Trialling urine diversion in Australia: technical and social learnings Kumi Abeysuriya, Dena Fam and Cynthia Mitchell ABSTRACT This paper discusses a urine diversion (UD) trial implemented within the institutional setting of the University of Technology Sydney that sought to identify key issues for public UD and reuse systems at scale in the Australian urban context. The trial was novel in its transdisciplinary action research approach, that included consideration of urine diverting toilets (UDTs) as socio-technical systems where interactions between users’ practices and perceptions and the performance of the technology were explored. While the study explored a broad range of issues that included urine transport, reuse, and regulations, amongst others, the boundary of the work presented in this paper is the practicalities of UD practice within public urban buildings. Urine volume per urinal use, an important metric for sizing tanks for collecting urine from waterless urinal systems in commercial buildings, was also estimated. The project concluded that current UDTs are unsuitable to public/commercial spaces, but waterless urinals have a key role. Kumi Abeysuriya (corresponding author) Dena Fam Cynthia Mitchell Institute for Sustainable Futures, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia E-mail: Kumi.Abeysuriya@uts.edu.au Key words | Australian, commercial buildings, nutrient recovery, social learning, transdisciplinarity, urine diversion INTRODUCTION As the world faces multiple environmental, economic and resource constraints, there are strong drivers for transition- ing to sanitation systems that enable resource recovery and reuse, reduce environmental pollution, and reduce costs. Urine diversion (UD) and reuse has potential to contribute to this vision on many fronts. Urine contributes approxi- mately 80% of nitrogen and 50% of phosphorus to the domestic wastewater stream (Larsen et al. ) that could be captured for agricultural applications. The phosphorus content in urine is particularly pertinent in the context of growing demands for finite mineral phosphorus resources that requires finding ways to recycle phosphorus, an essen- tial input for food production (Cordell et al. ). Reducing nutrients in wastewater also reduces resources and energy needs for sewage treatment, and reduces nutri- ent pollution and eutrophication in receiving aquatic environments (Larsen et al. ; Wilsenach & Loosdrecht ; Jönsson ). Implementing new socio-technical systems at any signifi- cant scale requires a co-evolution of technological and mutually reinforcing institutional and socio-cultural trans- formation (Geels ). For UD systems, these would include developing new regulations and institutional arrangements; new articulations of personal responsibility (e.g. behavioural change, socio-cultural habits and prac- tices); stimulation of markets for urine products and new technologies, amongst others. Experimentation is a key step in facilitating such transitions through learning about the potential of UD across the multiple dimensions of the system, in collaboration with a broad range of stakeholders from industry, government and civil society, as well as those directly involved in the use and maintenance of UD systems (Mitchell et al. ). This paper presents some insights from a transdisciplin- ary action research project implemented within an urban institutional setting to illuminate a range of interdependent factors that determine the viability of UD in the Australian context. Since institutional/commercial buildings in cities are where populations converge, they must be part of a resource-efficient sanitation system. The project at the Uni- versity of Technology Sydney (UTS) involved an on- campus trial of a system to collect urine from UD toilets and waterless urinals, for reuse in pot trials at the agricul- tural campus of University of Western Sydney (UWS). It 2186 © IWA Publishing 2013 Water Science & Technology | 68.10 | 2013 doi: 10.2166/wst.2013.473