Enhanced Pathogen and Pollutant Monitoring of the Colorado River Municipal Water District Raw Water Production Facility at Big Spring Texas
Type: Scientific Investigation
Program: Tailored Collaboration
Funding Partner: Carollo Engineers
Total Investment: $516,703 (Cash: $99,579, In-Kind cash and service: $ 417,124)
Principal Investigator: Eva Steinle-Darling, PhD, PE, Carollo Engineers
Across the country, successful indirect potable reuse (IPR) projects are now creating more than 100 million gallons per day of potable water; several have been doing it safely for nearly half a century with no ill effects on public health. These include the Orange County Water District, California; the West Basin Municipal Water District, California; El Paso, Texas; Upper Occoquan Service Authority, Virginia; and Scottsdale, Arizona.
Throughout large parts of Texas, water shortages reached crisis levels in 2011, the height of the recent and still ongoing drought in that area. At the same time, direct potable reuse (DPR) has quickly turned from being viewed as “an act of desperation” to a potentially viable part of the region’s water supply solution. In May of last year, the first of several Texas projects exploring the path towards DPR, implemented by the Colorado River Municipal Water District (CRMWD) at Big Spring, began directly augmenting raw water supplies with advanced treated reclaimed water.
In California, the evolution towards DPR as a viable water supply alternative is being driven by the California DPR Initiative and the regulatory impetus to determine the feasibility of implementing DPR in California by 2016. The current severe drought has only accelerated this process. Many utilities in California and across the nation are actively investigating, piloting, and demonstrating this feasibility with advanced treatment plants, public communication campaigns, and monitoring studies.
But all of these utilities are looking toward the one operating DPR facility in the western hemisphere, the Raw Water Production Facility (RWPF) in Big Spring,Texas. It is now up to the reuse research community to demonstrate that this project, which implements full advanced treatment (FAT) in direct analogy to the Groundwater Replenishment System at the Orange County Water District, is providing reliable and safe water to the CRMWD’s customers.
Goals and Objectives
The project will provide a comprehensive, technically sound, and independent verification that potable reuse, as implemented at Big Spring and proposed by others, can be a safe and reliable source of high-quality drinking water. This will be done through a state-of-the art sampling campaign for the DPR plant at Big Spring, including trace chemical analyses for pharmaceuticals, hormones, and other compounds of interest, a full suite of pathogens (virus, protozoa, and bacteria), and a comprehensive set of both chemical and microbial indicators and surrogates.
Task 1. Evaluate Current Treatment Process and Develop Testing Protocol
Task 2. Perform Sampling and Evaluate Results. Under TWDB funded portions of the project, we plan to sample MF influent, RO concentrate, RO effluent, AOP effluent (i.e., finished water), and conventional raw water. Sampling is proposed to occur on a quarterly basis. We will monitor for a comprehensive list of constituents of emerging concern (CECs) of CECs. A full list of the CECs our team proposes for monitoring is provided in Table 1 of the proposal, incoroporated herein by reference. Fluorescence Excitation Emission Matrices (EEMs) will also be collected at each sample location. Collimated beam testing for validation of the AOP system, and reverse osmosis (RO) challenge testing with MS-2 bacteriophage and a surrogate tracer at the CRMWD’s advanced treatment plant is also planned. Most of this work will be funded by TWDB and is described in the proposal on pages 5-6. We will also monitor for an extensive list of microbial water quality parameters, including enteric virus (adeno-, entero-, and norovirus), protozoa (Cryptosporidium and Giardia) and bacteria (E Coli and total coliform). Indicators and surrogates will also be sampled, including MS-2 (seeded for RO challenge testing), particle count analysis (surrogate for protozoa), and chloramines residual for UV disinfection effectiveness.
Task 3. Communicate Results. A significant amount of data will be generated by this research project, including results regarding the presence of trace chemicals and pathogens in the water samples collected from secondary effluent through finished water, as well as the current conventional raw water source. These data have the potential to create significant controversy in the public sphere regarding the quality of advanced-treated and conventional raw water. The team will develop a comprehensive public communication strategy to disseminate the data in a way that is meaningful and accessible to a lay audience.