Development of an electrochemical module for combined water disinfection and softening

Aims

Disinfection in industrial processes e.g. in beverage industries can be performed by dosage of biocides as well as electrochemical production of biocides as chlorine and ozone. The usage of ozone is more environment-friendly than the usage of chlorines. Boron doped diamond (BDD) electrodes are an innovation with high market potential. Their application for water disinfection by means of electrolytic ozone generation offers advantages compared to ozonisation by gas injection. BDD electrodes used for water disinfection are arranged in SPE (solid polymer electrolyte) technology, BDD anode and cathode are seperated by an ion exchanger membrane.

Operation of these electrodes in water with high Ca- und Mg-contents causes scaling of the BDD electrodes.

Aim of this project is to prevent impairment of the BDD electrodes and to implement a method for combined water disinfection and softening.

A technical loop for testing the BDD stacks has been constructed. Different polarisation routines are tested to prevent scaling of the BDD and to develop a method for combined disinfection and softening. Extensive online sensor technology is installed and supplemented by sampling. The ozone production is recorded online as well as determined by photometric measurement with indigo carmine.

To investigate the ozone production and to enhance the cleaning procedure supplemental experiments will be conducted in a laboratory loop.

Das IGF-Vorhaben Nr. 15506N der Forschungsvereinigung DECHEMA e.V., Theodor-Heuss-Allee 25, 60486 Frankfurt am Main wurde über die AiF im Rahmen des Programms zur Förderung der industriellen Gemeinschaftsforschung (IGF) vom Bundesministerium für Wirtschaft und Energie aufgrund eines Beschlusses des Deutschen Bundestages gefördert.