City of Davis– Waste Water Treatment Plant Secondary and Tertiary Improvements
Northern Division, Wastewater Treatment
W. M. Lyles Co. joint ventured with AECOM to design and build the STI Project for the City of Davis.
The upgrades to the existing wastewater treatment plant will provide compliance with Title 22 regulatory requirements and better protect the public health and the natural environment by improving the quality of water discharged to the environment.
Project Description: The project consists of:
- Replacing the existing oxidation pond process with an activated sludge process that includes four Aeration Tanks, four 75’ diameter Secondary Clarifiers, two RAS/WAS Pump Stations, and two Scum Pump Stations.
- A new Blower Building with three single-stage turbo blowers will provide aeration air to the fine bubble diffusers in the aerobic zones of the Aeration Tank.
- The old Chlorine Contact Basin will be converted into a new Primary Effluent Pump Station with four new vertical turbine solids handling pumps to transfer primary effluent to the Aeration Tank.
- The new solids handling facilities consist of a Dewatering Building with two screw presses, two rotary drum thickeners, thickened sludge feed pumps, and a system of sludge conveyors, a-canopy covered sludge storage area, and two above grade bolted steel digested sludge storage tanks.
- A new Cogeneration Building with a biogas cogeneration unit will also be provided to generate electricity for the WWTP and to provide recovered heat for hot water loop digester and building heating.
- The new tertiary process facilities consist of a covered Filter Building with four cloth disc filters, a Chlorine Contact Basin and Reaeration Tank with positive displacement blowers, a Chemical Disinfection Building to store and deliver sodium bisulfite and sodium hypochlorite, and an Effluent Pump Station to discharge treated wastewater into the Willow Slough bypass.
- Two pairs of 500kW emergency generators will be installed to provide standby power to the plant. In addition to the process improvements, the project will also upgrade and expand the existing Administration, Lab, and Maintenance Buildings.
Completion Date: Expected October 2018