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Item type:Publication, Access status: with files , Untersuchung des Verhaltens von Beuteln aus biologisch abbaubaren Kunststoffen in der Kompostierungsanlage NeumünsterWaste bags made of biodegradable plastics (BDP) were tested for their degradability under industrial-scale conditions at the Neumünster composting plant. The aerated intensive rotting lasted two weeks, the naturally ventilated curing four weeks. Four different types of bags were used, two starch blends and two PLA blends. For each type, 160 bags, distributed over 8 nets, were introduced and removed after 2, 3, 4, 5 and 6 weeks, respectively. The net contents were analyzed for BDP residues, differentiating between micro (< 1 mm, 1-2 mm), meso (2-8 mm) and macro (>8 mm) particles. The BDP degradation level was determined approximately. Based on the residual particle areas, the possible maximum degree of degradation could be determined, and based on residual particle masses, the minimum degree of degradation that occurred. The actual degree of degradation will be in between. The determined residual masses were subject to uncertainties mainly due to particle impurities, the residual areas due to a neglect of the 3-dimensionality for large particles. The development of temperatures and water contents in the rotting material over the treatment period was typical for biowaste composting in most of the nets, including the expected inhomogeneities. The strongest BDP degradation occurred in all bag types in the first three weeks, with significant degradation already after two weeks. Starch blends showed a faster degradation than the PLA blends. After 4 to 6 weeks, most starch blend batches showed a degradation rate above 90%. Although most PLA blend batches had a degradation level by area above 90%, it must be assumed that their real degradation level will be partly below 90%. The minimum degradation level by mass for the bags with a drawstring was between 58 and 80%, and between 71 and 94% for those without a drawstring. Micro and meso particles were detected in all batches at all sampling times, and macro particles were detected in most. Some starch blend batches were free or almost free of macro particles, in one case already after three weeks. Besides the type of material, the thickness of the material had an influence on the BDP degradation. In the worst degraded bag type, residues of the thicker drawstrings accumulated. In addition, the rotting material moisture was significant. There were some dried-out zones with water contents below 20% in which no biodegradation activity took place and, accordingly, BDP degradation did not progress.Publicationtype: Technical Report514 1055