Exploring the potential impacts of microplastics on greenhouse gas emissions in wastewater treatment

Microplastics (MPs) have emerged as pervasive contaminants in wastewater treatment plants (WWTPs), where they interact extensively with microbial communities responsible for greenhouse gas (GHG) production. Despite growing concerns about MP impacts on wastewater treatment processes, the underlying mechanisms by which MPs affect GHG emissions remain largely unexplored. This review provides a comprehensive analysis of the intricate relationships between MPs and GHG emissions in WWTPs. MP sources, properties, and removal efficiencies are systematically examined, and the fundamental mechanisms governing GHG production in the plastisphere are analyzed. The mechanisms by which MPs modulate microbial processes through physical, chemical, and biological pathways are summarized, with particular focus on methane and nitrous oxide emissions. By critically assessing existing literature and identifying knowledge gaps, this review establishes the scientific foundation for developing integrated management strategies that simultaneously address MP contamination and GHG emission in wastewater treatment.