A floating decanter and method for charging supernatant from a vesel without drawing floating solids or scum into the discharge. The decanter includes a weir (16) having a central opening, and a solid bottom side, a float (12) adjacent to an outer edge of the weir, a weir lift and drive (14) having at least two screw jacks (20) attached to the float and a attachment arm (26) extending to the weir, and an discharge pipe (32) attached to the bottom of the weir. The weir is lowered with respect to the float to discharge supernatant.