Sewer

Purpose:

To provide treatment for the wastewater emanating from the City. Plant is designed to produce an effluent whose quality meets standards set forth by the California Regional Water Quality Control Board.

Description:

Plant size is currently at 1.55 MGD with an average monthly flow of 1.1 MGD.  Wastewater Plant consist of two complete mix aerated lagoons operated in parallel, and two partial mix aerated lagoons operated in series. Each lagoon has an operating depth of 12 ft. and has a detention time of 3 days at design flow.  Flows enters plant through 18” and 24” diameter gravity sewers, which discharge into two separate headworks structures made from concrete and both have mechanically cleaned barscreens. Screenings are pressed and collected in a plastic bag and disposed of as a solid waste.  From heaworks, influent flows into a manhole where streams are combined and metered and recorded through a magnetic flow meter. Then flow enters a splitter box where flow is split and gravity flows into lagoon 1a and 1b. theese lagoons provide the primary aeration of incoming flows. Most of settleable solids will settle out and undergo anaerobic digestion on the lagoon bottoms.  From lagoons 1a and 1b, the primary treated wastewater flows by gravity through flow control structures and buried piping into lagoon # 2. Flow in lagoon also goes through same treatment process as lagoon 1a and 1b. From lagoon # 2, wastewater is pumped to lagoon # 3. The pump station has 3 constant speed pumps. The operator varies the number of pumps online, which sets the flow, based on the level of lagoons.  From lagoon # 3, treated wastewater flows by gravity through a flow control structure and buried piping into one of the 3 storage reservoirs, with the capacity of 472 acre feet of storage.  A recirculation line draws water from pump station and discharges into incoming untreated wastewater. Recirculated water is also used for washdown water at headworks. Recirculated flow is designed to initiate bacterial activity in incoming wastewater. All treated effluent flows into the storage reservoirs are disposed of onsite by agricultural irrigation on city owned farmland.
 
Sewer Rates