Estimation of energy content in municipal solid waste of Bhutan and its potential as alternate powers source

Abstract

Conversion of Solid waste into energy is the most resourceful process to combat landfill saturation and environmental impression. Bhutan, with an exponential rise in the waste production, Waste to Energy (WTE) conversion is an alternative solution for municipal solid waste management (MSW). The study for MSW composition and its energy potential analysis for Memelakha (Thimphu) and Pekarshing (Phuntsholing) landfills was done to resolve the waste management challenges in the country. The standard number of samples from two dumpsites were used to analyze for the waste characterization (waste composition, proximate analysis, chemical analysis) and high heating value (HHV) of MSW. MSW of two landfills showed that the main elemental constituents were Carbon and Oxygen with 17.26% and 9.97% by mass respectively for Pekarshing and 16.52% (Carbon) and 11.07% (Oxygen) by mass for Memelakha landfill. Based on the physio-chemical analysis of MSW, the average calorific HHV of MSW obtained were 10.028 MJ/kg (26.04% of coal energy) for Pekarshing dumpsite and 9.6 MJ/kg (24.94% of coal energy) for Memelakha. The analysis showed that by the year 2050 Memelakha landfill has the potential to generate the power of 8.85 Megawatt (MW) and 1.44 Megawatt (MW) for Pekarshing. For (WTE) conversion, incineration, pyrolysis, and gasification technologies are found suitable based on the current composition MSW of Bhutan. Furthermore, in terms of energy efficiency and percentage of wastage, the gasification process was the most feasible method for WTE conversion at two locations with a waste volume reduction of 80 to 90 percent at the landfill.