Advanced approaches to microplastic removal in landfill leachate: Advanced oxidation processes (AOPs), biodegradation, and membrane filtration

Landfill leachate treatment (LLT) processes contribute to the release of microplastics (MPs) into surface waters during solid waste disposal. These MPs can be transported and accumulate in various environmental compartments. This review highlights studies on the treatment of microplastics in landfill leachates and identifies current mitigation techniques. Feasible methods for reducing microplastics at laboratory and pilot scales include sequencing batch reactors (SBRs), artificial soil filtration (ASF), sand bed filtration (SBF), membrane bioreactors (MBRs) with ultrafiltration (UF), nanofiltration (NF), aerobic bioreactors with UF, membrane bioreactors with activated sludge (AS), and reverse osmosis (RO). The effectiveness of these methods depends significantly on the techniques used for MP extraction and polymer identification. Despite these advancements, the removal of microplastics through leachate treatment plants remains largely underexplored. It is critical to develop novel, efficient, and sustainable strategies for mitigating microplastics from landfill sites. Further research is urgently needed to enhance our understanding of the quantities, shapes, and types of polymers released into the environment through landfill leachate. • Treated landfill leachate contains microplastics and poses a threat to surface water. • Predominant microplastics in leachate are polypropylene and polyethylene. • Microplastic in leachate is biased with different sampling and extraction techniques. • There are no international standards for managing microplastics in leachate effluents. • Challenges of combining AOPs with biodegradation and membranes were discussed.