Affinity adsorption

The presence of pharmaceuticals and degradation products in surface water represents a threat to ecological water quality and drinking water sources. The removal of pharmaceuticals and organic micropollutants is also becoming more and more topical. Many pharmaceuticals end up in wastewater through urine. The most effective way of controlling the emission of pharmaceuticals is by tackling them at-source, that is, in the toilet. In this project adsorption materials will be made which can adsorb the pharmaceuticals at-source. The loaded adsorbent can then settle in the WWTP, and be disposed of and processed together with the sludge. This would prevent the pharmaceuticals from ending up in the surface water and drinking water sources.

Technology

In the first instance, an appropriate adsorbent was developed for specific, frequently-occurring and difficult-to-remove pharmaceuticals, such as diclofenac. This adsorbent was tested in the laboratory. In addition, a method was developed to compress this powder into a small ball. Preparations have also been made for a pilot project at the University Medical Center Utrecht. This will study how patients accept such a system, and whether the amount of these pharmaceuticals in the wastewater actually decreases.

Challenge

During the pilot patients and employees of the Water board are asked to place an adsorbent ball in the toilet before they use it. If they don’t use pharmaceuticals themselves, maybe their colleagues or other patients do, and then the adsorbent still can adsorb the pharmaceuticals in the wastewater. The pharmaceuticals are adsorbed from the urine in the toilet and as they travel to the sewer. The loaded adsorbent settles in the WWTP and can be disposed of and incinerated together with the sludge. All that is left over is the carrier material of the adsorbent, which is a harmless substance such as silica oxide or sand.

Solution

Together with their medication, patients are given an adsorbent – e.g., a small paper bag or a toilet block– which they have to place in the toilet before using it. This can be done in the hospital, but also at home and in the office. The pharmaceuticals are adsorbed from the urine in the toilet and as they travel to the sewer. The loaded adsorbent settles in the WWTP and can be disposed of and incinerated together with the sludge. All that is left over is the carrier material of the adsorbent, which is a harmless substance such as silica oxide or sand.