A grit chamber is designed to remove sand of 0.08 mm and larger for a design flow of 2.2 m³/s (50 mgd). The maximum flow rate is approximately 1.5 times the average flow and the water temperature is 15°C. Assume a typical water depth of 3.5 m for each tank and a factor of safety of 1.5 is to be used. Determine the number and shape of tanks required and their size. Determine the configuration of the diffuser wall.