Chitosan-coated Sorbents for In Situ Treatment of Nonpoint Source Contaminants in Urban Runoff

Urban runoff is becoming an increasingly daunting environmental issue, plaguing nations around the world. Water bodies surrounding urban areas have seen an increase in water quality degradation from pollutants such as, heavy metals (Fe, Pb, Cd, etc.) and nitrates. While Best Management Practices (BMPs) are being implemented to reduce the pollutant load to urban water bodies, efficiently treating pollutants in urban runoff remains a challenge. In this study, we aim to develop an in situ treatment scheme using chitosan as a sorbent for heavy metals and nitrates. Chitosan hydrogel beads cross-linked with alginate and chitosan-coated inert grains have been developed. While column test data indicated high sorption capacity for the chitosan beads and chitosan-coated media, the need for development of a chitosan-coated porous media was identified. Chitosan-coated multi-porous media that can provide a treatment option for pollutants in short-term, high-flows in urban storm runoff will provide an alternative to BMPs that will effectively remove heavy metal and nitrate contaminants.