Severn Trent Water pioneers "world-first," carbon-neutral wastewater plant

Severn Trent Water has unveiled plans to create the world’s first carbon neutral wastewater treatment plant, which it hopes will become a blueprint for decarbonising sewage works around the world.

Work valued at around £40m is set to start in September to transform the large Strongford site which serves Stoke-on-Trent, into the world’s first retro-fit carbon neutral plant. The idea is to install the most promising technologies at the single site to eradicate 34,000 tonnes of carbon a year.

The site is already home to advanced digestion and "gas to grid" technology. Among the new processes to be installed to reduce methane emissions and natural gas consumption and to produce additional biogas are:

• Actilayer from Suez – a cover for sludge plants which reduces levels of nitrous oxide through the use of catalytst and sunlight;

• cellulose recovery from Dutch company, Cirtec, to remove toilet paper from sewage and recycle it into a valuable, sustainable material that can be used as insulation or in construction products;

• digital twin technology with Atkins, Explore AI, Siemens and Xylem to optimise technologies and reduce energy consumption;

• a vacuum technology, from Eliquo Hydrok, to increase biogas extraction;

• ta digestion optimisation process, Ephyra, from Royal Haskoning DHV; and

• technology from thermal hydrolysis specialist, from CAMBI, to minimise the heat requirement in the digestion process.

The project is backed by all UK and Irish water companies and international Net Zero Partnership with Aarhus Vand in Denmark and Melbourne Water in Australia. Severn Trent is investing £28m; £10m will come from the latest round of Ofwat’s Innovation fund, and a further £0.9 million from Horizon Europe.

Severn Trent chief executive, Liv Garfield, said: “Combatting the climate emergency to protect generations to come is a challenge that requires everyone to reinvent ways of working. This commitment to create the world’s first carbon neutral hub has the possibility of changing the face of wastewater treatment worldwide. The impact of this cannot be underestimated given emissions from wastewater are 80% of our operational emissions, and the hub will solve that.

“Coming together to share ideas and collaborating to combat climate change is key, that’s why we’re committed to sharing our carbon neutral hub’s blueprint with all other water companies, so wastewater treatment plants around the world can be retrofitted with these new technologies that we’re rolling out at scale.”