OCWD Ground Water Replenishment System

The Orange County Water District in Fountain Valley, California operates the largest advanced water treatment facility in the world known as the Groundwater Replenishment System (GWRS), where wastewater is treated to potable water standards and injected into the groundwater aquifer to supplement drinking water needs throughout the region. McCarthy played a major role in this journey, completing the Phase 2 Expansion to increase capacity of the facility to 100 MGD. McCarthy purchased, installed and commissioned major equipment and also performed all civil work to demolish and modify existing facilities and build new structures. 

The project included an extensive amount of civil and yard work, including pouring of XX membrane filtration concrete basins and addition of canopies for those basins; expansion of the existing RO building to accommodate both Phase 2 and Phase 3 expansion capacities; demolition of XX; installation of over 3,000 deep pile foundations; construction of 2 x 7.5 MG above ground carbon steel equalization tanks; and trenching, excavation and shoring. The project also included a significant process mechanical scope, with several advanced treatment technologies installed into the facility to provide multi-level barriers to meet potable reuse standards. Specifically, McCarthy incorporated a 40 MGD submerged microfiltration membrane system, including membrane modules, filtrate and air headers, air blower systems, filtrate and backwash pumping systems, Clean-In-Place system, overhead gantry crane mechanisms, instrumentation and controls; a 30 MGD two-stage reverse osmosis system, including cartridge filters, vertical turbine feed pumps, energy recovery devices and CIP systems; a ultraviolet advanced oxidation process using UV reactors and hydrogen peroxide injection; a lime saturation system; multiple chemical dosing systems; ancillary pumping systems; and yard piping and valves throughout the facility. There was also a large electrical package to expand service to future capacity needs and upgrade the existing SCADA system. McCarthy self-performed all process mechanical piping and structural concrete, and provided design assistance throughout the entire project to verify and optimize all scopes of work.

The project proved to be very complex, with over 130 identified tie-ins and tasks affecting existing operations. McCarthy worked closely with the Owner, OA, Engineer and specialty design consultants to create extensive plans for performing these tasks and performing startup and commissioning activities without impacting ongoing operation. In the end, McCarthy met the budget set by the Owner and also started up on schedule.