Meaning
Rotating cylindrical sieves used in industrial composting facilities separate processed organic matter from oversized materials, including partially degraded polymer packaging. A trommel screen sorts the material by size as it tumbles through the tilted, perforated drum, allowing fine compost to fall through while directing larger fragments to the discharge end. This mechanical classification is essential for isolating non-compostable contaminants and undegraded plastic residues from the final product.
Operation Control
The efficiency of the separation process depends on the drum speed, angle of inclination, and the diameter of the screen openings. Adjusting these parameters on a trommel screen prevents fine compost from being lost to the overs stream and ensures that polymer fragments are properly isolated. This calibration is particularly important when processing batches that contain compostable plastics of varying wall thicknesses.
Contamination Separation
Sifting the compost before packaging ensures that any plastics that failed to disintegrate are removed from the marketable soil amendment. These recovered polymers are then returned to the start of the composting cycle for further exposure to moisture and heat. This recirculating step ensures that the final compost meets purity and quality standards.
Equipment Maintenance
Sticky or wet organic matter can clog the screen openings and reduce sorting efficiency. Automated cleaning brushes are mounted on the exterior of the drum to continuously clear the mesh during operation.
