TVCSD Wastewater Treatment Plant

The System in Brief

Wastewater from the town and schools of Tomales flows or is pumped into the three-pond treatment system. Primary and secondary treatments occur there involving settling of solids and breakdown of the wastewater components. The three new aerated ponds are piped in series that allows the cleanest water from pond #1 to flow into pond #2, and again from pond #2 to pond #3. The wastewater is continually treated by settling and aeration as it moves from pond to pond. A final "polished" effluent is created in pond #3.

This three pond system is very new and was the final phase of the wastewater upgrades begun shortly after the formation of the district. The original system consisted of a single pond, and contained many years of accumulated sludge. The new system's ponds are lined with a 50 year plastic liner to insure there is no leakage into the surrounding ground. Additionally any of the three ponds can be taken offline for repairs without having to shut down the whole system.

The treated effluent is then pumped to large storage ponds located a mile or so from the plant. Here the water is disinfected with chlorine and spray irrigated during the summer months onto the surrounding fields. These upper ponds serve two purposes: to give the wastewater additional time for further settling and biological breakdown, and to provide storage during the wet winter months when irrigation is not permitted. This irrigated pasture land is grazed by cattle to control vegetation growth.

The system is maintained and operated by Phillips and Associates of Napa, California. They are registered with the State Water Resources Control Board as a licensed contract operator, and are certified by the Department of Health Services to provide operations, management and maintenance services. They have been under contract to operate the system since the late 1990's. 

Approved System Operator Contract (PDF)