Effects of Runoff Characteristics and Filter Type on Geotextile Storm Water Treatment

Urban storm water runoff carries particulate matter and other pollutants to water bodies, causing environmental problems. Removing suspended solids from runoff through geotextile filtration is a storm water control measure currently under investigation, which could help lessen the negative impacts of storm water on aquatic ecosystems. In this study, three geotextiles were tested in a laboratory setup with influent suspensions having hydraulic loading rates, total suspended solids (TSS) concentration, and particle-size distributions similar to those reported for urban highway storm water runoff. The results indicated that after a short priming period, all three geotextiles can effectively remove suspended solids to below a target concentration of 30mg/L. The results also showed that influent hydraulic loading rate and TSS concentration have minimal effects on the total mass of solids captured by the filter, whereas particle-size distribution does affect the total mass of solids captured by the filters. The retention criteria for choosing the appropriate geotextile for storm water treatment established in recent literature were evaluated by using the laboratory results. The geotextiles and sand filters were directly compared by using the results of the laboratory column testing of sand filters performed for this study. The results indicate that a geotextile will outlast a sand filter in terms of total solids loading under similar conditions.