Capacitive deionization

A further process for the separation of ions from an aqueous solution is capacitive deionization. Here the ions to be separated move according to their charge to the anode or cathode and charge these like a plate capacitor. Unlike other processes such as electrodialysis, however, no charge transfer takes place among the ions or with the electrodes, which is why this technology requires only low voltages of around 1.6 V. The energy consumption is therefore low. Once the charging capacity of the electrode is reached (if a capacitor is completely charged), the concentrate is released by polarity reversal and discharged as a concentrated electrolyte.

Together with our project partners in the EU project “REWAGEN” – after the separation of oils and particulate contaminations as well as the degradation of the organic load – we also finally remove dissolved salts in a fourth stage using capacitive deionization. The process is outstanding when combined with electrodialysis, as this makes available a concentrate, which additionally increases its efficiency significantly.

Reference projects

demEAUmed – Demonstrating integrated innovative technologies for an optimal and safe closed water cycle in Mediterranean tourist facilities


The aim of demEAUmed project is promoting innovative technologies, for an optimal and safe closed water cycle in Euro-Mediterranean tourist facilities, leading to their eventual market uptake.


Duration: January 2014 – June 2017

REWAGEN – Electrochemical WAter treatment system in the dairy industry with hydroGEN REcovery and electricity production


In the REWAGEN project a European project consortium consisting of partners from research and industry and led by the Fraunhofer IGB is developing a multistage process for the efficient electrochemical treatment of effluents from the dairy industry.


Duration: June 2012 – May 2016