The Beaver Dam (Wisconsin) Wastewater Treatment Plant is an extended aeration facility. Its activated sludge process allows the wastewater to spend 24 hours in aeration under average flows.It takes a lot of air to operate that kind of plant, so saving energy on blowers has a big impact, says Rob Minnema, director of utilities for Beaver Dam, population 16,000, in southeastern Wisconsin. So, when an opportunity arose to upgrade the plant’s blowers at a subsidized price, he jumped on it.Minnema was faced with overhauling or replacing the 150 hp blowers installed in 1985 at the plant (5.5 mgd design, 4
