Flocculation

Calculate the dimensions for a single compartment, rectangular floor plan flocculation basin to meet the following criteria:

• Detention time = 35 minutes (if necessary, you may adjust it within the range of 30-40 min)
• Tapered flocculation is to be provided, and three compartments of equal depth in series (Acceptable GT range: 70,000 to 120,000)
• Velocity gradient (G) = 65, 50, and 35 sec^-1 for the three compartments (based on jar tests)
• Two horizontal paddle wheels in series, rotating at the same speed, with the axis oriented perpendicular to the direction of water flow.
• Each paddle wheel has up to four arms. On each arm are up to three blades. If you use 2 blades per arm, then the blades are placed at the points. If you use three blades per arm, then the blades are placed at the 1/3 points.
• The compartments are separated by slotted, redwood baffle fences. The floor of the basin is level.
• The velocity of paddle wheels relative to the water = 0.75.

Calculate

• Number of basins
• The basin dimensions
• The paddle-wheel design (show plan and profile views)
• The power imparted to the water in each compartment
• The rotational speed of each horizontal shaft (in rpm)
• The peripheral speed of the outside paddle blades in m/s. Also calculate the rotational speed (rpm) of the paddle wheels and the horizontal (flow through) water velocity (m/min).