Biodegradation of poly (butylene adipate-co-terephthalate)/poly (lactic acid) under food waste composting: CO2 emissions and compost maturity characteristics.

Substituting conventional plastics with biodegradable plastics represents a promising mitigation strategy for plastic pollution. However, the non-degraded bioplastics can partially result in a heterogeneous, diffusion-limited, and metabolically suppressed state in the compost, thus leading to the composting unstability. This study employed three levels of additions (2, 8 and 16%) of poly (butylene adipate-co-terephthalate)/poly (lactic acid) (PBAT/PLA) bioplastics to canteen food waste to investigate the impact of biodegradable plastics addition on bioplastic degradation efficiency and compost quality. Results showed that 2, 8, and 16% of PBAT/PLA addition had the biodegradation rates of 59.49, 20.99, and 16.72%, respectively. Water-soluble substances and humic acid (5.32 g/kg and 0.94 g/kg) are generated from the treatment of 2% addition, however, 16% of PBAT/PLA addition significantly reduced the formation of water-soluble substances and humic acid with 4.89 g/kg and 0.73 g/kg. Finally, the potential application scenarios for this co-compost are discussed. It is suggested to be used as a soil conditioner in urban greening and public spaces, thereby reducing municipal maintenance and fertilizer procurement costs. This work provides operational thresholds for efficient biodegradable plastic waste treatment via co-composting and advances sustainable development paradigms within the plastics industry, aligning with circular economy principles.