An Evaluation of Pathogen Removal in Stormwater Best Management Practices in Charlotte and Wilmington, North Carolina

Abstract

Pathogens are a target pollutant in many parts of North Carolina, particularly in areas that drain to shellfish waters. Standards have been established for pathogen indicators in fresh water (200 cfu/ 100 ml for fecal coliform, 126 col/100 ml for E. coli, and 33 cfu/100 ml for enterrococcus) and marine waters (35 cfu/100 ml for enterrococcus) being used as full body recreational areas in an attempt to reduce public health risks. Runoff samples collected from urbanized watersheds often are high in pathogenic indicator bacteria, leading to the need for treatment (Bright, 2007; MOAWMS, 2003; Schoonover and Lockacy, 2006). However, there is little peer reviewed literature regarding stormwater Best Management Practice (BMP) treatment of pathogens. The NCSU Biological and Agricultural Engineering Department monitored 14 stormwater BMPs, 9 in Charlotte, NC, and 5 in Wilmington, NC, to evaluate their efficiency with respect to indicator bacteria removal. The study locations included 2 bioretention areas, 4 stormwater wetlands, 3 wet ponds, 2 dry detention, and 3 proprietary BMPs.