The Orange County Sanitation District has hired Black & Veatch to design the overhaul and upgrade of Wastewater Plant No. 2 in Huntington Beach, Calif. The new facilities will replace units built in the 1970s and will facilitate the increase in the Orange County Water District groundwater replenishment system plant’s capacity from 100 million gallons per day (mgd) to 130 mgd. The project will require replacing four primary clarifiers and upgrading 10 existing clarifiers. Investigations during the design phase uncovered two earthquake faults beneath the plant that the sanitation district had not known about. The discovery led to a decision to relocate the new clarifiers. The estimated construction cost will be $120 million, and work is expected to start in 2021. The upgrades will improve the plant’s ability to provide source water for the county’s groundwater replenishment system. The system, the world’s largest for indirect potable reuse, takes highly treated wastewater from throughout the county and further treats the water before injecting it back into the ground for a seawater-intrusion barrier or to increase the local drinking-water supply.

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