The town of Eau Gaullie has requested proposals for a new coagulation water treatment plant. The design flow for the plant is 0.1065 m 3 /s. The average annual water temperature is 19 o C. The following design assumptions for

The town of Eau Gaullie has requested proposals for a new coagulation water treatment plant. The design flow for the plant is 0.1065 m³/s. The average annual water temperature is 19^oC. The following design assumptions for a rapid-mix tank have been made:

    

    1. Number of tanks = 1 (with 1 backup spare)

    2. Tank configuration: circular with liquid depth = 2 × diameter

    3. Detention time = 10 s

    4. Velocity gradient = 800 s ^– 1

    5. Impeller type: turbine, 6 flat blades, N _p = 5.7

    6. Available impeller diameters: 0.45, 0.60, and 1.2 m

    7. Assume B = (1/3) H

  

Design the rapid-mix system by providing the following:

  

    1. Water power input in kW

    2. Tank dimensions in m

    3. Diameter of the impeller in m

    4. Rotational speed of impeller in rpm 

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