Sewage contains valuable substances that can be used as raw materials for biobased products. It is, however, a resource whose potential remains to be fully realized.
With topics like resource depletion and sustainability at the top of agendas everywhere, solutions are being sought in areas that have long remained unexplored. It is currently recognised that there are market opportunities for raw materials from sewage, but for these to materialise, the sewage treatment plants and the industry needed to be better aligned with one another. Moreover, the sewerage treatment plants would need to make the transition from simply treating sewerage to producing valuable materials, while the parties in the market would have to learn that sewerage was a valuable resource and not just dirty or contaminated water. New policies were also needed to fit with the new circular approach.
This led last year to the birth of the Interreg North-West Europe project WOW! – Wider business Opportunities for raw materials from Waste water. WOW! kicked off in June 2018, when 12 partners from 6 countries – the UK, France, Belgium, Germany, Luxembourg and the Netherlands – gathered together to plan the activities that would be part of the project.
To realize the opportunities presented by sewerage as a raw material, the consortium will seek to develop value chains for three separate raw materials derived from sewage: cellulose, PHA bioplastics and lipids.
To that end, the following activities will be deployed:
- High potential value chains for raw materials from sewage will be identified
- A Decision Support Tool that guides sewage treatment plants in their transition towards a circular approach on sewage will be developed
- Three WOW! pilots will be built to optimize and implement innovative recovery and upcycling techniques.
- Bioproducts made out of sewage, such as bioplastics, biofuel and bio-char will be created.
- National policy action plans and an EU policy roadmap will be compiled.
What has happened to date?
The Wupperverband – a member of the consortium – is building a pilot plant for the production of PHA bioplastics at the Buchenhofen wastewater treatment plant. Another participant in the project, Avans University of Applied Sciences, has been investigating the PHA production plant. The team has found a green solvent for the extraction of the PHA from the biomass, but the resultant plastic is an unappealing brown. The Avans team is now working to find a purification process that will yield colourless PHA.
The University of Luxembourg is also taking part in the project. Marie-Louise Uwizeye, a doctoral candidate at the University of Luxembourg, is designing a bioreactor for enhanced growth and lipid accumulation of a microorganism responsible for generation of sewage sludge rich in lipids. The bioreactor is first being developed in the lab after which it will be upscaled, implemented and tested in a real sewage treatment plant (Audun le Tiche, France).
The current recovery and reuse of wastewater-lipids is limited to biogas production in digesters. The residual (majority) of lipid potential in sewage is currently incinerated or landfilled.
Consortium member Severn Trent has been working to deliver energy neutral processing, recover the resources found in sewage and create products and materials for use in other sectors for the past five years already. Last week, the treatment plant announced it was building a resource recovery testbed that should be ready to host technology trials in spring 2019.
The test-bed will enable the plant to evaluate energy neutral sewage treatment and to recover valuable materials contained in sewage – such as fertilizers, bio-plastics, cellulose and even protein – that will drive revenues, by selling back to industry and ultimately cost savings for customers.
Peter Vale, the technical lead on the project said: “Partnering with experts across Europe through the Interreg NWE Project WOW! research programme, is hugely important in helping us deliver our resource recovery vision, through both the development of technologies and in developing the market for recovered products. “
WOW! is supported by the Interreg North-West Europe program.
The project will run through 2021.