You are here:
USE OF NATURAL FILTER MEDIA FOR STORMWATER TREATMENT
Citation:
Wojtenko**, I, A. Ray, AND R Field*. USE OF NATURAL FILTER MEDIA FOR STORMWATER TREATMENT. Presented at ASCE World Water & Env Resources Congress, Orlando, Fl, 5/20-24/2001.
Description:
The overall objective of this study ws to evaluate the feasibility of low-cost and readily available natural filter material for stormwater treatment. Previous research indicates that urban SW contributes a significant amount of contamination (including heavy metals and PAHs) to surface and ground waters. In addition, various materials (e.g., sand, peat moss, and compost) have been investigated and have proven to be feasible for pollutant removal from SW runoff. During this study, generic mulch, pine-bark mulch, and processed jute were evaluated for metal and organic pollutant removal from actual SW samples collected from a "hot spot" area in NJ. The retention and release behavior of various concentrations of copper and benzo(a)pyrene in different filter materials were evaluated using a specially constructed bench-scale filtration apparatus which allowed for the simultaneous testing of up to ten different media conditions. The flow through the individual columns as well as the sorption capacity of each filter media were studied under a wide variety of conditions. Previous investigations suggest that the amount of surface area within the filter media available for contact with the SW is directly proportional to the removal efficiency. In this study, the surface area was increased by breaking up the jute and the mulch into significantly smaller pieces. Tests were performed initially to evaluate the basic performance of the reduced media size without the addition of sand. In addition, the benefits of combining the smaller particle size filter materials with sand (in ratios of 0.25, 0.50, and 0.75) to improve the hydraulic properties, removal ability, and cumulative capacity of the filter for a specific pollutant were evaluated. The effectiveness of the filtration process was found to be dependent upon the SW quality and the physical characteristics of the filter media. No "desorption" of pollutants from the media was observed after column flushing with distilled water. Results, described in detail in this paper, indicate that both mulch and jute appear to be feasible filter materials for copper and benzo(a)pyrene removal from urban SW. Further investigations are necessary to evaluate their practicality in field applications.