A gas/liquid contacting apparatus is provided wherein sedimentation of particulate solids at the corner of liquid overflow weirs of perforated trays is substantially reduced. This is achieved by bowing outwardly in a downstream direction the overflow weirs, to even out the liquid flow over them, and providing downcomer chutes from the weirs, which conform to the weir contour at the upper end. The downcomer chutes have sides converging in a downstream direction on a base to draw liquid away from the weir sides. The invention may be used in a single two or four pass gas/liquid contacting apparatus.