Treating wastewater is a very energy intensive process, and it accounts for about 3% of energy use in the U.K. It is also a vital process as it removes pathogens and protects the environment. Severn Trent, a water and waste company, was searching for a more energy-efficient means of treating wastewater and turned to the WMG at the University of Warwick for help.  

Building on research into Microbial Electrolysis Cells, a process using electromagnetic microorganisms to break down organic pollutants in wastewater to produce clean water and hydrogen gas, the team at the University of Warwick implemented a more sustainable method of treatment, using recycled carbon fiber mats to produce hydrogen from the wastewater. Testing proved that the bacteria developed on the recycled carbon fiber anode had better temperature tolerance and produced more hydrogen than previously used materials.  

A pilot project ran at Severn Trent’s Minworth waste treatment site and the process produced 18 times more hydrogen (at 100% purity) than the previously used graphite material while removing 51% of organic pollutants and up to 100% of suspended solids from the water. The hydrogen gas can be sold for use in hydrogen fuel cells for energy storage or electric vehicles or for other purposes. 

Dr. Stuart Coles, leader of the research team at the 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.” Dr. Coles continued, “The next phase of this work is look at optimizing 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!” 

Bob Steer, chief engineer at Severn Trent explained, “The performance boost and cost savings demonstrated from this research mean that MEC technology is one step closer to being cost competitive with existing wastewater treatment assets. WMG have also demonstrated that this technology has the potential to create a more circular wastewater treatment process which will be essential to delivering on our long term sustainability goals and Net Zero plans.”