Comparative Analysis of Waste-to-Energy Technologies in Municipal Solid Waste Treatment

Thesis Abstract

The escalating volume of municipal solid waste (MSW) and the increasing demand for sustainable waste management solutions have underscored the significance of waste-to-energy (WTE) technologies as viable alternatives to conventional disposal methods. Despite the proliferation of diverse WTE processes—including incineration, gasification, pyrolysis, and anaerobic digestion—comparative evaluations of their efficiencies, environmental impacts, economic viability, and operational challenges remain limited, necessitating a rigorous analysis to guide policy and industrial practice. This study aims to conduct a comprehensive comparative analysis of prominent WTE technologies in MSW treatment, with specific objectives to evaluate their energy recovery efficiencies, environmental emissions, techno-economic performance, and sustainability potentials within urban waste management contexts. The research adopts a mixed-methods approach, combining quantitative assessments with qualitative insights, to enhance the robustness of findings. The study population encompasses WTE facilities operating within a regional jurisdiction handling approximately 2 million tonnes of MSW annually. A stratified random sampling technique selected 15 operational plants representing incineration, gasification, pyrolysis, and anaerobic digestion processes, with a sample size of 60 respondents comprising facility managers, environmental engineers, and financial analysts. Data collection instruments include structured questionnaires, structured interviews, on-site observation checklists, and secondary data obtained from facility records, environmental reports, and government publications. Instrument validity is established through expert review, while reliability is ensured via pilot testing and Cronbach's alpha coefficients exceeding 0.8. Data analysis involves descriptive statistics to profile facility characteristics, followed by inferential techniques such as analysis of variance (ANOVA) and regression analysis to determine differences and relationships among the technologies. The study employs Life Cycle Assessment (LCA) methodologies to quantify environmental impacts, and cost-benefit analysis models to evaluate economic performance. Theoretically, the analysis is underpinned by the Technology Acceptance Model (TAM) to assess the adoption potential of various WTE systems, and the Socio-Technical Systems Theory to explore the integration of technological, social, and policy factors influencing implementation. Expected findings indicate that incineration and gasification technologies demonstrate higher energy recovery efficiencies (averaging 25-30% of input waste calorific values) compared to pyrolysis (around 15%), while anaerobic digestion primarily processes organic fractions with lower energy yields but offers substantial biogas production potential. Emissions profiles reveal that modern gasification plants emit significantly fewer pollutants such as dioxins and furans compared to traditional incinerators, which still face challenges with particulate matter and heavy metal releases. Economically, pyrolysis and gasification show promising profitability in regions with favorable feedstock quality and policy incentives, although high capital costs and technological complexities pose barriers. Environmental analyses underscore that gasification offers the most reduced environmental footprint, especially concerning greenhouse gas emissions and residual waste. This research contributes to existing body of knowledge by providing a nuanced, systems-level comparison of WTE technologies pertinent to urban waste management strategies. It fills critical gaps regarding integrated environmental, economic, and social evaluations, thereby informing policymakers, industry stakeholders, and researchers on optimal WTE modality selection aligned with sustainability goals. The main conclusion advocates for a context-specific, hybrid approach utilizing gasification for high-calorific waste streams, complemented by anaerobic digestion for organic-rich waste, supported by robust policy frameworks to mitigate environmental risks and enhance operational efficiency. Recommendations include fostering investments in advanced emissions control, incentivizing research into cost reductions, and developing integrated waste management policies that promote the adoption of technically and economically viable WTE options. Future studies should explore longitudinal performance assessments and the integration of emerging technologies such as plasma arc gasification to expand sustainable waste-to-energy solutions.