Influence of heat insulation on temperature and moisture variations in municipal solid waste landfills under diverse environmental conditions

Abstract

Elevated temperatures (ETs) in municipal solid waste (MSW) landfills, caused by the decomposition of organic waste, pose significant risks to landfill liner integrity, increase leachate production and greenhouse gas emissions. Heat accumulation, with ETs exceeding 35 °C, can negatively impact liner performance. Existing heat mitigation strategies, such as gas collection and cover systems, offer limited thermal mitigation. Gas collection mainly focuses on emissions, meanwhile, cover systems often trap heat and degrade over time. Advanced methods like waste-to-energy and heat exchangers are expensive and require high maintenance. In contrast, integrating thermal insulation within landfill liners provides a sustainable and efficient solution. This study evaluates the performance of three insulation materials, rockwool, hot sprayed polyurea (HSP), and casted polyurea (CP), under varying environmental conditions. Laboratory experiments and numerical simulations using ANSYS analyzed their performance across different ETs (40 and 70 °C), moisture conditions (dry and wet), and insulation thicknesses (20, 35, 50 mm). Rockwool demonstrated the best performance in dry conditions, reducing ETs by up to 30 %, but dropped by 13 % when wet. HSP maintained better stability under wet and extreme ETs, with reductions up to 31 % in base conditions and 57 % at 70 °C. CP was effective in moderate ETs and wet conditions but underperformed at high temperatures. Increasing insulation thickness improved thermal resistance, though the significance reduced beyond 35  mm. These results highlight the importance of material selection and configuration in balancing thermal and cost effectiveness of MSW landfill systems and further validate thermal insulation as an effective and sustainable solution.