Problem $4$

The average flow rate at a small municipal wastewater treatment plant is $20,000\frac{m^3}{?}$ day. The

highest observed peak daily flow rate is $50,000\frac{m^3}{?}$ day. Design rectangular primary clarifier with

a channel width of $6$ m $.$ Use a minimum number of clarifiers. Use an over flow rate of $40\frac{m^3}{m^2}$

day.

Also design the tank on peak flow.

Design Criteria Rectangular Sedimentation Tank

Length

$30$m

Width

$10$m$(13$m max$)$

L:W

$<mn>4</mn>$:$1(2$:$1$ generally$)$

Bottom slope

$1-2\%($w$/$o scrapers$)$

Design Criteria circular Sedimentation Tank

Dia

$30$m$($max$)$

Depth

$3-5$m

Bottom slope

$($max$)$

$8\%($hopper bottom $+$ scrapers$)$