Electroosmosis or application of Electroosmotic flow can be used as a method to dewater and make the sludge denser by utilizing electrical current in order to make the whole process possible. The working principle is that colloidal particles are usually charged and thus when electric field is present, it will cause the particles to migrate. If those are negatively charged, it will be attracted and move towards anode, vice versa for water molecules which will migrate out of the mass of the negatively charged colloidal thus leading towards good separation. Usually electroosmosis can be applied towards gravity-thickened sludge not only to lower the concentration of water present in it but this will also help to decrease the percentage of heavy metals which will make disposal much safer and more feasible including composting later part.
Application of electroosmosis in wastewater treatment plant has not been fully commercialized and applied in large scale processes. However, in other industries such as the paint, construction and clay recovery field, its use has been more widespread. The challenges facing its full application when it comes to using electroosmosis is mainly on power consumption aspect on how to make it efficient using the least energy and yet achieve the desired results. In fact recent developments have shown that it can be improved by adding cationic coagulant to further achieve better separation leading towards lower water content. So far, laboratory scale testing has confirmed reduction of at least another 10 – 20% of water content being removed from the sludge just by applying this method.
Related application that operates based on the same working principle and techniques: Electrocoagulation