Nutrient enrichment is a leading cause of water quality impairment in the waters of the United States, and wastewater inputs are a significant source of phosphorus pollution in aquatic ecosystems. Although there has been considerable focus on reduction of P in effluent from public wastewater treatment plants in the U.S., the environmental impacts of onsite wastewater treatment systems have received much less attention. A  growing body of research suggests that conventional onsite systems relying on septic tanks and soil absorption systems for P removal do not always prevent impairment of surface waters.

Understanding and managing sources of phosphorus pollution in the landscape necessitates evaluating and minimizing the P contribution from onsite systems to surface waters. The project team will report on phosphorus removal technologies that have been proposed and/or tested for use in decentralized wastewater treatment. The report will include information about the application, performance, cost-effectiveness, and other factors associated with each technology. In keeping with the "soft path" approach to wastewater treatment, we will examine a range of phosphorus-removal technologies, including source reduction, source separation, septic tank treatment, secondary treatment technologies, and soil aborption system design. The alternatives selected will be evaluated with a set of criteria including removal capability, cost, system robustness, secondary benefits, maintenance requirements, and costs.

A list of prioritized research needs will be developed based on review of work conducted since the review by Gold and Sims (2000) as well as earlier literature not considered by the authors, and an integrated list including the needs identified by Gold and Sims will be produced. Carl Etnier of Stone Environmental, Inc. will be the project manager of a team including nationally and internationally recognized experts in phosphorus removal and in onsite wastewater treatment technologies.