City of Vacaville, Easterly Wastewater Treatment Facility

This comprehensive project involved upgrades at the plant to meet regulatory and permit requirements, including compliance with numerical ammonia limits, nitrate limits, elimination of blending and dry weather filtration/Title 22 reclamation. Various project components included the following: HEADWORKS FACILITY – Involved replacement of the existing mechanical screens with perforated plate screens and a third perforated screen and screenings washer compactor. The screening conveyor was replaced with a hydraulic sluice. GRIT HANDLING – Involved replacement of the existing grit cyclones and classifiers to allow for direct discharge into storage bins. AERATION BASINS – Involved expansion of the aeration basins with addition of two new basins to the west, allowing for denitrification. The new facility includes a flow split structure to divide flows between the three “coupled” basins and increased build out capacity. FLOW EQUALIZATION BASIN – Involved construction of a new, 4-cell flow equalization basin which includes concrete lining, wash-down system, piping, valves, gates and associated facilities and receives both primary and secondary effluent flows. The project included addition of an emergency overflow storage basin. BIOSOLIDS STORAGE – Involved modification of the existing bio solids storage lagoon, adding floating aerator/mixers and a concrete lining. ELECTRICAL ROOM – Construction of a new electrical room to support the new instrumentation and control systems and a second 2 MW generator with new 12KW to 480 V transformer systems to serve the load banks at the facility.