Scientists “spend a penny” in the name of wastewater science

12/07/2023
Dr Xavier Alexis Walter, a senior researcher in water and wastewater management in a circular economy at The James Hutton Institute in Aberdeen, feeding his experiment.

SCIENTISTS at The James Hutton Institute are contributing more than just their grey cells to help reduce greenhouse gas emissions and energy use – thanks to a newly installed urinal.

The otherwise unassuming facility, at the independent research organisation’s Aberdeen campus, is collecting urine from staff to help advance a wastewater treatment technology using power-producing common microbes.

Every day in the UK, more than 11 billion litres of wastewater is treated at about 9,000 sewage treatment facilities, many of which use energy intensive processes that emit greenhouse gas emissions, including methane and nitrous oxide.

But by putting the microbes used to munch through wastewater contaminants into an electrical circuit, Hutton researchers have shown that those greenhouse emissions could be halved, while also producing power.

This could be especially beneficial in rural areas, where achieving the same cut in greenhouse gas emissions would otherwise require significant investment, but also in cities, where it could have energy saving benefits. 

Dr Xavier Alexis Walter, the senior researcher leading the project at the Hutton, says, “An estimated 1-3% of the UK’s electricity production is used in wastewater treatment, mostly in cities where the wastewater has to be aerated.

“We could potentially decrease this consumption significantly by using the natural electro-chemical capability of microbes to self-power the process. In large cities, where urban farming is becoming more popular – and necessary – we could replace more energy intensive treatment processes and also tweak the process to draw off nitrogen that can be used as fertiliser.”

Dr Walter’s experiments, focusing on wastewater treatment, require about 3.3 litres of urine per day (an average well hydrated person passes around 2.2 litres over 24 hours), which is why the urinal has been installed. 

A form of the technology has already been trialled to power lighting in a toilet block at an isolated school in Africa, after being successfully trialled over several years at Glastonbury Music Festival, using festival goers’ urine.

Dr Walter’s latest work, in collaboration with Scottish Water and the University of Glasgow, which showed the process could reduce greenhouse gas emissions by 50%, was funded by the Hydro Nation Chair Research & Innovation Programme, hosted by the University of Stirling through their Catalyst Fund.

The Catalyst Fund provides valuable pump priming funds to develop proof of concepts, trial and test technology solutions and leverage new funding to deliver next generation solutions to support Scottish Water’s ambitions to realise net zero.

Professor Andrew Tyler FRSE, Scotland Hydro Nation Chair at the University of Stirling, says, “As one of our first Hydro Nation Chair Catalyst Funded projects, following our Crucible on Process Emissions, we are excited by the research being delivered by Dr Walter. When funding this project, we were encouraged by the potential impact on offer from the dual stages and significant nitrous-oxide mitigation that could be possible. We are delighted that Dr Walter’s ambitions are being realised.”

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