Orange County Agencies Celebrate Final Expansion of the Groundwater Replenishment System

By on November 17, 2019
Water Treatment Plant opens

The Final Expansion of the Groundwater Replenishment System (GWRS), Orange County’s award-winning and the world’s largest water reuse project of its kind, is now underway with an estimated completion date of 2023. The joint project of the Orange County Water District (OCWD) and Orange County Sanitation District (OCSD) was celebrated last week with a groundbreaking ceremony attended by project stakeholders, industry professionals and elected officials.

The first of the three phases of the GWRS was brought online in 2008 and produced 70 million gallons of water a day (MGD) — from wastewater. When the second GWRS phase was completed in 2015, it produced an additional 30- MGD for central and northwest Orange County residents. When the final expansion is completed, the GWRS will produce 130 MGD. The GWRS has been a feat of decades of collaboration between OCWD and OCSD for not only the building of the system but also in overcoming the stigma associated with this type of wastewater project and using it to bring water reliability to the region.

“Today marks an important milestone in Orange County’s water future,” said OCWD President Vicente Sarmiento. This is what we work for day in and day out—to provide a high-quality, reliable water supply to 2.5 million people in our service area. Total production will be enough water for 1 million people when the expansion is completed. The GWRS is vital to combatting climate change and sustaining Orange County’s water supplies and its thriving economy.”

Instead of discharging treated wastewater to the Pacific Ocean, OCSD and OCWD regard wastewater as a resource. The two agencies collaborate on the wastewater’s treatment, purification and its ultimately being pumped into recharge basins.

OCSD first collects and treats the wastewater producing water clean enough to undergo purification at the GWRS. Next, the water is purified at the GWRS using a three-step advanced process of microfiltration, reverse osmosis and ultraviolet light with hydrogen peroxide. This produces high quality water that meets and exceeds state and federal drinking water standards. The purified water is then injected into a seawater barrier and pumped to recharge basins allowing natural percolation into the Orange County Groundwater Basin where it is managed by OCWD.

“We are honored to partner with the Orange County Water District in ensuring strict source control of the wastewater and working to increase the amount of water sent to the GWRS,” stated OCSD Board Chairman David J. Shawver. “We have made significant investments and are dedicated to the prudent use of public funds for this and all future projects benefiting our community.”

The GWRS produces water at a lower cost than imported water. Funding for the Final Expansion includes $135 million from the Environmental Protection Agency’s Water Infrastructure Finance and Innovation Act (WIFIA) program and $1.1 million in grants from the U.S. Department of the Interior Bureau of Reclamation Title XVI Water Infrastructure Improvements for the Nation (WIIN) program.

“The Orange County Water District’s advanced system expansion will benefit the local community, the economy and the environment,” said United States Environmental Protection Agency (EPA) Pacific Southwest Regional Administrator Mike Stoker. “We are honored to help fund this project and reduce borrowing costs through our WIFIA loan program.”

The GWRS Final Expansion is additionally slated to receive $3.6 million in grants through the Integrated Regional Water Management (IRWM) program for Prop 1 grant funding managed by the California Department of Water Resources. The remaining $186 million will be funded through the Clean Water State Revolving Fund (SRF) Loan program.

The Final Expansion requires a total treated wastewater flow from OCSD of approximately 175 MGD in order to produce 130 MGD of advanced purified recycled water. “This project will allow the region to recycle 100% of OCSD’s reclaimable flows, which will be yet another first in the industry,” added Shawver.

GWRS water currently accounts for one-third of the water that is put into the Orange County Groundwater Basin. Water from the GWRS supplements Orange County’s other drinking water supplies.