Microplastics research team welcomes Dr Fisayo Olotu
Published on: 16 Oct 2023
Read moreThe Water Research Centre (WRc) and Queen Mary University of London (QMUL) have joined forces to develop an advanced method for detecting microplastics in water—in real time and at the point of use. The programme blends WRc’s applied innovation and environmental monitoring expertise with QMUL’s internationally recognised leadership in terahertz (THz) electronics to close a critical evidence gap in water quality monitoring, management and regulation.
Dr SaeJune Park (QMUL) is leading the project, with Chi Him Liu serving as the PhD researcher. The project is supervised by Dr Imad Ahmed (WRc) and supported by Dr Leo Carswell. Funding is provided by the Engineering and Physical Sciences Research Council (EPSRC) and the WRc.
Dr SaeJune Park (right) with PhD researcher Chi Him Liu (“Jerry”) pictured in the Terahertz Laboratory at the School of Electronic Engineering and Computer Science, Queen Mary University of London
Project overview
Microplastics—plastic particles between 1 micrometre (µm) and 5 millimetres (mm)—are an increasingly recognised challenge for the environment, public health and water systems. Small enough to enter ecosystems and food chains yet large enough to be characterised by modern techniques, they sit at the centre of current monitoring practice and regulatory attention. While nanoplastics below one micrometre raise separate questions, this phase of work concentrates on the established microplastic range that regulators define and the scientific community can validate with confidence.
Figure 1. Microplastics in everyday life: Tiny plastic particles originating from bottles, packaging, personal care products, textiles, e-waste, and other materials are routinely shed into the environment. These microplastics can enter rivers, reservoirs, and drinking-water systems, creating pathways for human exposure through water and food. Their widespread presence has raised growing concerns about potential risks to public and environmental health.
The QMUL-WRc team is developing a terahertz (THz) metamaterial sensor that facilitates real-time microplastic detection to the point of sampling. By translating advanced physics into a practical, portable device, they seek to enable quicker, more frequent, and more accurate measurements in operational environments. Their goal is clear: to provide reliable, timely data that supports better decision-making, stronger policies, and the protection of both the environment and public health. Dr Imad Ahmed, Head of Innovation at WRc, said:
Real-time, In-situ detection is the crucial missing link for credible, routine microplastics monitoring. Our partnership with QMUL focuses on translating advanced terahertz science from the lab into operational use—providing practical, regulation-ready tools that enable utilities to make quicker, better-informed decisions and demonstrate progress.
How it works: THz metamaterial sensing of microplastics
At the core of the platform is a THz metamaterial surface patterned with micro-scale resonators that concentrate electromagnetic energy into ultra-small, highly sensitive gap regions. Using a combination of high-resolution 3D printing and lithography, the geometry of these resonators can be tuned with micron-level precision, enabling rapid design iteration for specific sensing tasks and water matrices.
As water passes through a microfluidic channel above the metasurface, microplastic particles are guided across the active region. When a THz wave interrogates the sensor, the presence of plastic in or near the gaps subtly alters the local dielectric environment, resulting in a measurable shift in the resonant frequency. That shift encodes information about particle size, shape, and composition, including aspects of chemical bonding, without labels, dyes, or destructive preparation. Because the interaction is non-contact and immediate, the system is being engineered for real-time, at-source measurements in treatment works, distribution networks and natural waters.
Figure 2. Real-time microplastic characterisation using a terahertz (THz) metamaterial sensor. Water samples containing microplastic particles are introduced through a microfluidic distribution chip (top), which directs flow over a metasurface composed of high-resolution metamaterial unit cells (bottom left). When a THz wave interacts with this surface, microplastic particles entering the electromagnetic hotspots of the resonators cause shifts in the transmitted THz signal. The plot (bottom right) illustrates simulated transmission spectra for three common polymers—Polyvinyl Chloride (PVC), Polyethylene Terephthalate (PET), and Polypropylene—demonstrating how particle type influences the spectral response. These material-specific signatures enable label-free, non-destructive identification of microplastics directly at the point of use.
Dr SaeJune Park, Senior Lecturer in Terahertz Electronics at Queen Mary University of London, explained:
Terahertz metamaterials provide precise control over microscale particles. We are developing this capability for real-world water environments by optimising the metasurface, microfluidics, and read-out systems for improved sensitivity, robustness, and usability. We highly value our close collaboration with WRc in order to accelerate progress.
What to expect next
This programme is progressing through laboratory design, simulation and prototyping. The current focus is on optimising the metasurface for operation in real water matrices, integrating microfluidic handling for continuous sampling, and progressing towards a miniaturised, on-chip system suitable for pilot trials. Over the coming months, the team will report on metasurface fabrication and performance in controlled water matrices, as well as on models for particle characterisation. As results are validated, findings will be shared through conference papers and peer-reviewed publications, with periodic updates on the WRc website.
A responsible pathway to impact
While the goal is ultimately real-time, at-source sensing, translation to field use will follow a measured pathway—bench validation, inter-comparison with established laboratory workflows, and independent verification of accuracy and reproducibility. This staged approach reflects WRc’s commitment to robust evidence and the needs of regulators and operators for transparent, defensible data.
Stay informed
Media and academic enquiries are welcome at ventures@wrcgroup.com. Please quote “THz Microplastics” in the subject line.
This research is funded by the Engineering and Physical Sciences Research Council (EPSRC) and supported by WRc, in partnership with Queen Mary University of London.