Swiss Startup Turns Urine Into Certified Fertilizer — Europe’s First Aurin

Most people rarely think about what happens to their urine after it flows away in a toilet. Swiss startup VunaNexus asks a different question: why not capture the nitrogen and other nutrients in human urine and turn them into a useful fertilizer?

How The System Works

Co-founders Nadège and David de Chambrier have built a compact wastewater-processing system that collects urine from dry urinals and urine-diverting toilets and channels it into a biological reactor. Inside the reactor, a two-stage bacterial nitrification process converts ammonium into nitrate, stabilizing the liquid and removing the characteristic urine odor within five to 10 days.

After nitrification, the treated liquid is filtered to remove micropollutants, pasteurized to ensure safety, and concentrated using a distillation step. The process yields reusable distilled water and a concentrated fertilizer product called Aurin, which VunaNexus describes as Europe’s first certified urine-based fertilizer. According to the company website, the system is automated, can be monitored and operated remotely, and requires minimal maintenance.

Scale And Deployments

VunaNexus reports treating roughly 8,000 litres of urine per day (about 2,113 U.S. liquid gallons). The company has installations in six projects across commercial and residential sites, including one installation inside a major Swiss private bank. The system is designed for compact placement — for example, small treatment units can be installed in the basement of large buildings or urban infrastructures.

Origins And Support

The idea traces back to collaborative research with the European Space Agency (ESA). ESA’s MELiSSA project studied regenerative life-support systems that recycle nutrients from human wastewater for long-duration space missions — an approach that inspired VunaNexus’s on-Earth application. The startup now works with technical support from the ESA and other partners.

Environmental Benefits

Recovering nutrients from urine tackles several environmental problems: it prevents nitrogen and phosphorus from entering waterways, reduces the need for fossil-fuel‑intensive synthetic nitrogen production, and lowers water waste and greenhouse-gas emissions associated with conventional fertilizer manufacture. As Nadège put it, "Today we consider this as a waste; we want to recycle it and close the nutrient loop."

David de Chambrier: "Our vision is that in the future, most large buildings in dense city centres will have technologies to recycle nutrients from urine."

VunaNexus positions Aurin as a practical, certified alternative that can be sold in bulk to farmers or used by consumers for houseplants and gardens, turning a daily waste stream into a circular-resource solution.