Nitrogen mass balance and microbial analysis of constructed wetlands treating municipal landfill leachate.
Experiments were conducted to investigate the feasibility of applying constructed wetlands (CW) to treat a sanitary landfill leachate containing high nitrogen (TN) and bacterial contents. Under the tropical conditions (temperature of about 30 degres C), the CW units operating at a hydraulic retention time (HRT) of 8 days yielded the best treatment efficiencies with BOD5 removal of 91%, TN removal of 96%, total and fecal coliforms (TC and FC) removal of more than 99%. Cadmium removal in the in the SFCW bed was found to be 99.7%. Mass balance analysis, based on TN contents of the plant biomass and dissolved oxygen (DO) and oxidation - reduction potential (ORP) values, suggested that 88% of the input TN were uptaken by the plant biomass. Fluorescence in situ hybridization (FISH) results revealed the predominance of bacteria including the heterotrophic and autotrophic bacteria responsible for BOD5 removal. Nitrifying bacteria was not found to be present in the SSFCW beds.
Polprasert
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School of Environment, Resources and Development, Asian Institute of Technology (AIT), P.O. Box 4, Klong Luang, Pathumthani 12120, Thailand. Chongrak@ait.ac.th
Sawaittayothin
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D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification; D002947:Cities / Q000706:statistics & numerical data*; D005243:Feces / Q000382:microbiology; D006723:Hong Kong; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D009584:Nitrogen / Q000032:analysis*; D010865:Pilot Projects; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000032:analysis*
D014874:Water Pollutants, Chemical; D009584:Nitrogen