Aerated Rock Filters for Enhanced Ammonia and Fecal Coliform Removal from Facultative Pond Effluents |
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Authors: | D Duncan Mara Michelle L Johnson |
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Affiliation: | 1School of Civil Engineering, Univ. of Leeds, Leeds LS2 9JT, England (corresponding author). E-mail: d.d.mara@leeds.ac.uk 2School of Civil Engineering, Univ. of Leeds, Leeds LS2 9JT, England.
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Abstract: | Rock filters used to treat effluents from waste stabilization ponds do not remove ammonia as they are anoxic. A pilot-scale aerated rock filter was investigated, in parallel with an unaerated control, over an 18-month period to determine whether aeration provided conditions within the rock filter for nitrification to occur. Facultative pond effluent containing ~ 10?mg NH4–N/L was applied to the filters at a hydraulic loading rate of 0.15?m3/m3?day during the first 8?months and at 0.3?m3/m3?day thereafter. The results show that the ammonia and nitrate concentrations in the effluent from the aerated filter were <3 and ~ 5?mg?N/L, respectively, whereas the ammonia concentration in the effluent from the control filter was ~ 7?mg?N/L. Fecal coliforms were reduced in the aerated filter to a geometric mean count of 65?per?100?mL; in contrast the effluent from the control filter contained 103–104 fecal coliforms per 100?mL. Aerated rock filters are thus a useful land-saving alternative to aerobic maturation ponds. |
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Keywords: | Aeration Ammonia Bacteria Effluents Filters Rocks Waste stabilization ponds Abatement and removal |
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