The Process and Water Quality Specialists

Recycled Water
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San Jose Creek Prelimary Ozonation Evaluation

Stetson Engineers / Upper San Gabriel Valley Municipal Water District (Upper District)

The Upper San Gabriel Valley Municipal Water District (Upper District) currently obtains its imported water supplies from the Metropolitan Water District of Southern California (MWD). MWD imports water from northern California through the California Aqueduct and the Colorado River. In order to support groundwater production from the Main San Gabriel Basin, Upper District delivered imported water at an average rate of 32,000 acre-feet per year over the past two decades. Since these imported water supplies will be less reliable in the future, Upper District is pursuing alternative strategies to supplement its potable water portfolio with a renewable source. Indirect potable reuse (IPR) via groundwater spreading has been identified as the most appropriate and promising option. Furthermore, Upper District would like to implement some form of advanced wastewater treatment to improve the quality of the tertiary effluent intended for spreading. Due to the significant costs of full advanced treatment (i.e., microfiltration, reverse osmosis, and UV/H2O2), Upper District is evaluating alternative treatment trains, including ozone and biological activated carbon (BAC), that are capable of providing comparable effluent water quality and public health protection to that of MF-RO-UV/H2O2. To support this evaluation, samples were collected from the San Jose Creek Water Reclamation Plant (SJCWRP), and bench-scale ozonation experiments were performed to highlight the benefits and identify potential concerns with this form of treatment. Upper District and Trussell Tech are now collaborating on a proposal to the WateReuse Research Foundation to obtain funding for additional studies. If successful, Trussell Tech will perform a comprehensive evaluation of IPR alternatives, which will include identification of the most appropriate treatment train for potable reuse; design and operation of a pilot-scale system to demonstrate the efficacy of the preferred treatment train; and optimization of operational conditions for continuous, long-term operation of the pilot- and future full-scale system.