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Water companies Severn Trent and Wessex Water are launching an open market challenge to potential new partners to find innovative new solutions for the treatment of wastewater ‘sludge’.  

The semisolid by-product of the wastewater treatment process, sludge can be processed into useful products such as biogas, which can be used to generate electricity via a CHP system, and biosolids for nutrient-rich agricultural fertiliser. 

While current methods rely on processes such as conventional or advanced anaerobic digestion, or the addition of lime, the partnership is keen to explore new methods that could further maximise the value of sludge, while minimising environmental impacts. 

Collectively, Severn Trent and Wessex Water treat over 320,000 tonnes dry solids of sewage sludge every year. Both companies operate anaerobic digestion processes to generate renewable electricity and biogas from the sludge, with the nutrient rich end product utilised by farmers.  

The companies have issued the challenge to the market to come forward with new ideas and methods as the industry faces an increase in demand for treatment capacity as a result of population growth and to drive greater innovation.   

A cornerstone of the challenge is to find a partner which can both deliver an operational plant by 2030 and contribute to broader environmental targets, including both companies achieving net zero carbon emissions by 2030, and Severn Trent’s goal of generating 100% of energy from renewable sources by the same year, as outlined in its triple carbon pledge. 

Any interested parties are invited to join a webinar on Wednesday 29 June where they can learn more about putting forward a submission ahead of the deadline of Friday 29 July.  

Declan Barlow, trading and biosolids manager at Severn Trent, said: “The treatment of sewage sludge is an important process that creates significant benefits for both energy production and agriculture. However, with growing populations and modern issues such as the prevalence of microplastics it is important that we consider how best to futureproof the industry.  

“This is why we are engaging the market to open discussions about what processes we can use in the future to meet growing demand while ensuring the quality of the biogas and biosolids produced.  

“It would be ideal if we could find a pioneering partner that can provide an end-to-end solution, including development and operation of the plant, with whom we can build a long-lasting relationship.” 

Will Wormald, sewage treatment planning engineer at Wessex Water, said: “Working alongside Severn Trent, we have a shared ambition to explore market options that offer the best value solution to the need for additional treatment capacity, while maximising the potential benefits of sludge, which is a valuable and sustainable resource. A joint approach using our open ‘Marketplace’ platform increases the potential for alternative approaches to be put forward, so we’re excited to see the proposals.”   

Interested parties can visit the Severn Trent and Wessex Water teams at stand C801 at The World BioGas Expo at The NEC on 15 – 16 June and to join a webinar on 29 June to hear more about the challenge.  

For more information on the challenge, how to join the webinar or for details around the submission requirements, visit: https://www.severntrent.com/sustainability-strategy/environment/bioresources/marketplace/challenges/regional-bioresources-treatment/ 

Questions and points of clarification should be submitted by 1 July 2022 to regionalbioresources@wessexwater.co.uk. 

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