Stormwater runoff is a major source of toxic metal and nutrient pollution in the Puget Sound. To counteract this, Washington State has begun utilizing bioretention systems to treat stormwater and prevent pollutants from reaching major bodies of water.
Generally, in these systems, traditional compost used is able to filter toxic metals out. However, as traditional compost decomposes, it adds nutrient pollution to stormwater. Researchers Zhenqing Shi, James Harsh, and Markus Flury are investigating the use of iron-enhanced compost as a more efficient alternative to traditional compost in bioretention systems.
Iron-enhanced compost potentially has a higher capacity to retain two common storm water pollutants, lead and phosphorous. After they evaluate the efficiency, stability, and longevity of iron-enhanced compost, the team will begin building models to predict stormwater runoff quality and to learn where the nutrient pollutants end up after sorption into the bioretention system.