A method for static mixing in a waste water settling tank to increase the percentage of recovery of entrained solids from the waste water comprising a settling tank having a recirculation ring and a hopper bottom defining a sludge hopper, a fluid deflector centrally disposed within the space contained in the hopper bottom having a flat portion, and an inlet pipe for introduction of waste water containing second entrained solids into the settling tank and having a discharge outlet in proximity to the underside of the deflector dome and a nozzle facing downward. Influent waste water is directed vertically downward toward the flat portion and upward into the center of the fluid deflector which distributes the influent radially into contact, preferably turbulent, with previously introduced waste water containing first entrained solids to cause coalescence of the first and second entrained solids to form larger particles having increased settling velocity.