Circular Sanitation Systems – What would make the transition possible?

Managing the global sanitation crisis is one of the major challenges facing our generation. The World Health Organization estimates that 2.4 billion people in the world lack access to a proper toilet and the excreta from nearly twice that number is not safely managed.

Poor sanitation poses serious risks to human health through the spread of infection and pollutes our cities and waterways. Human waste contains nutrients and organic matter, which if safely recovered can contribute to a circular economy for agricultural and energy production. At the same time, if these resources end up in the wrong place they cause eutrophication of our waterways, which is a serious threat to a sustainable future. Modern wastewater treatment systems use large amounts of energy and chemicals to remove these resources from our wastewater.

However, if we could instead capture and reuse these resources it would make a significant contribution to achieving the Sustainable Development Goals. Thus, there is an urgent need for innovations that can both improve access to toilets for those who do not have it today and at the same time recover energy and nutrients.

To be able to safely recover resources in urine and feces, a functioning sanitation chain is required from "production" of excreta, through collection and treatment to reuse. This sanitary chain works poorly in many places in the world. This is because implementation of circular systems requires increased collaboration between many different actors, including households, service providers, and policy makers.

It requires not only the development of new technologies, but also the development of management arrangements and communication strategies to ensure that all actors within the system know and perform their role. In other words, creating sustainable sanitation systems means that we have to consider both social and technical factors.

My research focuses on understanding drivers and barriers for increased use of resource recovery systems in sanitation. Major research questions aim to quantify how these systems can contribute to sustainable development goals, but also how we can understand the decision-making processes that result in implementation (or not) of resource-recovery systems. I work with municipalities and decision-making organizations, using case study methodology and action research, to answer these questions.

The results show that the drivers for resource recovery are variable and not always linked directly to the nutrients recovered. For example, there can be other benefits of energy or water savings, which led to the decision to implement nutrient-recovery. In many cases, the major barriers for implementation of resource recovery are organizational rather than technical. In these cases, we have been testing planning and decision-support tools that may help organizations to identify management strategies and raise awareness about the multiple benefits of resource-recovery.

If we can gain a better understanding of how decisions are made in sanitation today and how resource recovery systems can be linked to the interests of key actors in the system, we can open the door for change in the sanitation sector.