From sewage to ‘sugar’ – United Utilities achieves UK first

United Utilities has achieved a UK first at Blackburn Wastewater Treatment Works by successfully trialling a groundbreaking technology to extract naturally occurring glucose from sewage.

The technology captures toilet paper from the untreated sewage and processes it to break it down into a glucose substance which could be used as a lower carbon product in industrial processes.

The trial has also demonstrated that the technology also has potential to improve the efficiency of the wastewater treatment process by increasing capacity at the site and reducing energy use.

Developed in the Netherlands, ‘Cellvation’ is being trialled at Blackburn as part of the £6.8m Biopolymers in the Circular Economy project. United Utilities is leading the project which is backed by Ofwat’s innovation fund.

Biopolymers are naturally occurring and include substances such as starch, gelatin, collagen and cellulose. Recovered glucose has numerous potential uses in manufacturing and energy processes including in bioplastics and biofuels.

Lisa Mansell, Chief Engineer, Innovation and Carbon, at United Utilities explained why the development is so exciting: “This project is demonstrating that we can capture useful by-products from sewage which can then be used as lower carbon alternatives to conventional polymers and plastics.

“Blackburn Wastewater Treatment Works serves a population of around 200,000 people – this means that millions of sheets of toilet paper end up there every day. Toilet paper is mainly made from trees or other plant materials and these all contain cellulose which is a form of glucose.

“This technology captures the toilet paper from the incoming untreated sewage water. It is filtered and compacted before enzymes and chemicals are added to begin the digestion process. The mixture is then heated for 48 hours to allow the cellulose material to be broken down and transformed into glucose.

There are numerous potential uses for biopolymers such as glucose, including in the production of biofuels and as an alternative material for manufacturing things like bioplastics and more sustainable detergents.”

United Utilities is working with partners to explore uses for the glucose including whether it could replace some of the oil-based biopolymers that are used in the wastewater treatment process.

Lisa Mansell added: “A second technology will also be trialled to recover biopolymers from the sewage sludge that is left at the end of the treatment process. This is an exciting project which has potential to deliver significant carbon reduction benefits for the water sector and many other industries in the UK.

“As well as providing us with useful products, biopolymer recovery can also help make our treatment processes more efficient by increasing available capacity or reducing our energy consumption."