Treatment of three types of landfill leachate with reverse osmosis

Abstract

Treatment of landfill leachate has gained increasing attention during recent years, and several commercial RO leachate treatment plants have been installed in, e.g., Germany, the Netherlands and Switzerland. In this investigation the influence on membrane performance when treating new types of landfill leachate was studied. Three different types of landfill leachate were included in this study: leachate from a conventional landfill and two leachates from a new type of landfill. At the new landfill the waste is divided into different categories and deposed in waste cells with separate leachate collecting systems. Leachate from a cell with biodegradable waste and from a cell with special waste, containing mainly ashes, were included in this study. A linear correlation between flux and conductivity was found for leachate both from the conventional landfill and from the biodegradable waste cell. The flux varied, depending on the conductivity of the leachate, between 48 and 3 l/m 2/h. The reduction of pollutants was high. The reduction of the chemical oxygen demand and NH 4N was more than 98% for leachate from both the conventional landfill and the biodegradable waste, for example. The salt concentration, and thus the osmotic pressure, was very high in the leachate from the cell containing special waste. The flux was therefore too low for RO to be a suitable treatment process for this leachate.