title: Transformation of metals speciation in a combined landfill leachate treatment.
abstract: Landfill leachate was treated by a combined sequential batch reactor (SBR), coagulation, Fenton oxidation and biological aerated filter (BAF) technology. The metals in treatment process were fractionated into three fractions: particulate and colloidal (size charge filtration), free ion/labile (cation exchange) and non-labile fractions. Fifty percent to 66% Cu, Ni, Zn, Mn, Pb and Cd were present as particulate/colloidal matter in raw leachate, whereas Cr was present 94.9% as non-labile complexes. The free ion/labile fractions of Ni, Zn, Mg, Mn, Pb and Cd increased significantly after treatment except Cr. Fifty-nine percent to 100% of Al was present mainly as particulate/colloidal matter >0.45 μm and the remaining portions were predicted as non-labile complexes except in coagulation effluent. The speciation of Fe varied significantly in various individual processes. Visual MINTEQ simulation showed that 95-100% colloidal species for Cu, Cd and Pb were present as metal-humic complexes even with the lower dissolved organic carbon. Optimum agreements for the free ion/labile species were within acidic solution, whereas under-estimated in alkaline effluents. Overestimated particulate/colloidal fraction consisted with the hypothesis that a portion of colloids in fraction <0.45 μm were considered as dissolved.
authors.affiliation: College of Environmental Science and Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou 510006, PR China.
authors.forename: Yanyu
authors.initials: Y
authors.lastname: Wu
authors.forename: Shaoqi
authors.initials: S
authors.lastname: Zhou
authors.forename: Dongyu
authors.initials: D
authors.lastname: Chen
authors.forename: Rong
authors.initials: R
authors.lastname: Zhao
authors.forename: Huosheng
authors.initials: H
authors.lastname: Li
authors.forename: Yiming
authors.initials: Y
authors.lastname: Lin
mesh_terms: D003102:Colloids / Q000737:chemistry; D005618:Fresh Water / Q000737:chemistry; D007700:Kinetics; D008670:Metals / Q000032:analysis / Q000737:chemistry*; D012037:Refuse Disposal; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D003102:Colloids; D008670:Metals; D014874:Water Pollutants, Chemical