Color and organic compounds removal from secondary effluent of landfill leachate with a novel inorganic polymer coagulant

Emerging contaminants in landfill leachate are causing environmental concerns due to their adverse impacts on the aquatic environment. The most popular biological process is mostly the first stage in combination with additional physical-chemical process. Current post-treatments are limited by high operating costs, low treatment efficiencies, or sensitive operating conditions. Poly-aluminium(III)-magnesium(II)-sulfate (PMAS in brief) is used to remove color and organic compounds in secondary effluent of landfill leachate. More than 40 kinds of organic matters in the secondary effluent are identified and 10 of them belong to the Black List of environmental preferred controlled pollutants considered by EPA of USA or China. Removals of COD, BOD₅, UV₂₅₄ and color by coagulation with PAMS can reach above 60%, 55%, 85% and 85% respectively under the optimum conditions. The species of alkyl, alkene, acyclic alcohol and acyclic acyl amine are efficiently removed (about 85%), with some of them removed completely, while the species of acid, ester and ketone are mostly removed (about 65%) and such matters with benzene ring as aromatic hydrocarbon, hydroxybenzene, aromatic alcohol, aromatic acyl amine are partially removed (about 50%). Organic pollutants in the secondary effluent are greatly removed with high efficiency here, which greatly weakens its pollution extent.