Intermediate dark fermentation as a platform technology for chemical recycling and biorefineries

Reducing dependency on external chemical supplies for wastewater treatment is a strategic priority for the water sector, in order to sustain a resilient treatment that is not exposed to availability and costs of chemical supplies. Separately, decarbonising the chemical supply for treatment plays a key role on the long-term ambition of water utilities to deliver a low carbon service to customers. This project will investigate the strategic role of biorefineries in generating bio-based materials that can substitute fossil-based fuels and chemicals.

In the short term, intermediate dark fermentation can offer a route to recover volatile fatty acids (VFAs) for internal use within wastewater treatment plants (WWTPs), suppressing the need for external carbon sources for biological nitrogen and phosphorus removal (BNPR) and providing a carbon neutral chemical source. In the longer term, VFAs, as the most versatile platform chemical extractable form sewage sludge, can be physically extracted or chemically/biologically converted to a range of high value products and fuels, with bioplastics, animal feed, biogas, hydrogen as examples. Although underexplored for sludge feedstocks, the potential of dark fermentation to generate green hydrogen is also a concomitant benefit.

This project aims to develop dark fermentation as an enabling technology for circular economy in the water sector.