Municipal Solid Waste Management in the Top 25 Most Populated Countries: A Review on the Application of LCA to Select Appropriate System in Reducing Greenhouse Gas Emissions

Population growth effectuates the continuous increase of municipal solid waste (MSW) generation. As it becomes a source of greenhouse gas (GHG) emissions calls for a strategic effort to manage MSW is needed to secure environmental sustainability. The life cycle assessment (LCA) tool has been proven as an effective method to assist policymakers in finding or evaluating various treatments for municipal solid waste management (MSWM) by quantifying the environmental impacts. This study reviewed the application of LCA to select preferred MSWM strategies in reducing GHG emissions in the top 25 most inhabited countries, which have about 74% of the total population worldwide. Systematic assessment has been conducted for 74 manuscripts from 2010–2021, resulting in a summary of the goal/purpose of study, functional unit (FU), LCA software, and considered MSWM options. The study found that per ton of MSW and amount of MSW in the study area were almost equally used, and SimaPro was utilized by 14 LCA studies, while 35 didn’t mention the software preference. Among the various treatments, incineration with energy conversion was claimed to be the most environmentally friendly option. Meanwhile, most developed scenarios included landfill but an agreement to equip with a gas collection system was observed to minimize GHG emissions. Concurrence on applying the waste hierarchy approach to get emissions benefits was also detected. Based on income classification, all countries belonging to High Income (HI) and Upper Middle Income (UMI) have produced LCA manuscripts, while no LCA finding in 3 out of 10 Lower Middle Income (LMI) and 2 Lower Income (LI) countries. Although most listed countries have published the LCA studies, better distribution of the study area is still needed. Therefore active support from the government mainly in providing a standardized data collection system, financial backup for research activity and building consciousness among relate