In late 2014, design for increasing the treatment plant’s digestion capacity began. Digesters receive organic waste to then be reduced and stabilized, while generating a biogas that is recovered for beneficial use as heat and power generation. The project built or replaced many of the digestion and biogas elements. Some examples are a fourth 1.1 million gallon digester, biogas piping, heating water system (boiler, heat exchangers, pumps), dual waste gas flares, a digester cleaning station, and measures to receive fats, oils, and grease (FOG) in the future.
The construction phase of the project had to overcome two major challenges. The first was to keep the three existing digesters, heating system, and gas system online and meeting permit limits while accommodating outages to connect and commission the new systems. This project was challenging because two other major construction projects were happening while this project was underway. Second, the process control system hardware and programming were upgraded. This added an extra layer of complexity during startup. After four and a half years, $15 million, and a lot of work by staff, all new systems came online and are now operational!