Sustainability assessment and synergistic optimization of multi-source municipal solid waste management: carbon, economic, reduction, energy, and health perspectives in Jinan, China

Abstract

Transitioning toward ‘Zero-Waste’ and dual-carbon urban ecosystems requires overcoming critical bottlenecks in multi-source waste synergy. This study develops a bottom-up sustainability assessment and optimization framework integrating life cycle assessment, life cycle cost analysis, NSGA-II, and TOPSIS. Using Jinan, China, as a case study, the model allocates household waste and municipal sewage sludge among feasible treatment pathways subject to exogenously specified facility capacities and policy constraints. It minimizes carbon footprints while maximizing economic benefits and integrated reduction-resource recovery-harmless treatment performance. Under the integrated preference, the selected 2030 allocation achieved a carbon footprint of 609.5 kt CO₂-eq yr⁻¹, an annual economic benefit of CNY 423.79 million yr⁻¹, a waste reduction rate of 80.01 %, net energy recovery of 580.93 TJ yr⁻¹ and human health damage of 1882.83 DALYs yr⁻¹. Relative to the non-synergistic reference, coordinated treatment reduced carbon emissions and human health damage by 29.93 % and 21.87 %, respectively, increased economic benefit by 8.61 %, and improved net energy performance by 1502.49 TJ yr⁻¹. Sensitivity and uncertainty analyses identified source-separation performance and municipal sewage sludge allocation as the main drivers of system variation, while the overall treatment configuration remained comparatively stable. The framework provides conditional decision support for comparing coordinated multi-source waste pathways while explicitly recognizing uncertainty in forecasting, inventory parameters, and implementation feasibility.