Effects of inescapable waste composition on microplastic release and sulfate reduction in landfill

This study systematically investigated the co-regulatory mechanism between waste composition, microplastic (MP) release, and sulfate reduction processes in simulated landfill environments under various waste composition conditions. Key findings include higher MP release and sulfate consumption in high-biodegradable waste groups compared to low-biodegradable waste ones, and a more sensitive coupling between sulfate concentration attenuation and MP release response in the low-biodegradable waste group. Biodegradable waste emerged as an inescapable source of MP release, contributing 17.42% of total MP release. Notably, high-biodegradable waste groups generated MP levels 2.75-2.38 times higher than their low-biodegradable counterparts. The abundant organic matter in biodegradable waste synergized with the sulfate reduction process, substantially exacerbating secondary MP release. Furthermore, leachate circulation enhanced the dynamic coupling between MP release and sulfate reduction. Based on these findings, a targeted strategy for waste source classification and leachate regulation was proposed to achieve coordinated control of new pollutants and legacy pollutants in landfills. This approach provides scientific support for pollution control and sustainable landfill management.