Characterization and treatment of landfill leachate membrane concentrate by Fe 2+ /NaClO combined with advanced oxidation processes

摘要

Landfill leachate membrane concentrate (LLMC) is a type of non-biodegradable wastewater intercepted by the membrane filtration of the landfill leachate membrane bioreactor (MBR) effluent. The concentrations of chemical oxygen demand (COD) and ammonia nitrogen (NH₄+-N) in the LLMC collected from a landfill in Beijing were determined to be 4700?mg/L and 487?mg/L, 2–5 times higher than those in the MBR effluent. The photoelectro oxidation (PEO) followed with the NaClO enhanced Fe2+ coagulation were more effective for the removal of COD than the Fenton oxidation followed with the enhanced coagulation. The final removal efficiencies of COD, UV₂₅₄, NH₄+-N and color degree were 86%, 95%, 93% and 95% with Fe2+ (90?mmol/L) and NaClO (60?mmol/L, Fe2+:NaClO?=?1.5:1), and PEO for 3?hours with a current density of 400?A/m2. Due to the existence of Cl?, the chlorinated intermediates, which would be more toxic, were detected in the PEO treatment. However, the intermediates could be eliminated finally. As a result, the NaClO enhanced Fe2+ coagulation treatment combined with PEO treatment was efficient for the treatment of LLMC.