Pharmaceuticals do not disappear completely in the body, rather they are often composed of persistent molecules that take a long time to break down. Purifying wastewater from these is an increasingly important task. RISE, IVL and Alfa Laval have been studying the possibilities for reducing emissions with the aid of photocatalytic degradation.
The systems used to transport our water are better than ever; however, they are also exposed to new challenges and stresses. One such challenge is presented by pharmaceutical residues.
“Today, some of these residues remain even after normal water treatment. Although these are trace amounts, when you combine them with the fact that there are so many different types, this is a strain on the system,” says Karin Persson at RISE, leader of the study A Photocatalytic Membrane For Treatment of Pharmaceuticals in Wastewater.
Can affect plant and animal life
Several studies have shown that small amounts of pharmaceutical residues can adversely affect plant and animal life. A new method for reducing levels in treated water has now been tested by RISE, IVL and Alfa Laval. This process uses ultraviolet light in combination with a photocatalytic membrane filter to improve degradation.
“It has proved very educational; the importance of knowing which pharmaceutical residues one is targeting is clear in order to optimise the effectiveness of various substances. One valuable effect was that testing led to an improved flux rate (an increased flow compared to systems without UV light).”
The study tested effectiveness against 25 different pharmaceutical substances. Taken as a whole, it proved possible to remove 90% of residues from the water.
“We were able to demonstrate that this is an interesting method that both provides good results and increases flux,” says Karin Person.
Important finding new methods
It is important to identify new methods of water treatment. It is entirely likely that regulations regarding residual amounts of pharmaceuticals will be tightened.
“This is not solely a matter of clean water. It is also about our attitude to pharmaceuticals management. Work is ongoing to reduce the amount of pharmaceuticals in circulation so that they do not end up in the wrong places. For example, smaller packets when testing a new medicine might be one way.
Another idea is to install special treatment plants, for example close to major hospitals, in order to clean water where the need is greatest.”