Method and apparatus for cleaning pollution control equipment, such as particulate removal devices, including wet electrostatic precipitators (WESP). The apparatus may comprise a plenum having a gas inlet for the introduction of process gas into said housing; a gas outlet for discharge of treated process gas from said housing; at least one ionizing electrode; at least one particulate collection electrode; the plenum being in fluid communication with the at least one ionizing electrode and the at least one particulate collection electrode; an upper support frame; a lower support frame connected to the upper support frame and comprising at least one electrode support beam supporting the at least one ionizing electrode; and at least one movable nozzle in the plenum for discharging washing liquid towards the at least one collection electrode to dislodge particulate matter from the at least one collection electrode.