APPENDIX D Water Agency Profile: City of San Diego

Transcription

1 APPENDIX D Water Agency Profile: City of San Diego Recycled Water Summary Source 1 Total Water Demand 227, , , , , UWMP, Table Wastewater Collected & Treated (AF) 247, , , , , UWMP, Table Treatment Plant Capacity 37.5 MGD TBD Water Reuse Study 2006 (Tertiary only) 4 Tertiary Flows 16.5 MGD TBD Water Reuse Study Projected Quantity of Wastewater Collected & Treated that Meets Reclaimed Water Standard 8,759 13,139 16,029 19,555 20, UWMP, Table Planned Reclaimed Water Production 4,294 8,525 [1] 12,200 [1] 15,200 [1] 15,200 [1] 2005 UWMP, Table Projected Recycled Water Demand: 7a Landscape (Tertiary) 9,441 8,025 8,325 8, UWMP, Table 5-5 7b Industrial (Tertiary) 2,450 2,450 2,450 2, UWMP, Table 5-5 7c Wholesale (Tertiary) 4,338 5,754 6,612 7, UWMP, Table 5-5 7d Total Tertiary Direct Use 11,263 [1 ] 16,229 [1] 17,387 [1] 17,906 [1] 2005 UWMP, Table Amount of Wastewater Projected to be Discharged to the Ocean 251, , , , , UWMP, Table 5-3 Note: All above numbers are in acre-feet per year, unless otherwise noted. [1] Includes commitments to provide up to 6MGD of tertiary-treated recycled water to Otay Water District under a 20 year agreement. [2] Primary or better. The City of San Diego (the City), with a population of 1.3 million, is the second largest city in California and the seventh largest city in the nation. Its population is projected to grow 28%, to nearly 1.7 million by Current water demand of 230,000 acre feet per year is expected to increase 20% to 276,000 acre feet per year by With a dry, Mediterranean climate, the City has limited local water supplies. It is a member of the San Diego County Water Authority (SDCWA) which provides the majority of the City s potable water supplies. Most of these supplies are imported from northern California (the Sacramento San Joaquin delta) or the Colorado River via the Metropolitan Water District of Southern California (MWD), in which SDCWA is a member. The City s departments treat wastewater and sell both potable and recycled water. The San Diego Metropolitan Wastewater Department (MWWD) provides City of San Diego Urban Water Management Plan, p. 2 9 D 1

2 wastewater collection and treatment to the City and 16 surrounding municipalities and sewer districts. 2 The San Diego Water Department procures, treats, and delivers potable water to end users in the City. Note that only water needed to meet recycled water demand is treated to tertiary levels. All other water is treated to secondary standards. In addition, the department sells potable water on a wholesale basis to the City of Del Mar, the Santa Fe and San Dieguito Irrigation Districts, and the California American Water Company (which in turn serves the Cities of Coronado and Imperial Beach and portions of south San Diego). Finally, the Department delivers recycled water to over 400 end users, and sells on a wholesale basis to the City of Poway, Olivenhain MWD, and Otay WD during summer months. The City has three wastewater treatment plants (WWTPs). The main treatment plant, Point Loma, provides advanced primary treatment. Two WWTPs treat wastewater to tertiary standards, providing the City s recycled water supplies: the North City Water Reclamation Plant (NCWRP) and the South Bay Water Reclamation Plant (SBWRP). NCWRP has a wastewater treatment capacity of 30 million gallons per day (MGD) of which 24 MGD is tertiary. It currently produces an average of 6 MGD of recycled water. The remaining wastewater is treated to secondary and sent to Pt. Loma for discharge to the ocean outfall. SBWRP has a wastewater treatment capacity of 15 MGD and a tertiary treatment capacity of 13.5 MGD. Recycled water production from this plant during summer months peaks at 7.5 MGD. Water Supply The majority of the City s water supplies are imported. The SDCWA supplies 75% to 90% of the City s water; these supplies are primarily imported via the State Water Project (SWP) and the Colorado River Aqueduct (which is supplied by MWD). Remaining City supplies are local resources comprised of surface water and recycled water. The City is the largest customer in the SDCWA, which serves the western third of San Diego County and parts of Riverside and Orange Counties. SDCWA includes 22 other member agencies (Figure D 1). These other agencies represent potential partners and customers for recycled water. 2 Customers include the following entities: The Cities of Chula Vista, Coronado, Del Mar, El Cajon, Imperial Beach, La Mesa, National City, and Poway; the Lemon Grove Sanitation District; the Otay Water District; the Padre Dam Municipal Water District; and the County of San Diego (including Lakeside/Alpine, Spring Valley, Wintergardens, and East Otay Mesa). D 2

3 Figure D 1 Map of San Diego County Water Authority Service Territory and Member Agencies The water purchased from SDCWA costs, on average, about $500/af. 3 The purchase price includes the cost of power, water, and other charges. The City procures, treats, and delivers water to retail customers and neighboring water districts. The City delivers both potable and recycled water to their customers. 3 Calculated from San Diego CWA 2000 through 2006 Annual Reports D 3

4 Table D 1 Water Customers in the City of San Diego Resource Potable water (retail) Potable water (wholesale) Recycled water (retail) Recycled water (wholesale) Customer End-use customers City of Del Mar; California-American Water Company; Otay Water District: Santa Fe and San Dieguito Irrigation Districts End-use customers (>100 afy), including Metropolitan Biosolids Center, International Boundary & Water Commission, City Park & Recreation Department including Torrey Pines Golf Course, the developments of Black Mountain Ranch and Santa Luz, Marine Corp Air Station Miramar, CalTrans, University of California San Diego and La Jolla Colony HOA Olivenhain MWD, City of Poway, Otay WD Over the next 25 years, the City will continue to rely heavily on water supplies purchased from the SDCWA. In addition, the city anticipates recycled water supplies to increase (Table D 2). Maximum annual recycled water production is projected at 24,300 acre feet. A significant portion of the recycled water would be used in the treatment of untreated wastewater and ultimately discharged to the ocean. Table D 2 Projected Water Supply Sources for the City of San Diego, Water Supply Sources Projected Water Supply (acre-feet) SDCWA (Purchased) 201, , , , ,725 Local Surface Water 29,000 29,000 29,000 29,000 29,000 Recycled Water 8,525 12,200 15,200 15,200 15,200 Total 239, , , , ,925 Note: The above projections reflect the expected quantity of recycled water availability, given current expectations of capital investments in recycled water infrastructure over the projection period. They do not reflect the maximum potential, which is the amount of wastewater effluent produced by wastewater treatment currently and in the future that could be reclaimed and used as recycled water. Recycled Water Supplies The City has one wastewater treatment plant and two water reclamation plants. The wastewater treatment plant, Point Loma, provides advanced primary treatment. The wastewater effluent from this plant is discharged to the ocean. Two water reclamation plants treat wastewater to tertiary standards, providing the City s recycled water supplies: the North City Water Reclamation Plant (NCWRP) and the South Bay Water Reclamation Plant (SBWRP). NCWRP has a wastewater treatment capacity of 30 MGD. Tertiary treatment capacity is 24 MGD. (The actual amount of recycled water produced is less than the rated capacity due to internal treatment process uses.) 5 The NCWRP currently produces an average of 6 MGD of recycled water (peaking at 9 MGD City of San Diego Urban Water Management Plan, p City of San Diego Water Reuse Study, March 2006, p D 4

5 during the 2007 summer months). The remaining wastewater is treated to secondary and sent to Pt. Loma for discharge to the ocean outfall. SBWRP has a wastewater treatment capacity of 15 MGD and a tertiary treatment capacity of 13.5 MGD. As with the NCWRP, the actual amount of recycled water producd is less than the rated capacity due to internal treatment process uses. 6 Recycled water production during 2007 summer months peaked at 7.5 MGD. On June 1, 2007, the Otay Water Districtʹs (OWD) Recycled Water Supply Link Project was completed and placed in service. This project connects OWDʹs recycled water distribution system to the City of San Diegoʹs South Bay Water Reclamation Plant (SBWRP). Under a 20 year agreement entered into between OWD and San Diego in 2003, up to 6 MGD of recycled water will be delivered by San Diego to OWD through this link. This water is being used to irrigate parks, golf courses, open space and road medians in eastern Chula Vista. OWD paid a one time reservation charge of $3.6 million. OWD will also pay the City Council approved recycled water rate. Plant Wastewater Treatment Capacity (MGD) Table D 3 Capacity and Flows of San Diego s Wastewater Treatment Plants 7 Planned Tertiary Capacity by 2010 (MGD) Existing Beneficial Reuse (MGD) Planned Reuse by 2010 (MGD) Current Average Flows (MGD) Peak Tertiary Flow (MGD) [1] Current Volume of Flows (AF) [2] Amount of Tertiary Water Produced Now (AF) Potential Additional Tertiary Production after 2010 Point 240 n/a n/a n/a n/a 165,146 n/a n/a Loma North City [3] [4] 25,192 8, MGD 16,794 AF South Bay [3] [5] 11,196 4,478 6 MGD 6,718 AF Notes: [1] Peak flows during summer months. [2] Current average flows (MGD) x 365 days/per, divided by 326,000 gallons per acre-foot (AF). [3] Additional facilities have come on-line since the UWMP was completed. Actual tertiary treatment capacity less than rated plant capacity due to internal treatment processes. [4] Total planned reuse by 2010 with completion of ongoing reuse projects (distribution system expansion Phase 1 & II). Phase I is currently being completed, and Phase II is in various stages of planning, design or construction. Phase III expansion has not been funded. 8 [5] SBWRP became operational in Summer Production as of 2006 was 5-6 MGD of secondary treated wastewater that is disposed via the South Bay Ocean Outfall. Certification of the tertiary treatment facilities was granted by RWQCB in City of San Diego Water Reuse Study, March 2006, p City of San Diego Water Reuse Study, March 2006, pp. 3 4 and City of San Diego Water Reuse Study, March 2006, p City of San Diego Water Reuse Study, March 2006, p D 5

6 In its March 2005 Water Reuse Study, San Diego outlined a number of strategies for accelerating use of its existing recycled water supplies. A component of those strategies is Indirect Potable Reuse (IPR). IPR takes recycled water through advanced water treatment (AWT) to produce a raw water supply for potable groundwater basins and reservoirs. For the City, this approach would enable full beneficial use of recycled water supplies. Table D 4 Strategies for Development of Recycled Water Infrastructure North City South Bay Strategy NC1 NC2 NC3 SB1 SB2 SB3 Incremental Demand 19,680 [1] 18,040 [1] 23,760 [1] 13,040 [2] 8,960 [2] 12,660 [2] % of Tertiary Flows Served 73% 69% 100% 86% 62% 96% Est. Capital Cost[3] $284.7M $188.3M $237.6M $1.0M[4] $21.6M $96.1M Wtd. Avg. $/AF[3] $1,960 $1,370 $1,230 $70[4] $1,330 $1,530 Description of Strategies: NC1 - Expansion of the non-potable system to serve infill, Phase III Rancho Bernardo, the Central Service Area, and Rose Canyon wetlands (p.7-6). NC2 - Expansion of the non-potable system to serve infill and Phase III Rancho Bernardo, followed by a small-scale indirect potable reuse (IPR) project at Lake Hodges (p.7-8). NC3 - Expansion of the non-potable system to serve infill, followed by a large-scale San Vicente Reservoir IPR project sized to maximize available supplies (p.7-10). SB1 - Expansion of the non-potable system to serve OWD and Sweetwater Authority (p.7-16). SB2 - Expansion of the non-potable system to serve OWD, followed by a small-scale IPR opportunity at Lower Otay Reservoir (p.7-18). SB3 - Expansion of the non-potable system to serve OWD, followed by a large-scale IPR opportunity at Lower Otay Reservoir (p.7-20). Notes: [1] From Table 7-1. Each strategy includes completing existing work that would enable serving 9,440 acre-feet per year of demand plus an additional 3,820 acre-feet per year of infill. [2] From Table 7-2. [3] City of San Diego Water Reuse Study, March pp 7-26 to Does not include potential incentives from MWD and/or SDCWA. [4] The low cost of this option relative to others is due to the revenues paid by Otay Water District to access this water. Also in its Water Reuse Study, San Diego stated its commitment to completing Phases I and II expansions of the North City recycled water distribution system. In addition, San Diego stated its intent to pursue infill opportunities that would help meet the City s Northern Service Area goal of beneficially using 12 MGD (13,400 AFY) by Other opportunities were more costly and/or could not be completed by In the Northern Service Area, the City has more than 80 miles of recycled water pipelines, two storage tanks, and three pumping stations. 10 The City anticipates expanding the recycled water system in several phases. Current and planned future distribution lines, storage, and treatment facilities are shown in Figures D 2 and D City of San Diego Urban Water Management Plan, p. 1 5 D 6

7 The City s highest priority for increasing recycled water use is to connect new customers to existing distribution lines ( in fill developments). In fill is especially applicable to the Northern Service Area since the City has made strategic infrastructure investments to move transmission facilities to areas of high water demand. 11 In fill development is particularly important since new customer connections on existing distribution lines represent the quickest and best way to expand recycled water use. Customer retrofit costs, however, represent an impediment to full utilization of available recycled water and an additional impediment to full utilization of seasonal demand. This challenge is not unique to the City. The SDCWA confirms that customer retrofit costs are the primary challenge to recycled water system expansion for most agencies. The City does not currently have funding to offset these customer retrofit costs and facilitate in fill development. 11 City of San Diego Water Reuse Study, March 2006, p D 7

8 Figure D 2 Existing and Planned Distribution Lines, Storage, and Treatment Facilities Surrounding the North City Water Reclamation Plant D 8

9 Figure D 3 Existing and Planned Distribution Lines, Storage, and Treatment Facilities Surrounding the South Bay Water Reclamation Plant In addition to the planned recycled water system expansions (Phases 2 and 3 of the North District project), several other opportunities for system expansion were identified by the City in its 2006 Water Reuse Study. D 9

10 Table D 5 Recycled Water System Expansion Opportunities Beyond Baseline Expansions Additional Recycling Opportunities Identified Phase I Project Comment 1 In-fill of North City existing distribution area City indicates this is highest priority to increase recycling, and that limited funding is available for public projects, no funding available for private entities. 2 North City Phase II - Distribution System Expansion along State Route 56 corridor Includes service to Caltrans and residential developments adjacent to SR 56. Portions of Phase II have been completed, outstanding construction projects include Carmel Valley, Los 3 North City WRP Phase III - Distribution System Expansion (8 golf courses, nearby HOAs; 2.5 MGD avg, 5 MGD max) 4 Extension of NCWRP water to central area (Mission Bay, Balboa Park; 2.35 MGD avg) 5 Extension of NCWRP water to Rose Canyon Penasquitos, and Camino Del Sur. Project not yet funded and presently on hold. City indicates project not likely as pipeline extensions to these sites are expected to be costly. City indicates project not likely due to state restrictions on water releases at site. (wetlands; 0.75MGD avg over year) 6 Expansion of NCWRP water to Santa Fe ID City indicates there could be possibilities since wholesale sales are more cost-effective, but that the Santa Fe Irrigation District has not pursued inquiries. 7 Expansion of SBWRP water to Sweetwater Authority (power plant; 5.25 MGD) 8 Construction of new treatment plant in Mission Valley (5 MGD) City indicates project is unlikely. City indicates this is not a priority, but a longrange concept. Under Phase II, the Water Department will complete the remaining capital improvement projects identified in the Recycled Water Master Plan Phase II: the Carmel Valley and the Los Penasquitos recycled water pipeline projects. Demand Current and Future Despite population growth, total demand for water has actually decreased over the past five years. The City attributes this to aggressive conservation and demand management measures, which it estimates saved over 45,000 acre feet of water in These savings are projected to increase in the future to approximately 60,000 acre feet per year by 2030 (Table D 6). Between 2005 and 2030, however, the City anticipates total water demand to increase in all sectors, with the greatest growth (in terms of absolute volume) occurring in the single family residential sector. Proportionally, the highest rate of growth is projected to occur among facilities in the Institutional 2 category, which includes city, public, and governmental agencies. One sector is projected to decrease in demand: deliveries to facilities outside the city limits (Figure D 4). D 10

11 Table D 6 Total Potable Water Use and Estimated Savings from Existing and Potential (Undeveloped) Demand Management and Conservation Programs Total water use 213, , , , , , ,050 Conservation measures existing demand 30,425 36,135 38,110 40,400 42,681 44,967 management measures Conservation measures potential demand management measures 9,088 10,413 11,416 12,523 14,094 15,131 Note: All above numbers are in acre feet per year, unless otherwise noted. 100,000 Figure D 4 Annual Water Demands by Sector for the City of San Diego 90,000 80,000 70,000 Demand (af) 60,000 50,000 40,000 30,000 20,000 10, Year Other (Outside City) Landscape Institutional 2 Institutional 1 Industrial Commerical Multi-Family Single Family In addition to the water demand projections described above, the City anticipates increased deliveries of potable and recycled water to several wholesalers. Potable water wholesalers include the California American Water Company and the City of Del Mar. Recycled water wholesale customers include Olivenhain MWD, the City of Poway, and Otay WD 13 (Table D 7). The City of Poway, in turn, delivers recycled water to 195 customers (as of March 31, 2006) Data from the 2005 City of San Diego Urban Water Management Plan, pp. 2 7 and 2 18 (Footnote re: Otay not needed. Information is already provided in the above Table D City of San Diego 2006 Water Reuse Study, p D 11

12 Table D 7 Projected Deliveries of Potable and Recycled Water to Wholesale Customers Outside of San Diego s City Limits 15 Customer California American - Potable 13,700 11,620 13,170 12,125 13,350 13,580 13,810 Del Mar Potable 1,556 1,301 1,417 1,494 1,533 1,572 1,561 Olivenhain- Recycled Poway Recycled Otay - Recycled - - 2,584 3,228 3,974 4,838 5,840 Note: Under a 20 year agreement with Otay Water District, San Diego has committed to sell up to 6 MGD (6718 AFY) of tertiary water from its South Bay Plant. Note: All above numbers are in acre feet per year, unless otherwise noted. Recycled Water Recycled water is a local supply that reduces demand for imported water. Imported water is provided by regional wholesalers, SDCWA and MWD. Both of these wholesale water agencies offer incentives to their members to shift their reliance on water supplies from expensive and uncertain imports, primarily from the SWP and the Colorado River, to local supplies. The City has two agreements with SDCWA: one for North City and one for South Bay. Under these agreements, SDCWA pays the City incentives on the amount of recycled water utilized by customers of the City s water department. Last year, the incentive was raised to $200 per acre foot. MWD offers incentives for development of local water supplies through competitive bid processes. The North City Plan qualifies for incentives of $250 per acre foot of recycled water production. The City s South Bay application was unsuccessful but it is planned that the application, in some form, will be resubmitted. There are many categories for recycled water use, as outlined in Title 22. However, for ease of discussion, recycled water use has been aggregated into three primary end use categories 16 : landscape irrigation, industrial applications, and wholesale deliveries City of San Diego Urban Water Management Plan, p City water customers have used or currently use recycled water for landscape irrigation, ornamental nursery stock irrigation, commercial and industrial purposes (e.g., cooling towers) and processes, decorative fountains, soil compaction, and dust suppression. One customer also uses recycled water for toilet/urinal flushing. D 12

13 Currently, landscape irrigation represents the most common end use of recycled water. Customers using recycled water for irrigation are large, commercial customers. The use of recycled water in private residences (for landscape irrigation) is resisted because of concerns about potential cross connections. 17 Table D 8 Recycled Water Use in 2005 in San Diego 18 Type of Use Treatment Level Amount (af) Landscaping Tertiary 2,134 Industrial Tertiary 1,639 Wholesale Tertiary 467 Agricultural n/a 0 Environmental n/a 0 Groundwater Recharge n/a 0 Total 4,240 The City anticipates that wholesale deliveries could be an important sector for increasing recycled water use in the future. In addition to the current wholesale customers (the City of Poway, and Olivenhain and Otay WDs), the Santa Fe Irrigation District and Sweetwater Authority are potential customers. 19 Additional Factors Cost The City pays for treatment and distribution facilities. Customers pay for a new meter, on site retrofitting, and the cost to connect to the recycled water distribution system. With new construction, developers may have to pay for some incremental distribution and possibly new service connections. On site retrofitting, by definition, applies to older, existing facilities. The City does not offer direct financial incentives for customer costs, other than through discounted recycled water rates. The current rate for recycled water is approximately $350 per acre foot, 68% below the applicable potable water rate (Construction and Irrigation), which is approximately $1,100 per acre foot. The City is in the process of reviewing the cost of providing recycled water with the objective of restructuring its rates to cover the actual costs of producing and delivering recycled water. City Council approval will be needed to change its rates Use of recycled water for irrigation for private residences was embraced by the El Dorado development near Sacramento, but the development created a homeowners organization to manage the recycled water system. (UWMP p. 91) City of San Diego Urban Water Management Plan, p City of San Diego Urban Water Management Plan, p D 13

14 The SDCWA provides information on several funding programs for recycled water development. These programs include the Financial Assistance Program, Local Water Source Development Program, the Local Resources Program (funded through the MWD), the U.S. Bureau of Reclamation s Title XVI Grant Program, SWRCB s low interest loan programs, and Proposition 50 funding. 21 The details and important stipulations regarding these programs are summarized below. Table D 9 Funding Programs Available to Recycled Water Programs in the Greater San Diego Area Funding Program Financial Assistance Program Local Water Sources Development (LWSD) Local Resources Program (LRP) U.S. Bureau of Reclamation, Title XVI State Revolving Fund Loans, Water Recycling Loan Program, Water Recycling Grants Type of Funding Loan Grant Grant Grant Grant Loans Limit Eligible Uses Stipulations $50,000/project activity; $150,000/total project or GW basin 25% of remaining study cost, up to $25,000 Provides up to $200/AF of recycled water; funding available for up to 25 years Provides up to $250/AF recycled water; up to 25 years 25% of recycling projects capital costs 25% of eligible construction costs, up to $5 million/agency Facilities planning, feasibility investigations, engineering studies, research projects Research and development SDCWA member agencies; projects that reduce demand on SDCWA Projects must reduce demand for imported supplies eligible) Grant $75,000/project Project planning, feasibility studies Funds reimbursed if funding from other sources or within 5 years of the EIR Project/agency secured funding from other sources Project expenses exceed revenues Policies San Diego adopted an ordinance mandating use of recycled water in 1989, which was amended in Known as the Mandatory Reuse Ordinance (MRO), it established a policy that recycled water shall be used within the City of San Diego where feasible. In July 2000, upon City Council direction, staff began conditioning 21 funding.phtml D 14

15 new development projects, within current or proposed recycled water service areas, to incorporate recycled water usage into the project design. Another key element of the MRO was the development of procedures and criteria to implement the aspects of the MRO relating to the mandatory conversion of potable customers to recycled water. This was discussed at City Council subcommittee meetings in July 2002, April 2004 and July This was also discussed by the full City Council in November No further action was taken. The City is continuing to pursue voluntary compliance with current potable water customers. The MRO requires recycled water use in the following situations when facilities are adjacent to a recycled water main (criteria for potential use were proposed in 2004 and outlined in greater detail in Tables D 10 and D 11): 1. New buildings 55 feet in height, or projected to have at least 800 occupants, or encompass greater than 80,000 square feet, 2. New buildings using 300 ton or heavier cooling systems, or 3. Old buildings using more than 20 acre feet per year (these buildings must retrofit). In addition, manufacturing facilities using more than 5 acre feet per year must submit a feasibility analysis for recycled water use. D 15

16 Table D 10 Proposed Mandatory Use of Recycled Water in Existing Buildings 22 Title 22 Uses of Disinfected Tertiary Recycled Water Irrigation Dual Plumbing - Sanitary Uses HVAC - Cooling Towers Manufacturing Process Other Uses Single-Family Dwelling Not Required Residential Multi- Family/HOA Required if = of > 20 AFY usage for irrigation Retrofit Market Schools, Commercial, Industrial, Governmental Required if = of > 20 AFY usage for irrigation Parks and Cemeteries Required Golf Courses Required Not Allowed Not Allowed Voluntary Not Required Not Required n/a Not Required Voluntary n/a n/a n/a n/a Voluntary n/a n/a May be Required Table D 11 Proposed Mandatory Use of Recycled Water in New Buildings 23 Title 22 Uses of Disinfected Tertiary Recycled Water Single-Family Dwelling Residential Multi- Family/HOA New Development Market Schools, Commercial, Industrial, Governmental Parks and Cemeteries Golf Courses Irrigation Not Required Required Required Required Required Dual Plumbing - Required, with Not Allowed Not Allowed Sanitary Uses exceptions Not Required Not Required HVAC - Cooling Required, with n/a Not Required Towers exceptions n/a n/a Manufacturing Required, with n/a n/a Process exceptions n/a n/a Other Uses May be Required City of San Diego Urban Water Management Plan, pp and City of San Diego Urban Water Management Plan, p D 16

17 Barriers to Recycled Water Development The two main hurdles to increasing use of recycled water in San Diego are public perception and the lack of infrastructure. While the general public remains skeptical of using recycled water for indirect potable use, non potable uses are generally accepted in Southern California. A recent survey conducted by the City found that non potable uses of recycled water receive broad based public support, but only 26% of residents favor supplementing drinking water sources with treated recycled water. With an intensive information and public participation process, however, the study found that indirect potable reuse projects can garner public support. 24 Storage and delivery systems represent the second major challenge in San Diego. In the County of San Diego, groundwater storage opportunities are limited, and demand for recycled water does not necessarily coincide with available supplies. Agricultural uses, for example, peak during the summer months. Building storage facilities to meet peak (seasonal) agricultural needs would be very expensive, and the facilities may lay dormant during the off season. 25 In addition, most WWTPs in San Diego County are located along the coast. Delivering reclaimed wastewater from these plants would require pumping inland to higher elevations. Finally, the City has marketed recycled water to agricultural, commercial, and industrial customers, but the high cost of retrofitting customer sites for dual plumbing, required by law when using recycled water, is a major barrier. Energy Profile The following table summarizes the energy requirements associated with different facilities in providing water, treatment, conveyance, and recycling. 24 City of San Diego 2006 Water Reuse Study, p recycling.phtml D 17

18 Table D 12 City of San Diego Energy Requirements and Water Summary Facility Water Type System Element Annual Production (AFY) Annual Conveyance and Storage (AFY) Energy Requirement (kwh/af) Energy Cost ($AF) Annual Energy Usage (MWh) Principal Energy Provider SWP Raw Conveyance 31,000 n/a 3, ,440 Ca DWR Colorado River Raw Conveyance 173,000 n/a 2, ,000 WAPA Local Runoff Raw Conveyance 23,000 n/a SDGE Conveyance to Miramar WTP Raw Conveyance n/a 93, ,280 SDGE Conveyance to Otay WTP Raw Conveyance n/a 22, ,850 SDGE Treatment at Miramar WTP Potable Treatment (Potable) 93,000 n/a ,650 SDGE Treatment at Otay WTP Potable Treatment (Potable) 22,000 n/a ,870 SDGE Transport to North City WRP Waste Sewage Collection n/a 15, SDGE Transport to South Bay WRP Waste Sewage Collection n/a 9, SDGE Treatment to North City WRP Secondary Treatment (Recycled) 25,000 n/a ,750 SDGE [5] Treatment to North City WRP Tertiary Treatment (Recycled) 7,600 n/a ,430 SDGE Treatment to South Bay WRP Secondary Treatment (Recycled) 9,000 n/a ,060 SDGE Treatment to South Bay WRP Tertiary Treatment (Recycled) 7,000 n/a ,890 SDGE NCWRP Reclaimed Water Use SBWRP Reclaimed Water Use Reclaimed Distribution n/a 2, ,940 SDGE Reclaimed Distribution n/a 2, SDGE Conveyance to User Potable Distribution n/a 115, ,200 SDGE Notes: [1] Data from Water Reuse Study and from City of San Diego. [2] Power usage associated with conveyance to Otay WTP was assumed equal to conveyance to Miramar WTP. [3] Energy associated with reclaimed water use is for pumping. [4] Energy associated with SBWRP Reclaimed water use is estimated from Water Reuse Study, Technical Appendix 7. [5] SDGE supplies power resources that are needed in excess of what is supplied through landfill and digester gas. D 18

19 The City is served from three raw water sources: the SWP, Colorado River, and local precipitation. The City has two potable water treatment plants. Of these, the Otay WTP treats lower volumes of water and has a higher unit cost. The average conveyance and treatment power usage for both plants is 225 kwh per acre foot. The City has three wastewater treatment plants, two of which produce reclaimed water. The NCWRP treats nearly twice as much wastewater as the SBWRP. However, both plants produce similar amounts of volumes of tertiary water. Of the approximately 15,000 acre feet per year of tertiary water, about 4,000 acre feet per year is delivered for reuse (e.g., irrigation, industrial purposes) with the remainder discharged into secondary treated effluent. The weighted average power use rate for secondary treatment is 730 kwh per acre foot and 430 kwh per acre foot for tertiary. Table D 13 Total Energy Intensity of the City of San Diego Water Supplies Source Energy Intensity (kwh/af) Conveyance Treatment Distribution Total SWP 3, ,745 Colorado River 2, ,535 Recycled Water ,150 The City of San Diego Water Reuse Study included an evaluation of 15 potential recycled water projects. These potential projects involve expansion of storage and distribution facilities. However, expansion of the customer base was not included. The following table summarizes the energy requirements associated with potential recycled water projects identified in the Water Reuse Study. D 19

20 Facility Table D 14 City of San Diego Energy Requirements and Water Summary for Water Reuse Alternatives Water Type Annual Production (AFY) Pumping Energy Requirement (kwh/af) 1 AWT Energy Requirement (kwh/af) 2 Advance Water Treatment (IPR) Energy Cost ($/AF) Annual Capital and Operations Cost ($M) 3 Annual Energy Usage (MWh) San Vincente - Northern Rte - 8 MGD Reclaimed 7,100 1,730 1, ,280 SDGE San Vincente - Northern Rte - 12 MGD Reclaimed 9,600 1,870 1, ,950 SDGE San Vincente - Northern Rte - 16 MGD Reclaimed 10,500 1,870 1, ,640 SDGE San Vincente - Southern Rte - 8 MGD Reclaimed 7,100 1,080 1, ,670 SDGE San Vincente - Southern Rte - 12 MGD Reclaimed 9,600 1,170 1, ,230 SDGE San Vincente - Southern Rte - 16 MGD Reclaimed 10,500 1,190 1, ,500 SDGE Lower Otay - 1 MGD Reclaimed , SDGE Lower Otay MGD Reclaimed 2, , ,700 SDGE Lower Otay MGD Reclaimed 5, , ,390 SDGE Lower Otay MGD Reclaimed 5, , ,660 SDGE Title 22 Recycling Infill with existing Transmission Facilities Reclaimed 4, ,880 SDGE Rancho Bernardo Phase III Expansion Reclaimed 4,000 1, ,600 SDGE North to Central Service Area Connection Reclaimed 4, ,880 SDGE Central Service Area Expansion Reclaimed 5, ,630 SDGE Groundwater Augmentation in San Dieguito Reclaimed 5,600 1, ,960 SDGE Notes: Water Reuse Study, City of San Diego. Cost Analysis Technical Memorandum 7. Appendix A, Table 11 lists energy costs associated with pumping. Energy requirements is estimated energy use divided pumping volume listed in that table. 2. Assumed Advanced Water Treatment (AWT) energy requirements are the same for North City and South Bay. North City value (1,070) provided by City of San Diego Water Reuse Study, City of San Diego. Cost Analysis Technical Memorandum 7. Tables 2-8 through 2-15, 2-1 through 2-4, and 2-6 list capital annual costs and operating costs. Column represents that summation. Principal Energy Provider D 20

21 Power usage estimates were prepared for the water reuse operations included in the Water Reuse Study. There were two different types of water reuse projects discussed in the Water Reuse Study (Reservoir Augmentation and Distribution Expansion). The principal capital costs associated with each project type are pipeline installation and pump station construction. The power usage associated with the options has a range of 470 to 1,870 kwh per acre foot. Future Energy Usage in Producing Water The Water Reuse Study provided scenarios of future water reuse. A number of strategies were considered. Strategy NC 1 consists of the development of the following projects: 1) Expanded infill, 2) Rancho Bernardo Phase III, and 3) North Service Area to Central Service Area connector. For the purpose of analysis in this case study, they were assumed to go online in 2010, 2015, and 2020, respectively. Table D 15 presents their energy use in reusing water. Table D 15 Energy Savings Summary for Water Reuse Study Strategy NC Water Reuse (ac-ft) 1 4,100 8,100 12,132 16,164 Incremental Annual Energy Use Associated with Tertiary (MWh) 1,763 3,483 5,217 6,951 Incremental Annual Energy Use Associated with Individual Projects (MWh) 2 1,867 1,867 5,645 1,882 Cumulative Annual Energy Use Associated with Using Recycled Water (MWh) 3,630 7,217 14,596 18,212 Source Water Incremental Energy Equivalent (3,200 kwh/ac-ft) 3 13,120 25,920 38,822 51,725 - Water Treatment Incremental Energy Equivalent (225 kwh/ac-ft) ,823 2,730 3,637 - Water Distrib. to Local System Incremental Energy Equivalent (280 kwh/ac-ft) 5 1,148 2,268 3,397 4,526 Total Water Treatment and Distribution Incremental Energy Equivalent (MWh) 2,071 4,091 6,127 8,163 Cumulative Energy Savings (MWh) 7,931 15,577 15,757 23,464 Energy Value at $0.10/kWh ($M) Capital Cost ($M) Cumulative Capital Cost ($M) Notes: 1 Projects assumed to start in five year increments (consistent with 2005 UWMP). Assumed 2010 project is expanded in-fill, 2015-Rancho Bernardo Ph. III, 2020-North to Central Service Area Connector and 2025 is Wetlands. Projections represent best available information. 2 Energy value reported in Water Reuse Study. 3 Source Water Incremental Energy Equivalent is the amount of energy required (@3,200 kwh/af) to deliver the same volume of water from the SWP. 4 Water Treatment Incremental Energy Equivalent is the amount of energy required to treat source water. 225 kwh/af is the weighted average between Otay and Miramar WTPs. 5 Water distribution energy equivalent (280 kwh) is the weighted average of the energy use associated with potable water pumping stations. 6 Secondary treatment energy equivalent (730 kwh) is the weight average of conveyance and treatment energy for NCWRP and SBWRP. 7 Capital costs are from Water Reuse Study in 2005 dollars. D 21

22 The annual energy use associated with treating 4,100 acre feet of water from a secondary level to a tertiary level and distributing this water for reuse is approximately 3,630 MWh. If the City was to receive an equivalent volume of water from the SWP, the energy usage would be 13,120 MWh. The energy use associated with treatment to potable, distribution for use, and treatment to secondary for that volume of water (4,100 af) is 2,071 MWh. The energy saved by recycling water is 7,931 MWh when considering source water energy. For 2020, the total energy savings of 23,464 MWh. In general (for 2020), approximately three times as much energy is needed to deliver SWP water to SDCWA as needed to treat and deliver the same amount of reclaimed water, when evaluating planned future conditions. The energy needed to deliver SWP water to SDCWA increases to ten times when just comparing the energy needed to treat from secondary to tertiary. It is also generally true for the 2010 condition. Assuming an energy value of $0.10/kWh, the annual dollar savings is approximately $2.35M. Energy savings due to recycling can be associated with the different energy providers relied upon by the City. SDG&E provides energy service to the City treatment and distribution systems. SWP energy is provided from a variety of sources but the principal source is DWR. Table D 16 Summary of Energy Savings Annual Energy Savings (MWh) Year Annual Water Reuse (af) by Others than SDG&E SDG&E ,100 9,490 2, ,100 18,703 4, ,132 24,227 6, ,164 33,513 8,163 There are two incentive programs that provide rebates for water reuse. The programs are sponsored by MWD and SDCWA and the rebates are $250 per acre foot and $200 per acre foot. The table below lists the potential rebates associated with implementing the water reuse plan in the Strategy NC 1. It was assumed that the City would be successful in applying for MWD incentives. Table D 17 Summary of Water Reuse Rebates for Strategy NC 1 Annual Water Reuse (AF) Water Reuse Incentives ($M) ,100 $ ,100 $ ,132 $ ,164 $7.27 D 22

23 If Strategy NC 1 of the Water Reuse Plan was implemented, the 2020 rebates could potentially be in excess of $7M. The following table compares the annual costs, incentives, and avoided energy costs for projects that comprise Water Reuse Strategy NC 1. Table D 18 Comparison of Costs, Rebates, and Avoided Costs for Strategy NC 1 Capital Costs ($M) Annual Costs ($M) Incentives ($M) Avoided Energy Costs ($M) Avoided Water Costs ($M) Incentives and Avoided Costs minus Annual Costs ($M) Project 2005 Dollars Capital Equiv. Operating Energy Total MWD SDCWA SWP SDG&E Expanded Infill $ $1.800 $0.400 $0.220 $2.420 $1.00 $0.80 $0.980 $0.210 $3.07 $2.66 Rancho Bernardo - Phase III $ $3.300 $0.650 $0.680 $4.630 $1.00 $0.81 $0.500 $0.20 $5.57 $2.95 Expansion to Central Service Area $ $4.300 $0.720 $0.300 $5.320 $1.01 $0.80 $0.930 $0.20 $7.13 $3.82 Total $ $9.400 $1.770 $1.200 $ $3.01 $2.41 $2.410 $0.20 $15.79 $9.04 Notes: 1. Capital costs are in January 2005 dollars. 2. Amortized capital costs over a 40-year term at 6% discount. 3. Operating costs are based on percentage of capital costs. 4. Power costs at $0.12kWh. 5. All cost values provided from Water Reuse Study. 6. Avoided water costs are equal to $500 per acre-foot times the volume of recycled water associated with Strategy NC-1 alternatives minus the power associated with SWP. D 23