STATUS OF POTABLE REUSE IN CALIFORNIA: HISTORY, REGULATIONS AND PROJECTS. Abstract. Key Words. Indirect Potable Reuse Projects in California

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1 STATUS OF POTABLE REUSE IN CALIFORNIA: HISTORY, REGULATIONS AND PROJECTS Ufuk G. Erdal, CH2M 6 Hutton Centre Dr. Suite 700, Santa Ana, CA uerdal@ch2m.com, Phone: Larry Schimmoller, CH2M, Englewood, C Abstract Non potable reuse to offset potable water demand is a century old concept in California. California is also one of the first States where indirect potable reuse (IPR) projects were implemented by injecting (groundwater injection) highly treated recycled water into the ground or using surface basins to spread recycled water (surface spreading). The State Water Resources Control Board Division of Drinking Water (DDW) (formerly CDPH) draft groundwater recharge regulations have helped water and wastewater agencies understand what requirements must be met to assure that public health will not be compromised. More than a dozen draft regulations was published which provided guidance for planning and implementation of the IPR projects in California since This paper provides a historical perspective on how the groundwater recharge regulations have evolved and type of projects implemented over the time and highlight current status of IPR via surface water augmentation and direct potable reuse regulations. Key Words DDW, groundwater recharge, IPR, potable reuse, regulations, water recycling Indirect Potable Reuse Projects in California California has led the nation in developing drought-resistant, sustainable water supplies through the use of water recycling by treating municipal wastewater for beneficial purposes such as irrigation, industrial uses, toilet flushing, and replenishing groundwater basins. Over 250 water recycling plants currently operate in the State, such as the Groundwater Replenishment System in Orange County. According to survey results released by the California State Water Resources Control Board in 2011, over 650,000 acre-feet of wastewater is being recycled in the State per year. California is now in the process of increasing the amount of recycled water used over the next two decades by an additional 1 to 2 million acre-feet per year (NWRI, 2013) California is also one of the first States where indirect potable reuse (IPR) projects were implemented by injecting (groundwater injection) highly treated recycled water into the ground or using surface basins to spread recycled water (surface spreading) to replenish groundwater. Planned IPR, discharge of recycled water to a drinking water source of supply with the intended purpose of augmenting the potable supply, has been practiced in California since 1962, and there are several IPR projects in California (Crook 2010). IPR is the augmentation of a drinking water source (surface water or groundwater) with recycled water followed by an environmental buffer 1

2 that precedes normal drinking water treatment. As shown in Table 1, the number of IPR projects has increased significantly in the last ten years and many other projects have already been planned or under construction. Augmenting surface water sources have not been implemented or permitted yet in California but development of the uniform criteria for IPR via surface water augmentation is underway. Therefore, all the IPR projects in Table 1 are groundwater recharge projects (either surface spreading or sub surface injection). Table 1. California IPR Projects (Adapted from Crook, 2010) Project/Agency Type of Potable Reuse Startup Date Projects Montebello Forebay Groundwater Recharge Project, Water Replenishment District of Southern California 1962 Water Factory 21, Orange County Water District (replaced by the Groundwater Replenishment System in 2008) West Coast Basin Barrier Project, West Basin Municipal Water District and Los Angeles County Department of Public Works Ely Basin Project, Inland Empire Utilities District (now part of the Chino Basin Groundwater Recharge Project) Alamitos Barrier Project (3 mgd), Water Replenishment District of Southern California Chino Basin Groundwater Recharge Project, Inland Empire Utilities Agency Harbor Water Recycling Project Dominguez Gap Project, City of Los Angeles Groundwater Replenishment System (70 mgd), Orange County Water District City of Oxnard GREAT Program Oxnard Water Purification Facility, City of Oxnard Silicon Valley Advanced Water Purification Center, Santa Clara Valley Municipal Water District and City of San Jose 2 and Currently blended with recycled water for non potable use. Designed to augment potable water supply in future (Commissioned) 2014

3 Groundwater Replenishment System Expansion (100 mgd), Orange County Water District Alamitos Barrier Project Expansion (8 mgd), Water Replenishment District of Southern California and Potable Reuse Regulatory Framework in California A Historical Perspective The use of recycled water is regulated by several agencies in California. The state laws and regulations have been passed to protect public health and the quality of the groundwater. State Water Resources Control Board s Divison of Drinking Water [DDW], formerly known as Department of Health Services [DHS] and California Department of Public Health [CDPH], regulates public water systems and develops criteria and rules for recycled water projects that include groundwater recharge projects. Regional Water Quality Control Boards (RWQCBs) issue permit and have ongoing oversight on groundwater recharge projects. There are total of 9 RWQCBs in California which are under State Water Resources Control Board (SWRCB). The SWRCB adapts plans and policies (i.e. Salt and Nutrient Management) that may impact groundwater recharge project. The Policies and plans that are adopted at the state level are often rolled down to the local RWQCBs (Forbes, 2011) Due to the potential for confusion and duplication of effort between CDPH & RWQCBs, CDPH & SWRCB signed a Memorandum of Agreement (MOA) in The MOA delineated responsibilities of each agency in review and approval of recycled water projects. According to the 1996 MOA, CDPH (now DDW) had following responsibilities (Forbes, 2011): Develops recycled water criteria Reviews recycled water proposals for compliance with Title 22 Criteria Provides requirements and recommendations to RWQCB for recycled water permits Coordinates with other agencies Interfaces with recycled water industry Reviews new and emerging technologies Collects fees from project applicants for CDPH reviews What are known as the Title 22 standards for water reclamation were first established under Title 22, Division 4, Environmental Health, in the California Administrative Code in These standards addressed types of use which included new uses, treatment levels, and performance and design parameters. The Tithe 22 document published in 1978 had a section (Section 60320) that contained three paragraphs and broadly regulated groundwater recharge with lacks of details (Forbes 2011). The first Draft regulations only covered surface spreading and injection projects were not considered to be acceptable at that time. 3

4 The pertinent requirements in 1978 Draft included the following main criteria for ground water recharge: Minimum of secondary treatment and granular activated carbon (GAC). 10-foot vadose zone (minimum). Meet drinking water standard. Chemical oxygen demand (COD) 5 mg/l (in the product water after recharge) Total organic carbon (TOC) 3 mg/l. Dilution: 50-percent reclaimed water. One-year residence time underground. In 1986, A Scientific Advisory Panel commissioned by the California State Water Resources Control Board, Department of Water Resources, and Department of Health Services was charged with defining the health significance of using reclaimed water for groundwater recharge, evaluate the benefits and risks associated with such recharge, and provide information needed to establish statewide criteria. In 1988, the first Draft Ground Water Recharge Regulations were proposed for surface spreading projects based on Scientific Advisory Panel recommendations. In this draft regulation (and all subsequent versions), dilution of the treated reclaimed water to meet the TOC requirement was found acceptable. The main requirements for groundwater recharge via surface spreading included (NWRI, 2012): Minimum treatment: oxidation, filtration, disinfection, carbon adsorption. GAC not required if dilution 20 percent. Meet drinking water standards. Total Nitrogen (TN) 10 mg/l. COD 5 mg/l. TOC 3 mg/l. One-year residence time underground. Distance to withdrawal = 500 feet. In 1989, some changes were made to the 1988 Draft and it extended to cover subsurface injection projects. GAC or reverse osmosis (RO) were specified as the required organics removal treatment processes. Requirements for included for the first time. Used formulas/tables to determine TOC requirement for spreading. TOC 1 mg/l for injection. In 2001, GAC treatment was no longer acceptable as the sole organics removal process for the subsurface injection. Subsequently, RO had become a standard process to meet TOC requirement since then (NWRI, 2012). 4

5 2002 Draft Groundwater Recharge Regulations reduced TOC Limit from 1 mg/l to 0.5 mg/l. The reduction of the acceptable TOC limit from 1.0 mg/l to 0.5 mg/l was principally due to a finding that N-Nitrosodimethylamine (NDMA) and 1,4-dioxane found in groundwater were caused by the recharge of recycled water at an operational groundwater recharge project (NWRI, 2012) In 2004, 2007 and 2008 Draft Regulations, additional tweaking made to the draft regulations to deal with total nitrogen (three methods to meet TN requirement) and monitoring requirements were established for notification level chemicals (i.e. NDMA, boron, chlorate, 1,4-dioxane, etc.) and chemicals of emerging concern (CECs). In 2008, for the entire recycled municipal wastewater stream, reverse osmosis treatment as well as subsequent advanced oxidation treatment was required to provide at minimum, a level of treatment equivalent to a 1.2 log NDMA reduction and a 0.5 log 1.4-dioxane reduction thru advanced oxidation. California Senate Bill 918 signed into law by the Governor and became effective in September 2010 required CDPH to adopt uniform water recycling criteria by December 31, 2013, for indirect potable reuse by groundwater recharge and to adopt uniform water recycled criteria by December 31, 2016, for indirect potable reuse by surface water augmentation. The bill also required CDPH to investigate and report on the feasibility of developing criteria for direct potable reuse by December 31, The main changes with the 2011 and 2013 Draft Groundwater Recharge Regulations were the requirements pertinent to pathogenic microorganisms for surface spreading and subsurface injection projects such that the recycled municipal wastewater used as recharge water for a GRRP receives treatment that achieves at least 12-log enteric virus reduction, 10-log Giardia cyst reduction, and 10-log Cryptosporidium oocyst reduction. The treatment train shall consist of at least three separate treatment processes. For each pathogen (i.e., virus, Giardia cyst, and Cryptosporidium oocyst), a separate treatment process may be credited with no more than 6-log reduction and shall achieve at least 1-log reduction and for each month retained underground, the recycled municipal wastewater or recharge water will be credited with 1-log virus reduction. A GRRP providing advanced treatment complying with section , that also demonstrates at least six months retention underground will be credited with 10-log Giardia cyst reduction and 10-log Cryptosporidium oocyst reduction. Starting by 2011, the Draft Regulations required that a reverse osmosis and advanced oxidation should minimum meet the following criteria: 1. A reverse osmosis membrane should be selected by project sponsor that demonstrates an average rejection of sodium chloride greater than or equal to 99.5 percent by RO, with a 15 percent recovery utilizing ASTM method D4194 RO permeate having TOC concentrations of 0.25 mg/l or less initially 2. For the reverse osmosis treatment process, a project sponsor shall propose, for Department review and approval, on-going performance monitoring (e.g. conductivity or TOC) that indicates when the integrity of the process has been compromised. The proposal shall include at least one form of continuous monitoring, as well as the 5

6 associated surrogate and/or operational parameter limits and alarm settings that indicate when the integrity has been compromised. 3. To demonstrate a sufficient oxidation process has been designed for implementation, a project sponsor shall: a) Perform an occurrence study on the project s municipal wastewater to identify indicator compounds and select a total of at least nine indicator compounds, with at least one from each of the functional groups in subparagraphs (A) through (I) below. The project sponsor shall submit an occurrence study protocol, as well as the subsequent results and chosen indicator compounds, to the Department for review and approval. (A) Hydroxy Aromatic (B) Amino/Acylamino Aromatic (C) Nonaromatic with carbon double bonds (D) Deprotonated Amine (E) Alkoxy Polyaromatic (F) Alkoxy Aromatic (G) Alkyl Aromatic (H) Saturated Aliphatic (I) Nitro Aromatic b) (Utilize an oxidation process that achieves optimal removal of the indicator compounds selected in paragraph (1) such that removal is no less than; 0.5-log (69 percent) for each indicator compound representing the functional groups in paragraph (1)(A) through (1)(G), and 0.3-log (50 percent) for each indicator compound representing the functional groups in paragraph (1) (H) and (1)(I). Before the release of the 2011 Draft Regulations, a notification limit of 10 ng/l was established by CDPH for NDMA in California. Because of this numeric limit, providing a minimum 1.2-log reduction through advanced oxidation was no longer required by the Draft Regulations released in 2011 and thereafter. Per SB 918, the Final Ground Water Recharge Regulations were established on June 2014 (a slight delay occurred compared to the anticipated completion date of Dec 2013). The main difference between 2014 Final and Previous two Drafts (2011 and 2013) are that the Final Regulations require only one method to comply with the total nitrogen limit of 10 mg/l in the recharge water. Substantial changes were made in the Final Regulations for describing reverse osmosis membrane selection criteria. The revised changes include: each membrane element used in the project has achieved a minimum rejection of sodium chloride of no less than 99.0 percent and an average (nominal) rejection of sodium chloride of no less than 99.2 percent, as demonstrated through Method A of ASTM International s method D (2008) using the following substitute test conditions: (A) tests are operated at a recovery of no less than 15 percent; 6

7 (B) sodium chloride rejection is based on three or more successive measurements, after flushing and following at least 30 minutes of operation having demonstrated that rejection has stabilized; (C) an influent ph no less than 6.5 and no greater than 8.0; and (D) an influent sodium chloride concentration of no greater than 2,000 mg/l, to be verified prior to the start of testing; and during the first month of full-scale operation the membrane produces a permeate having no TOC concentration greater than 0.25 mg/l, as verified through monitoring no less frequent than weekly. No changes were made to the AOP portion. All other specific requirements and a copy of June 2014 Ground Water Recharge Regulations can be found at Water Boards website Upcoming Regulations and Next Steps In 2013, the National Water Research Institute (NWRI) of Fountain Valley, a nonprofit organization, appointed state and national water industry experts to an independent, third-party Expert Panel to provide advice to the State of California on developing Water Recycling Criteria for indirect potable reuse (IPR) through surface water augmentation (SWA) by December and determining the feasibility of developing criteria for direct potable reuse (DPR) by December The Panel was originally formed on behalf of the Drinking Water Program of the CDPH. As of July 1, 2014, the Drinking Water Program was officially transferred from CDPH to the State Board and renamed as the Division of Drinking Water (DDW). IPR via surface water augmentation means the planned placement of recycled water into a surface water reservoir used as a source of domestic drinking water supply. Direct potable reuse is defined as the planned introduction of recycled water either directly into a public water system, as defined in Section of the Health and Safety Code, or into a raw water supply immediately upstream of a water treatment plant (NWRI, 2015). Unlike IPR, DPR does not include an environmental (natural) buffer such as groundwater or surface water (i.e. lake) but it considers incorporation of an engineered storage to provide ample time for monitoring and assessing integrity of the produced water. The developed criteria for surface water augmentation are expected to be similar to those required for the GWR via subsurface injection per the current GWR regulations. It is imperative that reuse community develop quick and reliable monitoring techniques (i.e. surrogates) to assess integrity of the produced water to ensure that drinking water is safe. One of the initial challenges with SWA is to define the maximum recycled water contribution and minimum dilution requirements for the drinking water reservoir. The other challenge is that what or how MCLs and action levels fit into the criteria since they apply at the tap and not at the delivery point to the augmented reservoir. A number of agencies (City of San Diego, City of Los Angeles) in California is considering implementation of the IPR via surface water augmentation and looking forward to see the 7

8 uniform criteria for SWA. The implementation of IPR via SWA projects will provide an important support for future DPR projects in California and around the nation. DPR is a technically feasible method of stabilizing water supplies for municipalities and agriculture; preventing, minimizing, or correcting environmental damage resulting from interbasin water transfers; and conserving energy. However, the application of DPR on a large scale may not be easy task thereby requiring a closed collaboration among water and wastewater industry to develop a planning process to examine the potential of DPR and impediments to its implementation (Schroeder et al. 2012). One of the major steps that should be taken by the water and wastewater industry is to develop closer ties with respect to the management of available water resources. As water distribution system modifications and replacements are planned and implemented, attention should be focused on appropriate locations within an existing system where engineered storage buffers or water purification plants can be located (e.g., near existing water treatment plants or other suitable locations within the service area). Studies should be undertaken to assess what blending ratios would be acceptable with the existing water supply to protect public health, maintain water quality, and control corrosion (Schroeder et al. 2012). References James Crook Regulatory Aspects of Direct Potable Reuse in California- A White Paper. National Water Research Institute Publications. April Cindy Forbes CDPH Ground Water Recharge Regulations. Edward Schroeder, George Tchobanoglous, Harold L. Leverenz, and Takashi Asano Direct Potable Reuse: Benefits for Public Water Supplies, Agriculture, the Environment, and Energy Conservation- A White Paper. National Water Research Institute Publications. January National Water Research Institute BDOC as a Performance Measure for Organics Removal in Groundwater Recharge of Recycled Water Final Report. September 26, National Water Research Institute Final Panel Meeting Report #5: Surface Water Augmentation IPR Criteria Review. June 2-3,