Effect of Leachate Application on the Composting of Organic Fraction of Municipal Solid Waste

Abstract

The disposal of generated leachate is one of the major problems in the composting of Organic Fraction of Municipal Solid Waste (OFMSW). Therefore, it is essential to have a proper, environmental friendly leachate disposal method. The objective of this study was to determine the quality of compost produced from OFMSW by the application of leachate generated during composting process. Research was conducted in composting yard at "Green Park" land filling site Kirindiwela, Western Province of Sri Lanka. The experimental compost beds were prepared ( I x lx l m) manually in the composting site. Completely randomized design (CRD) with four different leachate dilution levels (100%, 50%, 25% and 0% leachate), each having three replicates was used for the experiment After one week, leachate (35 L) was added to experimental composing units while turning of composting beds, once a week. Temperature was measured daily while Electrical Conductivity (EC), pH, Moisture Content (MC), Organic Carbon (OC) were recorded weekly. At the end of the study (~ 12 Weeks), composting quality parameters were also determined. Temperature profiles in experimental composting piles during study period showed that the composting process was satisfactory. pH though was acidic (5-7) at the beginning, reached to near 8 at the end of the study. Showing that the organic matter was hydrolyzed by microorganism, electrical conductivity was high (13-15 mS) at the beginning but finally reduced (~10). The electrical conductivity of compost in all experimental composting piles were higher than the that of recommended EC (0.5-4.0 mS) values while pH, MC, OC and bulk density were within the recommended range. Further, Nitrogen, Phosphorus, Potassium contents were well within the recommended range. Even though significant increase of nutrients (N, P and K) in leachate added compost was noted, all nutrients were within the recommended level. Therefore, it can be concluded that use of leachate does not have significant bad impact on compost quality. Addition of leachate reduces the disposal burden of leachate while increasing the nutrient levels of compost significantly.