KJ Consultants (KJ) is providing engineering and program support services for a potable reuse project in East San Diego County. Recent droughts and increasing costs of imported water have Southern California communities looking at alternative water supplies. The East County Advanced Water Purification Program (Program) is a collaborative partnership between Padre Dam Municipal Water District (Padre Dam), Helix Water District (Helix), the County of San Diego, and the City of El Cajon.
Currently, Padre Dam imports all its potable water supply and Helix imports approximately 85% of its potable water supply from the Colorado River and the Sacramento-San Joaquin Bay Delta. Costs of this imported water have increased over the past decade and are projected to continue rising, while the supply itself is subject to wildfire, earthquakes, and other emergencies at the source.
The communities served by the Program generate approximately 15 million gallons per day (mgd) of wastewater. Currently, 2 mgd is treated at Padre Dam’s Ray Stoyer Water Recycling Facility (WRF), while the remaining 13 mgd is sent to the City of San Diego’s Point Loma Wastewater Treatment Plant to be treated and disposed of into the Pacific Ocean. Wastewater treatment costs are projected to increase through the City of San Diego. With KJ’s engineering expertise, this Program will create a locally controlled, non-interrupted drinking water supply for the community by treating wastewater and producing Advanced Water Purification (AWP) purified water for potable reuse.
The initial phase of the Program will expand Padre Dam’s Ray Stoyer WRF to be able to process up to 15 mgd of wastewater and produce of new potable water supply. The recycled water from the Ray Stoyer WRF will be treated at the new AWP Facility, for potable reuse through surface water augmentation (SWA). Through the AWP process, the recycled water will undergo free chlorine disinfection, microfiltration, reverse osmosis, and ultraviolet disinfection/advanced oxidation to become purified water. After the water has been purified at the AWP Facility, it will be dechlorinated for surface water augmentation at Lake Jennings. From Lake Jennings, the purified water will be treated at the R. M. Levy Water Treatment Plant, owned by Helix, before being distributed to the surrounding communities as a new, local, reliable, and clean drinking water supply.
KJ’s design will reduce cost for the four agencies involved in the Program by reducing their reliance on imported water and wastewater treatment through the City of San Diego. The design includes new solids handling and energy recovery facilities that will be used for repurposing wastewater treatment by-products for beneficial use, including electricity generation from biosolids. This, along with decreasing the amount of water that is imported to the region, will reduce the overall amount of energy consumption. These benefits will provide a big win for all agencies involved in this collaborative effort.
Be sure to check out the East County Advanced Water Purification Program website at http://eastcountyawp.com/