Assessment of HRT’s Impact on COD Reduction of Leachate Through Lab-Scale UASB Reactor

In this work, the performance of the UASB reactor for treating leachate was evaluated to determine the parameters of anaerobic digestion enhancement at various hydraulic retention times (HRTs). A one-stage laboratory scale Upflow Anaerobic Sludge Blanket (UASB) reactor was used to treat partially stabilized landfill leachate samples taken from the sanitary landfill site of Lamdeng Khunou Solid Waste Management Plant in Imphal, Manipur, India. The reactor ran continuously for 105 days. The study focused on leachate treatment at varied hydraulic retention times (HRTs) of 16, 24, and 48 h at room temperature with an upflow velocity of 0.1 m/h. It was found that 48 h HRT was the optimal HRT among the other two taken and could treat the leachate effectively. This work investigated the removal efficiencies of chloride content, dissolved solids, and COD; it also examined the production of volatile fatty acids (VFAs) and determined the concentration of the constituent of biogas as a by-product, which is a combustible mixture of methane, carbon monoxide, hydrogen gases, etc. The concentration of volatile fatty acids was reduced from 325 to 25 mg/L. Biogas production was measured continuously using gas chromatography, yielding 925 ± 25 mL