The Gresham Wastewater Treatment Plant (WWTP) is a basic secondary activated sludge facility that receives an average of 13 million gallons per day of wastewater.
For decades, efforts were made to control excessive power use. Finally, they refocused their efforts on reducing power by increasing biogas production. Their primary goal was to reach “energy net zero,” generating the same amount of energy they use to operate.
The installation of a new Cat® G3508 gas genset led to more power output, allowing the facility to operate independent of power from the utility grid.
On schedule and budget, The Gresham WWTP reached energy net zero, generating more electrical energy on site from renewable biogas cogeneration and solar power than it consumed. This was made possible by the high uptime of the Cat gensets. Over the last four years, Gresham’s cogeneration plant has averaged about 95 percent uptime.
“One of the big reasons why we have a successful program here is because of the relationship we have with our local Cat dealer, Peterson Power Systems,” says Alan Johnston, senior engineer with the City of Gresham Wastewater Treatment Plant.
“Anytime we have issues with the engines, we call them, and we have a guaranteed 24-hour interval for their technicians to come out here to fix the problem.”