Question

1. as the impeller wears on a pump, the pump efficiency will

a. decrease
b. not change
c. improve
d. increase

1. the pressure against which a pump must operate is measured in terms of

a. psi
b. gal
c. hp
d. ft - lb

1. during the 24 - hour operation, a lift station pumped 3,000 gpm for a community of 27,000. what is the quantity of wastewater per capita, pumped?

a. 160 gpd/cap
b. 100 gpd/cap
c. 120 gpd/cap
d. 110 gpm/cap

1. a wet well has a diameter of 10 feet. the water depth is 10 feet it contains approximately

a. 6,204 gal
b. 9,872 gal
c. 5,875 gal
d. 10,720 gal

1. one cubic foot per second flow is equal to how many gpm?

a. 7.48 gpm
b. 64.5 gpm
c. 180 gpm
d. 449 gpm

1. what is the volume of 1,000 ft of 8 - inch line?

a. 4,220 gal
b. 9,163 gal
c. 2,609 gal
d. 2,200 gal

Explanation:

Question 7

Step1: Calculate total gallons pumped in 24 hours

Since the pump rate is \(3000\) gallons per minute (\(gpm\)), and there are \(60\) minutes in an hour and \(24\) hours in a day.
The total gallons pumped \(V = 3000\times60\times24\)

$$V=3000\times1440 = 4320000$$

Step2: Calculate gallons per capita per day (\(gpd/cap\))

The population \(N = 27000\).
The formula for gallons per capita per day is \(\text{gpd/cap}=\frac{V}{N}\)

$$ \text{gpd/cap}=\frac{4320000}{27000}=160 $$

Step1: Calculate the radius of the wet - well

The diameter \(d = 10\) feet, so the radius \(r=\frac{d}{2}=5\) feet.
The depth \(h = 10\) feet.
The volume of a cylinder \(V=\pi r^{2}h\) (the wet - well is approximately a cylinder).

$$V=\pi\times5^{2}\times10=250\pi$$

Since \(1\) cubic foot \(= 7.48\) gallons.

Step2: Convert cubic feet to gallons

$$V = 250\pi\times7.48$$

$$V\approx250\times3.14\times7.48$$

$$V\approx785\times7.48\approx5875$$

Step1: Use conversion factors

We know that \(1\) cubic foot \(= 7.48\) gallons and \(1\) minute \(= 60\) seconds.
If the flow rate is \(Q = 1\ ft^{3}/s\)
To convert to \(gpm\) (gallons per minute), we use the conversion:

$$Q=\frac{7.48\ gal}{1\ ft^{3}}\times\frac{60\ s}{1\ min}\times1\ ft^{3}/s$$

$$Q = 449\ gpm$$

Answer:

A. \(160\ gpd/cap\)

Question 8