525 Golden Gate Avenue, 10th Floor
San Francisco, CA 94102
T 415.554.3155
Date: June
1, 2022
To: Anson M
oran, President
Newsha Ajami, Vice President
Tim Paulson, Commissioner
Sophie Maxwell, Commissioner
Through: Den
nis Herrera, General Manager
Steve Ritchie, Assistant General Manager, Water
From: Pau
la Kehoe, Director of Water Resources
Subject
: Recycled Water and Purified Water Opportunities in San Francisco Memorandum
Presented here is a copy of a memorandum provided to the San Francisco Board of Supervisors evaluating opportunities to develop a recycled water and purified water supply for San Francisco. The Sa n Francisco P ublic Utilities Commission was directed to prepare this report pursuant to the Non-potable Water Ordinance, Article 12C of the San Francisco Health Code, subsection 12C.1(g).
The report first provides the background and status of recycled water use in San
Francisco, including the Recycled Water Ordinance, San Francisco’s Non- potable Water
Ordinance, and San Francisco’s Onsite Water Reuse Grant Program. The report then provides a Feasibility
Study of a Recycled Water
Satellite
Treatment Facility in San Francisco. That feasibility study concludes that
San Francisco not pursue a satellite recycled water treatment facility due to the high cost and challenges of acquiring land in the target areas, and instead study a potential treatment facility that could generate recycled water at the SFPUC’s Southeast Treatment
Plant (SEP), and proposes that SFPUC
incentivize increased use of its Onsite Water Reuse Grant Program to allow for greater use of recycled water. Further study is needed to pursue a purified water supply, and the report identifies potential purified water projects within San Francisco.
For reference, the final studies are included here: SF Purified Water Study. Note that there is only one document in the link, but the SF Recycled Water Satellite Treatment Feasibility Study appears as Attachment A to the SF Purified Water Opportunities Study.
OUR MISSION: To provide our customers with high-quality, efficient and reliable water, power and sewer services in a manner that values environmental and community interests and sustains the resources entrusted t
o our care.
OUR MISSION: To provide our customers with high-quality, efficient and reliable water, power and sewer services in a manner that values environmental and community interests and sustains the resources entrusted to our care.
525 Golden Gate Avenue, 13th Floor
San Francisco, CA 94102
T 415.554.3155
F 415.554.3161
TTY 415.554.3488
Recycled Water and Purified Water Opportunities in San Francisco Memorandum to the Board of Supervisors
Introduction
Pursuant to the Non-potable Water Ordinance, Article 12C of the San Francisco Health Code, subsection 12C.1(g), the San Francisco Public Utilities Commission submits this report evaluating opportunities to develop a recycled water and purified water supply for San Francisco. The report first provides the background and status of recycled water use in San Francisco, including the Recycled Water Ordinance, San Francisco’s Non-potable Water Ordinance, and San Francisco’s Onsite Water Reuse Grant Program. The report then provides a Feasibility Study of a Recycled Water Satellite Treatment Facility in San Francisco. That feasibility study concludes that San Francisco not pursue a satellite recycled water treatment facility due to the high cost and challenges of acquiring land in the target areas, and instead study a potential treatment facility that could generate recycled water at the SFPUC’s Southeast Treatment Plant (SEP), and proposes that SFPUC incentivize increased use of its Onsite Water Reuse Grant Program to allow for greater use of recycled water. Further study is needed to pursue a purified water supply, and the report identifies potential purified water projects within San Francisco.
San Francisco’s Recycled Water Program
Guided by the OneWaterSF approach of matching the right resource to the right use, the SFPUC implements a program to promote recycled water use for non- drinking purposes such as landscape irrigation, while conserving drinking water supplies. As part of this effort, San Francisco enacted an ordinance in 1991, codified as Article 22 of the San Francisco Public Works Code. Also known as the Recycled Water Ordinance, this ordinance requires buildings located within designated recycled water use areas to install dual-plumbing in new and remodeled buildings and subdivisions (40,000 square feet or more) and in new and existing irrigated areas (10,000 square feet or more). The Recycled Water Ordinance requires buildings to be dual-plumbed to be able to serve recycled water to all applications that have been approved by the State of California, including irrigation, toilet flushing, air conditioning, decorative fountains, industrial processes, and other non-potable applications within buildings and in landscaped areas. The section below describing the Recycled Water Satellite Treatment Facility Feasibility Study provides more detail on the SFPUC’s efforts to evaluate the feasibility of the SFPUC providing recycled water to the dual-plumbed customers.
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In addition, through a long-standing partnership with Daly City, the SFPUC has been delivering recycled water to Harding Park and Fleming Golf Courses for irrigation since 2012. Similarly, in partnership with North Coast County Water District, recycled water deliveries began in 2014 to irrigate the eastside of the Sharp Park Golf Course in Pacifica (one of the SFPUC’s retail water customers, but located outside city limits).
In San Francisco, construction is nearing completion of the Westside Enhanced Water Recycling Project. The project includes a new recycled water treatment facility, storage reservoirs, and pump stations to deliver recycled water.
Construction has been completed on approximately 8 miles of recycled water pipelines. The irrigation retrofits are in progress for Golden Gate Park and Lincoln Park Golf Course and recycled water deliveries are expected to begin in Fall 2022. The SFPUC plans to save approximately 2 million gallons per day (mgd) of potable water with the Westside Enhanced Water Recycling Project.
The water produced by this project will be used initially to irrigate Golden Gate Park, the Panhandle, Lincoln Park Golf Course, and the San Francisco Zoo. For more information about the Recycled Water Program, visit www.sfpuc.org/programs/water-supply/recycled-water
.
San Francisco’s Onsite Water Reuse Program
In 2012, the City and County of San Francisco adopted the Non-potable Water Ordinance (NPO). It added Article 12C to the San Francisco Health Code allowing for the collection, treatment, and use of alternate water sources such as graywater, rainwater, stormwater, blackwater, and foundation drainage for non- potable applications such as toilet flushing and irrigation. In 2013, the Board of Supervisors amended the NPO to allow district-scale non-potable water systems consisting of two or more buildings sharing non-potable water. Subsequently, the Ordinance was amended in 2015 to mandate the installation of onsite water systems in new developments of 250,000 gross square feet or more.
Through an ongoing evaluation of the SFPUC’s existing water programs, SFPUC staff analyzed the Non-potable Water Ordinance to identify opportunities to increase potable water savings from new development projects and improve system implementation. This resulted in the Board of Supervisors amending the NPO in October 2021. The ordinance amendments require new development projects that apply for a site permit after January 1, 2022 of 100,000 gross square feet or more to install and operate an onsite water reuse system. The required alternate water sources and required non-potable uses are based on development project type. For commercial buildings, the project must meet its toilet and urinal flushing and drain trap priming demands through the collection, treatment, and use of available blackwater and condensate. For residential and mixed-use buildings, the project must meet its toilet and urinal flushing, irrigation, clothes washing, and drain trap priming demands through the collection, treatment, and use of available graywater and condensate. The requirements apply to both development projects consisting of a single building or multiple buildings.
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The SFPUC oversees the implementation of onsite water reuse systems in collaboration with San Francisco Department of Public Health-Environmental Health (SFDPH-EH), San Francisco Department of Building Inspection- Plumbing Inspection Division, and San Francisco Public Works. Onsite water systems are operated, maintained, and monitored by the property owner. Under the Onsite Water Reuse Program, SFDPH-EH has established ongoing monitoring requirements and water quality standards that are protective of public health. Different treatment levels are required depending on the alternate water source and end use. The frequency of monitoring and reporting also vary depending on the alternate water source, and they are identified in the SFDPH’s Director’s Rules and Regulations Regarding the Operation of Alternate Water Source Systems and the operating permit for the onsite water system issued by the SFDPH-EH.
In total, there are over 100 onsite water reuse projects that have submitted water budget applications, and are in the design, implementation, or operational phase.
Currently, the total potable water offset for the Onsite Water Reuse Program is approximately 0.1 mgd. By 2040, the expected potable water offset will be approximately 1.33 mgd. The SFPUC has also developed detailed case studies featuring onsite water reuse projects in San Francisco, as well as other innovative water recycling and resource recovery projects across the world.
More information on the Onsite Water Reuse Program and access to the case studies are available at
https://sfpuc.org/construction-contracts/design-
guidelines-standards/onsite-water-reuse.
San Francisco’s Onsite Water Reuse Grant Program
In addition, the SFPUC administers the Onsite Water Reuse Grant Program, which provides grant funding to encourage retail water users to reduce SFPUC water supply usage by collecting, treating, and using alternate water sources including rainwater, stormwater, graywater, foundation drainage, air conditioning condensate, and blackwater for non-potable uses such as toilet flushing, irrigation, and cooling tower makeup. Applicants can receive up to $1,000,000 in grant funding depending on the potential potable water offsets achieved by the proposed project.
The SFPUC also offers grant funding to breweries to collect, treat, and reuse process water (e.g. water used in the brewing process for applications such as rinsing bottles and cleaning equipment) generated onsite. The grant program includes water quality, treatment, and monitoring standards for brewery process water reuse systems. San Francisco’s oldest brewery Anchor Brewing Company received a grant from the SFPUC to install a brewery process water treatment system to reduce their water consumption. The new water reuse system will treat 100% of process water at the brewery, with the capacity to recycle up to 20 million gallons of water annually.
Furthermore, through the Onsite Water Reuse Program, the SFPUC is incentivizing the implementation of wastewater heat recovery systems within
4 May 2022
development projects installing onsite water reuse systems. The Grant Program requires all projects applying for a grant to estimate the potential energy offset that can be achieved with wastewater heat recovery. In addition, mixed-used and multi-family buildings that are grant recipients are required to implement wastewater heat recovery. SFPUC’s goal in integrating wastewater heat recovery into the Grant Program is to gather more information about the potential benefits of these systems and understand how implementation could occur successfully in San Francisco.
Additional Opportunities for Onsite Water Reuse
Two street cleaning fill stations are currently in operation to provide additional non-potable water for street cleaning: one at Moscone Convention Center and one at UN Plaza. Both of these fill stations are being partially funded through grants issued under the Onsite Water Reuse Grant Program.
As part of the Moscone Center Expansion effort, an onsite water reuse system was installed that is capturing and treating foundation drainage, rainwater, and steam condensate for toilet flushing and irrigation at the Moscone Center, and street cleaning. The project includes a truck-fill station for SFPW street cleaning trucks. Total water savings for the project are estimated to be approximately 11 million gallons of potable water annually.
The second fill station is at UN Plaza and is a partnership between the SFPUC and SFPW. The project diverts foundation drainage underneath the UN Plaza fountain and treats it for beneficial reuse in applications such as irrigation, street cleaning, and use in the UN Plaza fountain. Total water savings for the project are estimated to be approximately 5.2 million gallons of potable water annually.
In addition to street cleaning fill stations, the SFPUC also is encouraging its industrial customers to reuse water onsite. ECSF, the district steam heating system operator in San Francisco, received a grant from the SFPUC through the Onsite Water Reuse Grant Program to install a foundation drainage reuse system. ECSF partnered with Bay Area Rapid Transit (BART) to divert foundation drainage from Powell Street BART for use in the district steam loop that provides steam for heating, hot water and process steam to hotels and buildings in downtown. In total, ECSF is reducing their overall potable water use by 30 million gallons each year.
Feasibility Study of a Recycled Water Satellite Treatment Facility in San Francisco
To determine the feasibility of the SFPUC providing a recycled water supply to meet the non-potable demands of dual-plumbed buildings in San Francisco, the SFPUC completed a study assessing options to reduce potable water demands on the eastside of the City. The study focused on the potential to provide recycled water to dual-plumbed buildings as well as green spaces within the Eastside Recycled Water Use Area, as defined by the Recycled Water Ordinance, as the SFPUC is already pursuing the Westside Enhanced Water
5 May 2022
Recycling Projects to supply recycled water to meet the large irrigation demands on the westside of the City.
The study estimated the potential recycled water demand for existing dual- plumbed buildings and planned development projects that would be required to comply with the Recycled Water Ordinance to be between 1.07 – 1.2 mgd. To assess where a potential satellite recycled water treatment facility could be located, the demands were clustered based on geographic location, a summary of which is provided in Table 1.
Table 1. Summary of Recycled Water Demands of Dual-Plumbed Buildings
Customer Location Recycled Water Demand (mgd)
Financial District 0.61 – 0.66
Mission Bay 0.29
Candlestick Point and Hunters Point
Shipyard
0.16 – 0.25
Total 1.07 – 1.2
Potential siting options were then evaluated for a satellite treatment facility. The SFPUC commissioned a land site acquisition analysis from Century Urban, an independent strategic real estate advisory firm, to evaluate the cost of acquiring a suitable site for a satellite treatment facility. The SFPUC directed Century Urban to focus the real estate analysis on a limited area of approximately 2.7 square miles that encompassed the Financial District and Mission Bay customers and could accommodate a potential new 1-acre (or 43,000 square foot) satellite treatment facility (see Figure 1).
6 May 2022
Figure 1. Boundaries for Potential Siting of a Satellite Treatment Facility
Legend: Dual-plumbed buildings in Financial District Dual-plumbed buildings in Mission Bay
The real estate analysis concluded that due to the limited geographic area for which the site can be located, an acquisition of a parcel(s) that meets the site requirements will be very challenging. The area is highly developed with limited potential for undeveloped sites that can be readily acquired thus likely necessitating a parcel assemblage strategy that will entail additional time and cost. Furthermore, the cost of a development site based on recent sales comps is approximately $35 million and $44 million based on recently marketed sites, a significant cost that optimistically assumes a readily available site for a potential satellite treatment facility. This amount also does not include acquisition costs which can include entitlement, demolition, tenant relocation benefits, other due diligence costs and the cost of parcel assemblage to achieve the parcel size needed. In addition, as the SFPUC is considering acquiring this land in a three-to-five-year time frame, with escalation estimated at 10%-15% per year for a land assemblage. Therefore, Century Urban estimated a total transaction cost of $60 million to $86 million for an average total transaction cost of approximately $73 million.
Furthermore, while fewer office and residential sites have been sold since 2018, demand for industrial sites has increased. Consequently, Century Urban concluded:
• There are currently limited opportunities and likely fewer in the future for the SFPUC to acquire a site that is sufficient in size and would meet
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other site requirements for a potential satellite treatment facility within the area.
• The SFPUC would likely compete with developers of industrial sites for new logistics and distribution centers, which are currently in high demand.
• Given the limited number of land opportunities, the SFPUC would likely need to pursue a land assemblage strategy.
• Land prices for industrial sites with a parcel assemblage strategy are projected to increase 10% to 15% each year.
• Acquiring a site for a potential satellite treatment facility will take several years and significantly exceed today’s already high land costs.
The satellite feasibility study included another option of serving the identified recycled water demands from a potential treatment facility located at or near SEP that would generate up to 1.2 mgd of recycled water from plant effluent.
Water quality objectives and conceptual treatment trains that would meet the water quality objectives were developed for 4 options: a satellite treatment facility generating recycled water from raw sewage, a treatment facility located at or near SEP generating recycled water from SEP effluent, a treatment facility appropriate to meet current and anticipated potable reuse requirements (generating purified water) from SEP effluent, and a hybrid treatment facility that generates both purified and recycled water located at or near SEP.
Based on the conclusions of the feasibility study and the real estate analysis, it is recommended to not pursue a satellite recycled water treatment facility due to the high cost and challenges of acquiring land in the targeted area to be able to serve the recycled water demands of the Financial District and Mission Bay customers. It is recommended to continue planning for and evaluating the following options: a potential treatment facility at or near SEP that would produce recycled water to serve the total recycled water demand of 1.2 mgd, a potential treatment facility that would produce purified water to serve both recycled water and potable water demands, and a hybrid option of a treatment facility that would produce both recycled and purified water. Any potential changes to the Recycled Water Ordinance will be evaluated within the next phase of the feasibility study.
To assist existing dual-plumbed buildings that do not currently have a source of recycled water, the SFPUC changed the Onsite Water Reuse Grant Program eligibility. The grant program threshold eligibility was lowered to 450,000 gallons of water per year offset to incentivize existing dual-plumbed and smaller buildings to install onsite water reuse systems to be able to collect, treat, and reuse alternate water sources onsite for non-potable uses. The SFPUC recognizes that these buildings have already made the significant investment to install dual-plumbing and therefore, could be incentivized to apply for a grant to offset a portion of the capital cost to install an onsite treatment system.
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Summary of San Francisco’s Non-potable Demand and Potential Reuse Projects
Building on prior studies and SFPUC staff review, the City’s total accessible non-potable water demand is estimated to be 7.12 mgd. As shown in Table 2, once existing and planned non-potable projects are accounted for, there is an unmet non-potable demand of 3.73 mgd. This demand includes the potential recycled water demand for existing dual-plumbed buildings and planned development projects that was evaluated in the Recycled Water Satellite Treatment Facility Feasibility Study of up to 1.2 mgd. Assuming that 1.2 mgd can be planned for in conjunction with the purified water potential, there is a remaining unmet potential non-potable demand of 2.53 mgd. These remaining demands are small and scattered, and the pipeline costs and energy needs to serve these disparate demands would outweigh the water savings. Therefore, the purified water evaluation carries forward the 1.2 mgd of non-potable demands that could not be served with a satellite facility, but does not carry forward the remaining 2.53 mgd of remaining unmet non-potable demand. Meanwhile, SFPUC staff remain committed to reducing or offsetting potable demand wherever synergies make it feasible to do so. Examples include street cleaning fill stations, washdowns at wastewater facilities, technical assistance, and grants and rebate programs.
Table 2. Summary of Non-potable Demand, and Existing, Planned, and Potential Reuse Projects
Project Non-potable Demand
(mgd)
Non-potable Demand 7.12
Existing and Future Non-potable Reuse Projects:
Harding Park Golf Course 0.18
Onsite Non-potable Projects 1.33
Westside Recycled Water Project 1.88
Total Existing and Future Projects: 3.39
Unmet Non-potable Demand 3.73
Potential Reuse Projects:
Eastside Recycled Water Project 1.20
Remaining Unmet Non-potable Demand 2.53
San Francisco Purified Water Opportunities Study
In 2021, having successfully completed a building-scale research project that evaluated the technical feasibility of advanced treatment and online monitoring for purified water at the SFPUC headquarters in San Francisco, the SFPUC set out to explore the full potential for purified water opportunities within San Francisco. The study had three key objectives, each addressed in a separate Technical Memorandum (TM). Together, the three TMs make up the complete study (attached):
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• TM 1: An overview of the regulatory environment for both non-potable water recycling and purified water, and an estimate of the total non- potable water recycling potential in San Francisco;
• TM 2: An evaluation of four purified water project alternatives within San Francisco based on available wastewater flows, existing infrastructure and distribution considerations, and anticipated requirements based on current discharge requirements and draft reuse regulations. This TM also includes preliminary cost estimates for each alternative; and
• TM 3: A broad roadmap for sustained public engagement in the planning and development of purified water opportunities in San Francisco.
From a regulatory standpoint, there are four distinct pathways for producing purified water: groundwater augmentation, reservoir water (or surface water) augmentation, raw water augmentation, and treated drinking water augmentation. Each has unique permitting requirements and there are variations within these categories. Given the physical constraints in San Francisco, however, only treated water augmentation is viable within the City. Treated water augmentation is not yet regulated in the State of California. Two sets of draft criteria for the anticipated regulations that will include treated water augmentation were released by the State Water Resources Control Board in March and August of 2021, respectively. The August draft criteria are currently under review by an expert panel. While the regulations may change before they are expected to be finalized by December 2023, the study uses the draft criteria as a guide to what would likely be required to permit purified water in San Francisco.
Wastewater flows from SEP, located on the eastside of San Francisco, Oceanside Water Pollution Control Plant (OSP) on the westside of the City, and Northpoint Treatment Facility were considered for purified water. However, because Northpoint is a wet-weather facility that does not produce a consistent or significant flow (particularly in dry months when the need for purified water is likely to be greatest) and serves a small region of the City, it was not included in the development of alternatives.
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Figure 2. San Francisco Wastewater/Stormwater Drainage Areas
For both SEP and OSP, the study considered average daily flows over the three consecutive lowest flow months of the year between 2016 and 2019. 2020 had flows that were significantly lower than previous years, but that data was considered anomalous due to the effects of the Covid-19 pandemic and was not included in the calculations. Assuming an 80% recovery rate with advanced treatment, the maximum purified water that can be produced at OSP is 5.1 mgd and the maximum purified water that can be produced at SEP is 43.4 mgd.
However, in order to provide a buffer and maximize the potential for distribution, the study anticipates blending purified water in drinking water reservoirs before distribution. The study considered the draft blending requirements and the capacity at the reservoirs within three miles of each of the treatment plants. With this analysis, the maximum purified potential from SEP was reduced to 38.3 mgd.
For the purpose of this study, it was assumed that current challenges related to wastewater discharge requirements could be reasonably overcome in the future.
However, space limitations remain challenging for purified water treatment. As demonstrated in the real estate analysis completed by Century Urban for the Recycled Water Satellite Treatment Facility, the cost and complexity of acquiring and assembling sufficient space for a treatment facility will be very difficult, at least in the dense eastern portion of San Francisco. A 0.85-acre site has been designated at SEP for water reuse treatment, which can accommodate production of up to 2 mgd. To take advantage of greater available flows, a significantly larger space will be needed. The recommended site for a larger treatment facility is 1990 Newcomb Avenue, which is currently owned and occupied by the SFPUC City Distribution Division. The 7-acre size, proximity to wastewater flows from SEP, and consistent use for utility operations, make it the preferred site for up to 28 mgd of purified water. The City Distribution
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Division is planning for relocation to a new facility at 2000 Marin in the next few years. SFPUC staff continue to search for suitable sites for treatment of OSP flows on the west side of San Francisco.
In developing alternatives for evaluation, the study considered the objectives of maximizing reuse and blending purified water into the distribution system as evenly as possible. The study did not consider alternatives for treatment or distribution outside of San Francisco’s city limits. The four alternatives that were evaluated are described in Table 3.
Table 3. Summary of Purified Water Project Alternatives No
. Concept Projec
t No.
Sourc
e
Water
Facilit
y
AWPF
Location
Total
Purified
Water
(mgd)
Receiving
Reservoir(s)
1 Maximize reuse, using
the closest and best
reservoir(s) for
distribution
1.A OSP Unknown 5.1 Sunset
1B SEP
1990
Newcomb
Avenue
+ additional
space
Unknown (1)
38.3 University
Mound, College
Hill, Potrero
2 Small reuse project
based upon available
0.85-acre site at SEP,
and similar
production facility at
OSP, resulting in
similar purified water
blends on either side
of San Francisco
2A OSP Unknown 2.0 Sunset, Merced
2B SEP
Designated
Recycled
Water
Facilities
Site at SEP
2.1 University
Mound
3 Maintains equal
blends of purified
water across five
reservoirs
3A OSP Unknown 5.1 Sunset, Merced
3B SEP
1990
Newcomb
Avenue
6.8 University
Mound, College
Hill, Potrero
4 Maintains equal
blends of local water
supplies(2) in
five reservoirs
4A OSP Unknown 5.1 Sunset, Merced
4B SEP
1990
Newcomb
Ave
17.6 University
Mound, College
Hill, Potrero
Notes:
(1) The full 1990 Newcomb site is approximately 7 acres, which is expected to fit a purified water treatment facility of approximately 28 mgd. Therefore, 1990 Newcomb Avenue combined with an additional site may be needed for this option. Other site options have not been determined yet. (2) Local water supplies include groundwater, purified water from other regional projects under consideration that would include distribution in San Francisco, and purified water from this project.
The cost estimates provided in the study for the alternatives are preliminary and do not include escalation or standard financing assumptions typically used by the SFPUC for capital planning. Costs are included for illustrative and
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comparative purposes only. The capital costs for the alternatives range from approximately $215 million for the smallest project (Alternative 2) to $905 million for the largest project (Alternative 1). Similarly, the annual operating and maintenance costs range from about $15 million for Alternative 2 to over $45 million for Alternative 1.
While interest in purified water continues to rise in California and globally, there are still relatively few long-term use cases. The most prominent example of purified water is groundwater augmentation in Orange County, which has been in operation since 1976. The Groundwater Replenishment System has a capacity of 100 mgd and is expanding to 130 mgd. There is only one treated water augmentation project in operation currently, and that is in Windhoek, Namibia. It has been operating successfully since 1968. A second is being planned in El Paso, Texas and is expected to begin construction in 2023. San Diego and the Metropolitan Water District of Southern California are two other examples of large purified water projects that are in planning in California.
There are several other examples in California and beyond.
A key feature of successful purified water projects is direct and transparent public engagement from planning through implementation. Even though no decisions have been made regarding the future implementation of purified water in San Francisco, initiating a long-term commitment to outreach throughout the development stages is imperative. TM3 describes how short-, medium- and long-term goals over a 20-year period can be planned to demonstrate purified water in an understandable and accessible way at various scales to various audiences. During this time, operator engagement and training is also critical.
The study describes potential steps the SFPUC can take to engage both operators and the public, including establishing a mobile treatment unit, a permanent building-scale demonstration, and a large-scale demonstration facility that is widely accessible.
Recommendations
• Continue implementing current recycled water and onsite water reuse efforts and explore additional opportunities that could assist customers in reducing their water demands.
• Continue planning for and evaluating the following options: a potential treatment facility at SEP that would produce recycled water to serve the total recycled water demand of 1.2 mgd, a potential treatment facility that would produce purified water to serve both recycled water and potable water demands, and a hybrid option of a treatment facility that would produce both recycled and purified water.
• Continue tracking draft State regulations for purified water. • Continue evaluating the feasibility and scale of purified water from wastewater produced in San Francisco.
• Consider the combined effect of implementing alternative water supplies on distribution in San Francisco.
• Refine preliminary cost estimates based on assumptions for similar alternative water supply projects being considered by the SFPUC.
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• Initiate a sustained public engagement effort for purified water.