Question

• Calculate how many lots does a sewer line carry before you switch from and 8’’

  to a 10’’ pipe
  o Given (for an 8’’ line):

  § Each home assumes 3.5 people per house § Each person uses 100 gal/day
  § Peaking factor= 4
  § Mannings factor= 0.013

  § Slope = .4%

  § Assume pipe at maximum is 75% full

• 

  • Calculate how many lots does a sewer line carry before you switch from and 8” to a 10% pipe o Given (for an 8” line): • Each home assumes 3.5 people per house Each person uses 100 gal/day Peaking factor= 4 • Mannings factor=0.013 Slope = .4% Assume pipe at maximum is 75% full

Answer 1

on persan used roogalld lig allar = 3.785 litre briven data- size of pipe =8"to lo pipe for a 8" pipe dia Aug demand = 3.5 people per house & Lach person used to = 3.5x 100 x 3.785 4 [gallar = 3.72 - 1324.75/ = 1324.75 810 86400 = 1.533 for peak factor 4 disa According to WASA be upto 0.0283 m3/s. & discharge will used and additional so Q = 1.533x10 m3/s used and additional discharge 0.0283 m3/ arealso used sxlo mas Manning's factor = 0.013 slope (s) = 0.41 -014 000 = 4x103 Assume pipe at maximum is 75% full d=8" For the value of a = 20.54 cm 20-20sum Y=0.75d| Y 1. ДАОС (asx=0C АС cash = 10.750-0.50) 0.50 Cask = 0.5 [2=600] Then o= 1804 150-60

Now wetted perimeter P = &RO = 2x0.5dX 120xT 180 - 2x0.5X0.2054 X 120 JT 180 IP = 0.43m Area of the flow - (0.5x0.208438 2.0946-sin (2+126)] = 0.0105478 2.5276 A=0.026 m 2 Then hydraulic radious REAL = 0.026 0.43 R=0.0665m re sewage flow Now for calculating the discharge of the sewage pe using manning's formula Q = A R²/352 Q = 0.026.x (0.0605) 254x153 0.013 Q=0.309270.0632 Q=0.0195 m/s Sewage will show at the 0.0195 m/s having maximum depth upto 75% depth

As given discharge Qgiven = 1.533x105 + Opeak = 1.532 X16% +0.0283 = 0.0283 m3/ No. of lots required = 0.0283 0.0195 = 1.4512 2 80 two lots are required for a sewer line thout can carry for 8" pipe.