa Water Reuse District/Santa Clara Project Valley Water District Water Exchange NA-qrrh 1 gni a nri ria n Pnrkpt- Pnnp R1 nf 99r; CURRENT COMMITMENTS Plant Utility Water Zone 1 Concord Community Reuse Project (Naval Weapon Station ) — Will Serve Letter Diablo Country Club Satellite Water Recycling Facility (SWRF) Memorandums of Understanding (MOUs) : Moraga Country Club SWRF Water Exchange Board support letter in December 2017 MOU with CCWD and SCVWD in development 1 Title 22 CHALLENGE including Flow Concord Variability Community Reuse Project (CGRP) CHALLENGE Reduced Flow Water from Exchange Diversions Project STORAGE TYPICALLY ADDRESSES HOURLY & TEMPORARY WATER SUPPLY SHORTAGES I I I I I I I ♦Treatment Plant Flow(Water Supply Available) Peak Day Recycled Water Demand (Water Demand) I 3 0 0-4 0 W ter Supply Available >Water De and Wi ter Supply Available < Water De and Storage can help address hourly &temporary water supply challenges as long as the seasonal supply is more than the seasonal demand 12:00 AM 3:00 AM 6:00 AM 9:00 AM 12:00 PM 3:00 PM 6:00 PM 9:00 PM 12:00 AM =- STORAGE MAY NOT BE PRACTICAL FOR ROUTINE WATER SUPPLY SHORTAGES I I I }Treatment Plant Flow (Water Supply Available) Peak Day Recycled Water Demand (Water Demand) lO 77A O Wter Supply >Water D mand W ter Suppl < Water D mand i I Storage may not be practical if the seasonal supply is consistently less than the seasonal demand 12:00 AM 3:00 AM 6:00 AM 9:00 AM 12:00 PM 3:00 PM 6:00 PM 9:00 PM 12:00 AM =- WATER SUPPLY VERSUS WATER DEMAND 60 Sena Utility Water Peak Day Recycled Water Demand (Hourly Avg=1.2 mgd) -&a Zone 1 Peak Day Recycled Water Demand (Hourly Avg=2.2 mgd) (Total Current Peak Day Recycled Water Demand (Hourly Avg=3.4 mgd) e!-a CCRP Peak Day Recycled Water Demand (Hourly Avg=5.8 mgd) --S--Estimated Future Peak Day Title 22 Recycled Water Demand (Hourly Avg=9.2 mgd) 50 p-0 a Water Exchange Recycled Water Demand (Hourly Avg=23 mgd, 20 mgd +3 mgd Brine Reject) Total Future Peak Day Recycled Water Demand (32.2 mgd) 40 I � � E 30 - — 3 v ... .. .. .. .. .. .. .. .. .. .. peep.. .. .. .. ..�.. .. ..�.. .. ...� 20 -- 10 - - - .. ■.• pp�r.. .. .. .. .. .. .. .. 4.. . .. .. .. Sit-Ov 0 1 f I 12:00 AM 3:00 AM 6:00 AM 9:00 AM 12:00 PM 3:00 PM 6:00 PM 9:00 PM 12:00 AM March 1, 2018 Regular Board Meeting Agenda Packet- Page 66 of 225 WATER SUPPLY VERSUS WATER nEMAND 60 (Total Current Peak Day Recycled Water Demand {Hourly Avg=3.4 mgd} Estimated Future Peak Day Title 22 Recycled Water Demand {Hourly Avg=9.2 mgd} Total Future Peak Day Recycled Water Demand (Hourly Avg=32.2 mgd) •-6• Current Plant Influent ADWF{Hourly Avg=33 mgd} —&-Drought Year Influent ADWF e.g. 2015{Hourly Avg=27.4 mgd} 50 --@--Drought Year Influent ADWF Minus DCC SWRF{Hourly Avg=27.4-0.7=26.7 mgd} .. I • ■ ■ 40E 30 • •, 3 G LL 20 - 10 0 12:00 AM 3:00 AM 6:00 AM 9:00 AM 12:00 PM 3:00 PM 6:00 PM 9:00 PM 12:00 AM March 1, 2018 Regular Board Meeting Agenda Packet- Page 67 of 225 WATER SUPPLY VERSUS WATER DEMAND 60 (Total Current Peak Day Recycled Water Demand (Hourly Avg=3.4 mgd) Estimated Future Peak Day Title 22 Recycled Water Demand (Hourly Avg=9.2 mgd) (Total Future Peak Day Recycled Water Demand {Hourly Avg=32.2 mgd} f Draught Year Influent ADWF Minus DCC SWRF{Hourly Avg=27.4-0.7=26.7 mgd} ••!-• Future 2035 Drought Year Influent ADWF {Hourly Avg=39 mgd} •. 50 —*--Future 2035 Drought Year Influent ADWF Minus DCC SWRF {Hourly Avg=38.3 mgd} ' 40 I NO E 30 - - v � I 20 - 10 0 12:00 AM 3:00 AM 6:00 AM 9:00 AM 12:00 PM 3:00 PM 6:00 PM 9:00 PM 12:00 AM March 1, 2018 Regular Board Meeting Agenda Packet- Page 68 of 225 WATER SUPPLY VERSUS WATER DEMAND 60 ♦Total Current Peak Day Recycled Water Demand (Hourly Avg=3.4 mgd) Estimated Future Peak Day Title 22 RecycIed Water Demand (Hourly Avg=9.2 mgd) (Total Future Peak Day Recycled Water Demand (Hourly Avg=32.2 mgd) #Drought Year Influent ADWF Minus DCC SWRF (Hourly Avg=27.4-0.7=26.7 mgd) IL #Future 2035 Draught Year Influent ADWF Minus DCC SWRF (Hourly Avg=38.3 mgd) 50 - How much water (effluent) is required for diluting RO brine k*N 0-40...;/ to Outfall? Brine & dilution water storage required? E 30 - - 3 v 20 I - 10 - - 0 12:00 AM 3:00 AM 6:00 AM 9:00 AM 12:00 PM 3:00 PM 6:00 PM 9:00 PM 12:00 AM March 1, 2018 Regular Board Meeting Agenda Packet- Page 69 of 225 WHITE PAPER HIGHLIGHTS CHALLENGES WHILE ADAPTING TO DECLINING FLOWS AW-II-EPS M Holistic strategyfor water adapting to Change: Utility Systems and Declining Flows supply reliability table of contents// CONSERVE WAT M L& �# Impacts from declinin flows: RECLAIMED WATER IN USE ➢ Water Distribution DO DRINK" ' • S E SA Wastewater Conveyance ��•� � y Treatment Plant Operations ➢ Recycled Water Projects � A E.Ill.r.l. Water CASA O WATEREUSE '"" Research E.rlrr.n.n a lAriF:IRAVA A.i.�l.elt. FOiAtIL�dVQI1' Rssatiatiun �,F California IYVater Ag"cie$ CALIFORNIA ■R•AN NATAR AGENCIES WHITE PAPER HIGHLIGHTS CHALLENGES WHILE ADAPTING TO DECLINING FLOWS Drinking Water Distribution • Changes in water quality • Increased pipeline flushing Increased flushing Increased nitrification Recycled Water Changing irill uentwater quality Wastewater (increased ammonia loadingy Conveyance Decrease in recycled Increased odor production water production and complaints - Complaints from end users Increased rate of corrosion about water quality(i.e.salinity) Exacerbated settling and - Reduction in ability to offset blockages potable use • Increased number of 0&M work orders Wastewater Treatment Chang ng infl uentwater quality (increased ammonia loading) Potential to exceed discharge permit requirements POSSIBLE POLICY GUIDANCE ULTIMATELY NEEDED How do we prioritize potential future diversion & recycled water customers beyond existing commitments? First come first serve requests? Preference for year-round versus seasonal recycled water projects? Do we consider the value of wastewater? 1 NEXT STEPS Formal water balance evaluation with Woodard & Curran (formerly RMC) Coordinate further with CCWD and refineries on refinery demands & water quality requirements Finalize and approve MOU with CCWD and SCVWD for water exchange project Evaluate brine management options Develop a policy on recycled water if so desired 1 QUESTIONS ? "March 11 2018 R gar g Agenda - Page 19 of 74 A WHITE PAPER Adapting to Chang e : Utility Systems and Declining Flows NOVEMBER 2017 table of • I Executive Summary . ► 2 Supporting Supply Reliability 1 r3 Supporting • • California Way of Impacts • Declining Flowson RECLAIMED MATER IN USE Distribution 5 Impacts of Declining Conveyance 10 ! 06 Impacts • Declining Flows on Treatment Plant Operations 7 Impacts of Declining Flows on Recycled Water Projects z• ��k� 8 Policy Recommendations 9 References 10 • Abbreviations • California , Water CASA WAT EREUSE Water Research Environment - CALIFORNIA Association Foundation- Association of California Water Agencies CALIFORNIA URBAN WATER AGENCIES '�-,fr arra�ikin .4r=n•irn March 1, 2018 Regular Board Meeting Agenda Packet- Page 75 of 225 Page 20 of 74 SECTION 1 Executive Summary Drought is a recurring phenomenon in California, and dry periods are increasing in intensity and duration because of climate change, as demonstrated by the extreme and unprecedented drought over the past 5 years that has largely redefined the driest period on record. As the state's population continues to grow, there is a greater awareness of the need to maintain water supplies for both human consumption and wildlife habitats. Wise water use is a critical part of addressing California's new realities in a sustainable manner. At the same time, declining flows also create ancillary system impacts worthy of consideration. During the recent historic drought, Californians responded to the Working to understand call for emergency statewide water use reductions, which the state the impacts of has recognized as a highly successful outcome. However, this declining flows significant reduction in water demands has brought to light some unintended consequences of declining flows that ripple throughout the interconnected urban water cycle. These observations offer a 270 survey responses preview into the potential impact of establishing permanent indoor received water use targets at or below the thresholds achieved as a result of the governor's emergency conservation mandate. O O utilities interviewed California's water industry leaders, including regulators and purveyors, are working to understand the system-wide impacts of 50 p�0 of survey increased conservation so that decision makers are better informed respondents experienced an as they address California's current and future water challenges. impact on their drinking Through a partnership with California Association of Sanitation water, wastewater, or recycled-water infrastructure Agencies (CASA), Water Research Foundation (WRF), WateReuse California, and California Water Environment Association (CWEA), California Water Urban Agencies (CUWA) has developed this white paper to provide decision makers, water/wastewater system managers, and other stakeholders an understanding of the impacts of declining flows resulting from substantial reductions in indoor water use and how utilities are adapting to these circumstances. 2 March 1, 2018 Regular Board Meeting Agenda Packet- Page 76 of 225 Page 21 of 74 This white paper has been informed by the following activities: • Conducting a literature review to gain a foundational understanding of what impacts utilities may be experiencing because of declining flows • Distributing a high-level survey to determine the level and range of observed impacts in California • Holding one-on-one interviews and developing case studies to illustrate the broad range of issues agencies are experiencing and their associated impact Wisely managing demands is foundational to ensuring reliable water Conservation supply in years to come. California water agencies continue to prioritize wise water use through both short-term conservation (i.e., in Short-term,emergency response to a drought or emergency) and long-term efficiencies for response for demand lasting, sustainable effects. While some people use the term reductions during a drought "conservation"to describe both short-term and long-term strategies, this white paper distinguishes between conservation as an Water use efficiency emergency response to drought and water use efficiency(WUE) as a Long-term strategy for more long-term strategy for lasting demand reductions. Our objective is to sustained demand leverage the recent observations of utilities impacted by emergency management conservation measures in 2015 and 2016 to inform the state's long- term WUE policies. Efficient use of our water resources can have major environmental, public-health, and economic benefits by helping to improve water quality, maintain aquatic ecosystems, and protect drinking water resources. Potential benefits of demand management include: • Improved drought resilience • Sustained instream flows to support water quality and wildlife • Reduced, deferred, or avoided costs of new infrastructure or additional supply • Reduced energy costs due to decreased pumping of wastewater Demand management consequently decreases flows within the interconnected urban water cycle impacting drinking water distribution and water quality, wastewater conveyance and treatment, and recycled water production and quality (Figure ES-1). Drinking Water Distribution • Ghangesanges pipeliwater gflushi • ty Increased pipeline flushing • Increased flushing Increased nitrification Recycled Water • Changing influent water quality �� 1 Wastewater (increased ammonia loading) ` Conveyance Decrease• Decrease in recycled Increased odor production water production 's / and complaints • Complaints from end users — Increased rate of corrosion about water quality(i.e.salinity) • Reducti on in ability to offset Fxedsetdingand potable use _ blockages Increasednumberof0&M ` work orders I Wastewater Treatment , • Changing influent water quality (increased ammonia loading) • Potential to exceed discharge permit requirements Figure ES-1. Declining flows in the urban water cycle can potentially impact all areas of the cycle. 3 March 1, 2018 Regular Board Meeting Agenda Packet- Page 77 of 225 Page 22 of 74 Impacts on Water Distribution Systems With declining water system flows, drinking water has a longer residence time in pipes, leading to chemical, biological, and Of the impacted water physical water quality issues and potentially compromising public health and compliance with the Safe Drinking Water Act, system respondents, particularly for disinfection by-products (DBPs), coliform bacteria, 49% reported chlorine residual, and lead and copper action levels operational challenges A great deal of work has been done to address these concerns. in water distribution Best management practices include improving the hydraulics in storage facilities and managing water chemistry. Improvements systems due to low in storage facilities include installing baffling systems and flows. increasing the turnover rate through deep cycling pumping and tank mixing. Many water systems have implemented aggressive nitrification control and disinfection residual and DBP control practices. Water suppliers also increase pipeline flushing and discharge water from distribution system reservoirs as necessary. These mitigation methods are certainly feasible,though some system improvements and operational changes can take years to plan and implement, thus highlighting the importance of allowing sufficient time to adapt to declining flows with future WUE objectives. Impacts on Wastewater Conveyance Systems Declining system flows decrease wastewater flows and may increase pollutant and solids concentrations, which increase blockages, Of the impacted odors, and corrosion in pipes. This leads to increases in operation and maintenance (0&M) costs, odor complaints, and an accelerated wastewater degradation of infrastructure. conveyance Preventive measures are in place to mitigate blockages, including the use of garbage disposals that break up food waste and installing respondents, 50% grease traps/interceptors as necessary. However, declining flow can indicated increased exacerbate blockages. Furthermore,the increased concentration of solids deposition, organics and solids can lead to elevated levels of hydrogen sulfide (H2S) production. In addition to an increase in odors, higher levels of odor problems, and H2S can accelerate the rate of corrosion within the wastewater O&M challenges. infrastructure. 4 March 1, 2018 Regular Board Meeting Agenda Packet- Page 78 of 225 Page 23 of 74 Impacts on Wastewater Treatment Plant Operation Declining flows change the characteristics of wastewater, including the quantity and quality of wastewater treatment plant Of the impacted (WWTP) influent, causing impacts and stressing treatment processes as s salinity, ammonia, and biochemical oxygen wastewater treatment demand (BOD) concentrations increase beyond design respondents, 68% specifications. indicated changes in The effluent from WWTPs is held to standards mandated by their individual National Pollutant Discharge Elimination System wastewater influent (NPDES) permits, including effluent quality limits for constituents quality. like ammonia. Increasing influent concentrations can impact effluent quality, straining a plant's ability to meet its discharge permit requirements. To avoid exceeding permit limits, utilities may have to consider implementing costly WWTP upgrades. In addition to the noted changes in influent water quality, more than 40 percent of impacted survey respondents are facing subsequent challenges in meeting compliance requirements with respect to effluent quality. Impacts on Recycled Water Projects Declining flows can alter treatment and cost-effectiveness of recycled-water infrastructure by altering factors considered in Of the impacted system design, like anticipated flow and water quality. In California, the desire to improve water supply reliability has recycled water motivated water utilities to expand water reuse through non- respondents, 70% potable applications such as irrigation as well as potable reuse indicated a decrease in through groundwater or surface water augmentation and eventually raw or treated water augmentation. To expand water recycled water reuse statewide, California utilities are designing and production. constructing new infrastructure to treat and distribute the recycled and/or purified water. Thus, declining flows could lead to underutilized assets and could limit the ability to meet the state's water reuse goals of at least 1.5 million acre-feet per year (MAF/year) by 2020 and 2.5 MAF/year by 2030. As indoor residential water use decreases, the availability of treated wastewater for water reuse decreases,thus decreasing production potential. Declining flows can also result in generation of more concentrated wastewater streams, with elevated concentrations of total dissolved solids (TDS), nitrogen species, and organics. Informing Policy on Long-Term Water Use Efficiency Long-term WUE can produce many benefits as well as some ancillary effects on the water, wastewater, and recycled water systems. These impacts can be balanced through informed policy and achievable time frames. Regulators and utilities have been leading the charge in tackling California's ever-growing water challenges. When developing long-term WUE policy, the significantly interconnected nature of the system must be considered, and a holistic, one-water view can benefit smart policy and provide better solutions in managing California's water resources. 5 March 1, 2018 Regular Board Meeting Agenda Packet- Page 79 of 225 Page 24 of 74 -,TION 2 Supporting a Holistic Strategy for Water Supply Reliability Drought is a recurring phenomenon in California, and dry periods are increasing in intensity and duration because of climate change. Meanwhile, our population continues to grow and there is a greater awareness of our need to maintain water supplies for both human consumption and wildlife habitats. Wise water use is critical to supporting water supply reliability and resilience, and understanding its impacts on the interconnected water system supports a holistic approach to addressing California's water supply challenges. Utilities have been leading the charge in tackling California's water supply challenges, implementing innovative programs and California's water infrastructure to develop drought-resilient water systems. Part of this industry leaders are strategy is reducing California's overall demand on this finite working to resource. During the recent historic drought, Californians responded to the call for emergency statewide water use reductions, reducing understand how their use by as much as 31 percent in July 2015, which the State declining flows can has recognized as a highly successful outcome. However, this significant reduction in water demands brought to light some impact the unintended consequences of declining flows that ripple throughout interconnected the interconnected water supply system.These observations offer a water system to preview into the potential impact of establishing permanent indoor water use targets at or below the thresholds achieved as a result of help utilities most the governor's emergency conservation mandate. effectively address Through a partnership with California Association of Sanitation current and future Agencies (CASA), Water Research Foundation (WRF), WateReuse California, and California Water Environment Association (CWEA), water supply California Water Urban Agencies (CUWA) has developed this white challenges. paper to provide decision makers, water/wastewater system managers, and other stakeholders an understanding of the impacts of declining flows resulting from substantial reductions in indoor water use and how utilities are adapting to these circumstances. This research is intended to support long-term water use efficiency (WUE) planning and inform its development within the context of the entire urban water cycle to maximize the inherent benefits while mitigating negative impacts on our interconnected water systems. 6 March 1, 2018 Regular Board Meeting Agenda Packet- Page 80 of 225 Page 25 of 74 Distinguishing between Conservation and Water Use Efficiency Wisely managing demands is foundational to ensuring reliable water supply in years to come. California water agencies continue to prioritize Conservation wise water use through both short-term conservation efforts (i.e., in response to drought or emergency) and long-term WUE for lasting, Short-term,emergency sustainable effects. While some people use the term "conservation" to response for demand describe both short-term and long-term strategies,this white paper reductions during a drought distinguishes between conservation as an emergency response to drought and WUE as a long-term strategy for lasting demand reductions. Water use efficiency Our objective is to leverage the recent observations of utilities impacted Long-term strategy for more by emergency conservation measures in 2015 and 2016 to inform the sustained demand State's long-term WUE policies. Given the interconnected nature of our management water system (Figure 1), and that many decision makers and stakeholders have expressed strong interest in keeping water demands at emergency reduction levels, it is critical to review the lessons learned from this recent experience to inform how to optimize future water management. The One Water Cycle ri 6�OpkG W,�iFq O WATER TREATMENT ©WASTEWATER TREATMENT © '''y ©AOYANCEG 7REAYMENT �I111 EurtT - ' OGIGRM WATER MANAGEMENT V y.. SUSTAINABLE REVELGPMENT 1 44 W _ �^ GRf£N INFRASIfl VCIllflE R � I �w ,• ,I p ���' eWp V I I I P: _ �Ott{{,, ,.•9G l, SPP'9p,; 1 1 1 1 1 1 0 0 0 0 .. '•,'Yii, ••..CbE. ., '., Ham' - �I IIII I �a a InIn.N A FR dISCHAaGE © '�� O, VQ l 5 EP o' Figure 1. Understanding how the WUE strategies can affect an interconnected water supply system is critical to optimizing future water management. Source:Brown and Caldwell,2017 7 March 1, 2018 Regular Board Meeting Agenda Packet- Page 81 of 225 Page 26 of 74 Working to Understand the Impacts of Declining Flows This white paper was informed by the following: • A literature review to gain a foundational understanding of what 270 survey impacts utilities may be experiencing because of declining flows responses received • A high-level survey to determine the level and range of observed O impacts in California utilities interviewed • In-depth interviews and developing case studies to illustrate the broad range of issues agencies are experiencing and their 50 p�0 of survey associated impact respondents Through their collective membership, CASA, CWEA, and the Association experienced an impact of California Water Agencies (ACWA) distributed a high-level survey to on their drinking determine how widespread the impacts of declining flows had been felt water, wastewater, or in California during the drought.The survey sought input from recycled-water respondents regarding their experience with the impacts identified infrastructure during the literature review, namely the "key indicators of impacts" highlighted in each section. A total of 270 distinct responses were received, representing agencies throughout California. Respondents represented an array of services and service area sizes, as indicated in Figures 2 and 3, respectively. Given that agencies often provide multiple services, the survey was designed to give utilities the ability to address impacts on each part of their system. Services Provided Service Area Other 6% Water ' 1M < 100,000 31% 18% 49% Recycled Wastewater Water 39% 24% 100,0001M 33% ■Water ■Recycled Water ■Wastewater ■Other •<100,000 •100,000-1M •>1M Figures 2(left)and 3(right).Survey respondents represented wastewater,water, and recycled water service providers that served service areas ranging from less than 100,000 to more than 1 million. The nature of the survey allowed respondents to choose whether to identify themselves or remain anonymous. Out of the 270 responses, 74 distinct utilities shared their information and are listed in Appendix B. As illustrated in Figure 4, 70 out of the 74 identified utilities indicated that they experienced some kind of impact on their system. From the list of 65 impacted utilities, 9 utilities were selected to interview further to demonstrate the broad range of issues that utilities were experiencing, and to understand what adaptation strategies were already being implemented to address those impacts. A visual representation of the 65 utilities that indicated that they had experienced impacts is shown in Figure 4. 8 March 1, 2018 Regular Board Meeting Agenda Packet- Page 82 of 225 Page 27 of 74 Tuolumne Utilities District Victor Valley Reclamation Authority Service Area Size:<100,000 Service Area Size: 100,000-1,000,000 • Increased settling in sewer lines • Increased ammonia concentrations in wastewater influent • Increased potential for sanitary sewer overflows and blockages • Increased HzS in the collection system • Increase in work order calls • Increased odors and odor complaints • Increased odors and odor complaints • Accelerated rate of corrosion and degradation of infrastructure • Increased root intrusion in collection system Alameda County Water District Service Area Size:100,000-1,000,000 Orange County Water District/ • Distribution system nitrification • • • • Orange County Sanitation District • Occurrences of low chlorine residual :• Service Area Size: >1,000,000 • Operational challenges due to water age and reduced flows r • • Increased detention time of wastewater in conveyance system • Intermittent idling and operational adjustments at treatment facilities •��; leadingto deposition and septic conditions. ♦lopv • Increased grease build up and settling at Plant 2 • • Increased salinity due to RO concentrate from upstream facilities Santa Clara Valley Water District • treating more challenging water supplies � • Service Area Size: >1,000,000 • Increased THM formation • Increased taste and odor issues • Operational challenges due to water qua 14 changes and reduced flows San Diego County Water Authority A Service Area Size: >1,000,000 • • • Reduced distribution system residuals LA Department of Water and 0 • Distribution system nitrification Power/City of LA, Bureau of t• • Increased flushing to maintain water quality �• Sanitation •d.♦ Service Area Size: >1,000,000 ���•�`'• • Increased THM formation • Increased taste and odor issues on wastewater -.• • • • Increased taste and odor issues • • Operational challenges due to water quality �•� changes and reduced flows ■Water -Wastewater ■Recycled Water ■N/A for Utility • •Agencies that observed impacts 0 Agencies with no impact Figure 4. Utilities throughout California indicated that they had experienced impacts due to declining flows in the high-level survey,and nine utilities were selected for in-depth interviews. 9 March 1, 2018 Regular Board Meeting Agenda Packet- Page 83 of 225 Page 28 of 74 SECTION 3 SupportingConservation as a California Way of Life As a response to the recent extreme drought, Governor Jerry Brown issued an Executive Order (EO) directing State agencies to develop a long-term WUE framework, as specified in the report Making Conservation a California Way of Life. This white paper highlights observations and experiences of California utilities during the drought, which provide a preview into the potential impact of establishing permanent indoor water use targets at or below the thresholds achieved as a result of the governor's emergency conservation mandate. During the recent drought, Governor Brown issued an EO in April 2015 directing the State Water Board to issue emergency drought regulations that mandated a statewide urban water use reduction of 25 percent. Water agencies rose to the occasion, meeting or exceeding the State-mandated set point. Before lifting the emergency drought regulations in April 2017, the governor issued a subsequent EO reinforcing key strategies addressed in the California Water Action Plan—namely, Making Water Conservation a California Way of Life (B-37-16, May 2016). Through this E0, the governor directed State agencies to develop a long-term WUE framework and to improve planning to support California's water supply reliability and resiliency. Water Use Efficiency Guidelines Set Water Use Targets The Department of Water Resources' (DWR's) Making Water Conservation a California Way of Life report specifies the process for the State's urban water suppliers to meet new, long-term water use targets Supplier water use (DWR 2016). Each agency's target is an aggregate total of per capita target = water use budgets in three categories: residential indoor use, outdoor irrigation use, and distribution system water loss. (indoor water use budget) While the water use target equation includes the three considerations, + this white paper focuses on the indoor residential water use standard, (outdoor water use budget) because the aim is to evaluate the impact of WUE levels on engineered + water systems. After residential water is used within the home, it is (water loss budget) conveyed as sewage to a wastewater treatment plant(WWTP) and treated for discharge or reclaimed for non-potable or potable uses. Thus, water used in the outdoor irrigation or lost via the distribution system is less relevant to the focus of this white paper. 10 March 1, 2018 Regular Board Meeting Agenda Packet- Page 84 of 225 Page 29 of 74 Establishing Residential Indoor Water Use Standards The "residential indoor standard" is defined as "the volume of residential indoor water used by each person per day, expressed in gpcd" (DWR 2016). It is used to calculate a water supplier's "indoor water use budget," which is a function of the total service area population, i.e.: Residential indoor water use budget = (service area population) x(residential indoor standard)x(number of days in a year) Senate Bill (SB)x7-7 established 55 gallons per capita per day(gpcd) as a provisional standard for residential water use per California Water Code (CWC) 196O8.2O(b)(2)(A). Until a new standard for residential indoor water use is established, that existing standard will apply. As these standards are being developed, the impact of reduced indoor water use on wastewater and water systems is a critical consideration to inform policy decisions. Effects of Reduced Demand on an Interconnected Water System The interconnected nature of the water system means that change in one part of the cycle will inevitably have impacts, both positive and negative, on other parts of the system. For example, increased WUE can have environmental, public-health, and economic benefits by helping to improve water quality and maintaining aquatic ecosystems. It also improves drought resiliency and can defer the cost of building new infrastructure for additional water supply. While there are many benefits to conservation, it is also important to understand how conservation may impact the rest of the water system. With reduced water demands both drinking water and wastewater flows decline and quality change. The potential impacts of declining flows on the interconnected water system is shown in Figure 5. Drinking Water Distribution • Changes in water quality • Increased pipeline flushing • Increased flushing • Increased nitrification 14004 Recycled Water • Changing infl uentwater q uality 7� Wastewater (increased ammonia loading) ` O Conveyance • Decrease in recycled water production / Increased odor production and complaints • Complaints from end users J • Increased rate of corrosion about water quality(i.e.salinity) • Red uctioninabilitytooffset Exacerbated settling and blockages potable use • Increased number of 0&M / work orders Wastewater Treatment I • Changing influent water quality j (increased ammonia loading) • Potential to exceed discharge permit requirements Figure 5. Declining flows can impact the interconnected water system in several ways. 11 March 1, 2018 Regular Board Meeting Agenda Packet- Page 85 of 225 Page 30 of 74 Impacts Are Widespread across the State As seen in Figure 6, impacts were experienced in every type of system interviewed. They were experienced most often in water distribution systems, where 60 percent of survey respondents indicated that they were having to manage the effects of declining flows. Additionally, 52 percent of wastewater conveyance systems, 48 percent of WWTPs, and 43 percent of recycled water projects indicated that they experienced impacts due to declining flows. 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Drinking Water System Wastewater Conveyance Wastewater Treatment Recycled Water Project (Sample Size: 158) System System (Sample Size: 120) (Sample Size: 164) (Sample Size: 159) ■Yes 0 N Figure 6.Survey respondents experienced impacts of water conservation in all system types, most often in water distribution systems. The following sections dig deeper into impacts on each type of system based on the literature review, high-level survey results, and case studies with utilities that have experienced the most significant impacts and have already implemented adaptation strategies. 12 March 1, 2018 Regular Board Meeting Agenda Packet- Page 86 of 225 Page 31 of 74 SECTION 4 Impacts of DecliningFlows on Water Distribution Systems With declining water system flows, drinking water has a longer residence time in pipes, leading to chemical, biological, and physical issues that may have a potential impact on public health and compliance with the Safe Drinking Water Act. Decreased Potable Water Demand Increases Residence Time in Water Distribution Systems As water in the distribution system declines, residence time increases in reservoirs and pipes. While reduced consumption has Key indicators of its benefits (e.g., decreased groundwater overdraft), it also has impacts: potential ancillary impacts. Lower-than-expected WRF conducted two studies focused on indoor residential water use water use in select study sites throughout North America, once in 1999 and Changes in water the next in 2016. During that time, indoor water use decreased 15% quality within the from 69.3 to 58.6 gallons per capita per day(Figure 7). distribution system BS — Increased r:_ur9�9 150 disinfection by- 16... .................. 150 ■REU2016 ❑ECREASE product DBP tsz PER CAPITA formation a 12 "6 DAILY WATER USE Increased 1999 TO 2016 nitrification a B 7.s 6 — Changes in physical characteristics 9 2 2.5 . Increased flushing to t.a 12-ts i.o- ° maintain safe water TOW Shower F-0 Leak Other Bath Dlshwaxher quality Failure to comply with drinking water Figure 7.Two WRF studies showed a 15 percent decrease in average standards daily indoor per capita water use from 1999 to 2016. Source:DeOreo et al.,2016 13 March 1, 2018 Regular Board Meeting Agenda Packet- Page 87 of 225 Page 32 of 74 In 2002, the U.S. Environmental Protection Agency(EPA) published a report titled Effects of Water Age on Distribution System Water Quality. It discusses the impacts that increased "water age," i.e., residence time in pipes, can have on distribution water quality, leading to potential public-health implications. Water age is a function primarily of water demand, system operation, and system design. Table 1 lists water quality problems that can be caused or worsened by increased residence time in the distribution system.The items that are marked with an asterisk are identified as having direct potential health impacts. Water quality problems like discoloration or changes in other water aesthetics (taste, odor) are secondary though still important, as they directly impact customers' perception of the quality of their water. Table 1.Summary of Water Quality Problems Chemical lssug&. Biological DBP formation* DBP biodegradation* Temperature increases Disinfectant decay Nitrification* Sediment deposition Corrosion control effectiveness* Microbial regrowth,recovery,or shielding* Color Taste and odor Taste and odor Source:EPA 2002 *Denotes water quality problem with direct potential public-health impact. Increased water age exacerbates chemical, biological, and physical issues for water quality, leading to potential direct impacts on public health. This decline in water quality also puts water suppliers at risk of failing primary drinking water standards and being out of compliance with the Safe Drinking Water Act, particularly for DBPs, coliform bacteria, chlorine residual, and lead and copper action levels. Since the EPA report was published in 2002, a lot of work has been done to address these concerns. Modifications in best management practices include improving the hydraulics in storage facilities and managing water chemistry. Improvements in storage facilities include installing baffling systems, increasing the turnover rate through deep cycling pumping, and tank mixing. Many water systems have implemented aggressive nitrification control and disinfection residual and DBP control practices. Water suppliers also increase pipeline flushing and discharge water from distribution system reservoirs as necessary. These mitigation methods will be important as declining flows continue to increase the water age within the distribution system. 14 March 1, 2018 Regular Board Meeting Agenda Packet- Page 88 of 225 Page 33 of 74 47 Percent of Impacted Water Distribution Systems Indicated Operational Challenges due to Low Flows The key indicators of impacts to water distribution systems identified during the literature review were indeed observed by California utilities during the recent drought. Of water distribution respondents surveyed, 61 percent indicated that they had experienced some kind of impact during the period of mandated conservation. Of them, 49 percent of respondents experienced operational challenges due to low flows, 47 percent experienced changes in water quality, and 17 percent indicated another impact not included in the survey(Figure 8). Other impacts included items like lower revenue, increasing rates, and stranded storage assets. Impacts on Water Distribution Systems 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% - Lower than expected Operational challenges Changes in water Other* Idling of the plant due water demand due to low flows quality to reduced customer demand *Some items included in other lowerrevenues,increasing rates,strandedstorage assets. Figure 8.Operational challenges and changes in water quality were the most significant impacts on water distribution systems. San Diego County Water Authority(SDCWA) and Santa Clara Valley Water District(SCVWD) were interviewed in greater detail as they had experienced most of the impacts identified during the literature review and survey. A snapshot of some of the impacts they observed along with how the utilities have adapted are included in the case studies below. 15 March 1, 2018 Regular Board Meeting Agenda Packet- Page 89 of 225 Page 34 of 74 Case Study: San Diego County Water Authority SDCWA is a wholesale water agency serving 24-member retail agencies,with a population of 3.3 million people and a service area of 1500 square miles. SDCWA's conveyance system delivers treated water from the Twin Oaks Water Treatment Plant and Lewis Carlsbad Desalination Plant and both treated and untreated imported water sources through 300 miles of large-diameter pipelines in two aqueducts. Impacts experienced Adaptation strategies/financial impacts • Reduced conveyance system residuals:As Increased flushing:To manage water quality issues, detention time through the system has SDCWA will occasionally flush water from its treated increased,chlorine residuals consequently water system into its raw water system,where it is degrade.At the extremities of the aqueduct stored for treatment again at a later date. Due to system, up to a 1-milligram per liter(mg/L)loss increased detention times in the aqueduct,the rate in residual chlorine has been experienced. of flushing has been increased as much as ten • Conveyance system nitrification: Nitrification times.The cost associated with flushing and re- has likewise increased within the aqueduct treating the water have increased from $200.000 a system as a result of increased detention time, year to over$2 million per year. resulting in the unwanted production of nitrites 0 Investment in online monitoring equipment: in the drinking water. SDCWA has invested in the installation of multiple online water quality analyzers,which has been upwards of$250,000 in new equipment. Case Study: Santa Clara Valley Water District SCVWD provides Silicon Valley with safe,clean water for a healthy life, environment,and economy.SCVWD provides wholesale water and groundwater management services to 15 cities in Santa Clara County.On the wholesale water side,SCVWD operates three drinking water treatment plants(WTPs)that deliver wholesale drinking water to seven retailers through 39 miles of large-diameter distribution mains. Impacts experienced Adaptation strategies/financial impacts • Changes in water quality:SCVWD saw poorer- 0 Coagulant changes to address higher total quality source water in the recent drought from organic carbon(TOC):SCVWD used water imported through the Delta.Two out of coagulants from aluminum sulfate to ferric SCVWD's three WTPs were converted to chloride(FeCl3)for 3 months in 2016,and ozonation prior to the drought. During the period also applied a much higher dose to remove of mandated conservation,the remaining WTP TOC. not previously retrofitted to ozonation o Cost of ferric chloride: FeCl3 use resulted experienced increased trihalomethanes(THMs) in an additional cost of$150.000. and some taste and odor issues. • Established minimum flow rates in the • Operational challenges because of water quality Rinconada distribution system:To ensure that and reduced flows: Because of conservation, the most downstream retailer was not demand for water production was reduced,and disproportionately impacted by the reduced thus flows declined within the water distribution flow rates,SCVWD established minimum system. Retailers located the farthest required flow rates with each of its retailers. downstream of the WTP had the potential to sustain the greatest impact due to increased water age and THM formation. 16 March 1, 2018 Regular Board Meeting Agenda Packet- Page 90 of 225 Page 35 of 74 Case Study: Alameda County Water District Alameda County Water District(ACWD) provides a reliable source of high quality water to over 351,000 people in the cities of Fremont, Newark and Union City. ACWD is a water retailer and manages over 900 miles of distribution pipelines,83,000 service connections, 13 water storage tanks,and numerous pumping and regulating facilities in its 100-square mile service area.ACWD also currently operates three water treatment facilities. Impacts experienced Adaptation strategies/financial impacts • Water quality challenges: Reduced water Supplemental flushing operations:To address demands increased overall water age in the unusually low chlorine residuals at outlying ends of system,and changed system dynamics. As a the distribution system,supplemental flushing result,ACWD experienced nitrification events were required to bring fresh water into those conditions in a greater number of storage areas.This required significant staff time. facilities. Additionally,some outlying areas of Treatment facility idling and adjustments: Due to the distribution system with low water use reduced water demands,ACWD elected to shut experienced low chlorine residuals,which had down its smallest treatment facility for 10 years or not previously occurred in ACWD's system. more.Additionally, operation of ACWD's Blending • Operational challenges: In order to exercise Facility was adapted to an intermittent on/off distribution system storage and reduce water operation to cycle water system storage and reduce age,treatment facilities had to be operated at water age.At the Newark Desalination Facility,the lower-than-typical and/or variable rates and recovery rate on the reverse osmosis(RO) process water storage facilities had to be operated at was reduced in order to keep it online at lower lower levels. Less water in storage meant less flows. Although less efficient,this adjustment was water available in the event of an unexpected preferable to going off-line entirely,which would emergency or extended outage. Additional have impacted the life of the RO membranes and water quality monitoring,storage facility limited ACWD's ability to use local groundwater. management and flushing operations were also Water storage cycling and targets:To reduce water required. age,operational strategies were adapted to increase and intensify water storage cycling, and storage volume targets were reduced. 17 March 1, 2018 Regular Board Meeting Agenda Packet- Page 91 of 225 Page 36 of 74 SECTION 5 Impacts of Declining Flows on Wastewater Conveyance Systems Declining system flows decrease wastewater flows and may increase pollutant and solids concentrations, which increase blockages, odors, and corrosion in pipes. This leads to increases in operation and maintenance (OW) costs, odor complaints, and an accelerated degradation of infrastructure. Reduced Wastewater Flows Increase Blockages Standards used for hydraulic design include requirements of minimum slopes for various pipe diameters to achieve Key indicators of scouring velocities that minimize debris accumulation. impacts: However, external conditions could exacerbate debris Lower-than-expected accumulation, including root intrusion; increase in fats, oils, wastewater flows and grease (FOG); and pipe sags (Feeney et al. 2009). This debris accumulation results in sewer blockages, which is the Increased rate of odor number one cause of loss in sewer serviceability(Ashley complaints 2004). 0 Accelerated rate of Reduced water usage and wastewater production and corrosion constant solids loading leads to an increase in solids Increased operation and concentration within the sewer system, which increases debris maintenance(work orders) accumulation and exacerbates blockages in sewer networks. of sewer lines and pumps A study conducted by a water retailer in Australia correlated Pumps operating outside of the water consumption per household with the number of their preferred operating sewer blockages (Figure 9), indicating that lower water range (POR) consumption gives rise to a higher rate of sewer blockages — Signs of cavitation (Yarra Valley Water 2011).This subsequently leads to clogged — Increased vibration and pipes, loss of sewer serviceability, and an increase in operation noise and maintenance. 18 March 1, 2018 Regular Board Meeting Agenda Packet- Page 92 of 225 Page 37 of 74 30 o E • • 25 - 20 s 20 • + • r 10 • • • + • + 5 0 350 400 450 540 550 600 650 700 Average Water Usage per Household(Lfday) Figure 9. Lower water consumption gives rise to a higher rate of sewer blockages. Source:Yarra Valley Water 2011. Structural Condition Failures from Accelerated Corrosion Corrosion in the conveyance system occurs when the free water surface releases hydrogen sulfide (H2S)to the atmosphere during anaerobic conditions and is adsorbed by moist sewer pipe. On the pipe surface, H2S is converted to sulfuric acid (H2SO4), which corrodes the pipe. The changing characteristics of wastewater from declining flows can accelerate corrosion through two methods: • Increased concentration of organic material and sulfate:As wastewater flows decrease and organic and solids concentrations increase, concentrations of sulfate in sewage increase.This increase in sulfate generates additional corrosive sulfides. • Increased residence time: Longer flow residence enables more time for the high organic content in wastewater to consume oxygen, leading to anaerobic conditions. This accelerates the rate of corrosive sulfide production. Accelerated corrosion in pipes leads to a faster rate of structural failure. The primary failure mode for metal pipes is internal or external corrosion, which leads to holes in the pipe wall. Cast iron is particularly brittle, making it susceptible to cracking and subsequent collapse. Corrosion is also often a major factor in the failure of reinforced concrete pipe (RCP), which typically fails after the interior surface of the pipe wall has deteriorated to a point where the reinforcing steel is exposed. As the reinforcing steel corrodes, it swells, breaking up surrounding concrete and causing failure (Feeney et al. 2009). This increase in the rate of structural failure because of accelerated corrosion results in increased 0&M costs and accelerated aging of the infrastructure. Initiated by the National Association of Corrosion Engineers (NACE),the U.S. Federal Highway Administration (FHWA) released a 2-year study in 2002 on the direct costs associated with metallic corrosion in nearly every U.S. industry sector. It stated that the total annual cost of corrosion for drinking water and sewer systems is $36 billion, which included the costs of "replacing aging infrastructure, lost water from unaccounted-for leaks, corrosion inhibitors, internal mortar linings, external coatings, and cathodic protection" (NACE 2002). These costs will only be exacerbated as declining flows accelerate the rate of corrosion within wastewater infrastructure. 19 March 1, 2018 Regular Board Meeting Agenda Packet- Page 93 of 225 Page 38 of 74 Increase in Odor Production, Leading to Increased Odor Complaints Odors in sewers are dominated by H2S, which can be recognized by its characteristic rotten-egg odor. It is detectable by the human sense of smell at a concentration level of 0.001 part per million (ppm) and has sub-lethal effects (nausea and eye, nose, and throat irritation) at 10 to 50 ppm (ASCE 1989). Like corrosion,the production rate of odors in sewers is exacerbated by declining flows, which increases the concentrations of sulfate (leading to an increased production of H2S). This increase in odor production impacts quality of life. An article in the Los Angeles Times stated, "In San Francisco, officials also say foul odors have become noticeable in low-lying and flat areas of the city where gravity cannot help push solids through the system" (Stevens 2015). Increased odor production requires an investment of additional 0&M budget to address. 58 Percent of Impacted Wastewater Conveyance Respondents Indicated Increased Odor Problems As seen in Figure 10, a variety of the impacts described were experienced by wastewater conveyance utilities. Of wastewater conveyance respondents surveyed, 52 percent indicated that they had experienced some kind of impact during the period of mandated conservation. Of them, more than 50 percent experienced increased solids deposition, odor problems, and 0&M needs. Other issues observed included increased corrosion, root intrusion, and pH changes. Impacts on Wastewater Conveyance Systems 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Lower than Increased odor Increased solids Increased 0&M Increased corrosion Other* expected problems deposition needs wastewater flows *Some items included in other increased root intrusion,wastewaterpH changes Figure 10. Lower-than-expected wastewater flows and increased odor problems were most significant in wastewater conveyance systems. 20 March 1, 2018 Regular Board Meeting Agenda Packet- Page 94 of 225 Page 39 of 74 Case Study: Tuolumne Utilities District Tuolumne Utilities District(TUD) is a water and wastewater utility that serves nearly 44,000 residents in northern California's Tuolumne County. TUD operates 14 drinking water treatment plants and a wastewater system that treats 1.2 million gallons per day(mgd)of sewage at the Sonoma Regional WTP. Impacts experienced Adaptation strategies/financial impacts • Increased sanitary sewer overflows and Increased maintenance of the collection blockages: 65 percent of IUD's conveyance system:TUD has always maintained a hot spot system is 4 to 6 inches in diameter,which list of areas that staff would routinely check.As makes them prone to blockages.The reduced flows have declined,that list has increased. flows exacerbate this issue, leading to an Trucks are being sent out more often to increase in required maintenance. monitor those locations. • Increased root intrusion:When there is a Proactive pipe patching:TUD has implemented blockage in a gravity system, any crack has a pipe patching system to counter the the potential to leach moisture.TUD has increased root intrusion.TUD cleans the pipe observed increased root intrusion in these and cures a fiberglass material as an internal locations, causing further separation and liner,which both patches the pipe and, given cracks. that it's a smoother material, moves sewage more effectively. Case Study: Victor Valley Water Reclamation Authority The Victor Valley Water Reclamation Authority(VVWRA)operates as a Joint Powers Authority serving four member agencies. It provides wastewater treatment services through 42 miles of wastewater conveyance and a treatment facility that treats roughly 10.7 mgd. Impacts experienced Adaptation strategies/financial impacts • Increased odors and odor complaints: As . Operational improvements and increased flows have declined in its conveyance system, rehabilitation and maintenance of manholes:To solids remain in the system longer, leading to combat the increased odors and accelerated an increase in 1-12S.The increased 1-12S rate of corrosion,VVWRA has implemented produces more odors and more odor operational improvements and begun coating its complaints. manholes in epoxy.To proactively mitigate future • Accelerated rate of corrosion and corrosion,VVWRA has also updated its degradation of infrastructure: Because of the specifications for manhole coatings to include increased 1-12S,VVWRA has witnessed an epoxy coatings while exploring alternative acceleration of corrosion in its collection materials to concrete for manholes. system, primarily at its manholes. o Investment in epoxy coating:VVWRA has spent$300.000 per year over the past 5 years to address increased corrosion. 21 March 1, 2018 Regular Board Meeting Agenda Packet- Page 95 of 225 Page 40 of 74 SECTION 6 Impacts of Declining Flows on Wastewater Treatment Plant Operations Declining flows change the characteristics of wastewater, including the quantity and quality of WWTP influent, causing impacts and stressing treatment processes as it pushes ammonia, total dissolved solids JDS), and phosphorus concentrations beyond design specifications. This may require WWTPs to invest in improvements or expansions earlier than planned. Increasing Wastewater Influent Concentrations May Impact Effluent Quality The effluent from WWTPs is held to standards mandated by their Key indicators of individual National Pollutant Discharge Elimination System (NPDES) impacts: permits, including effluent quality limits for constituents like Lower-than-expected ammonia and nutrients. wastewater flows Increasing influent concentrations that trend upward because of Changing influent declining flows can reduce effluent quality, potentially impacting a water quality plant's ability to meet its discharge permit requirements. This increase in concentration may require the WWTP to invest in — Increased upgrades earlier than expected, resulting in additional cost. This is ammonia and of particular importance for plants that have discharge limits for nutrient loading ammonia. The following example describes a case of increased Exceeding discharge ammonia concentration in the influent flow, which subsequently permit requirements increases ammonia concentrations in the effluent. Ammonia Concentration Increasing in Silicon Valley Silicon Valley Clean Water(SVCW) has experienced an increase in ammonia in its influent, and subsequently, its effluent(as seen in the drought period in Figure 11 and Figure 12). SVCW's NPDES wastewater permit has a monthly average ammonia limit of 173 mg/L, and effluent concentrations are consistently below this value. With mandatory water rationing, ammonia concentrations entering the WWTP increased (Figure 11). Effluent concentrations of ammonia followed this trend (Figure 12). While still below their reporting limit, this raises the flag on potential problems further down the road. 22 March 1, 2018 Regular Board Meeting Agenda Packet- Page 96 of 225 Page 41 of 74 70 40 Ammonia Concentration Mandatory water Influent Flow ♦ rationing —60-day Average(Ammonia Concentration) •, 35 60 —60-day Average(Influent Flow) z ♦ ♦♦♦ ♦ : ♦� ♦ ♦ ♦» N w ♦♦♦♦ 50 • , •• ♦ • ♦ ♦♦♦ M♦ ♦♦ 25 '.•♦ ♦♦♦♦o40 ♦ i40♦♦ ♦ ♦ ♦ ♦ ♦♦ ♦♦ 20 40 ♦ f ji ♦ • 15 30 •� ' ' • ' ••♦! ♦ • j •• i ♦ ♦ • O♦ , htf = •j t< d ♦ ♦ • •.�r .• , . 10 20 ♦ ♦ 5 2012-2015 Drought 10 0 1/1/2010 1/1/2011 1/1/2012 1/1/2013 1/1/2014 1/1/2015 1/1/2016 Year Figure 11. Primary influent ammonia concentrations for SVCW increased during the period of mandatory water rationing. Source:Sawyer et al.2016. 70 M Plant B Mandatary water rationing —90-day average 64 ■ Zba ■ ■■ ■ ■ rti■ � 50 ■ ■ ■ WIN ■■ ■ ■ 40 �IL s uIN C ■■ ■■■ ■r ■ ■ ■ 30 0 • tii ■ 7� ■ � ■ IN ■ a � ■ ■ ■ ■ s ■ W � 10 2012-2615 Drought 0 1/1/2010 1/1/2011 1/1/2012 1{1/2013 1/1/2014 1/1/2015 1/1/2016 Year Figure 12. Plant effluent ammonia concentrations for SVCW increased during the period of mandatory water rationing. Source:Sawyer et al.2016. 23 March 1, 2018 Regular Board Meeting Agenda Packet- Page 97 of 225 Page 42 of 74 Santa Barbara Experiences Alkalinity Limitations When declining flows change the characteristics of that flow,treatment processes may become strained. For example, nitrification is a common process to remove ammonia, and it requires a ratio of alkalinity to stabilize the water's pH. As ammonia concentrations increase, as previously demonstrated, alkalinity must also increase to support nitrification. However, during the period of mandatory water rationing, alkalinity has remained relatively constant. That is because much of the alkalinity in water originates from the source water and is not added by the user. Thus, there may not be enough alkalinity to balance out the increase in ammonia. The following example describes a WWTP that has had to proactively address this potential limitation. EI Estero WWTP in Santa Barbara has experienced a strain on its current wastewater treatment processes based on alkalinity limitations. The plant is currently converting to nitrification, and a residual alkalinity of 80 to 100 mg/L is required to maintain the pH in the nitrified effluent. A marked decrease in flow and increase in ammonia concentration was observed from 2012 to 2014 (Figure 13). Influent ammonia concentrations increased by 32 percent, but influent alkalinity increased by only 4 percent. The amount of alkalinity available was predicted to be insufficient to meet the alkalinity demand for nitrification, indicating an alkalinity limitation. Based on process modeling, it was calculated that supplemental alkalinity would be required at times to maintain a pH above 6.0 for nitrification, which is necessary for effluent compliance. Based on those 2014 data, chemical facilities for alkalinity addition were added to the design. 20 70 • Influent Flow • 2012 Ammonia 18 • 2014 Ammonia ♦ —30-day Average(2012 Ammonia) . 60 16 30-day Aveoge(2014 Ammonia) 14 . ♦ 50 z 312 .sly# _~ _ ` ♦ ° Z° ��� �tw 40 10 c N ♦ lL. t' 0 c • Z • ♦ W 3�. a 8 30 6 20 4 2 10 Sep-11 Apr-12 Oct-12 May-13 Nov-13 Jun-14 Dec-14 Jul-15 Jan-16 Date Figure 13.At the EI Estero WWTP, Influent flows decreased from 2012 to 2014, and ammonia concentrations increased. Source:Sawyer et al.2016. 24 March 1, 2018 Regular Board Meeting Agenda Packet- Page 98 of 225 Page 43 of 74 Impacts to Plant Capacity Ratings WWTPs are typically rated based on average dry weather flows (ADWF), but the key criterion for biological processes (e.g., activated sludge) is often organic and nutrient loading. For processes that are governed by organic loading, a plant may reach loading capacity at a much lower flow than the rated design flow (Figure 14). Thus, a plant expansion for treatment processes governed by organic loading would need to occur at flows well below the original design flow capacity. 400 3.9 mgd 350 59 gal/capita-day 366 mg BODJL '1- 300 c 250 a 200 C CU 150 8 mgd 120 gal/capita-day 100 180 mg BOD/L 0 c0 50 0 0 2 4 6 8 10 Flow, mgd Figure 14. Declining flows may accelerate the need for investment in expansion of treatment processes governed by organic loading, as loading capacity could be reached at a much lower flow. Source:Sawyer et al.2016. 25 March 1, 2018 Regular Board Meeting Agenda Packet- Page 99 of 225 Page 44 of 74 40 Percent of Impacted Survey Respondents indicated Changes in Wastewater Influent Quality As seen in Figure 15, a variety of the impacts described were experienced by utilities providing wastewater treatment services. Of wastewater treatment respondents surveyed, 48 percent indicated that they had experienced some kind of impact during the period of mandated conservation. Of those impacted, more than 60 percent of respondents noted changes in influent water quality, and 40 percent faced subsequent challenges in meeting compliance requirements with respect to effluent quality(see Figure 15). Other issues experienced included plant upsets and staffing adjustments to manage the new conditions. Impacts on Wastewater Treatment Plants 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Lower than expected Changes in Influent Challenges in Increased use of Other* WWTP influent water quality compliance with chemicals to meet effluent quality effluent quality requirements requirements *Some items included in other higher recirculation flows,staffing adjustments,plantupsets. Figure 15. Lower-than-expected WWTP influent and changes in influent quality were the most significant impacts in wastewater treatment plants. 26 March 1, 2018 Regular Board Meeting Agenda Packet- Page 100 of 225 Page 45 of 74 Case Study: Victor Valley Water Reclamation Authority Introduced in the wastewater conveyance section,VVWRA provides wastewater treatment through a treatment facility that treats roughly 10.7 mgd.This plant discharges into a terminal river,which doesn't flow to the ocean.The facility is thus bound by strict regulatory requirements that require the entire wastewater effluent to be treated to Title 22 standards. Impacts experienced Adaptation strategies/financial impacts • Increased ammonia concentrations in the Changes to operations for the aeration basins: wastewater influent: Current ammonia levels To meet strict discharge requirements,the in the wastewater influent are much higher VVWRA treatment plant nitrifies and denitrifies than those recorded before 2010. Influent its wastewater. Changing ammonia ammonia concentrations prior to 2010 concentrations impact operations, as it averaged in the mid to high 20s mg/L. reduces the dilution of the ammonia and Concentrations are now between 30 and 40 makes it harder to treat. mg/L. Delivering less recycled water to customers: • Declining wastewater influent reduces To meet the base flow requirements set by CA wastewater effluent volumes:This is Fish and Wildlife,VVWRA is required to significant for VVWRA as it is required to discharge the 8.2 mgd first before sending its discharge a base flow of 8.2 mgd per day to effluent to reuse. However,the less recycled the river. water is available for reuse,the more customers will need to rely on potable resources(groundwater). Case Study: City of Los Angeles, Bureau of Sanitation The City of Los Angeles, Bureau of Sanitation (LASAN) provides wastewater services to more than 4 million customers through more than 6,700 miles of public sewers that convey about 400 mgd of flow from residences aed businesses. Impacts experienced Adaptation strategies/financial impacts • Large and bulky influx of trash associated 0 Managed large influx of trash through manual with wet weather events: Because of labor:When the automatic raking systems are declining flows,food waste and sanitary-type overwhelmed by the sudden and large influx of trash is getting stuck in the collection system. trash, LASAN has to manually pull trash out.This Then,when a large wet weather event occurs, is accomplished through manual rakes or a all of that trash is suddenly swept to the Bobcat. WWTP, overloading its automatic raking system. 27 March 1, 2018 Regular Board Meeting Agenda Packet- Page 101 of 225 Page 46 of 74 SECTION 7 Impacts of DecliningFlows on J Recycled Water Projects To expand water reuse statewide, California utilities are designing and constructing new infrastructure to treat and distribute the recycled and/or purified water. Declining flows can alter treatment and cost-effectiveness of recycled-water infrastructure by altering factors considered in system design, like anticipated flow and water quality. Thus, declining flows could lead to stranded community assets and could limit the ability to meet the State's water reuse goals. Key indicators of Changes in Wastewater Effluent Have Impacts on impacts: Recycled Water Effluent Quantity and Quality Lower-than-expected In California, the desire to improve water supply reliability has motivated wastewater flows water utilities to expand their recycled water use by designing and Changing influent water constructing new infrastructure to treat and distribute the recycled water. quality Specifically, indoor conservation can result in generation of a more — Increased ammonia concentrated wastewater stream, with elevated concentrations of TDS, loading nitrogen species, and carbon (Stevens 2015). — Increased nutrient A paper published on July 27, 2017, explores how drought and water loading conservation strategies combine to reduce influent and flow, and — Increase in pathogens subsequently, effluent flow and quality(Tran et al. 2017). The authors and contaminants of analyzed water quantity and quality data at the Inland Empire Utilities emerging concern Agency(IEUA) Regional Water Recycling Plant 1 (RP1) during drought and (CECs) pre-drought periods (2011 to 2015)to investigate the impacts during — Increased salinity this time. Their analysis showed that the combination of poorer-quality Decreased recycled water water supplies coupled with conservation activities resulted in a production decrease in wastewater influent flow and an increase in pollutants in the Complaints from recycled influent of IEUA - RP1 from 2011 and 2015 (Tran et al. 2017), as shown water end users about in Figure 16. This reduction in overall treated volumes resulted in lower water quality discharge into surface water by approximately 38 percent, which impacts Exceeding permit downstream agencies that rely on that surface water as their influent. requirements 28 March 1, 2018 Regular Board Meeting Agenda Packet- Page 102 of 225 Page 47 of 74 IEUA-RP 1 Influent Flow f IEUA-RPI Wastewater Produced per Capita 2011 2012 2013 2014 2015 30 460 29 450 a 28 440 eau ❑ 27 430 26 C 420 1y 25 5� �. es a� 410 24 0 23 400 22 390 2l380 .�' .1' .ti" .tib .� n`� .tib` .'��` Month Figure 16. IEUA - RPI influent flows and the wastewater produced per capita decreased from 2011 through 2015. Source:Tran et al.2017. The paper also analyzed wastewater quality and observed increases in certain constituents, including TDS, electrical conductivity(ECW) ions (sodium [Na+], chloride [CI-], calcium [Caz+], and bicarbonate [HCO3]), and nutrients (see Figures 17 and 18). Between 2011 and 2015, an 8 to 16 percent increase in many of the constituent concentrations at IEUA - RP1 led to potential discharge violations and fines. Thus, drought and water conservation measures combined to decrease both the quantity and quality of recycled water effluent. 29 March 1, 2018 Regular Board Meeting Agenda Packet- Page 103 of 225 Page 48 of 74 X2011 2012 2013 M 2014 M 2015 Constituents 3A 00 EC NO,-N B 3.2 �.1 3.D g 0.z 2.8 d 2.6 r 0.3 2.4 -0.4 2.2 'o.s 0 1-8 -0.7i 1.6 y 1.4 C L2 0 c 0.8 a 0.6 0.4 a.2 D-D 50 Constituents Figure 17. Certain constituents in the IEUA - RPI influent, like TDS, ions, and EC., increased from 2011 to 2015. Source:Tran et at.2017. X2011 2012 2013 2014W2015 Constituents 3.0 0.0 EC NHS-N B NTU 2.8 0.1 2.6 -0.2 2.4 0.3 0-M 2.2 C-0.5 Q.-0.6 E 2.0 r 1.6 ^-O.s �y i 1.4 1.2 1.0 c 0.8 a 0.6- 0.4- 0.2- 4, .60.40.2ro Gq, LO,G� 5d,$0 404 Constituents Figure 18. Constituents that increased in the IEUA - RP 1 influent also increased in the effluent from 2011 to 2015. Source:Tran et al.2017. 30 March 1, 2018 Regular Board Meeting Agenda Packet- Page 104 of 225 Page 49 of 74 Recycled water projects are expected to produce effluent of a specific quality per their intended end- use (e.g., non-potable reuse [NPR] and potable reuse [PR]), as regulated by the Division of Drinking Water (DDW). Some of the water quality requirements for PR through groundwater replenishment are listed in Table 2. As plant influent and effluent concentrations potentially increase because of declining flows, additional treatment processes may need to be built earlier than planned to meet effluent water quality requirements. QualityTable 2.Water Inorganic chemicals MCL(fable 64431-A) Quarterly Radionuclide chemicals MCL(fable 64442,64443) Quarterly Organic chemicals MCL(Table 6444-A) Quarterly Disinfection by-products MCL(Table 64533-A) Quarterly Lead and copper Action levels Quarterly Secondary drinking water SMCL(Table 64449-A,64449-13) Yearly contaminants Chemicals with NLs NL Quarterly Priority toxic pollutants 40 CFR Section 131.38 Quarterly Any other chemical DDW specifies on a TBD Quarterly case-by-case basis Impacts on Recycled Water Planning Assumptions The changes in influent quality coming into water recycling plants also have an impact on infrastructure that is currently in design. As with all infrastructure,facilities are designed to specific design criteria, including anticipated flow and water quality. For projects that are currently in design, changing wastewater effluent quantity and quality can push the limits of those criteria. For example, the Pure Water Program for the City of San Diego is currently designing a comprehensive surface water augmentation program that includes expanding San Diego's existing WWTP and building a full-scale advanced water purification facility and a pipeline to transport the water to Lake Miramar. The design currently assumes wastewater flows, total suspended solids (TSS), and biochemical oxygen demand (BOD) values for the wastewater influent entering the soon- to-be expanded North City Water Reclamation Plant(NCWRP). Projections were performed to understand the potential impacts that decreased indoor residential use could have on these assumptions. These projections showed that concentrations for TSS and BOD increased by 16 percent, which would substantially impact the design of aeration basins and other wastewater treatment processes. 31 March 1, 2018 Regular Board Meeting Agenda Packet- Page 105 of 225 Page 50 of 74 70 Percent of Impacted Recycled Water Respondents Indicated a Decrease in Recycled Water Production Out of all the survey respondents that provide recycled water services, 51 percent indicated some kind of impact due to declining flows resulting from the emergency mandate. As seen in Figure 19, the biggest challenge facing recycled water systems was the decline in recycled water produced. While influent and effluent recycled water quality is a concern because of increased concentrations of salt, organics, and other contaminants of concern, less than 30 percent of respondents observed significant impacts in this way. Impacts on Recycled Water Projects 100% 90% 80% 70% 60% 50% 40% 30% - 20% 10% ■ 0% Decrease in Other* Changes in influent Changes in recycled Challenges in Complaints from recycled water water quality(into water effluent meeting permit end users about production advanced water quality requirements recycled water treatment facilities) quality *Some items included in other,decrease in recycled water influent changes in recycled water demand. Figure 19. Decreased in recycled water production and changes in influent water quality were the most significant impacts in recycled water projects. 32 March 1, 2018 Regular Board Meeting Agenda Packet- Page 106 of 225 Page 51 of 74 OCWD and OCSD Orange County Water District(OCWD)and Orange County Sanitation District(OCSD) collaborate to provide water supply reliability in the Orange County service area. OCSD manages a 6-mile stretch of the Santa Ana River and also operates the Groundwater Replenishment System (GWRS). OCSD provides wastewater services for 2.6 million people and manages two WWTPs: Plants 1 and 2. Plant 1 produces the effluent that feeds GWRS. Impacts experienced Adaptation strategies/financial impacts Reduced flows at the WWTPs:The total Supplementing GWRS feed water flows with combined flow of Plants 1 and 2 has Plant 2 effluent:With the substantial decline in decreased from 240 mgd in the 2000s to OCSD influent wastewater flows,the upcoming 180 mgd currently.This decline in flows GWRS final expansion to 130 mgd will require reduces the wastewater effluent available for flow to be diverted from Plant 2 to Plant 1 groundwater recharge through GWRS. GWRS for purification. • Increasing salinity in discharge effluent from 0 Segregation of high-salinity flows: Higher-TDS upstream utilities: OCSD treats the reverse- flow is currently being processed at Plant 2, osmosis concentrate discharge of upstream which is destined for purification at GWRS as utilities.As inland water agencies seek out part of the final expansion.To prevent this and treat more challenging local water highly saline flow from negatively impacting the supply,the increased TDS is observed GWRS, OCSD has invested $60 million to downstream at OCSD. segregate these non-reclaimable flows from the water conveyed to GWRS. City of San Diego, Public Utilities Dept. The City of San Diego's Public Utilities Department provides water services to 1.3 million customers, wastewater services to a greater metropolitan community of 2.4 million customers and recycled water services.San Diego is a pioneer in potable reuse, promoting sustainable water use technologies through its Pure Water San Diego program. Pure Water San Diego is designed to provide one-third of San Diego's future water demands through advanced water purification,thereby effectively reducing its reliance on imported water and permanently reducing discharges of treated wastewater to the ocean. Potential impacts • Insufficient influent flow at the North City Water Reclamation Plant(NCWRP):The NCWRP serves as the first step for Phase I of Pure Water,which aims to deliver 42 mgd of recycled and purified water by the end of 2021, which requires approximately 52 mgd of influent.Since the City of San Diego's project is still in design,significant future declines in influent flow below current design specifications could: o limit the City's ability to meet Pure Water supply diversification goals and commitments o partially strand an important new asset o reduce regional drought resilience capabilities 33 March 1, 2018 Regular Board Meeting Agenda Packet- Page 107 of 225 Page 52 of 74 SECTION 8 Policy Recommendations Increasing water use efficiency results in both benefits and potential impacts on the water, wastewater, and recycled water systems, and these can be balanced through informed policy. Regulators and utilities have been leading the charge in tackling California's ever-growing water challenges. When developing policy associated with longterm water use efficiency and indoor water use, the significantly interconnected nature of the system must be considered. A holistic, one-water approach can benefit smart policy and provide better solutions in managing California's water resources. Based on our research on the impacts of declining flows, CUWA offers the following policy recommendations to inform the currently developing standards for WUE: • The entire interconnected urban water cycle as well as public health and safety must be considered in long-term WUE policies. The existing urban water cycle is challenged by ancillary impacts of declining flows on water, wastewater, and recycled water systems. Such low flows can bring complications, and adaptations may not be straightforward or without significant costs. For example, water systems are typically designed to carry fire flows and cannot be downsized to carry lower flows without adverse effects. Policies addressing long-term WUE must account for costs required to adapt to new flow expectations.The State should provide flexibility for utilities to adjust or offer variances to account for local impacts and investments in water supply reliability measures including increased use of recycled and purified water as recommended by the California Water Action Plan. • Actions appropriate for sustainable long-term WUE differ significantly from those for short-term, emergency water use reductions. Actions taken to address water shortage emergencies are intended to achieve short-term water use reductions through behavior change and sacrifice by water customers. Though some behavioral changes precipitated by emergency conditions may lead to positive lasting changes (e.g., California friendly landscapes), other extreme measures (e.g., insufficient tree watering) carry adverse impacts and are not sustainable for extended periods. When properly designed and implemented based on a holistic analysis of the urban water cycle, long-term WUE programs can result in sustainable potable demand offsets that support the economy, environment, and communities. • Greater flexibility, enabled by more diverse supply and storage options,will better position urban utilities to address future uncertainties. While WUE is an important element of water management programs, it is not in itself sufficient to manage all future water demands. The California Water Action Plan acknowledges the need for more comprehensive water management and supports "making regions more self-reliant by reducing water demand and by 34 March 1, 2018 Regular Board Meeting Agenda Packet- Page 108 of 225 Page 53 of 74 developing new or underused water resources locally" and expanding storage "to deal with the effects of drought and climate change on water supplies for both human and ecosystem needs." Acknowledging that declining flows have the potential to reduce the production of local, drought- resistant water supplies through water reuse, California policy on long-term WUE should prioritize outdoor water use restrictions, which will have a lower impact on interconnected water systems, to achieve statewide demand management goals. • An iterative and flexible approach is critical for the implementation and refinement of long-term WUE targets. Once long-term water use targets are established, water agencies should be provided sufficient time and full flexibility for implementing local and/or regional programs in the context of the entire interconnected water cycle. Customers' water rates will increase to address costs associated with adapting to potential impacts in the midst of reduced revenues. To lessen the financial impact on customers, particularly those in disadvantaged communities, water agencies need adequate time to fully achieve targets to allow for incremental rate increases. Given the long-term nature of WUE targets,the State should evaluate compliance through longer-term planning efforts such as UWMPs, and not on a monthly basis. 35 March 1, 2018 Regular Board Meeting Agenda Packet- Page 109 of 225 Page 54 of 74 SECTION 9 References American Society of Civil Engineers(ASCE), 1989.Sulfide in Wastewater Collection and Treatment Systems,ASCE Manuals and Reports on Engineering Practice,American Society of Civil Engineers. Ashley, R.M., 2004.Solids in Sewers:Characteristics, Effects, and Control of Sewer Solids and Associated Pollutants, IWA Publishing. Brown and Caldwell, 2017. Blueprint for One Water, Used with permission in WRF Project#4660,State of California. California Code of Regulations(CCR), 2016. Title 22. Social Security, "Division 4. Environmental Health, Chapter 3 Water Recycling Criteria,Article 1,5,"California Code of Regulations, https://Povt.westlaw.com/ca I regs/Browse/Home/Ca I iforn is/Cal iforn iaCodeofRegulations?guid=138842B2OD60 511DE88AEDDE29ED1DCOA&origination Context=documenttoc&transitionType=Defau It&contextData=(sc.Defa ult)&bhcp=l. California Department of Water Resources(DWR),State Water Resources Control Board,California Public Utilities Commission, California Department of Food and Agriculture,and California Energy Commission, 2016.Making Water Conservation a California Way of Life, Implementing Executive Order B-37-16, State of California. California Department of Water Resources(DWR), 2015. California's Most Significant Droughts:Comparing Historical and Recent Conditions,State of California. DeOreo,W. B., P. Mayer, B. Dziegelewski,and J. Kiefer. 2016. Residential End Uses of Water, Version 2:Executive Report. Project#4309A. Denver,Colo.:Water Research Foundation. Environmental Protection Agency(EPA), 2002. Effects of Water Age on Distribution System Water Quality,American Water Works Association, Economic and Engineering Services, Inc. Feeney, C.S.,Thayer,S., Bonomo, M., & Martel, K., 2009. White Paper on Assessment of Wastewater Collection Systems, EPA. National Association of Corrosion Engineers(NACE) International, 2002. Corrosion Costs and Preventive Strategies in the United States. San Francisco Bay Regional Water Quality Control Board, 2012. Order R2-2012-0062, NPDES CA0038369. Sawyer, L.K., Hamamoto, M., Merlo, R., Henneman,S., &Arroyo, L., 2016. Planning for Future Droughts - Lessons Learned at Water Resource Recovery Facilities, Brown and Caldwell,Silicon Valley Clean Water,City of Santa Barbara. Stevens, M., 2015. Unintended Consequences of Conserving Water:Leaky Pipes, Less Revenue, Bad Odors, Los Angeles Times. Sydney, R., Esfandi, E., et al., 1996. Control Concrete Sewer Corrosion via the Crown Spray Process,Water Environment Research. Tran, Q. K.,Jassby, D.,Schwabe, K.A., 2017. The implications of drought and water conservation on the reuse of municipal wastewater.Recognizing impacts and identifying mitigation possibilities, Water Research. Yarra Valley Water, 2011. Data Sewer Blockages vs Average Water Usage per Household, Melbourne. 36 March 1, 2018 Regular Board Meeting Agenda Packet- Page 110 of 225 Page 55 of 74 SECTION 10 Abbreviations ACWA Association of California Water Agencies ACWD Alameda County Water District ADWF average dry weather flows BOD biochemical oxygen demand Cat+ calcium CASA California Association of Sanitation Agencies CEC contaminant of emerging concern CFR Code of Federal Regulations Cl- chloride CUWA California Water Urban Agencies CWC California Water Code CWEA California Water Environment Association DBP disinfection by-product DDW Division of Drinking Water DWR Department of Water Resources ECW electrical conductivity EO Executive Order EPA U.S. Environmental Protection Agency FeC13 ferric chloride FHWA Federal Highway Administration FOG fats, oils, and grease gpcd gallon(s) per capita per day GWRS Groundwater Replenishment System HCO3- bicarbonate H2S hydrogen sulfide H2SO4 sulfuric acid IEUA Inland Empire Utilities Agency L liter(s) LASAN City of Los Angeles, Bureau of Sanitation MCL maximum contaminant level mg milligram(s) mgd million gallons per day 37 March 1, 2018 Regular Board Meeting Agenda Packet- Page 111 of 225 Page 56 of 74 Na+ sodium NACE National Association of Corrosion Engineers NCWRP North City Water Reclamation Plant NL notification level NPDES National Pollutant Discharge Elimination System NPR non-potable reuse OCSD Orange County Sanitation District OCWD Orange County Water District 0&M operation and maintenance POR preferred operating range ppm part(s) per million PR potable reuse RCP reinforced concrete pipe REU residential end use RP1 Regional Water Recycling Plant 1 SB Senate Bill SCVWD Santa Clara Valley Water District SDCWA San Diego County Water Authority SMCL secondary maximum contaminant level SVCW Silicon Valley Clean Water TDS total dissolved solids THM trihalomethane TOC total organic carbon TSS total suspended solids TUD Tuolumne Utilities District VVWRA Victor Valley Water Reclamation Authority WRF Water Research Foundation WTP water treatment plant WUE water use efficiency WWTP wastewater treatment plant 38 March 1, 2018 Regular Board Meeting Agenda Packet- Page 112 of 225 Page 57 of 74 Appendix A: Case Studies March 1, 2018 Regular Board Meeting Agenda Packet- Page 113 of 225 Page 58 of 74 Appendix A Case Studies Nine geographically diverse agencies were selected from the list of respondents, collectively experiencing a broad range of impacts resulting from declining flows. Representing a combination of water, wastewater, and recycled water systems, the agencies interviewed revealed not only the range of impacts experienced, but their technical, operational, and financial significance. The case studies are presented in the order they appear in the main report. San Diego County Water Authority San Diego County Water Authority(SDCWA) is a wholesale water agency serving 24-member retail agencies, with a population of 3.3 Major Impacts million people and a service area of 1500 square miles. SDCWA More than$2 million lost operates and maintains the San Diego region's aqueduct delivery to re-treat flushed water system, which includes 300 miles of large-diameter pipeline in two $250,000 invested in new aqueducts, 1,600 aqueduct-related structures, and 100 flow- water quality monitoring control facilities. equipment Other major facilities in the SDCWA system include the Olivenhain Dam, its 24,000-acre-foot reservoir, and the 100 mgd Twin Oaks Valley Water Treatment Plant(Twin Oaks WTP). In December 2015, the Lewis Carlsbad Desalination Plant began commercial operation and currently provides a highly reliable local supply of up to 56,000-acre-feet per year for the San Diego region. A Water Purchase Agreement between SDCWA and Poseidon provides the terms whereby SDCWA purchases the supply and includes assurances that all water quality regulations are satisfied before deliveries are taken by SDCWA. The Water Authority also entered into long-term agreements for the transfer of conserved Colorado River supplies, which currently totals approximately 180,000-acre-feet per year. The remainder of the Water Authority's supplies are purchased as supplemental supplies from the Metropolitan Water District, which receives water from the Colorado River and the State Water Project. The water flows into San Diego through five large-diameter pipelines, which range in diameter from 48 to 108 inches. These pipelines carry either fully treated potable water or untreated water(raw water). Impacts Experienced Declining flows have had a variety of impacts on SDCWA, including: • Reduced flows in aqueducts: Because of reduced demand from their member agencies, flows in the aqueducts have dropped from 50 to 80 percent of capacity of the pipeline (prior to 2014)to just 10 percent. Flows with historical velocities of 10 feet per second (ft/s) have declined to 1 ft/s. The decline in flow naturally increases detention time in the aqueduct, which results in increased water age and degradation of water quality. • Reduced conveyance system residuals: Detention time has increased from several hours to up to 6 days in certain places within the conveyance system. Due to this increase, chlorine residuals consequently degrade. At the extremities of the aqueduct system, up to a 1 mg/L loss in residual chlorine has been experienced. The water quality continues to degrade in the member agencies' distribution systems. A-1 March 1, 2018 Regular Board Meeting Agenda Packet- Page 114 of 225 Page 59 of 74 • Conveyance system nitrification:As detention time has increased, nitrification has likewise increased within the aqueduct system, resulting in the unwanted production of nitrites in the drinking water. Adaptation Strategies and Financial Impacts SDCWA has proactively taken action to address the impacts described. These adaptation strategies demonstrate SDCWA's commitment to water supply reliability and water quality, but they do have a financial impact, as described below: • Increased flushing: SDCWA has increased its rate of flushing to address water quality issues from increased detention time in the aqueduct. When SDCWA flushes the pipeline with treated water, it is discharged into one of two locations. It either cascades into the untreated raw water pipeline and is then purchased by agencies at the raw water rate, or the flushing water is discharged into the Terminal Reservoir. This water must be treated again before it can be used. Previously, SDCWA was flushing only 5 to 10 cubic feet per second (cfs)two to three times per year. Now, 20 to 30 cfs is flushed on average daily. The costs associated with flushing and re- treating the water have increased from $200,000 a year to over$2 million per year. • Investment in online monitoring equipment: To address changing water quality in the pipeline because of loss of residual and increased nitrification activity, SDCWA has invested in the installation of multiple online water quality analyzers. These analyzers provide real-time data to control room staff to make better operating decisions. o Cost of new equipment:SDCWA has made an investment of upwards of$250,000 in new equipment to ensure water quality throughout its system. • Additional sampling in the field: Operational staff members are responsible for not only controlling the water, but also managing water quality. The percentage of staff time spent performing water quality monitoring and management duties has increased from 15 percent to 35-40 percent as a result of the water quality changes observed within the system. A-2 March 1, 2018 Regular Board Meeting Agenda Packet- Page 115 of 225 Page 60 of 74 Santa Clara Valley Water District The Santa Clara Valley Water District(District) provides Silicon Valley safe, clean water for a healthy life, environment and Major Impacts economy. That includes managing an integrated water resources $1.63 million in powdered system that not only provides clean water, but is dedicated to activated carbon(PAC) keeping residents and businesses safe through its flood protection purchased to remove total programs and that is committed to protecting our environment organic carbon(TOC)and through habitat restoration, cleaning toxins from water and taste and odor compounds ensuring the efficient use of water throughout our community. An additional$150,000 The District manages 10 dams and surface water reservoirs,three from FeCh use water treatment plants with a total capacity of 220 mgd, an $350,000 in increased advanced recycled water purification center, a state-of-the-art water staff time for water quality quality laboratory, nearly 400 acres of groundwater recharge ponds monitoring and testing and more than 275 miles of streams. It provides wholesale water and groundwater management services to local municipalities and private water retailers who deliver drinking water directly to homes and businesses in Santa Clara County. The District's water sources include water imported through the Sacramento-San Joaquin Delta, local surface water, groundwater and purified water produced by its Silicon Valley Advanced Water Purification Center. Imported water accounts for half of the water used in the county. The District manages the groundwater basin with local and imported water through percolation ponds and stream beds and the water purification facility produces up to 8 mgd of near-distilled-quality water. Impacts Experienced During the drought years, lower water volumes flowing through the Sacramento-San Joaquin Delta resulted in higher total organic carbon (TOC), higher salinity, and more taste and odor(T&0) production in the water flowing through the Delta, which made up most of the water treated at the District's three WTPs. Combined with declining flows, SCVWD's operations sustained a variety of impacts, including reduced water production from all three WTPs, changes in water quality, and subsequent operational challenges: • Reduced water production in the three WTPs: During the recent extreme drought and subsequent emergency mandates, water demand decreased and water production was well below capacity. In 2013, the maximum daily water production was 161.7 mgd. In 2014,the maximum daily production was 119.8 mgd, and in 2015 the maximum daily water production was 128.4 mgd. • Changes in water quality: Two of the three WTPs operated by SCVWD were converted to use ozonation for primary disinfection in 2007.These WTPs experienced fewer water quality impacts than the third plant, which is now undergoing a major overhaul. The main driver for conversion of SCVWD's WTPs to ozonation was to improve their ability to treat poor-quality source water such as that experienced in the recent drought. The ozone plants produced lower trihalomethanes (THMs) and removed T&O compounds more effectively. During the period of mandated water reduction, the third WTP (Rinconada) experienced increased THM production and some T&O issues. • Operational challenges because of water quality and reduced flows: Due to reduced demand, flows declined in the water distribution system. This created the potential for the retailers located the furthest downstream to be adversely affected by abnormally high residences times. A-3 March 1, 2018 Regular Board Meeting Agenda Packet- Page 116 of 225 Page 61 of 74 Adaptation Strategies and Financial Impacts SCVWD has proactively taken actions to address the impacts of declining flows. The implemented adaptation strategies included: • Use of PAC to remove TOC: SCVWD was already using PAC to deal with T&O issues at the Rinconada Plant. However, in 2014 and 2015, it also used PAC to remove TOC, which came at a cost. o Cost of PAC: PAC use from 2014 to 2016 came in at$1.63 million, most of which was associated with high-TOC source water which required more TOC removal. • Changed chlorine injection point for WTP: To handle changing water quality, SCVWD's Rinconada plant eliminated its chlorine injection point halfway through the clarification process. The plant instead relied on a lower chlorine dose to the filter influent, and boosted the residual post-filtration. This change was driven by drought conditions, as the original injection point had served Rinconada well prior to that time. • Coagulant Changes to address higher TOC: SCVWD switched coagulants from aluminum sulfate (alum)to ferric chloride (FeC13)for approximately 3 months in 2016, and also applied a higher dose of FeC13 to achieve TOC-removal goals. o Cost of ferric chloride: FeC13 use resulted in an additional cost of$150,000 for both chemical and associated sludge disposal. • Increased laboratory monitoring of water quality parameters: Due to changing source water quality, SCVWD stepped up its water quality testing frequency.The agency conducted additional THM testing, and reduced analytical turnaround times, so the results could be used to adjust operational strategies.The THM data were shared with SCVWD's retailers, increasing reporting frequency from monthly to weekly, and sometimes semi-weekly. o Increased staff time: The increased staff time to manage treatment strategies and conduct additional testing cost approximately $350,000 from 2014 to 2016. • Reduced distribution residual to mitigate for THMs:SCVWD's internal goal for THMs is to remain below 80 percent of the MCL, which equates to 64 pg/L (MCL is 80 pg/L). To mitigate the production of THMs, SCVWD lowered its in-plant and effluent chlorine residuals at two WTPs. The Penitencia plant also operated with a lower clearwell level in order to reduce free chlorine contact time within the plant. • Established minimum flow rates in the Rinconada distribution system:To minimize the impact of reduced flow rates on the most downstream retailer, SCVWD established minimum required flow rates with each of its retailers. This minimized detention times and maximized turnover of water despite reduced demands. A-4 March 1, 2018 Regular Board Meeting Agenda Packet- Page 117 of 225 Page 62 of 74 Alameda County Water District Alameda County Water District (ACWD) provides a reliable source of high quality drinking water to over 351,000 people in the cities of Major Impacts Fremont, Newark and Union City. ACWD's water system consists of . Supplemental flushing nearly 900 miles of distribution pipelines, 13 water storage tanks, operations was necessary and numerous water pumping and regulating facilities spread out to address unusually low over a 100-square mile service area. As a retail water provider, chlorine residuals ACWD is responsible for all aspects of local water service for over Suspension of the main 83,000 direct customer service connections. flushing program during ACWD also operates 3 water treatment facilities: Water Treatment the drought resulted in Plant 2 (WTP2)treats surface water imported from the Sacramento- increased sediment San Joaquin Delta; Newark Desalination Facility uses reverse accumulation osmosis membrane technology to treat brackish groundwater from Idling of the PT Blending the Niles Cone Groundwater Basin; and the Peralta-Tyson (PT) Facility Blending Facility blends imported Hetch Hetchy water with local groundwater from the Niles Cone. A fourth treatment facility, the Mission San Jose Water Treatment Plant(MSJWTP) was taken out of service in 2015. About 40% of ACWD's water is from local sources;the balance of ACWD's water supplies are imported. Impacts Experienced During the drought, ACWD experienced operational challenges due to conservation, reduced flows in the local water system, and degraded source water quality. • Lower water demand: Due to significant conservation by ACWD customers, average daily water production decreased from 43.6 MGD prior to the drought (FY12-13)to 34.8 MGD following the drought(FY16-17). At the height of the drought, ACWD customers had reduced water demands by 27% in comparison to pre-drought levels. • Distribution system nitrification and areas of low chlorine residual: Reduced water demands increased overall water age in the system. Fluctuating flow rates from ACWD's three water treatment facilities to adjust to the low demands resulted in reversals of normal flow directions and changed areas of influence for certain treatment facilities at times. As a result, ACWD experienced nitrification conditions in a greater number of water storage facilities than in the past, and to a greater extent. Additionally, some outlying areas of the distribution system with low water use and high water age experienced low chlorine residuals, which had not previously occurred. • Operational challenges due to reduced flows: With reduced demands, the water treatment facilities had to be operated at lower-than-typical seasonal rates, and at variable flow rates to exercise distribution system storage and reduce water age in the system. Water storage facilities also had to be operated at lower levels to help reduce water age, which meant that less water remained in storage for use during unexpected emergencies or extended outages. These challenges increased attention to water quality monitoring, storage facility management and flushing operations which resulted in impacts on staff time and other operational needs. • Intermittent idling of the PT Blending Facility: During periods of very low flows, the PT Blending Facility had to be used in an atypical low flow mode or even shut off for a few days at a time to effect turnover in the system's water storage facilities A-5 March 1, 2018 Regular Board Meeting Agenda Packet- Page 118 of 225 Page 63 of 74 Adaptation Strategies and Financial Impacts ACWD took a proactive approach during and after the drought to address the impacts described above and continue to provide high-quality water under all conditions. Although not specifically quantified, many of these actions did have some level of financial impact in increased operational, monitoring, staff time or other costs as noted below. • Modified water storage strategies: To address increased nitrification in the water storage facilities and reduce water age in the distribution system, ACWD's operational strategies were adapted to increase and intensify water storage cycling. This included changes in seasonal and day-to-day flow rates from water treatment facilities and adapting targets for water storage volume to the lower water demands and storage needs. However, this also resulted in less water remaining in storage for use in the event of an extended outage or emergency. • Increased water quality monitoring and storage facility treatments: Due to high water age and issues with nitrification, water storage facilities were monitored more proactively to identify when supplemental chlorination treatments were needed. The frequency of supplemental chlorination treatment at the storage facilities (tanks and reservoirs) also increased, which can have potential water quality impacts. These adjustments resulted in additional staff time and overtime needs. • Supplemented flushing operations:To address unusually low chlorine residuals at outlying ends of the distribution system, supplemental flushing events were required to bring fresh water into a few areas. • Adjusted pumping and regulating operations:To address high water age and low chlorine residual at the end of one smaller residential zone with extremely reduced demands, adjustments were made to pumping and regulating operations to allow fresher water to pass more quickly through the zone. While this was an adjustment in only a small zone, it provides an example of how changes due to reduced demands can result in additional energy use and associated costs. • Shut down PT Blending Facility intermittently: Prior to the drought,the PT Blending Facility had never been turned off for much longer than a day, and only in very rare circumstances. As a result of low flows and the need to create flow variations in the system to cycle water storage levels,the facility had to be shut down intermittently, requiring operational adjustments and extra staff time and attention. • Reduced RO recovery rates at Newark Desalination Facility: To avoid overfilling the distribution system and balance the use of available water supplies while maintaining operation of facilities under low flow conditions,the recovery rate on the reverse osmosis process at the Newark Desalination Facility was reduced. Although this operation is less efficient, it allowed the plant to remain online during these periods rather than go off-line entirely, which would have impacted the life of the reverse osmosis membranes and limited ACWD's ability to use local groundwater. • Shutdown of Mission San Jose Water Treatment Plant(MSJWTP): Due to significantly reduced water demands, in lieu of making needed upgrades to the 3.5-MGD MSJWTP, ACWD elected to shut down the facility for 10 or more years. This has resulted in a stranded asset and requires heavier reliance on pumping operations to higher elevation zones that were formerly served by the facility. A-6 March 1, 2018 Regular Board Meeting Agenda Packet- Page 119 of 225 Page 64 of 74 Tuolumne Utilities District Tuolumne Utilities District(TUD) is a water and wastewater utility that serves nearly 44,000 residents in northern California's Major Impacts: Tuolumne County. Ninety-five percent of its source water is snow a Purchase of Persnickety from the Sierra Nevada, which runs through the South Fork lids to mitigate increased Stanislaus River and fills the Pinecrest and Lyons reservoirs. The odors last 5 percent of its supply is from 30 groundwater wells. Costs of pipe patching to TUD's main source water is the Lyons reservoir, which flows address increased root through canals, pipes, and open ditches until it reaches the WTPs, intrusion at which point it goes through a rigorous treatment process to turn it from raw water into drinking water. TUD currently owns and operates 14 WTPs, 9 of which intake water directly from the ditch system, and the rest draw raw water from small reservoirs. TUD also operates a wastewater management system and treats 1.2 mgd of sewage at the Sonoma Regional WWTP. TUD uses approximately 140 miles of a gravity collection system and 20 miles of force main to collect between 400 and 500 million gallons of sewage per year. There are 29 individual pump stations at various locations throughout the collection system, and 1 satellite treatment plant discharges effluent overnight into the main Sonoma Regional WWTP. Impacts Experienced Declining flows have had a variety of impacts on TUD, including reduced dry weather flow, decreased flows in the collection system, and increased root intrusion: • Reduced dry weather flow:TUD has experienced a decline in dry weather flow over time. It has decreased to 1.2 mgd of wastewater influent at the Sonoma Regional WWTP, which is well below its design capacity. • Reduced flows in the collection system: TUD's collection system was designed over a 100 years ago on typical specifications for toilets, washing machines, and other indoor residential appliances at the time of its inception. With increased water efficiency standards for indoor plumbing and appliances, pipes are not getting flushed out as effectively. Yet for gravity collection systems, water is the power that pushes the debris. Reduced flows have therefore had several impacts such as: o Increased settling in the larger-diameter lines: As flows have decreased in the collection system, there is less water to flush the debris. Thus, settling has increased in the larger- diameter pipelines. o Increased sanitary sewer overflow:The TUD collection system is mostly small-diameter pipelines (i.e., 15 inches or smaller). In fact, 65 percent of the system is 4-and 6-inch- diameter pipe. Such small pipes are prone to blockages, which are only exacerbated by reduced flows. In these situations, any amount of debris leads to sewer sanitary overflows and blockages. o Significant increase in work order calls for lateral pipelines:The increased settling and blockages have manifested in an increase in work order calls, especially for lateral pipelines. o Increased odors: The declining flows have also resulted in an increase in H2S, which generates additional odors. A-7 March 1, 2018 Regular Board Meeting Agenda Packet- Page 120 of 225 Page 65 of 74 • Increased root intrusion: Gravity collection systems are not designed to have debris and wastewater sitting in a single location. When there is a blockage, any crack or pinhole has the potential to leach moisture. TUD has observed increased root intrusion in these locations, causing further separation and cracks. Adaptation Strategies and Financial Impacts TUD has proactively taken action to address the impacts described above.These adaptation strategies include: • Increased maintenance of the collection system:TUD has always maintained a hot spot list that TUD staff would routinely check. As flows have declined, TUD has added locations to that hot spot list. It has also increased collection system surveys, and smaller service trucks are being sent out more often to monitor the manholes. • Proactive pipe patching: TUD has implemented a pipe patching system to counter the increased root intrusion. When there is a root intrusion,TUD cleans the inside of the pipe and then cures a fiberglass material as an internal liner. The benefits are twofold: (1) it patches the pipe and reduces leakage, and (2) given that the fiberglass is smoother than the traditional gravity collection pipe, it helps to move the wastewater. • Installed Persnickety lids to address odor problems:To address the increase in odors, TUD has installed about 20 PERSNICKETY lids, which are oxidizing filters that sit under the manhole cover. The gravity collection system naturally breathes air in and out of the system, and the filter cleans the odors as it passes through. A-8 March 1, 2018 Regular Board Meeting Agenda Packet- Page 121 of 225 Page 66 of 74 Victor Valley Water Reclamation Authority The Victor Valley Water Reclamation Authority(VVWRA) operates as a Joint Powers Authority and serves four member agencies, Major Impacts including San Bernardino County Service Areas 42 (Oro Grande) More than$300,000 per and 64 (Spring Valley Lake), City of Hesperia, Town of Apple Valley, year over the last 5years in and City of Victorville. It provides wastewater treatment services mitigating corrosion in the through 42 miles of wastewater conveyance systems and a wastewater collection treatment facility that treats roughly 10.7 mgd. system Its WWTP is a conventional activated sludge facility that discharges into the Mojave River, which is a terminal river that does not flow to the ocean. Thus, the facility is bound by stringent regulatory water quality requirements. In addition, due to the value of water in the Mojave area, VVWRA decided to treat all wastewater effluent to Title 22 standards to maximize its reuse potential. This is done through the addition of tertiary filtration and ultraviolet(UV) disinfection. After being purified,the reclaimed water is sent to percolation ponds, reused, or discharged into the Mojave River. Impacts Experienced Being in the Mojave region, water use efficiency as a water supply reliability measure was already being emphasized prior to the governor's mandate in 2014. VVWRA started experiencing reductions in flows as early as 2010, as local wholesalers went to extensive means to implement water use efficiency. By the time the governor enacted the mandatory reductions, local water use had already been reduced significantly, even beyond the 20 to 30 percent mandated by the State. Thus, VVWRA has seen the impacts of declining flows for several years. Because of the stringent nature of its discharge requirements, the impacts of declining flows, including increased ammonia concentrations in the wastewater influent and increased H2S in its collection system, are acute, as indicated below: • Declining wastewater influent reduces wastewater effluent volumes: Given its inland location, VVWRA relies on river discharge rather than an ocean outfall. Based on base flow requirements set by CA Fish and Wildlife, VVWRA is required to discharge 8.2 mgd per day to the river. The declining wastewater influent therefore reduces the amount of water available for recycling. The less recycled water is available for end-users, the more customers must rely on potable resources (groundwater). • Increased ammonia concentrations in wastewater influent: Current ammonia concentrations in the wastewater influent are much higher than those recorded prior to 2010. While influent ammonia concentrations averaged in the mid to high 2Os mg/L prior to 2010, VVWRA currently sees concentrations between 30 and 40 mg/L. Low-flow shower heads, low-flow toilets, and sink aerators have all decreased the amount of flow going into the wastewater system, subsequently increasing concentrations. • Increased H2S in the collection system: Much of the gravity collection system was designed to handle flows consistent with design standards of the 198O's, which would convey the solids to the WWTP. However, as flows entering the wastewater conveyance system have decreased, the solids have lost their transport medium. Thus, solids remain in the wastewater conveyance system for longer periods, producing an increased amount of H2S. This results in: o Increased odors and odor complaints:The increase of H2S produces more odors, which subsequently generates more odor complaints. o Accelerated rate of corrosion and degradation of infrastructure: Because of the increased H2S, VVWRA has witnessed an acceleration of corrosion in its collection system, primarily at its manholes. A-9 March 1, 2018 Regular Board Meeting Agenda Packet- Page 122 of 225 Page 67 of 74 Adaptation Strategies and Financial Impacts VVWRA has proactively taken the following steps to address the impacts it has experienced as a result of declining flows: • Increased rehabilitation and maintenance of collection system manholes:To combat the accelerated rate of corrosion in the manholes, VVWRA has begun coating its manholes in epoxy. To proactively mitigate future corrosion, VVWRA has also updated its specifications for manhole coatings and is exploring alternative materials to concrete for manholes to mitigate the accelerated corrosion. o Investment in the epoxy coating:VVWRA has spent$300,000 per year over the past 5 years to address increased corrosion in its collection system. • Increased maintenance frequency of the collection system: VVWRA has a third-party maintenance contract that services the locations that need to be cleaned. The entire collection system is cleaned once every three years, and areas of low flow are being cleaned more regularly to prevent the buildup of H2S and reduce the potential for sanitary sewer blockages and overflows. • Coordinating with member entities to operate pump stations to reduce H2S: Initially, VVWRA had to use more bioxide to overcome system deficiencies. However, due to their investment in lining their manholes, VVWRA has been able to decrease their annual bioxide use. Another part of the strategy to combating odor was also coordinating closely with their member entities to train them on how to operate their pump stations to reduce H2S. A-10 March 1, 2018 Regular Board Meeting Agenda Packet- Page 123 of 225 Page 68 of 74 Los Angeles Department of Water & Power and the Los Angeles Bureau of Sanitation The Los Angeles Department of Water and Power(LADWP) was established in 1902 to deliver water to the City of Los Angeles Major Impacts (LA). It serves over 4 million residents through 96 pump 0 Additional manual labor stations and 7,300 miles of pipe. necessary to remove large The Los Angeles Bureau of Sanitation (LASAN) provides influxes of trash that buildup in wastewater services through the operation of sewers, water the sewer system reclamation plants, and biosolids management. LASAN 0 Designing new infrastructure to operates more than 6,700 miles of sewers that convey about divert flows to the DC Tillman 400 MGD of flow to the City's four wastewater treatment and Water Reclamation Plant water reclamation plants. Impacts Experienced Declining flows has had a variety of impacts on the urban water cycle in LA, including: • Reduced flows in the WWTPs: Hyperion is designed to accommodate a flow of 450 MGD. In the summer of 2012,the average flow going to the Hyperion Water Reclamation plant was 285 MGD. Now, average flows going to Hyperion are around 250 MGD. • Declining flows for future groundwater recharge projects: LASAN and LADWP are currently designing an expansion of the treatment process at the DC Tillman Water Reclamation Plant to implement groundwater recharge. The reduced flows going to WWTPs has required LASAN to divert flows from other locations to supplement the reduced flows. • Lower flows lead to an increase in nitrogen concentrations: Due to declining flows, the nitrogen concentration in the influent wastewater at Hyperion has increased from 35 to 45 mg/L over the past decade. Higher nitrogen levels require additional nitrification. While Hyperion does not nitrify, it does convey 15 percent of its effluent to partner agencies, who then treats the water to different water quality standards depending on the reuse application. Wherever nitrification is necessary for the application, the increase in ammonia can present a significant challenge to meeting end-user water quality requirements. • Large and bulky influx of trash associated with wet weather events: Due to declining flows, food waste and sanitary-type trash is getting stuck in the collection system. Then, when a large wet weather event occurs, the built-up debris is suddenly swept to the water reclamation plant, overloading its automatic raking system. • Increase in H2S production: As described in the white paper, declining flows in the wastewater conveyance system leads to an increase in H2S production. This exacerbates odor production, leading to an increase in odor mitigation methods. Adaptation Strategies and Financial Impacts Due to the robustness of the LADWP and LASAN water and wastewater systems,they have been able to handle the impacts to the system effectively without too many changes. However, adaptation strategies have been implemented, including: • New infrastructure to supplement declining flows at DC Tillman: Due to declining flows going to WWTPs, LASAN has been proactively and creatively looking for ways to divert supplemental flow to DC Tillman. The East/West Valley Interceptor is one of those projects, and other potential projects are being evaluated. A-11 March 1, 2018 Regular Board Meeting Agenda Packet- Page 124 of 225 Page 69 of 74 • Managing large influxes of trash through manual labor: When the automatic raking systems are overwhelmed by the sudden and large influx of trash, LASAN must manually pull trash out using manual rakes or a Bobcat. • Increasing chemical injection and potential upsizing of existing carbon scrubbers: The increase in H2S production has resulted in an increase in chemical injection and recommendations to upsize 3 of the 7 existing carbon scrubbers. LASAN has also experienced beneficial financial impacts due to declining flows. For example,the treated effluent at Hyperion is pumped 5 miles to the ocean outfall with discharge pumps. Since wastewater influent has decreased, the energy required to pump the wastewater has also decreased. 15 years ago,the treated effluent pumps were operated daily. Now,the treated effluent flows by gravity, and the pumps are only necessary when it rains, resulting in significant energy savings. A-12 March 1, 2018 Regular Board Meeting Agenda Packet- Page 125 of 225 Page 70 of 74 Orange County Water District and Orange County Sanitation District Orange County Water District(OCWD) and Orange County Major Impacts Sanitation District(OCSD) collaborate to provide water supply $60 million to segregate non- reliability in their Orange County service area. reclaimable flows from the OCWD owns and manages 6 miles of the Santa Ana River, and the water conveyed to GWRS approximately 500,000 acre-feet Orange County Groundwater Basin. It also co-manages the Groundwater Water Replenishment System (GWRS) with OCSD, which is the world's largest advanced water purification system for PR through groundwater augmentation. OCSD provides wastewater collection,treatment, and disposal services for approximately 2.6 million residents in northwest and central Orange County. It operates two facilities, Plant 1 in Fountain Valley and Plant 2 in Huntington Beach, which treat wastewater from residential, commercial, and industrial sources. GWRS currently receives reclaimable water effluent from Plant 1 alone. The balance of flows, including non-reclaimable flows from the Santa Ana River Interceptor, which carries industrial inputs and RO concentrate from inland brackish water desalters, are treated at Plant 2. To meet the flow requirements of the initial expansion of GWRS to 100 mgd of purified water production, OCSD diverts flows within its system to increase the flow through Plant 1 for reclamation at GWRS. Impacts Experienced Given that flow otherwise destined for Plant 2 is currently diverted to Plant 1 to maximize reuse through GWRS,the effects of declining flows are experienced more acutely at Plant 2. The impacts are described below: • Reduced flows in the WWTPs: In the 2000s, the total combined flow of Plant 1 and Plant 2 was 240 mgd. Now, the combined flow of both plants is approximately 185 mgd. The decline in flows reduces the wastewater effluent available to be purified and used for groundwater augmentation. • Increased detention time of wastewater in conveyance system: Because of declining flows, wastewater remains in the conveyance system for longer periods. With that extended time comes the danger of the wastewater going septic. OCSD has also noticed increased deposition as a result of lower flows. • Increased grease buildup and settlement at Plant 2: With the flow diversions implemented to purposefully redirect flow to GWRS, Plant 2 consequently experiences lower flows, which leads to grease buildup and settling within the treatment process at Plant 2. Adaptation Strategies and Financial Impacts OCSD and OCWD have proactively taken action to address the impacts described above. These adaptations are described below: • Increased chemical addition in the conveyance system:To counteract the wastewater from going septic, OCSD has increased the amount of chemicals it has dosed into its system. • Change in conveyance operations to mitigate impacts from low flows: The flows to Plant 2 have been impacted both by declining flows and the increased diversion of wastewater to Plant 1. To mitigate the impacts of increased settling at Plant 2, OCSD leverages its diversion structures to channel flows into fewer pipelines. For example, instead of having four pipelines with low velocity, OCSD diverts the flows into two pipelines to regain that scouring velocity. Then every couple of months, it changes the pipelines to flush them out. A-13 March 1, 2018 Regular Board Meeting Agenda Packet- Page 126 of 225 Page 71 of 74 • Supplementing GWRS feed water flows with Plant 2 effluent: With the substantial decline in OCSD's influent flows, the upcoming GWRS final expansion to 130 mgd will require flow to be conveyed from Plant 2 to GWRS for purification.The Plant 2 effluent requires additional investment by OCSD and OCWD to segregate non-reclaimable flows and to purify effluent with a more challenging water quality. • Segregation of high-salinity flows to maximize reclamation:The flow received at Plant 2 contains industrial discharge as well as RO concentrate from inland desalters. As California prepares for increased frequency, intensity, and duration of future droughts, inland water agencies seek out and treat more challenging local water supplies like brackish groundwater to improve supply reliability. This high-TDS flow is currently processed at Plant 2,the effluent from which is destined for purification at GWRS as part of the final expansion.To prevent this highly saline flow from negatively impacting the purified water produced at GWRS, OCSD has invested $60 million to segregate these non-reclaimable flows from the water conveyed to GWRS. A-14 March 1, 2018 Regular Board Meeting Agenda Packet- Page 127 of 225 Page 72 of 74 Appendix B: Table of Utilities March 1, 2018 Regular Board Meeting Agenda Packet- Page 128 of 225 Page 73 of 74 Appendix E List of Agencies that Responded to the Survey Table B-1.List of Agencies that Responded to the Survey and Experienced Impacts F Services Provided Agency Name Water Recycled Water Wastewater ServiceArea Experienced Impacts Alameda County Water District ✓ 100,001-1M ✓ Amador Water Agency ✓ ✓ <100,000 ✓ Central Marin Sanitation Agency ✓ 100,001-1M ✓ City of Camarillo/Camarillo Sanitation District ✓ ✓ ✓ <100,000 ✓ City of Fairfield ✓ 100,001-1M ✓ City of Fontana ✓ ✓ <100,000 City of Fresno ✓ ✓ ✓ 100,001-1M ✓ City of Los Angeles,Bureau of Sanitation ✓ ✓ >1M ✓ City of Modesto ✓ ✓ ✓ 100,001-1M ✓ City of Pacifica ✓ <100,000 ✓ City of Palo Alto ✓ ✓ 100,001-1M ✓ City of Patterson ✓ ✓ <100,000 ✓ City of Pismo Beach ✓ ✓ <100,000 ✓ City of Rialto ✓ ✓ ✓ <100,000 ✓ City of San Diego ✓ ✓ ✓ >1M ✓ City of San Juan Capistrano ✓ ✓ ✓ <100,000 ✓ City of San Luis Obispo ✓ ✓ ✓ <100,000 ✓ City of Santa Barbara ✓ ✓ <100,000 ✓ City of Santa Clara ✓ ✓ ✓ 100,001-1M ✓ City of Scotts Valley ✓ ✓ <100,000 ✓ City of Stockton ✓ <100,000 ✓ City of Vacaville ✓ ✓ ✓ <100,000 ✓ Coachella Valley Water District ✓ ✓ ✓ 100,001-1M ✓ Contra Costa Water District ✓ 100,001-1M ✓ Delta Diablo Sanitation District ✓ ✓ 100,001-1M ✓ East Bay Municipal Utility District ✓ ✓ ✓ >1M ✓ East Orange County Water District ✓ ✓ <100,000 ✓ Eastern Municipal Water District ✓ ✓ ✓ 100,001-1M ✓ EI Dorado Irrigation District ✓ ✓ ✓ 100,001-1M ✓ Goleta Sanitary District ✓ ✓ <100,000 ✓ Idyllwild Water District ✓ ✓ <100,000 ✓ Jurupa Community Services District ✓ ✓ 100,001-1M ✓ Kern County Water Agency ✓ 100,001-1M ✓ Kinneloa Irrigation District ✓ <100,000 ✓ March 1, 2018 Regular Board Meeting Agenda Packet- Page 129 of 225 Page 74 of 74 Table B-1.List of Agencies that Responded to the Survey and Experienced Impacts Services Provided Agency Name Water Recycled Water Wastewater ServiceArea Experienced Impacts Lake Arrowhead Community Services District ✓ ✓ ✓ <100,000 ✓ Los Angeles Department of Water and Power ✓ ✓ >1M ✓ Mammoth Community Water District ✓ ✓ ✓ <100,000 ✓ Metropolitan Water District of Southern California ✓ >1M ✓ Mission Hills Community Services District ✓ ✓ <100,000 ✓ Monterey Regional Water Pollution Control Agency ✓ ✓ 100,001-1M ✓ Mt.View Sanitary District ✓ <100,000 ✓ Municipal Water District of Orange County ✓ >1M ✓ Orange County Sanitation District ✓ >1M ✓ Orange County Water District ✓ >1M ✓ Oro Loma Sanitary District ✓ 100,001-1M ✓ Otay Water District ✓ ✓ ✓ 100,001-1M ✓ Padre Dam Municipal Water District ✓ ✓ ✓ 100,001-1M ✓ Rincon del Diablo Municipal Water District ✓ ✓ <100,000 ✓ Sacremento Regional County Sanitation District ✓ <100,000 ✓ Sacremento Suburban Water District ✓ 100,001-1M ✓ San Bemadino Valley Water Conservation District ✓ 100,001-1M San Diego County Water Authority ✓ >1M ✓ San Francisco Public Utilities Commission ✓ ✓ ✓ >1M ✓ Santa Clara Valley Water District ✓ ✓ >1M ✓ Santa Margarita Water District ✓ ✓ ✓ 100,001-1M ✓ Sausalito Marin City Sanitary District ✓ >1M ✓ Scotts Valley Water District ✓ ✓ <100,000 ✓ Silicon Valley Clean Water ✓ ✓ 100,001- 1M ✓ South Coast Water District ✓ ✓ ✓ <100,000 ✓ South Orange County Wastewater Authority ✓ ✓ ✓ >1M ✓ South Tahoe Public Utility District ✓ ✓ ✓ <100,000 ✓ Sunnyslope County Water District ✓ ✓ <100,000 Tuolumne Utilities District ✓ ✓ ✓ <100,000 ✓ Union Sanitary District ✓ 100,001-1M ✓ Valley Center Municipal Water District ✓ ✓ ✓ <100,000 ✓ Valley County Water District ✓ <100,000 ✓ Veolia Water ✓ <100,000 ✓ Victor Valley Wastewater Reclamation Authority ✓ ✓ 100,001-1M ✓ Vista Irrigation District ✓ 100,001-1M ✓ West Bay Sanitary District ✓ ✓ <100,000 ✓ Western Municipal Water District ✓ ✓ ✓ 100,001-1M ✓ Yucaipa Valley Water District ✓ ✓ ✓ <100,000 ✓ Zone 7 Water Agency ✓ 100,001-1M ✓ Per data collected on October 13,2017. March 1, 2018 Regular Board Meeting Agenda Packet- Page 130 of 225