In the Netherlands we use more and more medicines. At least, you can draw that conclusion if you look at our sewage water, but also streams and ditches. Because medicine residues end up there. Bad for aquatic life and difficult for the preparation of drinking water.
From 2035, sewage treatment plants (WWTPs) will be obliged to purify at least eighty percent of these residues from the water. This is now only partially successful. But the solution is near and it comes from the municipality of Emmen. To be precise, at the NieuWater company near New Amsterdam.
The company advises companies in the field of water purification and also develops techniques for this. One of NieuWater’s well-known projects is the Pure Water Factory, where sewage water is converted into ultrapure water. NAM is one of the customers. The oil giant used this water as steam for the extraction of viscous oil in Schoonebeek.
The water is purified using membranes, which function as sieves. The problem is that bacteria will adhere to them, making them work less well. Instead, filters equipped with carbon were placed in front of the membranes.
“A method that not only helped tremendously, because there was also an unforeseen bycatch,” says NieuWater director Gerrit Veenendaal. The activated carbon also proved to be a champion at removing medicine residues in the water. “A completely unforeseen, but fortunate coincidence.”
The technology could be a solution for purifying sewage water into ultra-pure water. Were it not for the fact that this technology is actually too expensive for sewage treatment plants. According to Veenendaal, action could therefore be taken.
Because despite the purification techniques of the WWTPs, harmful residues still slip through their cracks. Which is bad for flora and fauna, such as tissue damage or even gender change in fish.
NieuWater therefore decided to look for a cheaper variant of the technology in 2021. A smaller scale test installation was installed on the factory premises, which had to perform a trick at the lowest possible cost.
The results of that research already proved promising last year. In fact, the same results were achieved as were previously ‘accidentally’ encountered in the factory. An additional follow-up investigation, which started last year, was necessary. Because in order to market this technique, it was necessary to know how quickly the cabbage starts to work. But also how long the cabbage will attack the medicine residues, because that was still unknown.
According to Veenendaal, the cabbage takes hold within a year and will certainly last twelve to fourteen years. “Possibly even thirty years. Moreover, research into CO2 showed that this is one of the friendliest purification techniques.” Regarding the investment, Veenendaal assumes one and a half million euros. “I assume a municipality with 100,000 inhabitants, such as Emmen. The technology therefore costs half as much as that at the Puurwaterfabriek.”
According to the director, it is now important to bring this technology to widespread attention. “We are looking together with commercial parties at how we can properly market this system.” In addition to WWTPs, the purification technology is also interesting for industry, he expects.
In the meantime, we are investigating whether the technology can be further improved. “Take, for example, the removal of phosphate from wastewater. That is also a major problem for sewage treatment plants. Activated carbon has no control over this. We are now looking at whether this can be effective with adjusted dosages.”