How algae pearls remove pollution from water

A green solution to a growing problem.

The Dutch and water go way back. Over centuries, we turned that relationship into a way of thinking: work with what you have, and design systems that turn a challenge into an advantage. That principle has now gone microscopic. In Arnhem, a student discovered that algae pearls can pull nitrogen and phosphates directly out of polluted water. And that student is Bas Emaus. He and his team built JiTiBa Algae Technologies: a system where algae does what they do best, only faster and at scale, without chemicals or heavy infrastructure.

The Netherlands faces, just like many other countries, environmental pressures. Our tap water is clean, yet our surface water is among the poorest in Europe. Rivers and canals fail to meet ecological standards, nitrogen and phosphate levels remain too high, and wastewater treatment facilities work hard yet still release effluent that contributes to pollution. JiTiBa steps in at the final stage of purification. Their so called ‘algae pearls’, tiny porous gel beads filled with microalgae, soak up what conventional systems miss. As treated wastewater flows past them, the algae trap nitrogen, phosphates and even heavy metals. What remains is cleaner water that meets the stricter regulations coming into force in the years ahead.

The benefit is not just cleaner rivers. Once the pearls are full, they are harvested and processed into new, usable materials. What enters the system as pollution leaves it as something useful, from organic fertilisers to ingredients for circular construction materials. This is where JiTiBa’s thinking becomes distinctly Dutch: waste is treated not as a burden, but as an opportunity. The technology creates a loop where nothing is lost and everything has value.

Algae that turn waste into value

The idea began the moment Bas Emaus noticed algae covering the Waal during a warm summer. He quickly asked himself: what could algae do in controlled conditions? He then built an early prototype with fellow students, starting with old aquarium tanks and a handful of ideas. The science was sound, but early applications proved commercially unviable. Instead of stopping, he looked elsewhere. Wastewater facilities produce huge amounts of sewage sludge every day. Disposing of it is costly. Emaus realised that algae thrive on this sludge and absorb its contaminants. What began as an experiment became a breakthrough: a biological system that grows on waste, cleans water and produces new resources, all at the same time.

Wastewater purified using algae.

Algae pearls, which absorb nitrogen, phosphates and other polluntans form the water.

JiTiBa’s progress is also a story of the Dutch approach to innovation. Emaus spoke to hundreds of people, from researchers and engineers to policymakers and industry leaders. Each connection opened another door. Partnerships followed with organisations working across the water chain, giving the startup the scientific grounding and operational scale needed to move from university project to working technology. The system now operates from Cleantech Park Arnhem, with the first prototype already sold and new pilots underway. Automated pumps, modular designs and low-maintenance operation make it suitable for both small facilities and large municipal installations.

The next step for cleaner water

By polishing effluent before it reaches rivers, JiTiBa reduces pollution at the source and supports wider ecological recovery. Healthier waterways mean fewer algal blooms, stronger biodiversity and cleaner ecosystems, all essential in a densely populated delta. More broadly, it helps ease the nitrogen crisis, supports the shift to circular materials and brings the Netherlands closer to meeting its water-quality commitments.

JiTiBa is now preparing to scale its technology with partners across the water sector. And Emaus, even as he advances his studies in biotechnology, continues to refine a system that promises to turn one of the country’s biggest environmental challenges into a tool for regeneration. In the Netherlands, waste is just a resource waiting for the right system. That’s New Dutch!