Summary

This project aims to explore the mechanisms and develop sustainable strategies to mitigate microplastics pollution in wastewater.

Project background

The accumulation of plastics in the aquatic environment is a global issue of emerging concern. Anthropogenic waste, 70% of which is plastic, has increased exponentially in the last decades. More than half of plastic becomes waste in less than a year from its production and most of it is not recycled or reused. Small plastic particles known as microplastics (MPs) represent about 92% of the total plastic waste and have been detected all over the world, from the poles to the equator, from coastal regions to aquatic ecosystems. Many organisms can ingest MPs, which are eventually transferred to humans through food chains. MPs can cause toxic and adverse effects on organisms, including endocrine disruption, mortality and delayed ovulation.

Wastewater Treatment Plants (WWTP) could be potentially one of the major sources of MPs. For example, microbeads used in facial scrubs, toothpaste, and other personal care products are transported in the raw effluent to WWTP where, because of their small size, they may bypass the treatment process. Furthermore, conventional biological processes cannot effectively destroy persistent and toxic organic compounds. Advanced oxidation processes (AOPs) have proven effective for the treatment of such biologically recalcitrant pollutants. The key advantage of AOPs is that they generate, in-situ, reactive oxygen species, which, in turn, react with the pollutants and eventually mineralize them to safe final products. Using an appropriate AOP, such as electrochemical oxidation, as post-treatment to conventional biological treatment could contribute to MPs removal.

Research questions

To what extent can electrochemical-based treatment technologies affect MPs in aqueous environment?

Which technologies could be coupled with oxidation treatment to enhance MPs removal?

What are the degradation mechanisms and pathways of MPs during wastewater treatment?

Could circular economy be applied to mitigate MPs pollution in wastewater?

Methodology

The following experimental tasks will take place to successfully address the project’s research questions:

Task 1. Electrochemical oxidation of microplastics in water.

Task 2. Coupling electrolysis with other oxidation, adsorption or filtration treatment technologies.

Task 3. Development of microscopy and analytical methods to monitor MPs and detect their degradation products in water. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) will be used. Gas chromatography (GC-MS) and/or liquid chromatography (HPLC) analytical protocols will be developed to quantify by-products in water samples.

Task 4. Application of circular economy concepts will be explored. Appropriate experimental set ups will be studied at bench scale.

Training

A comprehensive training programme will be provided comprising both specialist scientific training and generic transferable and professional skills.

Requirements

Student should have a solid background in Chemical Engineering, Civil and Environmental Engineering, Chemistry or Physics with fundamental knowledge in Water and Wastewater Systems. Basic knowledge on analytical chemistry and material characterisation techniques will also be desirable.