Taboos, toilets and biogas: Socio-technical pathways to acceptance of a sustainable household technology

Toilet-linked anaerobic digesters (TLADs) can provide users with a clean gaseous fuel and a fertiliser product as well as offer waste management services. Socio-cultural resistance towards domestic TLADs, due to the use of human excreta as a feedstock, is often articulated as a finite barrier to adoption. However, no research has specifically investigated the issues associated with TLADs separately from those associated with domestic digesters without toilet connections, consequently, there has been little attempt to discover what motivates users to use TLADs. Drawing on qualitative data from Nepal this paper explores how socio-cultural resistance impacts TLAD adoption and subsequent use of the biogas, and how adoption and transition pathways evolve. We argue that socio-cultural resistance is not a finite barrier to adoption and the opportunity to observe or trial a TLAD can positively influence adoption, especially amongst the older generations. Technical issues affected how TLADs were utilised more than socio-cultural norms and we discuss how socio-technical factors might co-evolve to influence sustainable adoption and use of TLADs. Caste and gender were not found to influence adoption pathways as much as the leadership or ‘risk-taking’ characteristics of specific adopters. Adoption of TLADs can occur within a year of a user first observing or trialling a TLAD; however, most users still do not use biogas for ritual cooking, despite having had a TLAD for many years. Grassroots initiatives that understand the diversity of localised socio-cultural norms will likely be imperative for successful TLAD dissemination. •Socio-cultural norms can adapt to allow adoption of human excreta derived products.•Technical and socio-cultural factors affecting adoption must be investigated together.•Multiple socio-technical pathways to adoption of toilet-linked anaerobic digesters identified.•Opportunities to trial toilet-linked anaerobic digesters positively influences adoption.•Initial adopters have an important role in wider adoption of the taboo technology.