Originally built in the 1960s, the Encina Water Pollution Control Facility (EWPCF) treats municipal wastewater in northwestern San Diego County. As the population of San Diego County continues to grow, the facility requires performance and reliability improvements so it can continue to meet the region’s wastewater treatment needs.

The improvements project will provide upgrades to the process equipment and rehabilitation of the digester systems for EWPCF. The project consists of structural and coating upgrades, installation of a new mixing system, new heat exchangers and equipment, a digester transfer and drawdown pump, and extension of piping from the existing alternative fuels receiving facility to a digester.

The project includes rehabilitation of the digester area drainage pit, installation of a new waste gas flare, replacement of a motor control center, replacement of power and control conduit and wiring to the digester and gas management systems, replacement and addition of instrumentation and actuation for improved automation of digester operation, and migration of digester and gas management systems to the new supervisory control and data acquisition (SCADA) platform.

The improvements project will provide robust upgrades and prolong the life of three anerobic digesters currently in service at EWPCF that provide critical biosolid treatment in the wastewater treatment process and help produce biogas, a valuable renewable resource. The biogas feeds low-emission engines located within EWPCF’s cogeneration facility. The engines are capable of producing 750 kilowatts of electricity; that combined with the thermal energy generated by the process offsets EWPCF’s electricity usage by over 80%. With the addition of the new low-emission waste gas flare, there is an increased capacity to convert access biogas produced from the digesters to clean emissions. This innovative system allows ECWA to reduce energy usage and costs.