1. Nutrient and Sediment Reduction through Upflow Filtration of Stormwater Retention Pond Effluent.
- Author
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Winston, Ryan J., Hunt, William F., and Pluer, William T.
- Subjects
STORM water retention basins ,SEWAGE lagoons ,RETROFITTING of sewage disposal plants ,WATER filters ,SEDIMENTS - Abstract
Wet ponds have often been installed to detain runoff with the intention of mitigating peak flow. However, significant current drivers exist to improve their ability to mitigate pollutants, and simple retrofits to existing ponds could help to meet total maximum daily load regulations. A review of past studies showed that ponds struggle to treat dissolved pollutants, which are often the most bioavailable. The present study evaluated the nutrient and sediment treatment performance of a retrofitted upflow filter (UF) attached to the drawdown orifice of an existing wet retention pond in Durham, North Carolina. The pond was studied during three periods: (1) control, where baseline pond performance was established; (2) after retrofit with floating treatment wetlands (FTWs); and (3) after retrofit with FTWs and an UF on the pond's drawdown orifice. The added UF was unable to improve the pond's retention of nitrogen. Further reduction of the TSS effluent concentrations by the UF may have been hampered by the low effluent concentrations during the FTW period (13 mg=L); however, the variability of TSS effluent concentrations was substantially reduced following UF retrofit. The UF significantly reduced mean effluent concentrations of orthophosphate (OP) to less than 0.01 mg=L. Effluent concentrations of OP and total phosphorus from the UF were similar to those from bioretention systems. Clogging of the filter media occurred in intervals of 5 to 9 months prior to breakthrough of OP. Future designs of UFs should incorporate microscale pretreatment and/or filter media cartridges that (1) are easy to remove and (2) provide a method to flush accumulated sediment from the media. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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