A new Installation for Road Runoff Treatment; Up-flow Filtration through Porous Polypropylene Media

Usage of a new device applying a sedimentation and an up-flow filtration process to treat the runoff from a roadway surface.

by S. Matsui, B.-C. Lee, S. Kimura, S. Kobayashi, K. Makita

Improvement of water quality in lakes, reservoirs and bay areas is not enough regarding a variety of such as suspended matter, COD, nitrogen, phosphorus, heavy metals and hazardous chemicals including carcinogens, endocrine disruptors, etc. Abatement of such diffuse sources pollutants is needed. Road runoff was Chosen as a target for this study. We installed a new device under a paved street to treat the runoff from a roadway surface. All the storm runoff was Diverted to the system and an amount of approximately 10 mm/hr was thus treated. The runoff above this value was passed to the overflow in the device. The treatment method consisted of a sedimentation and an up-flow filtration process. Treated runoff was discharged into the existing storm drain-pipe. The mean removal efficiency for the initial runoff which was highly polluted was about 90% for suspended matter (SS), about 70% for COD, (about) 40% for total phosphorus (T-P), (about) 80% for Pb and Cd, (about) 70% for Zn, Cu and Mn, and Cr and (about) 60% for major poly-cyclic aromatic hydrocarbons (PAHs). The overall removal efficiencies of the ex-periments run over four months remained above 60% for SS, above 40% for COD, above 60% for heavy metals, and above 40% for PAHs. The treatment media of porous polypropylene is excellent for adsorbing smaller size particles of sus-pended substances. The smaller size particles originate basically from diesel ex-haust, while the larger size particles originate from automobile tires, asphalt roads and other accumulative sources of clay and sand, etc. Maintenance of the device may need replacement of the media once or twice a year depending on local traffic conditions and other factors. This is not so expensive if waste polypropylene is used to make the media.

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published: TU München - Lehrstuhl für Siedlungswasserwirtschaft, 2003 - Regenwasserbewirtschaftung (February 2003), 2|2003
Keywords: Landfilling, Metals