SOLID WASTE LEACHATE TREATMENT THROUGH CONSTRUCTED WETLAND

Abstract

Solid Waste disposal in open dumps/landfills results in generation of highly contaminated liquid, called leachate. This is extremely harmful to environment, water bodies, humans & animals. To study the leachate constituents & possible treatment, a subsurface-flow type wetland was constructed at pilot scale at the Institute of Environmental Sciences & Engineering, NUST Islamabad, to demonstrate its use as a viable, simple & low-cost treatment option at small landfill sites. Four native wetland plant species (Typha latifolia, Ipomoea carnea var. Fistulosa, Phragmtis karka, and Ricinus communis) were cultivated in monoculture. The objective was comparison of effectiveness of these plants for nutrient removal in controlled wetland microcosms. Fresh municipal waste was collected from Rawalpindi and leachate was generated in closed drums for three weeks and was analysed for COD, TDS, EC, TOC, TN, Chloride & Sulphate etc. When applied to various selected plants it was observed that for COD & chloride removal Typha latifolia performed better. For TOC, Phosphate & TN, Ricinus communis, had better performance as compared to other plant species. Phragmitis karka reduced TDS & EC values more efficiently, while Ipomoea carnea var. Fistulosa was good at normalizing pH of the influent.