COMBINED ACTION OF ELECTROOSMOTIC DRAINAGE AND MECHANICAL COMPRESSIONON SLUDGE DEWATERING

The efficiency of the implemented industrial means of sludge dewaterin g, at the present time, is not sufficient. Therefore, research of new techniques of advanced dewatering is necessary. Electro-osmotic draina ge, notably used to consolidate soils, has recently been used to dewat er sludges. In this work, a laboratory cell has been constructed. It p ermits one to superimpose a mechanical pressure adjustable to 7 kg/cm( 2) to the electro-osmotic drainage. The application of an electrical f ield decreases the specific resistance of sludges to filtration with v ariable factor, which can result from both the electrical conductivity and the charge of the particles. However, in thickening, it enables o rganic sludges to reach very high solids concentration when compared t o their dewatering by filtration under high mechanical pressure. The e nergy consumption does not seem to bean important constraint in sludge dewatering with this technique.