An Evaluation of Aerated Lagoon Treatment for Combined Domestic Sewage and Pulp Mill Wastes

Historically, aerated lagoons were first used to overcome the overloading and odor problems associated with waste stabilization ponds. Today they are accepted as an economical and effective method of treatment for a wide variety of domestic and industrial wastes. The use of aerated lagoons for the treatment of wastes is a biological process. In order to optimize effective removal rates, the requirements for biological metabolism must be adhered to. These requirements for biological metabolism must be adhered to. These requirements not only include the presence of an aerobic environment but also the proper balance of essential nutrients such as nitrogen and phosphorus in addition to maintaining the desired range of pH. In December of 1970, Donohue and Associates, an engineering consulting firm in Sheboygan, Wisconsin prepared a treatment plant feasibility study to determine an economical means by which a Wisconsin community of 3500 people with a sulfite pulp and paper mill could comply with Wisconsin Department of Natural Resources orders to singularly or collectively achieve a 90% removal of biochemical oxygen demand and total dissolved solids. The city was operating a trickling filter sewage treatment plant which was not achieving the required removal rates due to hydraulic overload conditions. The pulp mill wastes were being discharged, untreated, directly into a nearby river. This study concluded that the most feasible method for meeting State pollution orders would be for the community and industry to work together in jointly solving their problems. It was further concluded that the use of an aerated lagoon treatment system would be the most economical method by which to achieve the required removal rates. While plans for the design of such a system were being developed, this research study was undertaken to evaluate the effectiveness of such a treatment system under both winter and summer operating conditions