Revised leachate pollution index (r-LPI): A tool to quantify the contamination potential of landfill leachate

The leachate pollution index (LPI), a technique to quantify the contamination potential of landfill leachate, was developed in 2003. Since then, numerous factors have challenged the relevance of the LPI, including advance-ments in technology, the long-term reliability of these indicators, the incidence of emerging contaminants, and the LPI's efficacy. As a result, using LPI as a benchmark can lead to misinterpretation of the magnitude of leachate pollution. To mitigate this, a revised leachate pollution index (r-LPI) was developed, which is more precise and robust in assessing the pollution potential of landfill leachate. This article presents a comprehensive account of the development of r-LPI. The r-LPI was developed by incorporating a fuzzy technique with a novel hybrid multi-criteria decision-making method, wherein the inputs from 60 experts in the field of the environ-ment, specifically solid waste management, were acquired at different stages during its development. The fuzzy Delphi method (FDM) was used to select the parameters. The fuzzy analytic hierarchy process (FAHP) was used to compute the relative weights of the parameters, and sub-index curves were used for the normalization of the parameters. As an application, the LPI and the r-LPI of the Bhalswa, Okhla, and Ghazipur landfills were calcu-lated. The results indicate that r-LPI provides a more comprehensive prediction of leachate pollution than LPI.