Stevens Point, Wisconsin
2016 ACEC Wisconsin State Finalist Award
Donohue & Associates and the City of Stevens Point received an Engineering Excellence State Finalist Award for the “Brewing a Better Future Together” project from the American Council of Engineering Companies (ACEC) of Wisconsin.
The Stevens Point wastewater treatment plant set the goal of achieving net-zero energy use and reducing operating costs and increasing efficiency.
The City worked collaboratively with Donohue on a two-phase project to implement new energy efficiency and energy production systems. Phase 1 of the project included a low-energy digester mixing system, low-energy pumping, and a biogas-driven engine generator. These improvements allowed the City to realize significant energy savings, to the point where it became routine to push excess power onto the grid.
Increased loadings from a local brewery were causing inefficient treatment. Phase 2 of the project entailed a new system for diverting high-strength waste from the brewery to the treatment plant and utilizing excess capacity in the anaerobic digester to accept additional high-strength waste from other sources such as regional grease and food wastes.
A simple, yet specialized waste separation and handling system was constructed at the brewery. The revised system stabilizes the loading to the treatment plant and increased system efficiency and biogas production.
The project is saving the City $150,000 per year and has reduced the potential cost to the brewery by $150,000 per year. It also restores excess wastewater treatment capacity for future growth.