Problem Solved: Flow Rate Formula - Water Treatment, Distribution and Wastewater Math

American Water College Presents - Problem Solved!

This is the solution to a typical flow rate problem, found on state certification exams. It is also an important calculation for water treatment, distribution system and wastewater treatment operators.

[AmericanWaterCollege]

Thank you for your comment. Using the numbers from the problem, the common equivalent 7.48 gal/cubic ft and the formula for the area of a circle as 0.785 x D x D, the answer works out to be 7, 046.16 gpm which we rounded to 7, 046 gpm. If you solve for the cross-sectional area of the pipe using the formula A = π x r x r, the answer works out to be 7049.73 gpm which would round to 7050 gpm. (π in this calculation came from the pi button on the calculator)

I hope this clears up any confusion

[feztoys]

Omg I was converting gpm to ft/s and spent like 2hrs trying to figure out what I did wrong. Found this video. And as soon as you said to convert the inches to ft for the diameter it clicked lol thank you. Go my answer correct now.

[michaelgreene]

The area of a circle (cross section of a round pipe) is pi * radius-squared, which is the same as pi * diameter-squared / 4 (radius-squared = [diameter/2]-squared = diameter-squared / 4)

[tyronemckinley]

Thank you very much for explaining it clearly.

[andyradin]

What an arcane formula for area of a circle! It's Pie-R-squared! Taught in every middle school in the world!

[kingofkong]

This is starting to make sense. Thank you

[Allanmr]

The 0, 785 is (Pi/4) as the formula is (pi*D^2)/4, its actually same as pi*r^2, just a different way to express

[juanmanuelespinoza]

the large treatment plant in texas can treat 500 mgd and uses 15 % bleach for disinfection.the bleach has a specific gravity of 1.25. at maximum flow rate, how many gallons of bleach will be used per day of the effluent demand is 7.0 mg/l and 1.0 mg/l residual is required

[siguenciajulio]

This helped me out for my pharmacy technician test 😆

[CivilTech]

Sir I have question. I have a multi storey building which contains 80 people and they use 200 gallons of water per person per day. For them how do I calculate the required diameter of sewerage pipe?

[richarddenny]

Was very informative . Thank you for your time.

[sweeyong]

Area of circle is it not pi (3.14) x r2? I looked up online. Can you explain why area is calculated using 0.785xdxd?

[plumbercanicon]

Thank you sir for lecture. To those who confused, they are displacement about the factor of conversation.

[ranasaleem]

If velocity is not given, only head of liquid and diameter of pipe is available. Then how can be calculated flow.

[trishamcmillan]

I'm a bit confused about the flow rate formula. Why do you divide Pi by 4 for this equation?

[samuraiNishant]

please folk i have a question for u a source of water supply to a town on a hill is under investigation and following data are being considered:
population - 2 lakh, water demand - 200lpcd, height of point of inlet to water works above the lowest water level in the source- 30m, friction and minor losses in the intake pipe system to be around 4 m, efficiency of pump- 80%, duration of pumping- 20 hrs/day, flow velocity through pipe- to be about 1.0 m/sec.
Determine the size of rising main and the horse power of the pump required .

[jeremyfort]

You have to make it make sense where are you getting the other numbers like the A=0.785

[coreyform]

please explain where you get the .785 from. is this a standard

[asyo]

i want to know how much valve opening with respect to the flowrate of tank to optimized backwashing and rinsing

[sachinchakravarthys]

For deep well (250feet) 5HP 8 stage 3 phase submersible Motor pump under 220v what is the pump impeller size and specifications to give out the water at high pressure and is it impeller size proportional to high pressure water out . Pipe size 2 inch and also high discharge rate that is LPM is same the so called pressure