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A circular tank has a depth of 10 feet and a diameter of 75 feet (with a flat bottom). How many gallons does this tank hold?

- 165,228 gallons
- 330,289 gallons
- 269,460 gallons
- 660,912 gallons

The plant flow rate is 13 mgd and the influent CBOD

_{5}concentration is 230 mg/L. How many pounds per day of CBOD_{5}are contained in this flow stream?- 24,937 lbs/day
- 8,681 lbs/day
- 10,643 lbs/day
- 5,550 lbs/day

A rectangular tank has a length of 125 feet, a width of 40 feet, and a side water depth of 11.5 feet. What is the surface area of this tank in square feet?

- 6,450 sq.ft.
- 4,600 sq.ft.
- 5,000 sq.ft.
- 7,500 sq.ft.

The pounds per day of chlorine used is 1,100 lbs and the plant flow rate is 12.5 mgd. What is the chlorine dosage in ppm?

- 10.55 ppm
- 5.86 ppm
- 20 ppm
- 8.56 ppm

An aeration tank holds 0.5 million gallons and the mixed liquor concentration is 4,000 ppm ... How many pounds of solids are in this tank?

- 16,680 pounds
- 14,740 pounds
- 17,680 pounds
- 15,680 pounds

A clarifier has a depth of 12 feet and a diameter of 100 feet. What is the surface area of this tank in square feet?

- 6,146 sq.ft.
- 5,854 sq.ft.
- 7,850 sq.ft
- 6,674 sq.ft.

The plant flow rate is 14.5 mgd and the effluent suspended solids concentration is 3 ppm. How many pounds of solids per day is the plant discharging?

- 253 lbs/day
- 363 lbs/day
- 196 lbs/day
- 235 lbs/day

What is the fraction for the decimal .37?

- .63
- 63/100
- 37/10
- 37/100

What is the decimal for the fraction ⅞ ?

- 1.14
- 0.875
- 56
- 8.7

What is the percent for the fraction ⅞ ?

- 87.5 %
- 99.12 %
- 12.5 %
- 1.14 %

Which is not an equal conversion to 1 mgd?

- 92.84 cfs
- 92.84 cfm
- 694 gpm
- 1,000,000 gallons/day

A standpipe is 7 inches in diameter, and 37 feet high. How much water will it hold? How much pressure in pounds per square inch would be exerted at the bottom of the pipe?

- 74 gal/ 85.5 psi
- 86 gal/16psi
- 74 gal/16 psi
- 148 gal/27 psi

A pump discharges 4.5 gallons per second. How many gallons will it deliver in a week?

- 2,721,600 gallons
- 113,400 gallons
- 45,360 gallons
- 1,810,624 gallons

How many gallons of water is in a tank that is 74 feet in diameter and 37 feet high when the water is 29 feet deep?

- 1,189,697 gallons
- 932,465 gallons
- 202,604 gallons
- 757,076 gallons

How many pounds of HTH containing 13% available chlorine would be needed to provide 73 pounds of chlorine?

- 561.5 pounds
- 9.5 pounds
- 70.9 pounds
- 476 pounds

How many pounds does 10.5 cubic feet of water weigh?

- 78.5 pounds
- 87.6 pounds
- 655 pounds
- 1210 pounds

A water main has failed and 130 yards of 8-inch pipe must be replaced. How many 21-foot sections of pipe will be needed?

- 27 pipes
- 19 pipes
- 43 pipes
- 5 pipes

How many days will it take in to fill a tank that is 30 feet in diameter by 27 feet deep if a pump is putting out 150 gpm?

- 15.85 days
- 0.26 days
- 1.83 days
- 0.66 days

What is the detention time in a storage tank that is 35 feet high and has a 24-foot radius when the flow rate is 2.3 mgd?

- 2.3 hours
- 4.9 hours
- 0.51 hours
- 3.7 hours

At what pH is a liquid considered to be neutral?

- 7.0
- 11.0
- 4.9
- 3.5

A temperature of 14 degrees centigrade is equal to what temperature on the Fahrenheit scale?

- 82.8 °F
- 57.2 °F
- 48.3 °F
- 97.5 °F

Calculate the dosage if the chlorinator is set to feed chlorine at a rate of 70 pounds per day when the flow rate is 2.1 mgd?

- 1.2 mg/L
- 4.0 mg/L
- 2.3 mg/L
- 3.7 mg/L

Your plant treats 27 million gallons during the month of July. There are 19.2 million gallons in various storage tanks. What percentage of treated water is unaccounted for?

- 29%
- 71%
- 14%
- 37%

If the chlorine demand of your raw water is 3.5 mg/L and a 1.2 mg/L residual is required, how many pounds of chlorine are needed for a flow of 1.8 mgd?

- 52.5 pounds
- 62 pounds
- 34.5 pounds
- 70.5 pounds

How many gallons of water would 1,324 feet of 8-inch pipe hold?

- 497,553 gallons
- 3,455 gallons
- 3,852 gallons
- 222,476 gallons

If two pumps are pumping 175 gpm each, how many days will it take to fill a tank that has a 26-foot radius and is 35 feet high to a depth of 29 feet?

- 0.9 days
- 21.9 days
- 2.1 days
- 0.2 days

The chlorine demand of your raw water is 3.8 mg/L. If you treat 755,000 gallons of this water with 35 pounds of chlorine gas, what will the chlorine residual be?

- 5.5 mg/L
- 1.75 mg/L
- 2.5 mg/L
- 9.3 mg/L

Determine the volume of a circular tank with a conical bottom if the tank is 17 feet in diameter, the cylinder height is 26 feet and the cone depth is 8 feet.

- 44,121 gallons
- 48,646 gallons
- 67,247 gallons
- 30,545 gallons

The water flowing through a 9-inch pipe has an average velocity of 3.5 feet per second. What is the flow rate in cubic feet per second?

- 1.55 cfs
- 2.2 cfs
- 1.75 cfs
- 2.57 cfs

Water is flowing into your plant at a rate of 650 gpm. How many pounds of chlorine would be needed to be fed over a 14-hour period if the required dose is 4.8 mg/L?

- 37.5 pounds
- 21.86 pounds
- 43.67 pounds
- 28.66 pounds

A circular clarifier treats a flow of 1.7 mgd. The diameter is 35 feet and the depth is 17 feet. What is the surface loading?

- 1,768 gpd/sq.ft.
- 3,640 gpd/sq.ft.
- 962 gpd/sq.ft.
- 2,876 gpd/sq.ft.

A temperature of 76 degrees Fahrenheit is equal to:

- 24.4° Centigrade
- 10.2° Centigrade
- 37.5° Centigrade
- 28.3° Centigrade

If chlorine cost $65.00 per 150-pound cylinder, how much would it cost to treat a flow of 1.4 mgd if the average dose is 1.2 mg/L for one year?

- $1,450.25 per year
- $2,760.15 per year
- $2,216.10 per year
- $3,409.75 per year

If water flows through a 6-inch pipe at a rate of 3.5 cubic feet per second (cfs), what is the velocity?

- 0.69 ft per sec (fps)
- 21.6 ft per sec
- 17.83 ft per sec
- 5.14 ft per sec

What is the length of a weir that runs around the rim of a clarifier that has a 37-foot diameter?

- 1,074 feet
- 85 feet
- 116 feet
- 29 feet

A chemical feed pump lowers the level of a chemical container by 18 inches in 8 hours. What is the chemical feed rate in gpd if the tank has a diameter of 42 inches?

- 324 gpd
- 559,324 gpd
- 72 gpd
- 283 gpd

Three acres are equal to :

- 14,520 sq. ft.
- 130,680 sq. ft.
- 5,280 ft.
- 1,203 sq. yd.

A rectangular tank is 65 feet long, 28 feet wide and 15 feet deep. How high will the level rise if 67,000 gallons are pumped into the tank?

- 5 feet
- 12 feet
- 8 feet
- 11 feet

Calculate the surface area of a clarifier with a radius of 24 feet.

- 452 sq. ft.
- 205 sq. ft.
- 1,394 sq. ft.
- 1,809 sq. ft.

Two pumps of equal output pump 3.5 mgd into a plant. What is the rating of each pump in gallons per minute?

- 900 gpm
- 725 gpm
- 1,215 gpm
- 2,430 gpm

Calculate the flow through a filter in gpm when 1.8 million gallons flows through the filter during a 42 hour run.

- 1,100 gpm
- 714 gpm
- 550 gpm
- 980 gpm

A plant uses 725 chlorine cylinders in a year. The average withdrawal from each is 142 pounds. What is the total number of pounds used in a year?

- 102,950 pounds
- 510,563 pounds
- 226,210 pounds
- 183,420 pounds

Determine the chlorinator setting in pounds per 24 hours to treat a flow of 2.7 mgd with a chlorine dose of 4.2 mg/L.

- 18 pounds
- 76.7 pounds
- 94.5 pounds
- 102 pounds

A circular tank must be built to hold 75,000 gallons of water. If the diameter of the tank is 35 feet, what is the height?

- 10.5 feet
- 20 feet
- 15.5 feet
- 30 feet

If water flows through a pipe at a rate of 120 cfm, how many gallons of water flow through the pipe in a day?

- 2.1 mgd
- .786 mgd
- 1.3 mgd
- 2.7 mgd

With a flow rate of 2.3 mgd, estimate the detention time of a circular clarifier that is 14 feet deep and has a diameter of 37 feet.

- 1.7 hours
- 1.2 hours
- 2.4 hours
- 3.0 hours

2.9 mg/L of chlorine are added to a water supply. After a 30 minute contact time there is a 1.3 mg/L residual. What is the chlorine demand of the water?

- 1.6 mg/L
- 4.2 mg/L
- 2.6 mg/L
- 5.2 mg/L

Raw water has a chlorine demand of 3.7 mg/L. If 2.7 mgd are being treated and a 1.2 mg/L residual is required, what must the chlorine feed rate be?

- 120 lbs/day
- 151 lbs/day
- 210 lbs/day
- 110 lbs/day

Water is pumped through a 10-inch main at a rate of 500 gpm. Calculate the velocity of flow in the line.

- 1.5 ft./sec.
- 0.5 ft./sec.
- 2.0 ft./sec.
- 0.66 ft./sec.

How many cubic yards of earth are excavated for a trench that is 450 feet long, 42 inches wide, and 8 feet deep?

- 1287 cu. yds.
- 283 cu. yds.
- 1,400 cu. yds.
- 467 cu. yds.

How long will it take to fill a ground storage tank that holds 125,000 gallons using two pumps that each have an output of 125 gpm?

- 3.0 hours
- 4.7 hours
- 5.8 hours
- 8.3 hours

A flow of 700 gpm is pumped against a total dynamic head (TDH) of 250 feet by a pump with an efficiency of 65%. What is the pump horsepower?

- 85 Hp
- 68 Hp
- 73 Hp
- 55 Hp

A flow of 825 gpm is pumped against a total head of 430 feet by a pump with an efficiency of 55% and a motor with an efficiency of 85%. What is the total horsepower?

- 192 Hp
- 105 Hp
- 163 Hp
- 87 Hp

A circular tank that has a diameter of 47 feet and is 28 feet high is filled with 194,562 gallons of treated water. How deep is the water in the tank?

- 18 feet
- 16 feet
- 15 feet
- 8 feet

If a circular clarifier has a radius of 22 feet, what is the length of the weir that runs around the rim?

- 138 feet
- 69 feet
- 157 feet
- 112 feet

What is the detention time in a rectangular clarifier that is 225 feet long, 45 feet wide, and 17 feet deep … when the flow is 3.7 mgd?

- 13.7 hours
- 8.4 hours
- 0.3 hours
- 1.8 hours

What is the flow if your plant uses 57 pounds of chlorine in 24 hours to achieve a dose of 2.3 mg/L?

- 4.2 mgd
- 3.3 mgd
- 245 gpd
- 3.0 mgd

Your plant treated 4,233,247 gallons during the month of August. There are 3,276,432 gallons in various storage tanks. What is the percentage of water that is unaccounted for?

- 18 %
- 23 %
- 27 %
- 21 %

If the velocity of the water traveling through a 12 inch pipe is 3.75 ft./sec., what is the flow?

- 4.8 cu.ft./sec.
- 2.9 cu.ft./sec.
- .2 cu.ft./sec.
- 3.1 cu.ft./sec.

A chemical feed pump lowers the level of a chemical container by 30 inches in 4 hours. If the tank has a 26 foot diameter and a depth of 16 feet, what is the chemical feed rate.

- 59,540 gpd
- 381,056 gpd
- 714,481 gpd
- 78,564 gpd

If the flow through a 7 inch pipe is traveling at 4.75 cu. ft./sec, how many gallons will travel through the pipe in 5 months?

- 4,460,646,800 gallons
- 4,646,800 gallons
- 465,806,452 gallons
- 46,460,800 gallons

Find the upward force on the bottom of an empty tank caused by a groundwater depth of 4 feet. The tank has a radius of 16 feet.

- 322,067 pounds
- 200,638 pounds
- 137,648 pounds
- 223,769 pounds

Find the force acting on a 7 foot side wall in a 5 foot deep tank.

- 12,001 pounds
- 6,578 pounds
- 5,460 pounds
- 2.234 pounds

Flow in a 7 inch pipe is 325 gpm … what is the average velocity?

- 4.1 ft./sec.
- 3.2 ft./sec.
- 5.4 ft./sec.
- 2.7 ft./sec.

A flow of 4.7 mgd flows through a clarifier that is 22 feet high and has an 18 foot radius. What is the detention time in minutes?

- 51 minutes
- 22 minutes
- 37 minutes
- 46 minutes

Find the upward force on the bottom of an empty tank caused by a groundwater depth of 9 feet. The tank has a diameter of 27 feet.

- 245,786 pounds
- 321,384 pounds
- 158,879 pounds
- 527,856 pounds

A flow of 280 gpm is pumped against a total head of 175 feet. If the efficiency of the pump is 65% and the efficiency of the motor is 90%, what is the horse power?

- 33 Hp
- 27 Hp
- 21 Hp
- 18 Hp

Find the force acting on an 11 foot side wall in a 7.5 foot deep tank.

- 12,040 pounds
- 19,305 pounds
- 14,443 pounds
- 17,654 pounds

A flow of 252,000 gpd is pumped against a total head of 57 yards. If the efficiency of the pump is 50% and the efficiency of the motor is 80% what is the horsepower?

- 19 Hp
- 22 Hp
- 6 Hp
- 11 Hp

Data: 14 foot radius

22 feet side wall

Fill depth 19 feet

Pump rate 250 gpm- 7 hours
- 5.8 hours
- 24 hours
- 2.6 hours

How many hours will it take to the fill depth?