The Portage Lake wastewater treatment plant was designed to treat a flow of 3.1 MGD, current average daily flow is 2.2 MGD, while serving a population of nearly 14,000 in the communities of Houghton, Hancock and parts of Portage, Franklin and Quincy Townships. Almost all of the flow comes from domestic and commercial sources. The plant does an outstanding job of pollutant removal consistently removing 98% of the biochemical oxygen demand and suspended solids, and more than 95% of the phosphorus from the incoming wastewater. Major treatment processes include preliminary treatment, primary clarification, phosphorus removal, biological treatment utilizing the activated sludge process, final clarification, and ultraviolet disinfection prior to discharge to Portage Lake, a part of the Keweenaw Waterway, which flows into Lake Superior at Keweenaw Bay. Residuals are anaerobically digested, dewatered by belt filter presses and applied, as biosolids, to area farm fields and the Mason Sands mine tailings area in Mason, MI as a soil amendment and to help promote vegetation growth.