Abstract: A first stage of a two stage apparatus for separating floating paint spray particulates from a collection tank that receives the waterfall backdrop from a commercial paint spray booth has a vertically pivotal weir hinged to a weir box that receives the resulting watery sludge as the floating solids and surface water skim over the weir. A float is connected with the weir by a dog-leg rod to control the flow over the weir at a preselected rate in response to the level of sludge in the weir box, thereby to minimize the proportion of water in the sludge. The sludge is pumped from the weir box into an inlet at the lower end of a consolidator tank. A compressed air diffuser emits streams of minute air bubbles below the inlet gently carries the floating particulates to the water surface where they accumulate and are gradually forced upward as a mass above the surface by underlying particulates continually entering the accumulator. Water from the uppermost particulates drains back into the accumulator.