Effectiveness of Compost Biofilters in Removal of Sediments from Construction Site Runoff

Abstract

Abstract The effectiveness of compost biofilters in removal of suspended sediments from stormwater runoff was evaluated. Field experiments were conducted in the summer of 2006 at the Guelph Turf Grass Institute, University of Guelph, to verify the sediment removal efficiency of the compost biofilter from synthetic stormwater runoff. The average sediment removal efficiency of 8-inch (20-cm) compost biofilters (socks) for 5, 10, and 15 rolls were 34, 48, and 60%, respectively. The average sediment removal efficiency for 18-inch (45-cm) socks for 5, 10, and 15 rolls were 69, 84, and 95%, respectively. The decrease in sediment removal efficiency of the biofilter over time was significant. The average sediment removal efficiency of 5 rolls of the 18-inch (45-cm) sock started to decrease gradually from 70 to 62, 58, 56, and 54% after 1, 5, 10, 15, and 20 consecutive runs. Sediment removal efficiency of the biofilter for sediment particles in the size range of clay was found to be 30%, while for coarser particles such as fine silt and coarse silt was 50 and 80% removal efficiencies, respectively.