Life Cycle Assessment of Different Options for Municipal Solid Waste Management

Abstract

The global increase in urbanization, population, and evolving lifestyles has resulted in a significant rise in solid waste production. Landfilling remains the most common method employed worldwide for managing municipal solid waste (MSW). However, given the limited space available, this approach is highly undesirable in the current situation. In developing countries like India, MSW is often dumped in open areas or openly burned without any pre treatment, leading to adverse environmental and human health effects. These unscientific methods of MSW management contribute to greenhouse gas emissions, emit air pollutants, and contaminate groundwater through leachate percolation. Therefore, there is an urgent need to adopt MSW management practices that minimize negative impacts on the environment, especially in densely populated metropolitan cities where land area is limited. The objective of this study is to model the environmental impact of MSW management methods employed in East Delhi using Life Cycle Assessment software called GaBi. The study compares the current MSW management method in East Delhi (referred to as Scenario S0) with three alternative scenarios, analyzing their respective environmental impacts. The four scenarios examined are as follows: S0 (landfilling of fresh waste and RDF incineration), S1 (landfilling of fresh MSW and RDF gasification), S2 (landfilling with LFG recovery of fresh waste and RDF incineration), and S3 (landfilling with LFG recovery of fresh waste and RDF gasification). The life cycle impact assessment is conducted for 1 ton of MSW collected per day, considering six impact categories: GWP, AP, EP, HTP, FAETP, and TETP. The life cycle impact assessment results indicate that the base scenario (S0) is the least favourable option for MSW management, while the S3 scenario is the most favourable. Furthermore, the energy recovery potential in the S3 scenario is the highest, amounting to 616 MWh (190 MWh from landfill gas recovery and 426 MWh from RDF gasification). The study also highlights the need to manage fresh MSW separately instead of open dumping or landfilling it at the Ghazipur landfill. Currently, the Ghazipur landfill emits approximately 44 Mg of greenhouse gases (GHGs), and adding more fresh MSW to it would exacerbate the problem by increasing the legacy waste and GHG emissions. Proper management techniques such as bioremediation and waste-to-energy (WTE) methods should be employed to clear the accumulated legacy waste. Currently, the East Delhi Municipal Corporation (EDMC) is utilizing legacy waste to produce refuse-derived fuel (RDF), which is then incinerated for energy recovery. However, the life cycle assessment results indicate that RDF incineration increases toxic impacts on humans and the environment, as evidenced by the high values of HTP and FAETP in the base scenario. RDF incineration releases air pollutants and toxic substances like furans and dioxins. Additionally, energy recovery from RDF gasification (983.8 kWh/ton) is higher than from RDF incineration (498.8 kWh/ton). Hence, effective management of fresh waste should involve source segregation of MSW and recycling practices. Organic waste should be treated separately, and gasification processes should be employed for managing legacy waste.