A consortium led by Thames Water has won more than £6 million from Ofwat’s first Water Breakthrough Challenge to help decarbonise wastewater treatment via the innovative use of cold anaerobic digestion processes.

Ben Martin, Lead Research Scientist at Thames Water commented:

“In collaboration with six other water companies, Welsh, Southwest, United Utilities, Scottish, Yorkshire, Northumbrian and the University of South Wales, we are setting out to transform wastewater.”

The water industry consumes between two and three per cent of the electricity produced in the UK - the same as around two million households - and around 55 per cent of the energy consumed by a typical sewage works is processing wastewater. Wastewater treatment typically contributes 30 to 40% of a water company's carbon emissions, mostly due to the release of nitrous oxide

Cold anaerobic treatment processes have the ability to reduce greenhouse gas emissions by 98%. In addition, by reducing electricity consumption by as much as 80%, the process will reduce operational costs helping to keep customer bills low.

Welsh Water has already built its first plant for low treatment or anaerobic treatment for a demonstration plant, which has been treating settled sewage for a couple of years now. To make the technology more beneficial for small sites, the water company is proposing is to adapt the demonstration plant to treat crude sewage.

According to Welsh Water, this will allow the removal of a treatment step and a reduction in sludge production by up to 96% which will make the movement of sludge for treatment at other sites almost redundant.

The consortium will work together to develop cutting-edge bioprocesses to reduce the energy required for wastewater treatment.

The innovative operation will cut nitrous oxide emissions – while recovering beneficial resources including phosphorus and nitrogen – and will form a major part of the UK’s target to become net zero by 2030.

Unlike aerobic wastewater treatment processes where nutrients can be recovered currently with carbon, anaerobic processes at will not directly remove ammonia and phosphorus.

The consortium will be undertaking a full lifecycle analysis of the processes being piloted and demonstrated to validate its benefits.

In addition to examining the performance of processes, not only in recovering and removing contaminants that are currently regulated, the companies will be looking at pollutants of emerging concern such as pharmaceuticals and microplastics as well.

Ben Martin from Thames continued:

“In parallel to those efforts, at Thames Water we're going to be developing a mobile pilot plant for testing on a cross section of sites that represent the UK water industries asset base. And these experiences will then be used to design and build a demonstration plant. And the final outputs will be a series of design guidelines that will enable the water sector to deploy the technology efficiently and effectively.

“ Cold anaerobic treatment has the potential to serve most of the UK population. Funding from this Ofwat Challenge will allow us to accelerate the adoption and rollout of the technology.”

Sarah Bentley, Thames Water CEO, said:

“I’m passionate about leaving a legacy for future generations, just like the Victorians did for us. So, I’m delighted that we’ve won this award, which will allow us to change our approach to the wastewater treatment process in a way that will reduce our carbon footprint. “

Prof Sandra Esteves, project lead at the University of South Wales, said:

“We have been at the forefront of R&D for anaerobic processes and recognise the importance that these bioprocesses can play in numerous sectors.

“The funding will enable the team to drive the novel concept integration and evaluate its impact in reducing society’s wastewater treatment energy footprint and in promoting sustainable resource recovery.”