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.

Related application that operates based on the same working principle and techniques: Electrocoagulation