Permeable Reactive Filter Systems for the Treatment of Urban Stormwater Runoff with Mixed Pollutants

摘要

This study investigated a new and practical approach to remediate urban stormwater runoff contaminated by mixed pollutants. The study consisted of evaluation of different permeable filter medium in terms of the removal efficiencies when addressing typical urban mixed pollutants; and development of a feasible design and recommendations for an effective in-ground filtration system. Mixed pollution indicators used to assess stormwater quality included: heavy metals (As, Cr, Cd, Cu, Ni, Pb, and Zn), nutrients (nitrates and phosphates), polycyclic aromatic hydrocarbons (PAHs) (naphthalene, phenanthrene and benzo(a)pyrene) and bacterial contamination {E. coli abundances), all of which are contaminants commonly found in urban stormwater runoff. To determine removal efficiencies of targeted contaminants in different permeable medium, synthetic stormwater (SS W) representative of urban stormwater runoff was applied to packed columns with different permeable filter medium, and the contaminant concentrations in the resulting effluents were analyzed. Batch tests were also conducted to determine the maximum removal efficiency of each filter medium. Based on the batch and column studies, it was found that a mixed media, consisting of calcite, zeolite, iron filings and sand was effective with high removal efficiencies for nutrients, TSS, E. coli, heavy metals and PAHs. Large-scale laboratory test and field pilot-scale demonstrations were conducted to evaluate the performance of this permeable mixed media filter system.