'Grazing' robot from Valkenswaard helps turn river water into drinking water for South Holland
Even in a water-rich country like the Netherlands, a shortage of drinking water is looming. How are we going to solve that? Partly with an ingenious robot from Valkenswaard, which helps water company Dunea in South Holland turn river water into drinking water.
On the sandy soils of Brabant, clean drinking water can simply be pumped up from the ground. But that is far from how it works everywhere in the Netherlands. Dunea, which supplies 1.3 million residents of South Holland with tap water, has to make none-too-fresh river water suitable for pumping into the water mains. It is a challenge that keeps growing. Soon, this water utility company will get help from a robot developed and built in Valkenswaard.
Guill Steijvers of High Tech Alliance in Valkenswaard proudly shows off the large, square, stainless-steel robot. A substantial piece of equipment with a 115-metre-long hose and an electrical cable connected to a large container. „This device can clean a clogged sand filter while it is still in operation. That means it no longer has to be shut down for cleaning, as has been the practice up to now.”
Manually cleaning a sand filter is an enormous job. These are basins of 1,500 to 2,000 square metres, of which Dunea has around twenty across three locations in South Holland. They contain a metre of filter sand through which the water slowly seeps downward. A layer of sludge builds up on top of the sand and, after around a year, starts to obstruct the flow of water.
Inside the machine, the top layer of sand is treated in such a way that sludge particles are released from the sand grains, while the bacteria remain in place
„The sand is then laid dry and staff remove that layer of sludge,” says Steijvers. „But the useful bacteria that break down the dirt in the water are lost in the process too. It takes about two months for those bacteria to grow back so the system can do its job again. So a significant portion of those sand filters is always out of action.”
Grazing robot
And that is precisely while Dunea needs to increase capacity, since demand for tap water is rising sharply. „There were already plans to build extra sand filters, but the costs and space requirements are enormous. They were looking for other ways to clean the filters without shutting them down.”
That is where the eight engineers at High Tech Alliance could really get their teeth into the problem. „We developed a system that scoops the top layer off the sand. Inside the machine, this is treated in such a way that sludge particles are released from the sand grains, while the bacteria remain in place. In a separate compartment, the sand grains sink and the sludge can be sucked away. The sand, with its bacteria, goes straight back to where it immediately gets back to work.”
That is how the robot slowly grazes off the layer of sludge, Steijvers explains. „Fully automatically, so it can keep working day and night. It does need to be lifted out of the basin regularly and cleaned; all the facilities for that are in the service container.”
Positive impact
The components of the ‘grazing’ robot were produced in the region, and if Steijvers has his way, they will not be the last. „I expect Dunea will want one or two more robots. The great thing is that there is no competition in that world. Innovations like this spread quickly once they prove to work well. There is already plenty of interest from several water companies in England, Belgium and Germany that also work with sand filters.”
Steijvers founded High Tech Alliance in 2016 together with two partners. Besides this robot, we love developing products with a positive impact. For example, we are working with grid operator Alliander on a system to connect power cables for new connections more quickly. In healthcare, we are building an aid that allows patients to wash and dry themselves without needing a carer.”
Source: Eindhovens Dagblad, Harrie Verrijt 12-04-24
Curious how the sand filter robot works? Watch the video below