Electrocoagulation-enhanced pretreatment for efficient operation of packed bed anaerobic filter treating leachate:...

A study was carried out on the sequential treatment of young high-strength landfill leachate using an aluminium electrode in a batch electrochemical cell reactor as a pretreatment, followed by a packed-bed upflow anaerobic filter (PBUAF) as a treatment method. Two landfill-simulating reactors, made of iron sheets having sizes of 1 m × 1 m × 1.1 m (Length × Width × Height), were operated under varying hydrological conditions where one was operated without rain (S1) and another with simulated rain (S2). The reactors were loaded with 450 kg of municipal solid waste, comprised of 51 % wet and 49 % dry fractions, typical of Indian waste. Electrocoagulation was performed as a pretreatment process with aluminium electrodes for 10 min, and it achieved 40-50 % removal efficiency, which preconditioned the leachate to be treated further by biological means. The pretreated leachate, supplemented with de-oiled rice bran (DORB), was introduced to the PBUAF. The PBUAF was able to achieve substantial pollutant removal, attaining 93.9 % of Chemical Oxygen Demand (COD), 97.46 % of Total Organic Carbon (TOC), and 94.24 % of Total Kjeldahl Nitrogen (TKN), in addition to other recalcitrant pollutants at an optimized organic loading rate (OLR) of 5.107 g COD/L/day and a hydraulic retention time of 8 days. Kinetic analysis indicated that the Stover-Kincannon and Monod models were highly consistent with experimental data. The Electrocoagulation-PBUAF hybrid system effectively removed persistent organic pollutants, including naphthalene, phenols, benzene derivatives, halogenated compounds, alcohols, and phthalates, demonstrating its capacity to treat both prevalent and resistant pollutants efficiently.