The degradation performance of different microplastics and their effect on microbial community during composting process

The objectives of this study were to investigate the degradation characteristics of different microplastics (polyethylene (PE), polyvinyl chloride (PVC), polyhydroxyalkanoates (PHA)) and their effect on the bacterial community during composting. In this study, 0.5% PE, 0.5% PVC and 0.5% PHA microplastics were individually added to the mixture of cow manure and sawdust and then composted for 60 days. The treatment without microplastics was regarded as control. Results indicated that the abundance and smaller size (0–800 μm) of microplastics in all treatments obviously decreased after composting, except PVC treatment. The surface morphology of all microplastics occurred obvious erosions and cracks and the carbon content of PE, PVC and PHA microplastics were reduced by 30, 17 and 30%, respectively. After composting, all microplastics were significantly oxidized and the functional groups O–H, C=O and C–O increased. Furthermore, all microplastics exposure reduced the richness and diversity of bacteria community at thermophilic phase, especially PVC microplastics.