A water treatment plant is required to process 28800 m3/d of raw water (density = 1000 kg/m3, kinematic viscosity = 10-6 m2/s). The rapid mixing tank imparts tank a velocity gradient of 900s-1 to blend 35 mg/l of alum with the flow for a detention time of 2 minutes. The power input (W) required for rapid mixing is

• 32.4
• 36
• 324
• 32400