Geosynthetic Filters for Water Quality Improvement of Urban Stormwater Runoff

A properly designed geotextile can effectively capture suspended solids in highway stormwater runoff through a filtration mechanism while maintaining minimal head loss. Because these solids can often carry hazardous pollutants, their removal lessens the deleterious impact of stormwater runoff on aquatic ecosystems. In this study, a geotextile was tested in the laboratory with influent suspensions having a hydraulic loading rate, total suspended solid (TSS) concentration, and particle size distributions similar to those reported for urban highway stormwater runoff. Preliminary results indicate that after a short priming period, a geotextile with an apparent opening size of 150 μm can effectively remove suspended solids to a target concentration of 30 mg/L, a common point discharge water quality target value. The results also showed that the change in hydraulic conductivity of the geotextile filter system can be related to suspended solids captured via a power function, which may be useful to predict the flow rate through the filter during its lifespan.