Microplastics' toxic effects and influencing factors on microorganisms in biological wastewater treatment units

Prior to entering the water body, microplastics (MPs) are mostly collected at the sewage treatment plant and the biological treatment unit is the sewage treatment facility's central processing unit. This review aims to present a comprehensive analysis of the detrimental impacts of MPs on the biological treatment unit of a sewage treatment plant and it covers how MPs harm the effluent quality of biological treatment processes. The structure of microbial communities is altered by MPs presence and additive release, which reduces functional microbial activity. Extracellular polymers, oxidative stress, and enzyme activity are explored as micro views on the harmful mechanism of MPs on microorganisms, examining the toxicity of additives released by MPs and the harm caused to microorganisms by harmful compounds that have been adsorbed in the aqueous environment. This article offers a theoretical framework for a thorough understanding of the potential problems posed by MPs in sewage treatment plants and suggests countermeasures to mitigate those risks to the aquatic environment.