Probabilistic resource recovery of legacy waste in Dhapa landfill: An approach of Bio-mining in Kolkata

Abstract

Rapid growing competition for resources, increasing price for raw materials, diminishing natural reservoirs for valuable resources and increasing environmental problems make resource extraction from alternative sources as viable option such as Bio-mining. NGT mandated for implementation of Bio-mining of legacy waste throughout the Indian landfills for environmental impact minimization and recovery of 10,000 hectares of urban land that is locked in these dumpsites. The waste generation of Kolkata is around 4500 MT/day which further get disposed in the major landfill site Dhapa which is exhausted with 25 years long legacy waste. From composition analysis, an estimated recovery of 85-90% of legacy waste is possible. From material balance, considering different components of Bio-mining like combustible and non-combustible materials, compostable, recyclables and residuals, a generic Linear Programing model can be developed. A waste to soil ratio of 60:40 is achieved. Recovered legacy waste will be further processed for Incineration/RDF/Co-processing, making of building materials, filling materials, waste plastics to paving blocks, compost processing and landscaping, primarily as a valuable material extraction and energy resource recovery strategy to meet the environmental sustainability towards circular economy. This generic methodology will be applicable to different landfill sites of India where Bio-mining is yet to be implemented.