Abstract: An improved mounting bracket for mounting diffusers on submerged air lateral pipes in a waste water treatment system. Each mounting bracket includes a pair of complemental saddle sections which can be clamped securely yet releasably on the air lateral with an outlet spout of the saddle in registration with a discharge port in the bottom of the air lateral. A Tee fitting has a pipe nipple connected with its inlet, and the pipe nipple can be threaded into the outlet spout. Virtually any type of diffuser can be solvent welded to each outlet of the Tee fitting. The mounting bracket surrounds and reinforces the air lateral at the diffuser connection point and takes advantage of relatively large diameter pipe at the threaded connection between the outlet spout and pipe nipple. All parts can be PVC or a similar plastic and can withstand the stresses which are applied because of the structural strength of the diffuser mounting arrangement.