Wastewater

Treatment Requirements

Wastewater discharges at Rancho Murieta are controlled by the California Regional Water Quality Control Board, Central Valley Region. Reclaimed water used for the irrigation of parks, playgrounds, schoolyards, and the golf course, must meet the requirements of Title 22, Division 4 of the California Code which require an adequately oxidized, coagulated, clarified, filtered, and disinfected wastewater, the standard our reclaimed water meets.

Treatment Process Overview

The treatment process utilized at Rancho Murieta is unique in that it utilizes a number of basic and proven processes to produce a very high quality effluent.

Wastewater is received at the treatment plant from three (3) major pumping stations and flows successively through five (5) ponds. Wastewater is treated in the ponds naturally through bacteriological action supplemented with mechanical aeration (wastewater aeration ponds). The pond effluent is stored in two (2) large reservoirs. Within these reservoirs, additional natural treatment occurs. These reservoirs allow storage of the secondary treated wastewater until the need arises for irrigation of the golf course. When this occurs, generally in April, stored secondary effluent is further treated in the tertiary plant. It is operated until the supply from the reservoirs is exhausted or the irrigation season ends, about the middle of October.

The tertiary plant utilizes the Dissolved Air Floatation process, followed by filtration. These processes remove algae and fine solids contained in the secondary effluent. The effluent from the filter is discharged to the chlorination contact chamber for disinfection.

Disinfected wastewater enters an equalization basin. It serves as a flow equalizer, as the demand from the golf course varies throughout the day, while it is most desirable to maintain a fixed flow through the tertiary process.

Title 22 requires that reclaimed wastewater must be disinfected and remain in contact with chlorine for a minimum detention time of 120 minutes. The contact chamber is baffled and routed to ensure the contact time is met for adequate disinfection.