The Pinole/Hercules Wastewater Treatment Plant is located at the foot of Tennent Avenue in the City of Pinole.
It was originally built in 1955 as a primary treatment facility. Since then, it has had two major expansions and several modifications in order to meet the needs of these cities' growing populations.
In 1972 the plant was upgraded from a primary to a secondary treatment facility, with a 2 MGD (million gallons per day) flow capacity. In 1985, the plant was again upgraded to handle a flow of 4.06 MGD. The plant serves a combined population of approximately 40,000, with an average daily flow of 3.5 million gallons.
The plant process (activated sludge) removes approximately 97% of the waste from the water. The water is then disinfected with hypochlorite. Once the disinfection process is complete, the hypochlorite is then removed and the water is pumped into the deep waters of San Pablo Bay.
All operators are certified by the state, grade levels vary from 1 through 5. Some plant personnel also hold certificates in maintenance and laboratory analysis.