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Wirijn Tholen is certain he’s struck gold. Well, maybe not literally, but with a device that ingeniously filters water, removing bacteria like Legionella. It’s particularly useful in places where water quality isn’t reliable. Even here in the Netherlands, water filters are finding more demand. They’re being used in campers, sailboats, and places with stored water where water quality can’t be guaranteed. “We’ve essentially managed to fit advanced technology into a small device,” says Tholen, owner of the Hague-based company.

Rainwater

How does it work? Tholen explains: “There are various ways to purify (contaminated) tap water, rainwater, or other water. Our device works completely differently from all other water filters.” The invention, originally his father’s and further developed by him, makes it easy to filter (drinking) water without the use of electricity.

He points out that even Dutch tap water contains viruses and bacteria. “It’s the concentration that can make you sick. In the Netherlands, the concentration is so low that the water is safe to drink and use. This is closely monitored here. But if you heat water, you get exponential growth of, among other things, Legionella between 20 and 50 degrees Celsius. If you take in too much or your immune system is low, you can get sick. At a minimum of 60 degrees, viruses and bacteria die, hence the requirement to heat shower water to 60 degrees.”

Salt Blocks

Another way to prevent bacterial growth is with disinfection methods like Sensiblue’s. The entrepreneur shows the device—a plastic cylinder with a turbine on it—to demonstrate how it works. Users must first fill the cylinder with salt blocks. As water flows through the device, the small turbine generates power. This current is applied to the water, oxidizing the salt and disinfecting the water. The water flowing out on the other side of the device is then safe for use. “There’s a tiny amount of chlorine in the water, but you can’t taste it.”

Wirijn emphasizes that this technology is entirely different from that in other water filters. In electrolysis, electricity is applied to water to split it into other substances, producing oxygen and hydrogen gases. “This technique is also used in swimming pools and data centers, but it hadn’t yet been achievable with a compact device like ours.”

Reliable

The first Sensiblue devices were initially sold mainly abroad, in areas with unreliable water quality. “But that didn’t go very well,” admits the Hague entrepreneur. Besides ineffective marketing, there were frequent issues with leaks. This prompted Wirijn, who took over the company from his father, to halt production of the old product and develop a completely new device that, as he claims, is 100% reliable. Large international investors see great potential in the patented technology and have invested millions to further develop the product.

And this seems to have paid off. The product will soon hit the market. Final tests are currently being conducted at the factory on Televisiestraat in The Hague, but within a few months, the first Sensiblues will be available from distributors both domestically and internationally. Consumers can also purchase the device directly from the company. The plan is to produce 5,000 Sensiblues next year, with numbers set to increase later. Part of the production takes place in a factory in Bleskensgraaf, while assembly is done in The Hague.

Wirijn expects high demand for his product. “There are 25 million people in Europe alone with their own water source,” he notes. “And there are even more worldwide.” Distribution is also not a concern, as one of their shareholders is a multinational with 40 locations globally.

It’s Cheaper than a Boiler

The entrepreneur is currently in talks with a Dutch municipality that wants to use Sensiblue for a large-scale heating network. The water in this network runs below 60 degrees, but in the Netherlands, it must be above 60 degrees to kill Legionella bacteria. With Sensiblue, no boilers or other measures are needed to increase the water temperature. Sensiblue can disinfect up to 1,000 liters per hour, enough for two people to shower per hour.

Since the device itself doesn’t need electricity, it also saves consumers money. “It will cost about 500 euros. But it saves between 500 and 1,200 kilowatt hours (kWh) per year, which is about 300 euros annually,” Wirijn quickly calculates. “So it’s cheaper than a boiler, which would be needed to further heat the water, and it pays for itself in two to four years.”

Patent

Since it doesn’t require electricity, the Dutch-made device is ideal for use in disaster and conflict zones. “This way, you can still have safe drinking water in such areas.” The cost of the necessary salt is also manageable. “With 1 kilogram of salt, you can disinfect about 70,000 liters of water. A 25-kilogram bag of salt costs 15 euros and can last you around 25 years of showering.”

Wirijn had already secured a Dutch patent. But to prevent foreign companies from copying his invention, he also applied for an international patent, which was granted in June. The Hague entrepreneur is optimistic about the future. However, money is not his main motivation. “I’m mainly doing this because I want to make a positive impact on the world. I also plan to give away many Sensiblues to those who need them most.”