Abstract: A flume mixer is provided which employs mixing cells; the mixing cells comprise first and second generally horizontally disposed flow directing elements extending between flume side walls. The mixing elements are generally in angular relationship to each other and the longitudinal axis of the flume. Each of the elements on an end projection along the longitudinal axis of the flume are asymmetric about a plane passing through the axis of the flume and extending parallel to the side walls thereof. Immediately adjacent, mixing elements or baffles have a major portion of their projected areas lying on opposite side of said plane.