Meaning
Residual materials that exceed the screen size during the final separation step of organic processing represent a critical monitoring point for the breakdown of biodegradable packaging. These compost overs consist of wood chips, bulky organic matter, and partially disintegrated polymer fragments that require further processing. Moulders of bio-plastics analyze this fraction to determine if their products are undergoing complete biological disintegration or simply resisting the industrial process.
Moulding Evaluation
Analyzing the polymer content within the recovered coarse fraction gives compounders feedback on resin formulation performance. If a high concentration of compost overs consists of thick-walled injection moulded parts, the resin may require a faster degradation profile or a thinner cross-section in the final part design. This analytical step prevents the accumulation of persistent microplastics in the final soil amendment product.
Recirculation Cost
Returning large organic fragments to the start of the composting cycle increases the total processing time and operating expense of the facility. When biodegradable polymer parts fail to disintegrate within the standard cycle, they are recovered as compost overs and subjected to repeated processing. This extra handling reduces the throughput of the facility and increases the unit cost of composting biodegradable plastic packaging.
Screening Variable
Sieving equipment must be calibrated to ensure that oversized polymer fragments are isolated from the refined compost. Heavy rotating drums separate the dense overs from the refined compost.
