Degradation of bioplastic waste with ammonia-nitrogen reduction in landfill leachate medium

Plastics made from fossil fuels lead to the deterioration of biodiversity and the environment. Small particles of plastic wastes, known as microplastics have been detected in the food chain of marine organisms and have contaminated deep-sea sediments. Research and development have been carried out to solve this problem through the invention of bioplastics as a replacement of petroleum-based plastics. Bioplastics can degrade faster than plastics made from fossil fuels, which require a long time to decompose. Bioplastics are mostly made from biomass and are safe for the environment. At the end of the life cycle of bioplastics, they are typically dumped at landfills as the ultimate disposal and they will go through the degradation process there. Thus, this study aims to investigate the degradation process of bioplastics, particularly corn starch-based bioplastics without fillers (BP) and corn starch-based bioplastics with chitosan (BPC) in landfills leachate, which mimics the on-site process. The characteristics of bioplastics before and after the experiments were evaluated. The small bioplastics (BP and BPC) particles were treated in landfill leachate in aerobic conditions. The experiment was conducted using batch culture with leachate medium collected from the Air Hitam Sanitary Landfill in Puchong, Selangor. The degradation of bioplastics (BP and BPC) was observed using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope for the morphology before and after the incubation period of 14 days. The FTIR spectra of both types of bioplastics before the batch culture experiment displayed the presence of O-H, C-H and C=O absorption peaks. However, after 14 days of incubation, the C-H group disappeared from both types of bioplastics towards the end of the experiment. It has been observed that the weight reduction of corn starch-based BP was 92.2% and corn starch-based BPC was 86.7% after 14 days. The ammonia-nitrogen reduction was 40.78% for BP and 38.03% for BPC. It can be concluded that BP degrades better than BPC.