Abstract: Liquid is clarified by passing it between spaced plates of a stack including two interleaved sets of plates, one set being connected to one direct current lead and the other set being connected to the other direct current lead. The liquid may flow through the spaces between the plates in a single direction in parallel paths or may flow in a serpentine path. Impurities removed from the liquid adhere to the plates and may be purged from the plates periodically by reversing the direction of flow of current between the plates. Impurities sloughed off the plates are trapped in a filter in the cell outlet.