Environmental and economic assessment of leachate concentrate treatment technologies using analytic hierarchy process

Abstract

Representing one of the most challenging operational tasks for landfill management, municipal solid waste (MSW) landfill leachate varies widely in composition and needs to be treated effectively before being discharged into the environment. To maximise resources recycling with the least negative environmental impacts, regulations on both landfill management and leachate discharge are becoming more and more stringent throughout the world. Membrane separation processes, e.g. Nano Filtration (NF) and Reverse Osmosis (RO), are becoming quite popular at most leachate treatment plants (LTPs), given high removal efficiencies, low cost, and easy operation. However, the need for further treatment of the concentrate from NF/RO has been identified as a major drawback for implementation of membrane processes at landfills. This study aims to evaluate current membrane concentrate treatment technologies, which include advanced oxidation and evaporation. An assessment indicator system for leachate concentrate treatment was developed, taking into consideration treatment efficiencies, operational costs, environmental benefits, and process stability. An analytic hierarchy process (AHP) was applied to the evaluation of leachate concentrate treatment performance. The weight of each index was determined through expert evaluation. Typical treatment technologies were evaluated and ranked based on data collected from full scale treatment plants. These results are helpful in designing cost effective concentrate treatment processes.