Phytoremediation of partially treated MSW leachate by selected free floating and emergent macrophytes in subsurface vertical flow constructed wetlands

Abstract

Phytoremediation of partially treated municipal solid waste (MSW) leachate with selected free floating (Eichhornia crassipes and Pistia stratiotes) and emergent macrophytes (Typha angustifolia and Chrysopogon zizanioides) was assessed at three steps in order to improve the quality of leachate prior to discharge to the environment. At the 1st step, growth performance of macrophytes was assessed at leachate dilutions of 0%, 25%, 50% and 75%. Results revealed that all leachate dilutions were detrimental to P. stratiotes. Nevertheless, leachate greater than 50% dilutions and all leachate dilutions favored the growth of E. crassipes and emergent macrophytes respectively. At the 2nd and 3rd steps, phytoremediation with E. crassipes and emergent macrophytes at 50% and phytoremediation with emergent macrophytes at 0% leachate dilution were assessed respectively. Results revealed that the percentage reductions of measured parameters (pH, EC, turbidity, color, TSS, BOD, COD, phosphate, ammonium nitrogen, nitrate, sulfate and color) increased in remediated leachate. Of the emergent macrophytes, C. zizanioides significantly reduced EC, COD, TSS, nitrates, ammonium nitrogen, sulphates and color (P<0.05: one way ANOVA) when compared with their controls and T. angustifolia. Moreover, C. zizanioides proved its higher ability in accumulating nitrogen and phosphorous from leachate than that of T. angustifolia. Nevertheless, accumulation of nitrogen was higher than phosphorous in shoots of both plants. Although both species performed better in harsh conditions, C. zizanioides could be recommended as the best plant for the remediation of partially treated MSW leachate.