The present invention provides a high volume, foul-resistant electrolytic process for treating contaminated water comprising at least one upflow electroflocculation cell consisting of (i) a lower (or “bottom”) electrode (3) in form of a porous, non-fluidized bed of loose iron or aluminium granules kept in periodic motion by pulsed gas injections and (ii) an upper (or “top”) vibrating electrode (4) made of an iron or aluminium grid mesh or ribmesh. A voltage potential between the upper (4) and lower (3) electrode causes ions to be released from the moving electrodes. These ions oxydise and/or render insoluble contaminants in the ascending flow of wastewater and create easy filterable insoluble contaminants resulting in substantially cleansed water. Such moving electrodes electroflocculation cells are useful at municipal water works and commercial and industrial applications were large amounts of raw water have to be processed.