Easterly Vacaville Wastewater Treatment Plant Tertiary Denitrification Improvements

Project Details

This project for the City of Vacaville’s Easterly Waste Water Treatment Plant includes a major renovation of the existing facility including aeration basins, equalization basin, grit handling and biosolids storage lagoon.

HEADWORKS FACILITY -the existing mechanical screens were replaced with perforated plate screens, and a third perforated screen and screenings washer compactor was installed. The screening conveyor was replaced with a hydraulic sluice.

GRIT HANDLING – The existing grit cyclones and classifiers were relocated to allow for direct discharge into storage bins. The grit slurry pipes were extended and the existing sludge strainers were removed.

AERATION BASINS – The aeration basins were expanded by adding two new basins to the west. The internal arrangements were modified to “coupled” basins to provide for denitrification. The MLE flow is achieved using “through the wall” MRL propeller pumps. The new facility includes a flow split structure to divide flows between the three “coupled” basins, and the two new basins increased buildout capacity. The aeration basins include air supply piping, and submerged diffusion aeration equipment.

FLOW EQUALIZATION BASIN – A new 4-cell flow equalization basin (total storage capacity approximately 5.5 mg) was constructed, including concrete lining, washdown system, piping, valves, gates and associated facilties. This basin receives both primary and secondary effluent flows. An emergency overflow storage basin was also added.

BIOSOLIDS STORAGE -The existing biosolids storage lagoon was modified by reducing the size, and adding a concrete lining. The lagoon has floating aerator/mixers;

LANDSCAPING AND SITEWORK – A 70-foot-wide, 7,000-foot-long landscape buffer was constructed around the perimeter of the City’s property. Sitework included mass grading, fencing, and the construction of a new access road.

ELECTRICAL ROOM – A new electrical room will house electrical gear to support the new instrumentation and control systems. A second 2 MW generator and new 12KW to 480 V transformer system will serve the load banks at the facility.

City of Vacaville
Vacaville, CA
HDR Engineering, Inc.
Construction Manager
Harris & Associates, CM
Project Cost
Completion Date
Project Excellence Award, NECA, No Cal Chapter 2016
  • Jeff Naff

    Jeff Naff

    Director of Work Acquisition - Municipal Infrastructure