Abstract: This invention is directed to an electrode unit to be used for purification of emulsions and polluted waters, especially oil-bearing waters, by electrolysis which comprises vertically placed adjacent electrode plates of a soluble material, spacers for adjusting the distance between the electrode plates and equipment for adjusting the depth of immersion of the electrode plates. The tips of the electrode plates defines the only area of the plates in contact with the liquid to be purified and the depth of immersion of the electrode plates is adjusted in order to keep the current density between the electrode tips within a desired area. In addition, the space in between the plates is also adjusted in order to keep the current density between the electrode tips within the desired area.