In this study the degradation behavior of different types of commercial T-type bags has been investigated. The bags tested according to their commercial description are: LDPE plastic, oxo-biodegradable plastic and paper. The investigation was performed over a period of 32 weeks under real conditions. The composting essays were inoculated with fresh commercial humus and the humidity was controlled over the complete period, while the temperature was kept at the low mesophilic regime at room temperature, without direct contact to sunlight. The determination of the degradation was based on the analyses of total solids and organic total solids, as well as visual observations.
The results show that only the paper bags were biodegraded appropriately, leaving no residue after 32 weeks. While neither the LDPE nor the oxo-biodegradable plastic bags show any signs of disintegration or degradation over the entire period. These results were expected for the LDPE bags, but not for the oxo-biodegradable plastics. As conclusion the low biodegradability of these bags is explained by the fact that even if the bags are commercially distributed as biodegradables, they are normal LDPE bags with an oxo-additive. Actually, according to the definition, they cannot be considered as biodegradable, since they can only be degraded by few microorganisms in a very slow rate. The degradation of their chemical structure occur by the action of heat or ultraviolet light. And since non of these conditions were found during this investigation, the bags suffer no disintegration.
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