This news release is available in German.
There are numerous things in our waste water that should not find their way into the environment yet waste water treatment plants only remove a portion of these contaminants. In particular, bacteria commonly employed in the biological treatment stage have no effect on persistent substances, which include highly stable hydrocarbon compounds. The result: cleaning agent residuals and pesticides as well as pharmacological substances are reaching environmental waters. The loading from these kinds of harmful substances in the North Sea, for instance, is already clearly measurable today.
Researchers of the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart together with international industrial partners have now developed a new chemical reaction system that breaks down these kinds of resilient and harmful molecules thoroughly and efficiently without having to add chemicals like hydrogen peroxide, for instance. Instead, the researchers are essentially utilizing the "self-healing" power of water aided by photolysis (a.k.a. photochemical dissociation). The principle of photolysis is based on splitting water molecules using photons. The shorter the wavelength of light, the higher the photons' energy. Researchers therefore use light sources in this system that emit UV light exclusively in the region of 172 nanometers i.e. extremely energetic photons. As soon as these photons enter water, they split the H2O molecules, forming highly reactive hydroxyl radials as a result. "These hydroxyl compounds have an even higher reaction potential than atomic oxygen, for example. They are therefore able to decompose even very stable hydrocarbon compounds contained in harmful residues," explains Siegfried Egner, head o
|Contact: Dipl.-Ing. Siegfried Egner|