Chemical Assessment of Different Landfill Leachate in Nepal

Abstract

Leachate analysis is a vital aspect of landfill operation & management, but limited studies have been conducted in Nepal in this regard. The study focuses on the chemical assessment of leachate's characteristics of 4 different landfill sites in Nepal in the year 2019 among which 3 are operational and 1 closed, and their variation due to age, functionality, seasons, and feeding amount and waste composition. The data of leachate samples at two months' interval was collected and assembled into 4 seasons viz. pre-monsoon (Mar-May), monsoon (June-Aug.), post-monsoon (Sep-Nov), and winter seasons (Dec-Feb.) of Nepal using Principal Component Analysis. One-way ANOVA tool is used to analyze data acquired from laboratory. Gradual increase of pH from pre-monsoon to winter seasons and as per age was observed. Amongst metals and heavy metals, the concentration of Fe descended from pre-monsoon to winter. Other metals like Ni, Pb, and Zn were detected in functional, and intermediate aged landfills. For old LFS, the concentrations of Fe, Cu, Cr, Hg, Ni, Pb, Cd, and Zn were lower. H2S and NH3 were high in intermediate than in mature site without seasonal variation. The chemical assessment generates useful data to construct treatment plants.