Use of Bioplastic Bags for the Collection of Organic Waste in an Electromechanical Composter: Effects on the Facility Management and the Compost Quality

Although the biodegradability of compostable bioplastic bags (CBBs) is well ascertained, concerns arise about the possibility of treating a massive quantity of compostable materials in composting facilities of all sizes and configurations. These concerns are even greater in small-scale composting where the biodegrading conditions may be milder that those in industrial composting. In this work, 7–15 lightweight CBBs were disposed of, together with organic food waste, in an electromechanical composter (EMC), every day for about 2 months. For the bulking agent, fragments and twigs of golden wattle wood were used instead of the recommended wood pellets. The composting process was carried out for 3 months in the EMC, and for further 4 months in a heap, in order to complete the maturation. During the process, critical issues in general, and any due to the presence of the CBBs, were reported: high temperatures, up to 72 °C, were constantly reached both in the ECM and in the heap, while critical anaerobic pockets were not detected. After 7 months, when the temperature and pH of the heap were equal to the ambient temperature and to 7.4, respectively, and were constant over time, the process was stopped and the compost produced underwent chemical, physical and biological analysis, in order to evaluate its quality. The CBBs did not produce any visual contamination of the final compost with bioplastic residues. Finally, all the stability, environmental and agronomic parameters were in compliance with the reference values established by law. This work shows how lightweight CBBs are perfectly managed by the EMC, at least with a CBB/organic waste mass ratio that is consistent with a normal use of CBBs as the collector of organic waste. Graphical abstract: [Figure not available: see fulltext.]