Complete the following problems dealing with rapid mix tanks and flocculation basins: 1. Design a rapid mix tank for water at 50° F flowing at Q = 4.0 MGD for a typical process train in a drinking water treatment plant. Use a square tank with a depth 1.25 times the width, a design velocity gradient G = 900 sec−1 , and a hydraulic detention time τ = 30 seconds. Specifically determine: a. Rapid mix tank dimensions in feet and inches, to the nearest one inch. b. Input water horsepower (hp). c. Impeller rotational speed if a vane-disc impeller is used having a diameter half of the tank width and employing six flat blades and a baffled tank. 2. Design a flocculation basin for water at 10°C flowing at Q = 49,200 m3 /day for a typical process train in a drinking water treatment plant. The basin shall be a cross-flow, horizontal-shaft, paddlewheel type with an average velocity gradient of G = 26.7 sec−1 , a detention time τ = 45 minutes, and a Gτ value of 50,000 to 100,000. Tapered flocculation shall be used in three compartments of equal depth in series. Compartments shall be separated by slotted, redwood baffle fences and have a level basin floor. G-values shall be 50, 20, and 10 sec−1 as the water passes through each compartment sequentially. The flocculation basin shall have a width of 27.43 m matching the adjacent sedimentation basin width. Paddle wheels shall have blades with a 150-mm width and a length of 3.05 m. Outer blades should clear the floor by 305 mm and be 305 mm below the water surface. Six blades shall be used per paddle wheel with a clear spacing of 305 mm between the blades. There shall be a clear spacing of 760 to 915 mm between the blades of adjacent paddle wheels, and an end wall clearance of 305 to 460 mm. Specifically determine: a. Basin dimensions to nearest 0.01 meters. b. Optional (zero points): Sketch a preliminary design for the paddle wheels – this is a mechanical engineering geometry problem, if you decide to give it a try do not spend too much time on it. c. Power input to the water in each compartment (watts), and the total power (watts). d. Optional (zero points): Range in rotational speed for each compartment using 1:4 variable speed drives – this is a mechanical engineering drive unit problem, again, if you decide to give it a try do not spend too much time on it.