Wastewater Reuse Evaluations
City of Davis, California

West Yost was originally retained by the City to perform facilities planning, design, and construction services for a major expansion and upgrade to the City’s Water Pollution Control Plant (WPCP). West Yost also provided a number of services to the City in evaluating various reuse opportunities on areas surrounding the WPCP.

Alternatives that have been considered include reuse of wastewater on an agricultural property for summer irrigation, reuse of wastewater on agricultural property for winter crop decomposition and use of recycled water for an enhancement wetland project. Most recently, West Yost has taken a lead role in assessing a year-round reuse alternative that could be implemented in lieu of constructing treatment plant upgrades identified under the Strategic Master Plan. The proposed alternative would involve the construction of storage facilities capable of holding all wastewater flows during the winter months when irrigation demands are limited: it  would eliminate the need for an extensive treatment facility upgrade, and systematically reduce energy consumption.

The project also included planning and providing engineering support related to the City’s 400 acre habitat wetlands project, which receives treated effluent and “first flush” stormwater. The 400 acre wetlands project, designed and constructed by the United States Army Corps of Engineers, is the only completely native-species constructed wetland in the state of California and also provides wildlife habitat benefits. On behalf of the City, West Yost performed permit report preparation and discharge permit negotiations for the wetlands project. The City currently discharges treated effluent from the wetlands under their current NPDES permit.