WATER CLARIFIER WITH FIRST FILTRATE ISOLATION, IMPROVED BACKWASHING AND IMPROVED BUBBLE GENERATION

摘要

A clarifier (10) with first stage flotation and second stage filtration divides at least the lower portion of a flotation tank (12) into independent cells (54). A branched conduit (78) collects clarified water. Valves (76) control the flow of clarified water to either a clarified water ring conduit (62) or to a first filtrate/bachwash ring conduit (64) connected to a storage tank (68). High cell walls (53) and inclined baffles (58) retain filter media during backwashing. A decompression valve (94) for pressurized water with dissolved air has a narrow annular slot set by a moveable member to create microscopic air bubbles. A mechanical or pneumatic actuator periodically opens the slot to flush trapped particles.