Application of leachate pollution indices for assessment of leachate pollution potential of landfills (a case study of an unlined landfill with lime sludge and fly ash)

Leachates from unlined landfills cause environmental degradation and health hazards due to resultant ground water pollution. Their pollution potential can be measured on a comparative scale using leachate pollution index (LPI). The selection of index involves 18 pollution parameters, their weightages and the sub-index values. The concentrations of pollutants are obtained from toxicity characteristic leaching procedure (TCLP) extracts of the lime sludge and fly ash generated. A comparative study of five different indices (unweighted arithmetic leachate pollution index, arithmetic leachate pollution index, unweighted multiplicative leachate pollution index, multiplicative leachate pollution index, weighted ambiguity and eclipsity free method) is presented for assessing the pollution potential of an unlined landfill site for ITC Bhadrachalam (India) paper mill. The five parameters with the highest, medium and low weightages are considered for analysis to evaluate a correlation among indices. Finally, the most suitable index method is suggested by substantiating with sensitivity analysis.