Tacoma, WA Wastewater Treatment Plant

Tacoma’s Central Plant features one of the most technologically advanced treatment processes in the country.  The pure oxygen activated sludge facility averages 22.7 MGD and has a peak of 60 MGD.  The plant’s wet weather treatment utilizes sand-ballasted sedimentation for any flow in excess of the 60 MGD.

The Tacoma facility also has a unique solids treatment train.  The plant has a three-stage sludge treatment process that includes autothermal thermophiic aerobic digestion followed by mesophylic digestion and then termophilic anaerobic digestion.  Every pound of biosolids processed at the plant is recycled and turned into TAGRO gardening products.

The process energy audit identified over $244,000 per year in savings.  The utility only pays $0.35 per kWh.