CONSIDERATIONS IN THE DESIGN OF TREATMENT BEST MANAGEMENT PRACTICES (BMPs) TO IMPROVE WATER QUALITY

For the past three decades, municipalities in the United States have successfully addressed pollution in the watershed by collecting and treating their wastewater. Currently, all municipalities provide secondary level treatment, and in some cases tertiary treatment, and industries provide best available/best practicable treatment. More rivers are meeting water quality standards, and the public health is being protected from waterborne disease. The challenge now is to address pollution associated with storm water runoff, the last major threat to water quality.Today, many municipalities are implementing low-cost best management practices (BMPs) to address stormwater pollution. The lowest cost BMPs, often termed non-structural or source control BMPs, include practices such as retaining rainwater on residential lots (currently termed Alow impact development@). There are a set of higher cost BMPs, which involve building a structure of some kind to store stormwater until it can be discharged into a nearby receiving water. These structural BMPs can also provide a level of pollutant removal.This paper presents factors that should be considered in the design of treatment BMPs to improve water quality. The state-of-the-practice is such that existing design guides vary and the performance of treatment BMPs to remove pollutants ranges widely.