Researchers at The James Hutton Institute have launched field trials of a pioneering wastewater treatment technology that could significantly reduce greenhouse gas emissions while improving operational efficiency across the UK water sector.
The trials mark a key step in scaling up ElecTrickle, a bioelectrochemical treatment process designed to enhance traditional trickling filters. Widely used across 60–70% of UK wastewater treatment works, these filters currently handle around a quarter of the nation’s wastewater but are also a notable source of emissions due to the biological processes involved.
The UK water utility sector produces approximately 2.5 million tonnes of carbon dioxide equivalent (CO₂e) annually, accounting for around a third of emissions from industrial processes and waste management. While three-quarters of this is linked to energy consumption, the remaining 25% stems from treatment processes themselves – an area ElecTrickle aims to address directly.
Developed through the Hydro Nation Crucible programme – an initiative launched in 2022 by Scottish Water and the Hydro Nation Chair to tackle net zero challenges -ElecTrickle emerged as one of the most promising concepts to reduce process emissions. The system builds on existing trickling filter infrastructure by introducing bioelectrochemical methods that limit the release of greenhouse gases generated by microbial activity.
Laboratory tests have delivered striking results, with emissions reduced by up to 90% and filtration efficiency increased threefold. The current field trials at a Scottish Water site will assess whether these gains can be replicated under real-world conditions.
If successful, the implications for the sector could be substantial. Retrofitting just 6,000 ageing trickling filters with ElecTrickle technology could reduce emissions by an estimated 140,000 tonnes of CO₂e each year—the equivalent of removing around 95,000 cars from UK roads. Increased efficiency could also ease pressure on infrastructure, reducing the need for costly plant expansions.
The project is a collaborative effort involving the University of Glasgow, with support from the Hydro Nation Chair at the University of Stirling, Scottish Water, and UK Research and Innovation (UKRI). It also forms part of the Wayfinder Programme led by James Hutton Scientific Services, with commercial applications now under consideration.
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Dr Xavier Alexis Walter, senior researcher at The James Hutton Institute and project lead, described the transition to field testing as a significant milestone. “It is an exciting moment as the technology leaves the laboratory to be tested in the field under real-world conditions,” he said. “If our collective efforts bear fruit in the real world, we will be thrilled to have identified and delivered a potential new solution for the UK’s sustainability portfolio.”
David Millar, Senior Innovation Fellow at the Hydro Nation Chair, highlighted the speed of development. “This collaborative approach to technology development has demonstrated how innovative ideas can be accelerated from concept to live field trial in less than five years,” he said. “We look forward to continuing our support… helping to scale the technology across the industry and drive meaningful progress towards reducing process emissions.”
With strong institutional backing and early performance data, ElecTrickle could represent a major step forward in decarbonising wastewater treatment – an often overlooked but critical component of the UK’s net zero ambitions.
