Leachate Generation and Characterization from Solid Waste Dumps of Islamabad and Rawalpindi

Abstract

This study was aimed to determine leachate generation potential and its chemical characterization from three main dumps of Islamabad and Rawalpindi using column cell approach. Compositions and density of the waste of sector H-10, Bhatta Chowk and sector H-12 dumps were studied to maintain the percentage of their components in their respective column cells, constructed and operated as leachate generating units. Percentage of organic waste in Bhatta Chowk dump is found to be higher than H-10 dump. Density of waste in H-12 dump has found to be greater than Bhatta Chowk dump which is greater than H-10 dump. The equations developed for determining leachate generation of three dumps for any rain fall are: Q (H-10) = 0.800(P) – 2.155, Q (BC) = 0.797(P) – 2.304 and Q (H – 12) = 0.684(P) – 1.847. Leachate generated for the dumps at an average depth of one, two and three meters was determined using the column cell results. Chemical characteristics of various samples of leachate sampled from the columns were determined as; COD 3390 - 8320mg/L, Sulphates 35 – 180 mg/L, Chlorides 325 – 1535 mg/L, Nitrites 5.1 – 56.33 mg/L, TDS 3.20 – 8.05 g/L, Turbidity 69 – 240 NTU, pH 6.0 – 8.0, Trivalent metal Iron 0.5 – 1.7 and Trivalent chromium 0.41 to 1.5 mg/L. Characterization study reveals that concentration of all parameters exceeded the NEQ safe limits for inland waters. Thus Phytocapping remediation at sector H-12 dump, MRF with compost facility at Bhatta Chowk dump and increasing the frequency of clay lining at sector H-10 dumps is recommended as preventive measure against leachate contamination.