PHOSPHORUS TREATMENT - ADVANCED REMOVAL MECHANISMS AND AMENDED DESIGN FOR STORMWATER BMPS

It has been well-documented that continued land development through urbanization is deteriorating surface water quality. One significant concern with our limited global fresh water resources is the onset of toxic algae blooms and reduced dissolved oxygen due to continued, uncontrolled phosphorus loading. This is leading to negative ecologic, economic, and human health impacts. As a result, regulators are beginning to acknowledge the impairment of fresh water bodies, and have begun implementation of Total Maximum Daily Loads (TMDLs). However, applying phosphorus related TMDLs specifically to stormwater runoff may not be effective without first understanding the available mechanisms and limitations involved in phosphorus treatment for stormwater applications. To understand how to achieve continued, high levels of permanent phosphorus removal, this paper reviews the transport and fate of Total Phosphorus, including both particulate- bound and dissolved phosphorus, in urban stormwater runoff. The advantages and disadvantages of removal mechanisms employed in both conventional Best Management Practices (BMPs) and newer Low Impact Development (LID) applications are discussed. Advances in phosphorus treatment technology have recently become available, providing the ability to capture high levels of both particulate-bound and dissolved phosphorus. Understanding the functional removal mechanisms and how to sustain high treatment levels are critical to protecting our water bodies. Amending both conventional BMPs and LID applications with new advanced phosphorus treatment provides a solution to achieve existing and future TMDLs. These concepts and amendments are discussed as a potential means to raise the performance bar for phosphorus treatment and implement practices that protect our fresh water resources.