A botanical effort to benefit both the wastewater treatment and aviation sectors is underway in the U.K. Northumbrian Water is pioneering the Green Machine project to transform algae grown in domestic sewage into sustainable aviation fuel (SAF). This approach offers an alternative to conventional jet fuel while enhancing wastewater treatment processes.

The goal is to use algae to extract nitrogen and phosphorous from wastewater, recover it and then convert it into sustainable fuels. Additional benefits include reductions in the environmental impacts of waste treatment and up to £1m ($1.2 million) annually in operational costs.

The research is underway in collaboration with U.S.-based BrightWave, which is providing the photobioreactors that are used to cultivate algae, and Ligoflux, a specialist filtration company that provides products for algae harvesting.

The Green Machine is expected to undergo trials at the Bran Sands Treatment Works, a major sludge treatment center, industrial effluent treatment site and gas-to-grid facility, in Teesside by the summer of 2025. Currently, the treatment process generates a challenging effluent that is costly to manage and contributes to the greenhouse gas emissions of the plant. Northumbrian has tested the remedial properties of microalgae to reduce treatment costs and the plant’s carbon footprint, and is looking to scale up the concept to provide full treatment of digested sludge liquor to yield biogas and SAF.