The formation of biofilms, which may contain hygienically alarming microorganisms, is often observed in pipelines for drinking and cooling water systems. Recently, all German health offices were interviewed about their experiences in the surveillance of home water installations and stated that about 5% of cold water and 20% of warm water installations showed hygienic-microbiological peculiarities [1]. The technical repercussions of biofilm formation can lead to a decreased flow rate, filter blockage and a reduced heat transfer in cooling/heating circuits. Thus, there is high demand for efficient remedies to reduce microbial growth in such installations.

Research at various conducting surfaces showed a significant decrease of biofilm formation induced by oscillations of the electrochemical potential [2]. In our contribution, we will discuss recent results from our labs how the electrode of surface activated metal foils is influenced by illumination with visible light. The electrochemical setup comprises a solar simulator, which emits a defined wavelength as well as a commercial high power LED. Specifically, the influence of the wavelength, as well as the duration and intensity of the illumination were investigated. Furthermore, cyclic voltammetry and open circuit potential measurements were performed to identify the parameters with the strongest influence on the inhibition of biofilm growth. In the outlook, we will discuss results on the construction of a prototype for large-scale water treatment.

• [1] Flemming, H.C.: Microbial Biofouling: Unsolved Problems, Insufficient Approaches, and Possible Solutions, Biofilm Highlights (2011), 81-109
• [2] Schaule, G.: Effects of electric polarization of indium tin oxide (ITO) and polypyrrole on biofilm formation, Water Science and Technology 58 (2008) 11, 2165-2172