Fractionation of zinc in municipal solid waste landfill leachate: effect of leachate recirculation

Two sets of simulated landfill reactors, namely conventional landfill (CL) and leachate recirculated landfill (RL) were operated to investigate the effect of leachate recirculation on the fractionation of Zn in municipal solid waste (MSW) landfill leachate. Zn in landfill leachate was fractionated into three fractionations: particulate and colloidal matter u003e0.45 m, non-labile complexes 0.45 m and non-labile complexes at the end of the study, for both of landfills. The recirculation of leachate could facilitate the transformation of the fractionation of Zn. Moreover, large amounts of Zn mainly present as free cations/labile complexes and non-labile complexes were leached out from CL, while only small amounts of Zn mainly present as was particulate and colloidal matter u003e0.45 m were leached out from RL all through the study. It suggested the leachate recirculation not only reduced total leaching amounts of Zn, but also decreased the bioavailability and toxicity of the leached Zn.