Abstract: A mixing apparatus and associated method comprising a system for supplying a first substance of liquid constitution and a system for supplying a second substance to an assembly of pipe elbows to effect mixing and transport of the substances along the assembly. The pipe elbows are right angle elbows connected one after the other in groups of three. Each group has an inlet and an outlet disposed in parallel planes and axially offset from one another. The pipe elbows in each group have center lines disposed in mutually perpendicular planes to cause the mixture to rotate as it travels along the pipe elbows.

Abstract: A plurality of support brackets are placed within a basin of a system for the aerobic treatment of liquid waste materials and are arranged in a pattern beneath continuous lines in a gas distribution line array, the lines being attached to the brackets, and mixer-aerator devices are capable of ready attachment to the brackets to enable selective location of a mixer-aerator devices over orifices placed in the line array at the brackets, or ready detachment from the brackets to enable selective removal of the mixer-aerator devices without disturbing the attachment of the lines to the brackets, the balance within the gas distribution line array, or the ability of the system to continue to operate, despite the removal of some mixer-aerator devices, without further modification of the system.