The Heart Of The Valley Metropolitan Sewerage District (HOVMSD), located in Kaukauna, Wisconsin, treats wastewater from five communities with a 6.5 mgd pure oxygen activated sludge Wastewater Treatment Facility. Wastewater treatment was originally provided at the site in the 1930’s for the City of Kaukauna. The plant was modified in the late 1970’s as a regional facility consisting of primary treatment, pure oxygen activated sludge, filtration and anaerobic digestion. The plant was again modified in the mid-1990’s to process a peak flow of 30 mgd using primary effluent filtration during peak flow events. Continued growth in the service area (60% increase in loadings), persistent peak wet weather flows in excess of 50 mgd, and the need to meet an ammonia nitrogen limit of 3.6 mg/l during the summer, precipitated the need for plant modifications.
Use of conventional technology, such as nitrifying activated sludge, was not possible due to limited site space and severe site restrictions, including shallow bedrock and space constraints (paper mill to the south and west of the triangular site, with a canal on the north). A new site was considered, but was cost prohibitive.
Creative application of emerging technology, using high rate treatment and biosolids processing systems, was necessary to expand on site cost effectively. The flow sheet chosen is the first of its kind in the United States. Construction of the new facilities was initiated in January 2006, and will start-up in Spring/Summer 2007.