Precision sorting of municipal solid waste using dynamic disc screen

Municipal solid waste (MSW) represents a large, low-cost biomass resource for bioenergy and bioproduct production. However, its heterogeneity and compositional variability limit its direct use as a conversion-ready feedstock. This study evaluated three mechanical pre-screening technologies vibratory screening, trommel screening, and a dynamic disc screen (DDS) for the recovery of the organic fraction of MSW (OFMSW), and removal of plastic contaminants from unprocessed black bag MSW. All systems separated MSW into fines and overs fractions based on particle size and density, with compositional analysis confirming enrichment of biodegradable organics in the fines and preferential concentration of plastics in the overs. Vibratory screening produced an organic fines fraction with 45.6% purity and 63.1% OFMSW recovery, whereas trommel screening achieved higher purity (70.5%) but substantially lower recovery (20.6%) on a dry basis. In contrast, DDS screening produced high-purity fines, with OFMSW purity ranging from 77.8% to 99.0% and OFMSW recovery varying between 25.3% and 99.1% across five batches. Across all DDS batches, plastic decontamination efficiency remained high (85.7-95.5%), demonstrating robust contaminant removal over a range of feed compositions and operating conditions. Extended operation using a larger waste mass (∼1,672 kg) further demonstrated the operational stability of the DDS under the tested conditions. The higher motor-speed condition was associated with lower OFMSW recovery in the fines fraction, suggesting a potential influence of motor speed on DDS separation performance. Overall, DDS-based mechanical pre-screening offers a scalable and effective approach for producing high-purity, low-contaminant OFMSW with the potential for downstream biochemical valorization and sustainable MSW management.