Donohue & Associates and the City of Appleton collaborated on an award-winning biogas system design at the Appleton Wastewater Treatment Plant. The project received a 2022 ACEC WI Best of State Engineering Excellence Award.

The plant serves over 75,000 residents and area businesses as it treats over five billion gallons of wastewater annually. Two 2-million-gallon egg-shaped anaerobic digesters biologically break down wastewater solids, generating biogas. The biogas energy component (methane) is sustainably reused in place of natural gas for heating, saving the plant $100,000 annually.

The new system delivers a consistent high-quality biogas product to the plant’s boilers while meeting the client’s environmental sustainability goals. The project team successfully addressed many project complexities. They include variable high strength waste volume and makeup, full heating capacity requirements of the anaerobic digesters, strict construction constraints to not impact existing operations, existing heating system inefficiencies, and limited gas storage.

The project’s short payback and the City’s desire for a more sustainable and efficient plant made this project a win for ratepayers, plant operations, and the environment.

Awards judge Tom Buchholz remarked, “Donohue designed a new 5.5 million BTU biogas boiler, biogas compression system to feed the three boilers, controls, stainless steel piping, and re-configured the biogas storage vessel piping for a flow-through design. This is the first time this technology has been used in Wisconsin and came in 12 percent under budget. Nice job.”

Engineering Excellence awards recognize quality engineering achievements. Entries are judged on the basis of excellence in design, the degree to which the client’s needs are met, as well as benefit to the public welfare and to engineering practices. Learn more at https://www.acecwi.org/news/new-biogas-boiler-more-than-a-boilerplate-solution