Uni of Warwick researchers able to power electric vehicles using sewage

The process has been extremely expensive until now

Author: Ellis MaddisonPublished 3rd Nov 2021

Researchers from the University of Warwick have figured out a cheap way to power electric vehicles using sewage.

Hydrogen, which can be harvested from wastewater, is a renewable energy source that can be used in hydrogen fuel cells for energy storage or electric vehicles.

The process of extracting hydrogen from waste water brings new economic and environmental opportunities, but it has since been very expensive to carry out.

However, using a recycled carbon fibre mat, researchers from Warwick University's WMG department have been able to extract hydrogen from sewage for Severn Trent.

Treating wastewater is vital for removing pathogens and protecting the environment, but the process uses around 3% of the UK's entire energy use, or 13 billion kilowatt hours.

A sample roll of graphene used in the carbon fibre mat

Severn Trent tasked Warwick Manufacturing Group researchers with a means of finding a less energy-consuming, more cost-effective means of treating wastewater.

After initially looking into Microbial Electrolysis Cells to solve the problem, which would see tiny graphite or carbon anodes break up the pollutants, the process was deemed too expensive.

Dr Stuart Coles and his team then refined the technique and discovered that recycled carbon fibre mats could act as an alternative anode.

Costing only £2 per square metre, the process is significantly cheaper than the existing anode materials, which would cost several hundred pounds per square metre.

When piloting the technique at Severn Trent's Minworth Waste treatment site, the researchers successfully processed 100 litres of water per day, removing 51% of organic pollutants and 100% of suspended solids.

They also produced 18 times more pure hydrogen, which can be sold to the chemicals and plastics industry, used for energy storage or in electric vehicles.

Dr Stuart Coles from WMG, University of Warwick with graphene

Dr Stuart Coles, from WMG, University of Warwick said:

“We are really excited about this technology. By taking waste from the automotive and aerospace sectors, we have developed a circular solution to a longstanding problem.

"Instead of just treating the wastewater, we are now able to extract value from it in the form of hydrogen at a lower cost than ever before.

“The next phase of this work is to look at optimising the design of the microbial electrolysis cells and further reduce the level of pollutants in the water. This in turn should help produce even more hydrogen.”

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