Very Good Question.. First of all i thankful to you.. My further research is going on.. Very soon i will reply.

Dear Areful Hoque,

Thank you so much.

I'm waiting for your kind reply.

https://www.sciencedirect.com/search?qs=microplastics%20in%20wastewater%20treatment%20plants&show=25&sortBy=relevance

Hi Ali,

Many wastewater treatment processes do remove microplastics from wastewater and incorporate them into sludge. You are quite right that if the sludge is applied as fertiliser, the microplastics will re-enter the environment, with unknown consequences. If the sludge is incinerated, the microplastics will be destroyed. Perhaps the more important question is how is sludge from wastewater treatment plants handled.

Martyn

Dear Md. Washim Akram

Thank you for providing useful information.

Dear Professor Martyn N. Futter

You are completely right, but, as you know, a large fraction of microplastics are separated from wastewater through primary treatment units (mainly screening, grit chamber, etc.). Therefore, a high amount of microplastics can enter into the environment through sand & grit and screenings disposal. Furthermore, as you have pointed out, we can use the incineration technology for final disposal of waste sludge, however, besides the advantages of this technology, using incinerators can bring some unfavorable aftermaths.

Best regards,

Ali

Dear doctor

The fate of microplastics in wastewater treatment plants: An overview of source and remediation technologies

A. Sudharshan Reddy , Abhilash T. Nair

Environmental Technology & Innovation

Volume 28, November 2022, 102815

"Microplastics (MPs) in everyday consumer products have paved the way for high MPs concentrations in wastewater. Wastewater treatment plants (WWTP)s are the significant focal points for MP pollution, as millions of MP particles with varying characteristics enter WWTPs through the sewage systems of urban areas. Although the units in the WWTPs are not primarily designed to target MPs specifically, researchers have reported a large amount of microplastic removal from various units of WWTPs. The scientific community has remarkably studied various conventional and advanced treatment methods to remediate MPs and nanoplastics (NPs) from wastewater.

Conclusion and future perspectives

• •The remediation of MPs and NPs in WWTPs has been comprehensively reviewed. Also, the interaction of MPs and NPs with the treatment processes have been discussed. Although no specific novel treatment technology is practically aimed at remediating the MPs/NPs, the performance of the existing technologies is explored more at the lab scale. The remediation of MPs/NPs is classified as removal and degradation methods.
• •Removal methods account for most of the MPs/NPs remediation compared to the degradation methods. The bioremediation approach is a cleaner, effective, and reasonable option for degrading the MP/NPs. However, the release of intermediate products or monomers and their fate and transport is unclear. Photocatalysis is a potential technology for degrading MPs/NPs. However, there is a lack of information regarding the release of by-products. Electrooxidation is another promising approach where MPs/ NPs will be converted into gas form without releasing any toxic by-products. However, the fate of released gases, the interaction of other co-existing contaminants, and the fouling of anode are some major issues that need more research. Membrane technology has shown attractive performance in removing the MP/NPs. However, blocking and membrane fouling are challenging issues that must be addressed to implement at a large scale. The presence of other contaminants may interact and adsorb to the MPs/NPs through hydrophobic interactions, electrostatic attraction, or ion exchange mechanisms. Clear insights need to be explored to understand the sorption of MP with coating or other surface modifications. Pilot studies and cost analysis are needed to evaluate the feasibility of different treatment technologies for mitigating the MPs/NPs.
• •Source remediation technologies needs much attention as they can reduce the load of MP/NPs on the WWTPs. Fig. 10 represents the common mitigation strategies required in remediating MPs/NPs. In addition, research efforts are still needed in the following directions to understand the clear picture of MPs/NPs in WWTPs in terms of removal, interaction, fate, and transport.
• •The scientific community has remarkably studied and reported concentrations of MPs/NPs from various WWTPs worldwide. These results cannot be compared directly as they involve several complications and disparities in the sampling and analysis procedures. Hence, standardization of sampling, purification, and characterization methods needs a priority for quality research output. Additional exploration is required to understand the concentration (both on a number and mass basis) and characteristic profile of MPs/NPs across the WWTPs and the mechanisms involved in their remediation. This will provide an opportunity to optimize the WWTP facility to identify any additional treatment requirements.
• •MPs/NPs have been reported to transport various heavy metals and toxic chemicals. However, additional studies are required to understand their transportation and bioaccumulation mechanism. This will help in estimating risk exposure and toxicity.
• •The chemical precipitation, filtration, and membrane separation technologies adopted for MPs removal need further optimization to be economical. Also, additional research towards blending combinations of various physical, chemical, and biological processes to remediate the MPs/NPs. Effective tertiary treatment options are needed to reduce the MPs/NPs load on effluent and the environment along with other green strategies.
• •Data from various regions can provide details about MPs’ pollution as a function of geographical regions and human behaviours and developmental activities, which can help make effective strategies for controlling the MPs at their origin.
• •Advanced techniques like remote sensing, satellite image processing, low-cost sensors, and data analysis can help predict the transport route and concentrations of MPs/NPs after being released from WWTPs.
• •Most of the MPs removed from WWTPs are retained in primary and secondary sludge. The major stake of sludge is applied in the agricultural field as fertilizers, resulting in further leaching of MPs into land and ultimately entering the environment. Hence, it is necessary to manage the sludge containing MPs from WWTP to prevent the re-entry of MPs into the environment. Some available alternatives to sludge management include incineration, anaerobic digestion, lime stabilization and selective floatation. These methods have proven to remove MPs effectively, but none of these methods is optimal, providing the researcher opportunities for further studies.
• •The MPs separated from wastewater can be carbonized to produce value-added carbon material to use as a catalyst for the degradation of pollutants. Such attractive novel concepts eliminate the need to dispose of or manage separated MPs.
• •Developing devices to collect the microfibres from the laundering process can also reduce the microfibres entering the sewage and WWTPs.
• •Policies toward restriction on the use of microbeads in cosmetics and other personal care products and industrial applications should be implemented by authorities to reduce the source of MPs."