| Abstract |
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The objective was to investigate the effect of heavy metals, antibiotic and diesel oil at low concentrations in an Upflow Anaerobic Sludge Blanket (UASB) reactor performance under continuous conditions and also evaluate metals geochemical distribution in anaerobic sludge analyzed by sequential extraction method. A lab scale UASB reactor was inoculated with prepared sludge (Cow dung + specialized Consortia developed from municipal wastewater) and allowed to acclimate during 2 months. After acclimation period, three different concentrations of five heavy metals, diesel oil and antibiotic(gentamicin) having equal ratio as well as found in municipal wastewater (Zn: 1.82, 3.64 & 7.28 mg/l; Pb: 0.44, 0.88 & 1.76 mg/l; Cu: 0.30, 0.60 & 1.20 mg/l; Cd: 0.18, 0.36 & 0.72; Cr: 0.06, 0.12 & 0.24 mg/l; Diesel oil: 12.44, 24.88 & 49.79mg/l; Gentamicin: 16, 32 & 64µl/l) in order to analyze the performance of an UASB reactor treating municipal wastewater with low metals, diesel oil and antibiotic concentrations during one month for each one. The result of sequential extractions showed that the major affinity with heavy metals found organic/sulfide bound, with 96% percentage distribution. Reactor performance affected through augments caused a total alkalinity diminution in the effluent; while the system buffer capacity was sufficient to overcome such instability, as the ratio of partial alkalinity/total alkalinity confirmed. Removal of COD decreased up to 15% when higher doses were added in comparison to acclimation period. Addition of lower doses in reactor influent affected adversely its performance; although, did not cause entire inhibition to anaerobic microbes. |
