Recent approaches and advanced wastewater treatment technologies for mitigating emerging microplastics contamination – A critical review

• Published in: The Science of the total environment Vol. 858; no. Pt 1; p. 159681
• Main Authors: Krishnan, Radhakrishnan Yedhu, Manikandan, Sivasubramanian, Subbaiya, Ramasamy, Karmegam, Natchimuthu, Kim, Woong, Govarthanan, Muthusamy
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2023
• Subjects: Advanced techniques; air; aquatic ecosystems; Bioremediation; electrocoagulation; environment; filtration; membrane bioreactors; Membrane technology; Microplastics; photocatalysis; pollutants; sand; soil; species; wastewater treatment; Wastewater treatment plants; Microplastics; Bioremediation; Wastewater treatment plants; Membrane technology; Advanced techniques
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.159681

Microplastics have been identified as an emerging pollutant due to their irrefutable prevalence in air, soil, and particularly, the aquatic ecosystem. Wastewater treatment plants (WWTPs) are seen as the last line of defense which creates a barrier between microplastics and the environment. These microplastics are discharged in large quantities into aquatic bodies due to their insufficient containment during water treatment. As a result, WWTPs are regarded as point sources of microplastics release into the environment. Assessing the prevalence and behavior of microplastics in WWTPs is therefore critical for their control. The removal efficiency of microplastics was 65 %, 0.2–14 %, and 0.2–2 % after the successful primary, secondary and tertiary treatment phases in WWTPs. In this review, other than conventional treatment methods, advanced treatment methods have also been discussed. For the removal of microplastics in the size range 20–190 μm, advanced treatment methods like membrane bioreactors, rapid sand filtration, electrocoagulation and photocatalytic degradation was found to be effective and these methods helps in increasing the removal efficiency to >99 %. Bioremediation based approaches has found that sea grasses, lugworm and blue mussels has the ability to mitigate microplastics by acting as a natural trap to the microplastics pollutants and could act as candidate species for possible incorporation in WWTPs. Also, there is a need for controlling the use and unchecked release of microplastics into the environment through laws and regulations. [Display omitted] •Smaller microplastics (MPs) <100 μm are not effectively separated by conventional WWTPs.•Granules and fragments were easier to separate than microfibers and pellet shaped MPs.•Blue mussels, lugworms and sea grasses are candidate species for MPs' bioremediation.•Rapid sand filters and membrane bioreactors can remove 97 % and 99 % MPs respectively.