math problems

Question 1

A 55-foot diameter ground-level tank with separate inlet and outlet piping has a constant water level of 20 feet in it while 9 MGD of water flows through it. Calculate the detention time.

A. 57 min
B. 47 min
C. 37 min
D. 67 min

Answer 1

A. 57 min

Question 2

If water flows into a rectangular basin at a rate of 550 gpm. What will the level be after 30 minutes?
The basin dimensions are: Length = 55 feet Width = 35 feet Depth = 14 feet

A. 3.1 ft
B. 0.5 ft
C. 4.0 ft
D. 1.2 ft

Answer 2

D. 1.2 ft

Question 3

A 50-foot diameter ground-level tank with separate inlet and outlet piping has a constant water level of 23 feet in it while 12 MGD of water flows through it. Calculate the detention time.

A. 20 min
B. 30 min
C. 40 min
D. 10 min

Answer 3

C. 40 min

Question 4

How long will it take to completely fill a tank that has a diameter of 55 feet, and a height of 24 ft if water is flowing into the tank at a rate of 325 gpm?

A. 19.9 hrs
B. 20.9 hrs
C. 18.9 hrs
D. 21.9 hrs

Answer 4

D. 21.9 hrs

Question 5

How long will it take to completely fill a tank that has a diameter of 50 feet, and a height of 20 ft if water is flowing into the tank at a rate of 350 gpm?

A. 16 hrs
B. 12 hrs
C. 18 hrs
D. 14 hrs

Answer 5

D. 14 hrs

Question 6

A 60-foot diameter ground-level tank with separate inlet and outlet piping has a constant water level of 24 feet in it while 10 MGD of water flows through it. Calculate the detention time.

A. 1.2 hrs
B. 3.2 hrs
C. 4.2 hrs
D. 2.2 hrs

Answer 6

A. 1.2 hrs

Question 7

If water flows into a rectangular basin at a rate of 650 gpm. What will the level be after 30 minutes?
The basin dimensions are: Length = 50 feet Width = 30 feet Depth = 20 feet

A. 0.9 ft
B. 4.7 ft
C. 1.7 ft
D. 2.5 ft

Answer 7

C. 1.7 ft

Question 8

If water flows into a rectangular basin at a rate of 450 gpm. What will the level be after 30 minutes?
The basin dimensions are: Length = 40 feet Width = 35 feet Depth = 15 feet

A. 2.0 ft
B. 1.3 ft
C. 3.8 ft
D. 0.8 ft

Answer 8

B. 1.3 ft

Question 9

How long will it take to completely fill a tank that has a diameter of 60 feet, and a height of 25 ft if water is flowing into the tank at a rate of 300 gpm?

A. 17.4 hrs
B. 35.4 hrs
C. 29.4 hrs
D. 23.4 hrs

Answer 9

C. 29.4 hrs

Question 10

Calculate how many days worth of chlorine storage the plant has. The plant has 6 one ton cylinders and uses 350 lb/day.

A. 22 days
B. 30 days
C. 26 days
D. 34 days

Answer 10

D. 34 days

Question 11

Calculate the flow of a hypochlorinator in gpd. The solution is in a container that has a diameter of 24 inches. The level dropped 18 inches in an eight hour shift.

A. 116 gpd
B. 106 gpd
C. 96 gpd
D. 126 gpd

Answer 11

B. 106 gpd

Question 12

Find the chlorine dose in mg/L if the chlorinator is set to feed 17 pounds of chlorine each day and plant flow is 0.83 MGD.

A. 3.1 mg/L
B. 2.5 mg/L
C. 2.9 mg/L
D. 2.7 mg/L

Answer 12

B. 2.5 mg/L

Question 13

Estimate the desired strength of a hypochlorite solution in percent (%) of chlorine for a chlorinator that delivers 100 gpd. The water being treated requires a dose of 10 lb/day.

A. 0.8%
B. 1.4%
C. 1.0%
D. 1.2%

Answer 13

D. 1.2%

Question 14

Calculate how many gallons of water are needed to dilute 2 gallons of a 12.5% hypochlorite solution to a 5 % solution.

A. 4 gallons
B. 5 gallons
C. 6 gallons
D. 3 gallons

Answer 14

D. 3 gallons

Question 15

What is the chlorine demand in mg/L for water with a dose of 3.2 mg/L and a residual of 0.8 mg/L.

A. 2.9 mg/L
B. 2.4 mg/L
C. 2.1 mg/L
D. 2.6 mg/L

Answer 15

B. 2.4 mg/L

Question 16

Find the amount of chlorine used in pounds if 175 gallons of a 12% solution are consumed.

A. 185 lb
B. 165 lb
C. 175 lb
D. 155 lb

Answer 16

C. 175 lb

Question 17

Calculate the flow of a hypochlorinator in gpd. The solution is in a container that has a diameter of 34 inches. The level dropped 13 inches in an eight hour shift.

A. 139 gpd
B. 153 gpd
C. 179 gpd
D. 163 gpd

Answer 17

B. 153 gpd

Question 18

What is the chlorine demand in mg/L for water with a dose of 5.1 mg/L and a residual of 0.6 mg/L.

A. 4.5 mg/L
B. 1.3 mg/L
C. 6.1 mg/L
D. 5.2 mg/L

Answer 18

A. 4.5 mg/L

Question 19

Calculate how many gallons of water are needed to dilute 1 gallon of a 10% hypochlorite solution to a 2.5 % solution.

A. 1 gallon
B. 4 gallons
C. 2 gallons
D. 3 gallons

Answer 19

D. 3 gallons

Question 20

Estimate the desired strength of a hypochlorite solution in percent (%) of chlorine for a chlorinator that delivers 100 gpd. The water being treated requires a dose of 12 lb/day.

A. 1.0%
B. 1.4%
C. 1.2%
D. 1.6%

Answer 20

B. 1.4%

Question 21

Find the amount of chlorine used in pounds if 135 gallons of a 12% solution are consumed.

A. 135 lb
B. 105 lb
C. 125 lb
D. 115 lb

Answer 21

A. 135 lb

Question 22

Calculate how many days worth of chlorine storage the plant has. The plant has 4 one ton cylinders and uses 250 lb/day.

A. 30 days
B. 32 days
C. 28 days
D. 24 days

Answer 22

B. 32 days

Question 23

Find the chlorine dose in mg/L if the chlorinator is set to feed 15 pounds of chlorine each day and plant flow is 0.65 MGD.

A. 2.5 mg/L
B. 2.4 mg/L
C. 2.9 mg/L
D. 2.8 mg/L

Answer 23

D. 2.8 mg/L

Question 24

Find the setting on a chlorinator in pounds per day if a well pump is pumping in a flow of 350 gallons per minute and the required chlorine dose is 2.2 mg/L.

A. 8.2 lb/day
B. 9.2 lb/day
C. 7.2 lb/day
D. 6.2 lb/day

Answer 24

B. 9.2 lb/day

Question 25

Calculate the feed rate of a dry chemical feeder in pounds per day. A bucket that weighs half a pound empty is placed under the outlet. After 20 minutes the total weight of the chemical and bucket is 2.5 pounds.

A. 164 lb/day
B. 194 lb/day
C. 140 lb/day
D. 144 lb/day

Answer 25

D. 144 lb/day

Question 26

Calculate the feed rate of a dry chemical feeder in pounds per day. A bucket that weighs half a pound empty is placed under the outlet. After 30 minutes the total weight of the chemical and bucket is 2.8 pounds.

A. 144 lb/day
B. 110 lb/day
C. 114 lb/day
D. 124 lb/day

Answer 26

B. 110 lb/day

Question 27

Find the setting on a chlorinator in pounds per day if a well pump is pumping in a flow of 675 gallons per minute and the required chlorine dose is 1.5 mg/L.

A. 11.2 lb/day
B. 19.2 lb/day
C. 14.4 lb/day
D. 12.2 lb/day

Answer 27

D. 12.2 lb/day

Question 28

Calculate the chlorine feed in pounds per day from a hypochlorinator that is feeding a 1.4% solution. The hypochlorinator is pumping 650 ml every 10 minutes.

A. 3.4 lb/day
B. 1.5 lb/day
C. 4.8 lb/day
D. 2.9 lb/day

Answer 28

D. 2.9 lb/day

Question 29

Calculate the chlorine feed in pounds per day from a hypochlorinator that is feeding a 1.2% solution. The hypochlorinator is pumping 400 ml every 10 minutes.

A. 4.0 lb/day
B. 1.5 lb/day
C. 7.4 lb/day
D. 3.4 lb/day

Answer 29

B. 1.5 lb/day

Question 30

Find the setting on a chlorinator in pounds per day if a well pump is pumping in a flow of 325 gallons per minute and the required chlorine dose is 2.4 mg/L.

A. 9.4 lb/day
B. 7.3 lb/day
C. 10.4 lb/day
D. 8.2 lb/day

Answer 30

A. 9.4 lb/day

Question 31

Find the setting on a chlorinator in pounds per day if a well pump is pumping in a flow of 250 gallons per minute and the required chlorine dose is 1.8 mg/L.

A. 7.2 lb/day
B. 5.4 lb/day
C. 9.4 lb/day
D. 6.4 lb/day

Answer 31

B. 5.4 lb/day

Question 32

Calculate the chlorine feed in pounds per day from a hypochlorinator that is feeding a 1.5% solution. The hypochlorinator is pumping 500 ml every 11 minutes.

A. 2.2 lb/day
B. 6.1 lb/day
C. 1.4 lb/day
D. 3.4 lb/day

Answer 32

A. 2.2 lb/day

Question 33

Calculate the feed rate of a dry chemical feeder in pounds per day. A bucket that weighs half a pound empty is placed under the outlet. After 15 minutes the total weight of the chemical and bucket is 1.8 pounds.

A. 134 lb/day
B. 125 lb/day
C. 173 lb/day
D. 184 lb/day

Answer 33

B. 125 lb/day

Question 34

Find the setting on a chlorinator in pounds per day if a well pump is pumping in a flow of 400 gallons per minute and the required chlorine dose is 2.0 mg/L.

A. 8.2 lb/day
B. 7.9 lb/day
C. 9.2 lb/day
D. 9.6 lb/day

Answer 34

D. 9.6 lb/day

Question 35

Calculate the feed rate of a dry chemical feeder in pounds per day. A bucket that weighs half a pound empty is placed under the outlet. After 25 minutes the total weight of the chemical and bucket is 4.2 pounds.

A. 249 lb/day
B. 142 lb/day
C. 264 lb/day
D. 213 lb/day

Answer 35

D. 213 lb/day

Question 36

Calculate the chlorine feed in pounds per day from a hypochlorinator that is feeding a 1.5% solution. The hypochlorinator is pumping 425 ml every 12 minutes.

A. 2.8 lb/day
B. 1.7 lb/day
C. 2.4 lb/day
D. 3.4 lb/day

Answer 36

B. 1.7 lb/day

Question 37

Calculate the chlorine feed in pounds per day from a hypochlorinator that is feeding a 1.2% solution. The hypochlorinator is pumping 375 ml every 10 minutes.

A. 5.4 lb/day
B. 4.4 lb/day
C. 1.4 lb/day
D. 3.4 lb/day

Answer 37

C. 1.4 lb/day

Question 38

Calculate the feed rate of a dry chemical feeder in pounds per day. A bucket that weighs half a pound empty is placed under the outlet. After 30 minutes the total weight of the chemical and bucket is 4 pounds.

A. 162 lb/day
B. 174 lb/day
C. 168 lb/day
D. 134 lb/day

Answer 38

C. 168 lb/day

Question 39

Find the setting on a chlorinator in pounds per day if a well pump is pumping in a flow of 675 gallons per minute and the required chlorine dose is 1.5 mg/L.

A. 19.2 lb/day
B. 14.4 lb/day
C. 11.2 lb/day
D. 12.2 lb/day

Answer 39

D. 12.2 lb/day

Question 40

Find the setting on a chlorinator in pounds per day if a well pump is pumping in a flow of 800 gallons per minute and the required chlorine dose is 2.0 mg/L.

A. 20.2 lb/day
B. 18.2 lb/day
C. 19.2 lb/day
D. 21.2 lb/day

Answer 40

C. 19.2 lb/day