A solubilizing apparatus includes a fluid permeable sleeve having opposed openings therein wherein a spray nozzle is in flow communication with one opening and a second opening is disposed to receive solids. The spray nozzle is designed to spray a fluid in a swirling spray sweeping the insides of the sleeve wall as it travels toward the opposite end. The solubilizing apparatus is specifically useful for dissolution of chemicals utilized in cleaning reverse osmosis membranes.
