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TREATMENT BY FILTRATION OF STORMWATER RUNOFF PRIOR TO GROUNDWATER RECHARGE
Citation:
Clark, S. E., R. Pitt, P. Brown, AND R Field*. TREATMENT BY FILTRATION OF STORMWATER RUNOFF PRIOR TO GROUNDWATER RECHARGE. Chapter , Proceedings of the Water Environment Federation's 71st Annual Conference & Exposition. Water Environment Federation, Alexandria, VA, ( ): , (1998).
Impact/Purpose:
Information
Description:
Generally, dry ponds, trenches and swales do not have the same pollutant removal capacity as wet detention ponds. Their pollutant removal ability results from the straining of particulate matter out of the water. However, infiltration ceases when the bottom of the pond, trench or swale becomes clogged. Dissolved pollutant removal ceases when the soil sorption/ion exchange capacity is exceeded. Adding a proven sorption/ion exchange filter with scheduled maintenance to these dry infiltration devices will improve their ability to not only remove water but also the colloidal and dissolved pollutants. Gravity filtration will work on intermittent flows without significant loss of capability, and the filters do not require a large surface area. These dry devices. therefore, may be easier to retrofit into urban areas than other stormwater treatment devices, since many can be installed below ground. This research tested the capabilities of several potential filtration media - sand, activated carbon, peat moss, compost, zeolite, cotton textile waste, and agrofiber - in both laboratory and field conditions for pollutant removal from both in the particulate and dissolved fractions. Since physical clogging was a problem (physical clogging occurred long before chemical breakthrough), it is recommended that filters be preceded by settling.