Apparatus for clarification of water

Apparatus for treatment of unclarified water comprising, in combination, an outer tank, an inner tank arranged within said outer tank, a carriage arranged on top of said outer tank and movable about the vertical axis thereof, conduit means opening into said inner tank for introducing unclarified water into said inner tank, supply means connected to said conduit means for adding flocculating material to the unclarified water, whereby the flocculating material is mixed with the unclarified water in said inner tank, the top of said inner tank being below the top of said outer tank, whereby the unclarified water with contaminant-attached flocculating material therein overflows from said inner tank into said outer tank, means for introducing into the upper portion of said inner tank gaseous material dissolved in water for attaching to the flocculated contaminant particles in the mixture and floating the same in said outer tank, means on said carriage for removing the sludge formed by the flocculated particles on the surface of the water in said outer tank, filter means at the bottom portion of said outer tank for removing downwardly flowing flocculated material, and discharge means for removing the thus clarified water, the walls of said inner and outer tanks defining an annular space therebetween, said filter means comprising a plurality of filter beds arranged in said annular space, said filter beds comprising porous material having surfaces on which said downwardly flowing flocculated material is deposited, and means for removing the thus deposited material, said removing means comprising suction means carried by said carriage for movement therewith around said annular space above said filter beds for removing said deposited material from the surface thereof, and second conduit means connected to said suction means for discharging the thus removed material into said inner tank, including means for lowering said suction means onto individual filter beds, and control means for selectively lowering said suctin means onto an individual filter bed after passing a predetermined number of filter beds, said control means comprising a plurality of projecting means spaced around said outer tank, switch means carried by said carriage adapted to sequentially engage said plurality of projecting means during rotation of said carriage, and electrical means connected to said switch means and operable to selectively start and stop the rotation of said carriage.