Qualitative Study of Landfill Leachate from Different Ages of Landfill Sites of Various Countries Including Nepal

The present paper describes the qualitative analysis of landfill leachate at different ages of landfill sites (LFS) around the world and it has been prepared on the basis of extensive survey of literatures. The main objective of this study was to explore the knowledge on qualitative analysis of municipal solid waste landfill leachate. This paper provides a reliable and robust database for the prediction of leachate quality when new landfills are to be developed in Nepal and other parts of the world. Large amount of biodegradable organic matter is indicated though high ratio of BOD/COD. This in turn leads to relative high concentration of Fe, Mn, Ni and Zn. The lower concentration of VFAs and high pH represents old leachate from the late methanogenic phase. The humic substances give a dark color to stabilized leachate. Due to the decreasing solubility of many metal ions with increasing pH, the concentration of metal ions is low in general. The strength of the leachate decreases with time with precipitation of soluble elements such as heavy metals as the organic compounds break down biologically. This is the reason why leachate management is problematic due to complexity in its design, operation, and composition, age of landfill, specific climate conditions and moisture routing through the landfill. In order to avoid pollution and toxicity level in the water bodies, it is legal necessity to treat landfill leachate before discharging it.