LAN and its contracting partner completed this design/build project to expand the Primary Effluent Pump Station (PEPS) at the District’s main wastewater treatment facility from a peak pumping capacity of 120- to 320-mgd. The project included the design and construction of a wet well expansion for the existing trench type wet well, as well as construction of a new odor control biofilter to mitigate impacts to surrounding neighborhoods.

LAN performed extensive computer modeling of the incoming sewer system from the plant’s existing primary clarifiers, and the force main from the plant to the present and future aeration basins. In addition, a physical model was constructed to visualize flow patterns under various flow conditions.

One large 72-inch influent sewer to the new wet well was rehabilitated by cured-in-place (CIP) method. The project also included a canopy for the expanded pump station, revision of the existing pump control programming, new instruments for flow and level measurements, new actuators for remote valve actuation, and a new motor control center.