12. Evaluation of Evolving Waste Management Strategies in Addis Ababa City, Ethiopia: A Life Cycle Assessment Approach

This study aims to evaluate the evolving municipal solid waste management (MSWM) strategies in Addis Ababa City, capital of Ethiopia, based on greenhouse gas (GHG) and short-lived climate pollutants (i.e., black carbon) emissions. Comparable to the existing practice of open disposal and burning, with only 5% recycling, four alternative scenarios were developed considering advances proposed on the City’s Structural Plan of 2017–2027. The first scenario (S-1) suggests mixed-waste collection and disposal in a sanitary landfill while keeping the current recycling. The second (S-2) promotes the source-separated collection, organic waste composting, recycling in material recycling facilities, and disposal in a sanitary landfill. The third (S-3) adds incineration with energy recovery on S-2 to divert a portion of waste from landfills. The fourth (S-4) replaces composting in S-2 by anaerobic digestion with biogas energy production. The existing practice is estimated to emit 703,291 t CO₂-eq GHG and 75.10 t black carbon (BC) from yearly waste. S-1 showed 55% increase in GHG emission and 92% reduction in BC; S-2 showed 1% increase in GHG and 93% reduction in BC; S-3 showed 83% reduction in GHG and 125% increase in BC; and S-4 showed 11% reduction in GHG and negative net emissions of BC. The results indicated that no proposed scenario is climate-friendly. However, S-3 performs better in GHG reduction, specifically for methane (CH₄). S-4, in turn, is safe in terms of BC. Although the sensitivity analysis revealed GHG emission from S-3 increases with future waste composition changes, it will remain the first choice for the climate. The study identified CH₄ and BC as critical parameters in tracking improvements. Hence, proper planning that involves increasing organic waste transformation, CH₄ recovery from landfills, and strict flue gas management during waste incineration can optimize the results.