There are many different and established technologies used in wastewater treatment. Nevertheless, approved biological processes are often not applicable for both toxic and persistent compounds. EAOP-technology is a promising alternative for these problems. By electrolysis on boron-doped diamond electrodes, oxidative species are generated in the wastewater, which are able to decompose the pollutants. The company VTU technology GmbH possesses a container facility „coolox®“ in pilot scale. The steady operation of the facility should be assured through multiple test runs and by adjusting the system, if necessary. The COD-degradation properties were tested and evaluated by a series of phenol-containing wastewaters. The pilot plant nearly reached the theoretical maximum of degradation with a current efficiency of 70 % and at a current density of 1000 A/m². The variation of the current density showed at current densities above 1500 A/m² an inhabitation of the COD-degradation. This can be explained with the high formation of gas bubbles in the electrolysis cell. Calcification of the electrodes during the operation was another challenge that needed to be fixed. Therefore, an appropriate cleaning step had to be developed and investigated. Furthermore the application of the activanode “AQUABION®” should be investigated. The results of a chemical cleaning step were satisfying. The properties of the sacrificial anode with a reduced calcification of the electrodes could not be validated. Investigations in a batch configuration showed no effect in the measured cell voltages.