In an effort to gain maximum engine performance and stay within the local exhaust emission limits over a wide range of engine load and ambient conditions, operators at the County Sanitation Districts of Los Angeles County’s Joint Water Pollution Control Plant wastewater treatment plant near downtown Los Angeles have installed Continental Controls Corp. ECV5 air/fuel ratio control valves on five gas-fueled engines in an effluent pump station. The engines were installed during a facility upgrade to comply with an EPA-mandated expansion of the facility’s secondary treatment process to increase flow.
The additional pumping capacity and expanded secondary treatment process allows the facility to treat 100% of the wastewater that flows into it with both the primary and secondary treatment process. Before the upgrade, only 60 to 65% of the flow went through both primary and secondary treatment processes before discharge. The remaining 35 to 40% completed only the primary treatment process. The upgrade has not changed the overall plant capacity; average flow is still about 325 million gallons per day (mgd).
The engine-driven pumps transfer effluent from the primary treatment facility to the secondary treatment process. During the transfer, the effluent overcomes an elevation gain of approximately 25 ft. from the end of the primary process to the head end of the secondary process.