Removal of selected pollutants from landfill leachate in constructed wetlands with different filling

Abstract

Constructed wetlands (CW) with vertical flow were used to treat leachate from municipal landfills (active and closed, at different concentrations) using a combination of substrates, i.e., gravel, sand and an exchangeable layer, depending on a variant: organic substrate (pine bark) or mineral substrate (zeolite, expanded clay). The systems were planted with Phragmites australis. The aim of this study was to compare the efficiency of removal of selected pollutants from landfill leachate in CW using different types of filling. For most parameters, the best reductions were obtained on zeolite substrates. In the investigated CW, reductions were achieved at the levels of: AN 96%-99%; TKN 75%-88.5%; TN 62.5%-70%, TP 84–88% and heavy metals (Zn, Ni, Cu, Cr) 41%-56%.