2.7.2 Design of V - Notch (To be installed on the periphery of Clarifier)

Design

Circumference of each clarifier = 3.14 x 91.56
= 287.31 Ft

Columns (1’ x 1’) shall be provided at every 12’ interval for supporting a beam on which one end of the Scrapper Bridge shall be placed. Therefore space for the installation of the notch shall be reduced compared to the circumference of the Clarifier.

Length of Span = 12’
No of available spans for the installation of notch = 287.31 /12
= 24
Size of columns = 1’ x 1’
No of Columns = 25
Length of Effective Spans for installation of notch = 287.31 -25
= 262.32 Ft
Center / Center spacing of notch = 1’
No of Weirs = 262

Flow per Notch (q) = 23.34 / 262
= 0.089 cusecs
Coefficient of Discharge (Cd) = 0.60
Gravity (g) = 32.2 Ft / s2
Depth of water over V - Notch =(15 x q / 8 x Cd x (2g)0.5)0.4
=(15x 0.089 / 8 x 0.60(2 x 32.2) 0.5) 0.4
= 0.26 Ft
= 3.15“
Add safety Allowance against submergence = 1.61 “
Total Depth of V Notch = 5”

Width of V- Notch at the top = 2 x .0
= 10.0 “
Under normal operating conditions when flow through each Clarifier shall be 11.67 cusecs, depth of flow over each notch shall be 2.36 “.