A rapid-mixing basin is to be designed for a water coagulation plant, and the design flow for the basin is 4.0 MGD (million gallons per day). The basin is to be square with a depth equal to 1.25 times the width. The velocity gradient is to be 900 sec-1 (at 50oF), and the detention time is 30 sec. Determine: The basin dimensions if increments of 1.0 inch are used, the input horsepower required, the impeller speed if a vane-disc impeller with six-flat blades is employed and the tank is baffled. The impeller diameter is to be 50% of the basin width.