The present paper aims at investigating an alternative methode for the degradation of oil-water emulsions/mixtures, which mainly originate from metalworking industry and which have to be treated in a physico-chemical plant. The technology applied is a comparative new method of anodic oxidation, using diamond electrodes. At the beginning it is investigated and analyzed if this method is adequate for degrading organic substances. Special attention is paid to the reduction of chemical oxygen demand (COD), which presents an essential cost factor for the disposal/discharge. Introducing liquid wastes laboratory tests, using different media from a nearby physico-chemical treatment plant, the general applicability of the anodic oxidation for degradation of the COD value was proved. Due to the positive results, a technical plant was installed next to the physico-chemical treatment plant, with which the real amount of waste water was treated in a bypass of the discharge. By the evaluation of economic efficiency and the comparison of treatment expenses and discharge costs, it can be estimated if an additional treatment step with the anodic oxidation needs to be integrated into the existing plant.