S&L Ventures has been named the ‘winner’ of the WaterCampus Business Challenge. Co-founders Hannah Seong and David Logeman have developed an innovation that tackles a persistent problem in agriculture: nitrate pollution.
Nitrate pollution of water and soil is a sensitive issue for policymakers. S&L Ventures (formerly Seaweedlink) sees it as an opportunity. The company, based in Wassenaar, has developed a technique that removes excess nitrates from water and soil and reuses them.
At the heart of this is SolPhyX, a carbon-based composite material to which nitrate particles actively bind. The material can be deployed in areas with high nitrate concentrations, such as ditches alongside farmland. Once saturated, it is not disposed of as waste but reused as a slow-release biofertiliser. In this way, nitrogen remains within the cycle rather than polluting the environment.
The technology is still at an early stage, as co-founder David Logeman explains. “Laboratory tests show that the material can effectively absorb nitrates from water. The next step is field research, in collaboration with farmers. This will examine how the system performs under realistic conditions, for example in ditch water. Together with water authorities, we then aim to scale up to larger pilot projects.”
Incidentally, the term ‘winner’ at an event such as the WaterCampus Business Challenge is somewhat relative. After a week of knowledge sharing, reflection and networking, all twelve participants felt they were returning home as winners.
Articles about all twelve participants will appear in the upcoming summer edition (2026) of WaterProof Magazine.
The WaterCampus Business Challenge was powered by WaterCampus, Wetsus, Water Alliance, New ttt and UPPWATER.
