Why do materials recovery facilities still use workers to sort items by hand?

At a materials recovery facility (MRF), manual labor remains a critical component of the sorting process to augment automated systems. While modern facilities utilize advanced technology—such as electromagnetic separators, vibrating screens, air classifiers, and optical scanners—to divide materials, human workers are still required for several key reasons:1

• Quality Control and Contamination: Automated systems can struggle with complex waste streams, particularly when items are contaminated with food residue, broken glass, or mixed materials. Workers identify and remove nonrecyclable items or contaminants that machines might miss, ensuring the final output meets the purity standards required by manufacturers.12
• Precision Sorting: Certain tasks, such as sorting glass by color, often require the nuanced judgment of human workers to ensure accurate separation.2
• System Augmentation: Manual sorting acts as a necessary supplement to mechanical processes, helping to refine the stream of materials and improve the overall efficiency of the facility.1

By combining human oversight with mechanical sorting, facilities can better manage the challenges of processing diverse and often commingled waste streams.12