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?

1.   ?    165,228 gallons
2.   ?    330,289 gallons
3.   ?    269,460 gallons
4.   ?    660,912 gallons

The plant flow rate is 13 mgd and the influent CBOD₅ concentration is 230 mg/L. How many pounds per day of CBOD₅ are contained in this flow stream?

1.   ?    24,937 lbs/day
2.   ?    8,681 lbs/day
3.   ?    10,643 lbs/day
4.   ?    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?

1.   ?    6,450 sq.ft.
2.   ?    4,600 sq.ft.
3.   ?    5,000 sq.ft.
4.   ?    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?

1.   ?    10.55 ppm
2.   ?    5.86 ppm
3.   ?    20 ppm
4.   ?    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?

1.   ?    16,680 pounds
2.   ?    14,740 pounds
3.   ?    17,680 pounds
4.   ?    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?

1.   ?    6,146 sq.ft.
2.   ?    5,854 sq.ft.
3.   ?    7,850 sq.ft
4.   ?    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?

1.   ?    253 lbs/day
2.   ?    363 lbs/day
3.   ?    196 lbs/day
4.   ?    235 lbs/day

What is the fraction for the decimal .37?

1.   ?    .63
2.   ?    63/100
3.   ?    37/10
4.   ?    37/100

What is the decimal for the fraction ⅞ ?

1.   ?    1.14
2.   ?    0.875
3.   ?    56
4.   ?    8.7

What is the percent for the fraction ⅞ ?

1.   ?    87.5 %
2.   ?    99.12 %
3.   ?    12.5 %
4.   ?    1.14 %

Which is not an equal conversion to 1 mgd?

1.   ?    92.84 cfs
2.   ?    92.84 cfm
3.   ?    694 gpm
4.   ?    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?

1.   ?    74 gal/ 85.5 psi
2.   ?    86 gal/16psi
3.   ?    74 gal/16 psi
4.   ?    148 gal/27 psi

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

1.   ?    2,721,600 gallons
2.   ?    113,400 gallons
3.   ?    45,360 gallons
4.   ?    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.   ?    1,189,697 gallons
2.   ?    932,465 gallons
3.   ?    202,604 gallons
4.   ?    757,076 gallons

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

1.   ?    561.5 pounds
2.   ?    9.5 pounds
3.   ?    70.9 pounds
4.   ?    476 pounds

How many pounds does 10.5 cubic feet of water weigh?

1.   ?    78.5 pounds
2.   ?    87.6 pounds
3.   ?    655 pounds
4.   ?    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?

1.   ?    27 pipes
2.   ?    19 pipes
3.   ?    43 pipes
4.   ?    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?

1.   ?    15.85 days
2.   ?    0.26 days
3.   ?    1.83 days
4.   ?    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?

1.   ?    2.3 hours
2.   ?    4.9 hours
3.   ?    0.51 hours
4.   ?    3.7 hours

At what pH is a liquid considered to be neutral?

1.   ?    7.0
2.   ?    11.0
3.   ?    4.9
4.   ?    3.5

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

1.   ?    82.8 °F
2.   ?    57.2 °F
3.   ?    48.3 °F
4.   ?    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.   ?    1.2 mg/L
2.   ?    4.0 mg/L
3.   ?    2.3 mg/L
4.   ?    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?

1.   ?    29%
2.   ?    71%
3.   ?    14%
4.   ?    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?

1.   ?    52.5 pounds
2.   ?    62 pounds
3.   ?    34.5 pounds
4.   ?    70.5 pounds

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

1.   ?    497,553 gallons
2.   ?    3,455 gallons
3.   ?    3,852 gallons
4.   ?    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?

1.   ?    0.9 days
2.   ?    21.9 days
3.   ?    2.1 days
4.   ?    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?

1.   ?    5.5 mg/L
2.   ?    1.75 mg/L
3.   ?    2.5 mg/L
4.   ?    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.

1.   ?    44,121 gallons
2.   ?    48,646 gallons
3.   ?    67,247 gallons
4.   ?    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.   ?    1.55 cfs
2.   ?    2.2 cfs
3.   ?    1.75 cfs
4.   ?    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?

1.   ?    37.5 pounds
2.   ?    21.86 pounds
3.   ?    43.67 pounds
4.   ?    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.   ?    1,768 gpd/sq.ft.
2.   ?    3,640 gpd/sq.ft.
3.   ?    962 gpd/sq.ft.
4.   ?    2,876 gpd/sq.ft.

A temperature of 76 degrees Fahrenheit is equal to:

1.   ?    24.4° Centigrade
2.   ?    10.2° Centigrade
3.   ?    37.5° Centigrade
4.   ?    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.   ?    $1,450.25 per year
2.   ?    $2,760.15 per year
3.   ?    $2,216.10 per year
4.   ?    $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?

1.   ?    0.69 ft per sec (fps)
2.   ?    21.6 ft per sec
3.   ?    17.83 ft per sec
4.   ?    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.   ?    1,074 feet
2.   ?    85 feet
3.   ?    116 feet
4.   ?    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?

1.   ?    324 gpd
2.   ?    559,324 gpd
3.   ?    72 gpd
4.   ?    283 gpd

Three acres are equal to :

1.   ?    14,520 sq. ft.
2.   ?    130,680 sq. ft.
3.   ?    5,280 ft.
4.   ?    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?

1.   ?    5 feet
2.   ?    12 feet
3.   ?    8 feet
4.   ?    11 feet

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

1.   ?    452 sq. ft.
2.   ?    205 sq. ft.
3.   ?    1,394 sq. ft.
4.   ?    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?

1.   ?    900 gpm
2.   ?    725 gpm
3.   ?    1,215 gpm
4.   ?    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.   ?    1,100 gpm
2.   ?    714 gpm
3.   ?    550 gpm
4.   ?    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?

1.   ?    102,950 pounds
2.   ?    510,563 pounds
3.   ?    226,210 pounds
4.   ?    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.

1.   ?    18 pounds
2.   ?    76.7 pounds
3.   ?    94.5 pounds
4.   ?    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?

1.   ?    10.5 feet
2.   ?    20 feet
3.   ?    15.5 feet
4.   ?    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?

1.   ?    2.1 mgd
2.   ?    .786 mgd
3.   ?    1.3 mgd
4.   ?    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.   ?    1.7 hours
2.   ?    1.2 hours
3.   ?    2.4 hours
4.   ?    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.   ?    1.6 mg/L
2.   ?    4.2 mg/L
3.   ?    2.6 mg/L
4.   ?    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?

1.   ?    120 lbs/day
2.   ?    151 lbs/day
3.   ?    210 lbs/day
4.   ?    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.   ?    1.5 ft./sec.
2.   ?    0.5 ft./sec.
3.   ?    2.0 ft./sec.
4.   ?    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?

1.   ?    1287 cu. yds.
2.   ?    283 cu. yds.
3.   ?    1,400 cu. yds.
4.   ?    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?

1.   ?    3.0 hours
2.   ?    4.7 hours
3.   ?    5.8 hours
4.   ?    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?

1.   ?    85 Hp
2.   ?    68 Hp
3.   ?    73 Hp
4.   ?    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?

1.   ?    192 Hp
2.   ?    105 Hp
3.   ?    163 Hp
4.   ?    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?

1.   ?    18 feet
2.   ?    16 feet
3.   ?    15 feet
4.   ?    8 feet

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

1.   ?    138 feet
2.   ?    69 feet
3.   ?    157 feet
4.   ?    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?

1.   ?    13.7 hours
2.   ?    8.4 hours
3.   ?    0.3 hours
4.   ?    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?

1.   ?    4.2 mgd
2.   ?    3.3 mgd
3.   ?    245 gpd
4.   ?    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?

1.   ?    18 %
2.   ?    23 %
3.   ?    27 %
4.   ?    21 %

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

1.   ?    4.8 cu.ft./sec.
2.   ?    2.9 cu.ft./sec.
3.   ?    .2 cu.ft./sec.
4.   ?    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.

1.   ?    59,540 gpd
2.   ?    381,056 gpd
3.   ?    714,481 gpd
4.   ?    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?

1.   ?    4,460,646,800 gallons
2.   ?    4,646,800 gallons
3.   ?    465,806,452 gallons
4.   ?    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.

1.   ?    322,067 pounds
2.   ?    200,638 pounds
3.   ?    137,648 pounds
4.   ?    223,769 pounds

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

1.   ?    12,001 pounds
2.   ?    6,578 pounds
3.   ?    5,460 pounds
4.   ?    2.234 pounds

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

1.   ?    4.1 ft./sec.
2.   ?    3.2 ft./sec.
3.   ?    5.4 ft./sec.
4.   ?    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?

1.   ?    51 minutes
2.   ?    22 minutes
3.   ?    37 minutes
4.   ?    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.

1.   ?    245,786 pounds
2.   ?    321,384 pounds
3.   ?    158,879 pounds
4.   ?    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?

1.   ?    33 Hp
2.   ?    27 Hp
3.   ?    21 Hp
4.   ?    18 Hp

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

1.   ?    12,040 pounds
2.   ?    19,305 pounds
3.   ?    14,443 pounds
4.   ?    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?

1.   ?    19 Hp
2.   ?    22 Hp
3.   ?    6 Hp
4.   ?    11 Hp

Data: 14 foot radius
22 feet side wall
Fill depth 19 feet
Pump rate 250 gpm

How many hours will it take to the fill depth?
1.   ?    7 hours
2.   ?    5.8 hours
3.   ?    24 hours
4.   ?    2.6 hours