Stormwater Treatment Field Demonstration and Evaluation

Pollution reduction in the Conasauga River is a high priority for Georgia due to the remaining biological diversity of the Conasauga. Home to 76 native species of fish, more than the Columbia and Colorado Rivers combined, the Conasauga serves residential, agricultural, and carpet industry needs in and around Dalton. Segments of the river are impaired due to sediment, nutrients, and fecal coliform bacteria from septic systems, agriculture, and stormwater runoff. As new stormwater regulations go into effect for Phase II communities, many agencies are asking for field performance data. A demonstration project was implemented in 2004 to reduce stormwater pollution by first using a hydrodynamic swirl separator and later by a mobile filter system, both manufactured by AquaShield, Inc. The swirl system was installed at the 5-acre Whitfield County Public Works (WCPW) facility yard located within a 30-acre watershed. Automatic flow samplers collected runoff at the swirl separator during four storm events for analysis of oils and grease (O&G) and total suspended solids (TSS). The swirl separator captured 2 to 3 inches of sediment per month from the site. Field testing for an AquaShield mobile filtration treatment system was also performed at the WCPW site. Grab samples collected during simulated storm events were analyzed for TSS and particle size distribution. The TSS removal efficiencies of the filtration system were greater than 90 percent. Success of this demonstration is measured by field observations of sediment captured by the swirl and by the high removal efficiencies of the filter system.