EVALUATION OF GROUNDWATER CONTAMINATION BY MSW LEACHATE

Abstract

Groundwater is the key source of drinking water. Identifying contaminant sources in ground and knowledge of variation of its concentration with respect to time and distance so that remediation strategies for groundwater contaminations can be developed. In present study groundwater contamination around Gazipur municipal solid landfill site in Delhi is estimated by using one-dimensional numerical model (advection-dispersion equation). To find the parameter affecting the movement of contaminants, a column test has been performed. The soil property used in column has same composition as of soil near to the landfill site. The soil was prepared in lab by sieve size analysis. Then leachate which was to be flown through the column was also generated in the lab. For synthesizing the leachate, waste composition according landfill site was prepared and after putting some water it was kept for 20 days. After characterization of leachate the ratio of BOD3/COD is 0.35. Which means most component of leachate is not easily decomposable. Using the lab data, different parameters were obtained and with the help of these parameters, models for different constituent (COD, BOD3, NO3 , NH3-N and P043) of leachate has been prepared. With the help of these models, it is shown that because all parameters which affect the contaminant transport are same for different contaminant the only affecting parameter is retardation factor which varies from one pollutant to other pollutant. The retardation factor for COD, BOD3, NO3 , NH3-N and P043 are 5.3, 8.78, 1.29, 4.35 and 2.9 respectively. According to this study, the groundwater would be seriously affected around the Gazipur landfill site. The concentration of COD would be equal to input concentration of upto 1600 m distance from leachate generation point after 15 years. The same distances for BOD3, nitrate, aminonical nitrogen and phosphate are ilOOm, 1650m, 1800m and I 300m respectively