Entsorgung von Öl-in-Wasser-Emulsionen durch Elektrokoagulation

Separation of oil-water emulsions by electrocoagulation. Separating emulsified fluid drops or suspended solid particles from oil-water mixtures is one of the central problems of disposal technology. Reprocessing used emulsions or suspensions, however, is complicated by emulsion stabilisers and impurities. The efficiency of mechanical separation methods often leaves much to be desired, so that flocculants or demulsifiers are added. These additives are expensive, produce secondary waste, and may have adverse effects on the properties of the resultant product as far as its reuse or disposal is concerned. Electrocoagulation, a treatment process developed at Battelle, has none of these drawbacks. It is based on the fact that the stability of colloids, suspensions, and emulsions is critically influenced by electric charges being repelled by like charges on the surface of particles. Therefore, if additional electric charges are supplied to the charged particles via appropriate electrodes, the surface charge of the particles is neutralised and several particles combine into larger, separable agglomerates. The process-technological design is such that the emulsion (or suspension) flows through an electrochemical cell where it is demulsified. Energy consumption for this is low, chemicals need not be added, and no secondary waste results. Thus, a pretreatment process is available with which the separating efficiency of existing processes can be increased without having to modify the relevant apparatus significantly.