Optimizing landfill mining operations: a comparative analysis of material flow and cost-benefit assessment for medium- and large-scale sites

Thailand produced 25.70 million tons of municipal solid waste in 2022, and with two-thirds going to landfills, many recoverable resources went unutilized. The re-utilization of landfill waste through landfill mining remains very limited. The lack of procedures to recover potential information and optimize operations constitute major obstacles to promoting landfill mining. This paper demonstrates the usability of material flow analysis for evaluating the landfill waste-sorting process by comparing Thailand's medium- and large-scale landfill mining operations. Analysis of the material recovery rate for two study sites shows that the current operation could serve the large-scale site's primary objective by producing a high quantity of refuse-derived fuel and the medium-scale site's objective by producing high-quality fuel. Based on these results, an improvement to the waste-sorting process is recommended. Material flow analysis shows that the large-scale site's recovery could increase from 32 to 63% while its sorting rate could increase from 53 to 78 tons hourly. This increased capacity supports the construction of additional waste-to-energy plants at this site, which demands 800 tons of refuse-derived fuel daily. Analyzing the duplication of the extant process and implementation of an improved process, this research finds that it could yield an increase of 2% net present value.