While sanitation is fundamental for health and wellbeing, cities of all sizes face growing challenges in providing safe, affordable and functional sanitation systems that are also sustainable. Factors such as limited political will, inadequate technical, financial and institutional capacities and failure to integrate safe sanitation systems into broader urban development have led to a persistence of unsustainable systems and missed opportunities to tackle overlapping and interacting urban challenges. This paper reviews challenges associated with providing sanitation systems in urban areas and explores ways to promote sustainable sanitation in cities. It focuses on opportunities to stimulate sustainable sanitation approaches from a resource recovery perspective, generating added value to society while protecting human and ecosystem health. We show how, if integrated within urban development, sustainable sanitation has great potential to catalyse action and contribute to multiple sustainable development goals.

Globally, more than 60% of the human population live without safely managed sanitation services or even lack access to basic sanitation facilities. In addition, most of the wastewater produced in the world is discharged without proper treatment. Integrated approaches are needed to address these issues and curb the resulting adverse impacts on public health and the environment, and associated societal economic losses. The United Nations 2030 Agenda for Sustainable Development provides an important framework towards more sustainable sanitation development, in terms of both safe sanitation access and wastewater management. Innovative solutions that treat and enable productive safe use of water, and facilitate recovery of nutrients and organic matter from waste resources are booming. Some examples of trends are decentralized solutions, separation of waste flows, low-or no-flushing toilets, and converting faecal sludge to energy. These alternative technologies show huge potential to address many development challenges, contributing to multiple sustainable development goals but achieving upscaling has proved to be a major challenge. A paradigm shift to ‘treatment for reuse’ instead of ‘treatment for disposal’ is already taking place in the wastewater sector. Nevertheless, a better understanding of driving forces and enabling environments, new organizational models based on more service-oriented sanitation provision, and highlighting potential multiple societal benefits to attract investments from new sectors are identified areas that need further attention.