Effective removal of pharmaceuticals from wastewater

Wastewater contains more and more pharmaceuticals that are difficult to remove in wastewater treatment plants (WWTPs). This issue calls for close collaboration between government, businesses and knowledge institutions. With this backdrop, KWR Watercycle Research Institute, Limburg Waterboard Company (WBL), Limburg Water Distribution Company (WML) and PureBlue Water have, within the TKI Water Technology programme, carried out a project aimed at removing pharmaceuticals using a two-step process: ion exchange followed by advanced oxidation. After having been tested in principle in a laboratory, the method was applied on a large scale in a pilot at the Panheel WWTP (watch the video). The outcome is that it is indeed technically possible to use this method to effectively remove a broad range of pharmaceuticals from the effluent.

It is known that wastewater contains relatively large amounts of pharmaceuticals which WWTPs are only able to remove at a rate of 60-70%. The remainder is discharged with the effluent into surface water. It is also expected that the concentrations of pharmaceuticals will grow significantly in the years ahead due to population aging and climate change. This can impact not only the environment but also drinking water treatment. Given that most pharmaceuticals are hydrophilic and freely water-soluble, they are not easy to remove. In addition, WWTP effluent contains relatively large amounts of organic material, which disturbs the removal process. This explains why advanced oxidation based on UV/peroxide is effective in removing organic micropollutants from drinking water, but is a lot less efficient in the case of wastewater. The idea was to use ion exchange, as a first step, to improve the water quality, so that the subsequent oxidation process could be rendered more effective and efficient.

Clean water at lower energy consumption

KWR and PureBlue Water found a research partner in WBL: the waterboard company promotes testing of innovative technologies at its WWTP locations. After the principle had first been tested in the laboratory, a pilot set-up was built at the Panheel WWTP. The ion exchanger did indeed remove the humic acids from the effluent. This improved the water quality to the point where the oxidation process became far more effective. Moreover, the energy consumption of the oxidation process was significantly lower following the pre-treatment stage, making the estimated cost of the total process comparable to that of other processes, such as filtration over activated carbon and ozonisation.

Great interest in the approach

This project was WBL’s first practical experience with the technology. The research contributes to the development of knowledge which is needed in the Netherlands – but certainly also in Germany and Switzerland – to enable the removal of pharmaceutical residues. Besides these so-called ‘end-of-pipe’ solutions, measures are also needed at-source to reduce emissions; for instance, in the treatment of hospital wastewater or the development of pharmaceuticals with lower environmental impact. In the meantime, the two-step removal approach has attracted a great deal of interest among institutions in the Netherlands and abroad. Read more about the project (including the upcoming report) on the TKI Water Technology website.