South County Regional Wastewater Authority WWTP Expansion

Santa Clara County, Ca

As part of a contract to design SCRWA’s $85M Wastewater Capacity Expansion Project, HydroScience has completed multiple upgrade projects throughout the facility, including:

Influent pump station and force main. HydroScience designed a 40 MGD influent pump station including two 1/2-inch spacing deep well screens ahead of the split wet well pump station to ensure reliable operations. The screens are contained in a new structure for odor and vector containment. To reduce construction costs, new electrical equipment was housed in an unused portion of the existing pump station building and the existing backup generator system was utilized in its current location to backup power supplies.

HydroScience also designed a 36-inch force main parallel to their existing pipeline to provide redundancy and expand pumping capacity for the newly upgraded pump station. HydroScience’s innovative design allowed for connection of the force main without interruptions of wastewater flows and eliminated the need for costly temporary pumping facilities during construction. A pressure rated fiberglass reinforced motor pipe was selected to provide the maximum service life in the highly corrosive soils at the plant, while not exceeding the limited construction budget or creating long term maintenance issues.

Secondary clarifier. The plant’s two existing 130 foot concrete tanks were susceptible to corrosion and required regular maintenance. High groundwater at the plant also made equipment repair and maintenance difficult and risky, and susceptible to a “float” condition when emptied for maintenance. HydroScience evaluated the existing clarifiers, provided recommendations, and designed a third clarifier to both handle the peak flows as well as provide redundancy for this critical process.

Maintenance projects. Upgrades included new anoxic zones for denitrification, additional aeration capacity in the oxidation ditch, expansion of the solids handling facility, and a new two-acre maintenance building. To maximize the utility of the existing oxidation ditch tankage, HydroScience designed a fine bubble diffuser oxygen delivery system to replace the current surface aeration system. This system will dramatically lower electrical costs associated with aeration.

HydroScience further provided design services to replace an outdated and congested SCADA communication network.