Brown Bag Seminar - Transforming Wastewater to Drinking Water: How Two Agencies Collaborated to Build the World’s Largest Indirect Potable Reuse Project
Adam Hutchinson, Recharge Planning Manager
In the early 2000’s, two Orange County agencies faced some challenges. The Orange County Sanitation District (OCSD) needed to replace on ocean outfall for treated sewer water that would cost millions of dollars. The Orange County Water District’s (OCWD) Water Factory 21, a groundbreaking water recycling facility constructed in the mid-1970s, was nearing the end of its useful life. Rather than focus on its individual needs, the two agencies got together and developed a mutually beneficial project that saved both money and generated tremendous benefits for the citizens of Orange County.
This project is the Groundwater Replenishment System, which currently generates 100 million gallons per day of advanced purified water that is recharged into the Orange County groundwater basin to supplement potable water supplies. By participating in this project, OCSD was able to avoid the need to construct an additional ocean outfall. Further expansion of the GWRS to 130 million gallons per day will result in the recycling of all the available wastewater within OCSD’s service area, further bolstering the reliability of Orange County’s water supplies. In addition to being a reliable source of supply, GWRS water is very pure, with a total dissolved solids (TDS) concentration of 70 mg/L, which greatly assists in reversing a salt imbalance in the basin and improving overall groundwater quality.