Operational Efficiency and Environmental Performance of Material Recovery Facilities in Integrated Municipal Solid Waste Management Systems

Abstract

Material recovery facilities (MRFs) occupy the pivotal position between collection and end-market reprocessing in integrated municipal solid waste management (IMSWM) systems, yet their operational and environmental performance is rarely evaluated jointly. This study analyses a four-year (2021–2024) panel of twelve MRFs in a single metropolitan region, comprising four single-stream, four dual-stream and four mixed-waste facilities with a combined annual throughput of 486,000 tonnes. Operational efficiency was measured using an input-oriented data envelopment analysis (DEA) with variable returns to scale, complemented by a panel regression of material recovery rate on plant, feedstock and configuration variables. Environmental performance was quantified through a gate-to-gate life cycle inventory expressed as net global warming potential (GWP) per tonne of input. Mean overall recovery across the fleet was 71.7%, ranging from 41.2% for mixed-waste facilities to 84.9% for dual-stream facilities. Mean constant-returns technical efficiency was 0.842, with scale efficiency of 0.939 indicating that most inefficiency is managerial rather than structural. Inbound contamination was the strongest negative determinant of recovery (−0.63 percentage points per percentage point, p < 0.001), while each additional optical sorter added 1.84 percentage points. Net GWP averaged −284.4 kg CO₂-eq per tonne of input, with direct process burdens of 10.5 kg CO₂-eq per tonne offset by avoided primary production. The results indicate that feedstock quality management, rather than incremental capital investment in sorting equipment, offers the largest marginal gains in both efficiency and climate performance.