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AN EVALUATION OF STORM DRAINAGE INLET DEVICES FOR STORMWATER QUALITY TREATMENT
Citation:
Pitt, R. AND R Field*. AN EVALUATION OF STORM DRAINAGE INLET DEVICES FOR STORMWATER QUALITY TREATMENT. In Proceedings, Proceedings of Water Environment Federation's WEFEC '98 Conference, Orlando, FL, October 03 - 07, 1998. Water Environment Federation, Alexandria, VA, ,, (1998).
Impact/Purpose:
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Description:
The activities summarized in this paper included the testing of three representative stormwater control devices that were located at storm drainage inlets. The two proprietary devices utilized screening and filtering (using filter fabric and a coarser mesh). A conventional catchbasin inlet, having a sump, was also tested for comparison. These devices were monitored in Stafford Township,NJ, to evaluate their removal effectiveness for stormwater pollutants. Twelve paired samples collected at each device represented composite inflow and outflow stormwater. The samples were split into filtered and unfiltered components for extensive analyses of conventional and toxic pollutants. The experimental design was capable of identifying significant pollutant removals of a least 15 to 50% at a 95% confidence level, depending on the pollutant. The only significant pollutant removals were found during tests of a conventional catchbasin having a suitable sump. The median removal rates were about 30% for suspended solids, about 40% for turbidity, about 15% for color, and about 20% for total solids. No other pollutants were found to be significantly reduced. However, the coarse screened inlet device was found to significantly reduce the discharges of trash and other large debris. Unfortunately, flows passing through trapped material caught on the screen had increased concentrations of suspended solids and volatile solids, probably due to washing of decomposing large organic material through the screen. The filter fabrics tested in the laboratory showed about 50% removals for suspended solids and COD, but they rapidly clogged, significantly shortening their run times and minimizing any benefit from their use. This research was conducted in partial fulfillment of cooperative agreement no. CR 819573 under the sponsorship of the U.S. Environmental Protection Agency.
