The Durham Treatment Facility has used cogeneration since 1993, but the 500 kW system was too small and getting old. Serving 250,000 people around Tigard, just south of Portland, Oregon, the 20 mgd plant was flaring excess biogas and the engine wasn’t as clean or efficient as today’s technology.“It was an old rich-burn system with no gas treatment, and we were producing about 30 percent more gas than the engine could use,” says Bruce Cordon, business opportunities manager for Clean Water Services, the regional wastewater management utility. “That’s wasteful.”In its place, the plant opened a 1.7 MW cogeneration system in
