If you go to the toilet after taking a painkiller or anti-inflammatory, not only your urine or faeces end up in the sewage water. Some of those medicines also end up in the water and that is harmful to nature. In Oijen they can now remove up to seventy percent of these residues from the water for the first time in Brabant.
Due to climate change, Brabant is increasingly experiencing dry periods in which water is scarce. The Aa en Maas water board therefore wants to reuse treated waste water as much as possible for horticulture, industry and drought control. And later also as drinking water.
But in that treated sewage water, medicine residues often remain behind and that is harmful to nature. “If there are a lot of medicine residues in the waste water, the life in that water will suffer. Mainly fish, but also other small insects,” says Peter van Dijk, board member at the Aa en Maas water board. “We see that fish, for example, develop feminine traits and that they become less mobile due to those medicines.”
“It works like a coffee filter, but in reverse.”
That is why they came up with a solution at the sewage treatment plant in Oijen: adding activated powdered carbon to the sewage water. Almost everyone knows it as Norit, which you use when you have diarrhea. But the substance can also remove medicines from sewage water, because these residues stick to this carbon.
“It works like a coffee filter, but in reverse. We have a lot of carbon sitting in a silo. We put water in at the top and that water comes out at the bottom,” explains Van Dijk.
“We remove seventy percent of medicine residues from the water.”
There is a large gray silo on the site in Oijen. It contains the black powder. Minister Mark Harbers of Infrastructure and Water Management opened the new part of the sewage treatment plant on Thursday. “With this new installation, we expect to remove up to seventy percent of all medicine residues from the water,” says Van Dijk.
It took the water board ten years to achieve this. “There are so many different types of medicines and therefore also different residues. We can measure about two hundred different species. You can think of the simple paracetamol and ibuprofen, but also more complex medicines such as diclofenac,” says Van Dijk. “We’ve tested the system dozens of times, so we now think the cabbage has an effect on all those species.”
“We don’t have to take out what isn’t in the water.”
Van Dijk is happy with this solution, but he would rather prevent the problem than cure it. “We don’t have to take out what isn’t in the water.”
Less than a ten-minute drive from the sewage treatment plant in Oijen, Oss is home to dozens of companies specializing in the development and production of medicines. In the coming period, the water board wants to enter into discussions with these companies, but also with other healthcare institutions such as general practitioners, in order to solve the problem even further.
