Vetiver landfill leachate performance under irrigation

Abstract

Landfill leachate in Vietnam differs from that produced in developed countries by its extremely high content of organic, heavy metals, and nutrients. In this study, vetiver grass (Chrysopogon zizanioides L.) is applied to treat landfill leachate. The grass is firstly irrigated by domestic wastewater for acclimatization, then by diluted landfill leachate with the quantity of 1L/d. Various dilution factors (leachate:domestic wastewater) of 1:5, 1:3, 1:2, 1:1, and original leachate are tested in turn. Different irrigation frequencies are applied for a dilution: twice a day and three times a day. The toxic threshold is firstly recorded at dilution factor of 1:1, where the vetiver grass shows limited growing. After 70 days more, the grass grows well when irrigated with leachate (no dilution). Best performance is recorded with a dilution factor of 1:2 and irrigation frequency of three times a day. The quality conforms to National Technical Regulation on Wastewater of the Solid Waste Landfill Sites in terms of BOD, N, P and heavy metals. The outcomes strongly present possible treatment of landfill leachate with vetiver by irrigation.