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New research explores ‘toilet-linked’ AD potential

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Research by the University of Stirling will help decision-makers understand and overcome the barriers preventing the uptake of 'toilet-linked' biogas technologies.

One pioneering process enables home toilets to be connected to an anaerobic digester, which converts the waste into biogas for use as a clean cooking fuel, and fertiliser to improve soils. However, despite its efficiency, the university said recycling human waste in this way is uncommon because it is considered ‘unsavoury’.

Multidisciplinary researchers from Stirling conducted in-depth interviews in Nepal, where uptake of toilet-linked anaerobic digesters (TLAD) is high, to understand how people overcame their aversion. Those who adopted TLAD improved their home sanitation, indoor quality and use of resources, the study found.

“I believe we have all the technology and the means to solve the world’s problems, but whether we are using it or not often depends on social factors,” said Natalie Boyd Williams, a PhD researcher in the division of Biological and Environmental Sciences at the University of Stirling.

“Particularly in the West, decision-makers often make assumptions about what people will or won’t accept – meaning that they don’t properly explore how certain technologies can be adopted. There has been community resistance to wind farms and biogas plants, for example, that has been dismissed and overlooked by developers, when engagement with these communities can, in fact, lead to acceptance.

“We wanted to challenge the assumption by exploring how an initially unacceptable technology – in this case, TLADs in Nepal – can become widely adopted. This is understood in Nepal, but less so outside it.”

Boyd Williams noted biogas is a clean cooking fuel compared to traditional wood fuel, and liquefied petroleum gas, which relies on fossil fuels.

“The closed, circular system of TLAD improved sanitation and provided fertiliser for crops,” she said.

“Lastly, adoption can take time – some had to wait for the older generation to die to adopt it. Policymakers and organisations should be prepared to demonstrate the technology, show the benefits, and be prepared for people taking time to get used to new technologies that they find challenging.”

The research was carried out with Durham University as part of an IAPETUS Doctoral Training Partnership, funded by the Natural Environment Research Council. The paper, ‘Taboos, toilets and biogas: Socio-technical pathways to acceptance of a sustainable household technology’, was published in Energy Research and Social Science.