At the European Space Agency’s headquarters in Paris, the process of dealing with human waste takes a significant turn; instead of simply flushing away urine, it is transformed into a valuable resource. David de Chambrier, CEO of VunaNexus, emphasized that while urine-diverting toilets may conjure images of unpleasant festival facilities, the practice of reclaiming nutrients from urine is a serious and practical endeavor.
De Chambrier likened the nutrient recovery from urine to the extraction of minerals from discarded electronics. “Urine is a highly concentrated resource. This is not merely an eco-friendly trend; we are actively recycling essential minerals,” he explained. Just as discarded batteries require proper recycling methods, “separating urine at the source significantly simplifies its treatment process.”
Specialized toilets, designed to resemble typical restroom facilities, divert undiluted urine into a piping system that leads to a compact treatment facility located in the building’s basement. Within this facility, the urine undergoes a series of processes designed to eliminate micropollutants, including antibiotics, while concentrating vital nutrients such as nitrogen and phosphorus, which are critical for plant growth. The treated liquid is pasteurized at 90 degrees Celsius, effectively eliminating any viruses or pathogens. The purified water is then reintroduced into the flushing system, while a liquid fertilizer known as Aurin is produced as a byproduct.
Aurin, developed by the Swiss startup VunaNexus, is the only mineral fertilizer derived entirely from human urine that has received market certification. It has been authorized for use on a variety of plants by Swiss and French regulatory bodies and is marketed to farmers, gardeners, and home plant enthusiasts. Additionally, it is currently being evaluated by city officials in Paris, Lausanne, and Zurich.
Prior to the onset of the conflict in Ukraine in 2022, which caused a surge in fertilizer prices, de Chambrier noted that the concept was often dismissed as overly idealistic. However, the current geopolitical climate has shifted perceptions. The control of the Strait of Hormuz, a key passage for a significant portion of the global trade in raw materials for fertilizers and liquefied fossil gas, has highlighted the fragility of the fertilizer supply chain and prompted increased interest in alternative solutions.
The United Nations has warned that 45 million individuals face acute hunger due to rising fertilizer costs and supply disruptions, which threaten food security in many impoverished regions.
Currently, the VunaNexus system is operational in multiple large-scale commercial and residential complexes, including a major private banking institution in Geneva, processing approximately three million liters of urine annually. The technology is also being implemented in a new eco-friendly neighborhood in Paris, which is set to become the largest initiative of its kind in Europe.
De Chambrier stated, “If we could recycle all the urine produced by the population of Europe, we could meet about 30% of the region’s nitrogen requirements.” While this contribution may not fully revolutionize the fertilizer market, it offers a viable alternative that enhances the resilience of urban water treatment systems and mitigates the environmental impacts of fertilizers.
The origins of VunaNexus trace back to a groundbreaking research initiative in South Africa over a decade ago, aimed at creating a cost-effective sanitation system capable of producing urine-based fertilizers. Named Vuna, which translates to “harvest” in isiZulu, the project involved the installation of over 80,000 urine-diverting dry toilets in the outskirts of Durban. This initiative, co-led by the Swiss water research institute Eawag, focused on collecting, treating, and concentrating urine nutrients for use as natural fertilizer among local farmers.
While the fertilizer’s efficacy was validated through testing on maize crops, the high logistical costs associated with transporting, storing, and processing urine hindered the project’s scalability. De Chambrier acknowledged that achieving economic viability remains a significant hurdle, even in Switzerland, where producing one kilogram of nitrogen from urine can cost 40 to 50 times more than synthetic fertilizers.
For VunaNexus to compete effectively in the agricultural market, the company must increase its fertilizer production capacity and secure compensation for the wastewater treatment services it provides. In Durban, ongoing efforts by researchers and NGOs continue to explore enhanced urban sanitation solutions capable of generating fertilizers.
One such initiative seeks to implement a urine collection system utilizing low-tech street-level urinals in a central area of Durban, catering to thousands of informal workers who lack adequate sanitation facilities. An old water treatment plant, previously part of the Vuna project, is being refurbished to convert collected urine into fertilizer.
Richard Dobson, co-founder of the NGO Asiye eTafuleni, which collaborates with informal workers utilizing public spaces for their livelihoods, remarked, “We must rethink what is considered waste and how we can transform a public nuisance into a valuable urban asset.” He further noted that this project could establish “a beneficial closed loop,” where the urine collected from vendors in public areas is converted into fertilizer, benefiting local farmers and fostering dignified job opportunities while reinvigorating the local economy.
Simultaneously, Maano Tshimange, a researcher at the University of Surrey who grew up without access to a toilet in one of South Africa’s underprivileged provinces, is investigating methods to enhance the efficiency of an energy-saving technique designed to concentrate nutrients from urine using membrane technology.
