Developing a safe and efficient method for the removal of micropollutants from water

University of Bath

A RESEARCHER at the University of Bath, UK, has been awarded a grant to develop the photocatalysis method of removing micropollutants from wastewater.

The removal of micropollutants from water is one of the biggest public health and environmental challenges facing the water industry. Micropollutants include highly toxic substances such as drugs, hormones, and pesticides. They are present in low concentrations in wastewater and slowly accumulate in the soil and groundwater, eventually finding their way into the food chain where they can become severe health hazards.

Current technology at most water treatment plants is incapable of removing micropollutants, requiring an additional treatment step. The UK water industry also accounts for 5% of UK carbon emissions, so there is an urgent need for efficient and low-carbon technologies which can safely remove micropollutants.

A promising method is photocatalysis, which uses light to increase the rate at which organic pollutants break down into non-harmful components. However, there are currently two drawbacks to this method. While photocatalytic nanoparticles mixed with wastewater in a slurry reactor will degrade micropollutants, costly downstream retention is required to stop the potentially-harmful nanoparticles from entering the environment. An alternative is to use a reactor where the catalyst is immobilised and therefore not mixed with the wastewater, but the immobilised catalyst has a lower activity due to a decreased surface area and higher scattering of the UV light.

Davide Mattia from the chemical engineering department at the University of Bath, UK, has been awarded five years of funding by the Engineering and Physical Sciences Research Council (EPSRC) to improve the photocatalysis technology. Mattia’s team are developing a technique that will forego the use of nanoparticles and replace them with a highly porous photocatalytic foam. As the foam has a large surface area, it will boost the activity of the catalyst, thereby addressing the problem of the low efficiency of UV light.

“I will be working with academic and industrial partners to retrofit existing water treatment plants to accommodate this new technology,” said Mattia. “We hope this will result in a more effective way of removing micropollutants in water without increasing carbon emissions or producing toxic by-products.”

Jan Hofman, director of the Water Innovation & Research Centre at the University of Bath added: “Removal of these compounds from drinking water and wastewater is extremely important for public health and aquatic life. The water sector has great need for innovations in this field, which Professor Mattia’s research can provide.”