Selection of the Most Appropriate Leachate Treatment Methods: Part 2: A Review of Recirculation, Irrigation and Potential Physical-chemical Treatment Methods

Abstract

Abstract This paper reviews potential leachate treatment methods that are non-biological from the traditional wastewater treatment viewpoint. The use and role of recirculation and irrigation in leachate management are reviewed. It is shown that, although recirculation cannot be used as a means of final leachate disposal, it does have a role in decreasing the strength of high strength, acidic phase leachates. Irrigation is shown to be a potential means of final disposal of treated leachate. Physical-chemical treatment (PCT) of leachate using chemical precipitation, coagulation and/or oxidation, activated carbon adsorption, air-stripping, pH adjustment, ion exchange and membrane separation are reviewed. It is shown that PCT is appropriate for leachate treatment when the leachate is low in volatile, degradable organics, i.e. the BOD5/COD ratio is less than 0.1, and/or the molecular weight of most of the organics is greater than 500 g/mole. As a result, it is shown that PCT is best used as a polishing step following biological treatment or treating a leachate from a mature landfill.