Water Distribution Operator (TX)
License D Questions and Answers
Verified 100% Correct
1. A sample of treated surface water has a chlorine demand of 3.5 mg/L. If the operator
wants a
residual of 1 mg/L in the clear well, what dosage must the operator apply? - ANSWER
2. If an operator applies a chlorine dosage of 2.75 mg/L to 5000 gallons of well water
and the
chlorine demand of the water is 1.25 mg/L, what will be the mg/L residual? - ANSWER
3. An operator applies 7 mg/L of chlorine to well water containing hydrogen sulfide. The
hydrogen sulfide reacts with all but 2.5 mg/L of the chlorine. What was the chlorine
demand? - ANSWER
4. After flushing a fire hydrant for 10 minutes at 200 gpm, a water sample shows a
chlorine
residual of 4.8 mg/L. If the chlorine demand is 2.2, what is the dosage? - ANSWER
5. The following alum dosages were applied during surface water treatment: - ANSWER
6. A surface water treatment plant produces 1,600,000 gallons per day using alum at 9
mg/L
, dosage. How many pounds of alum are used per day, per hour and per 30-day month?
- ANSWER
7. An operator is using a 150-pound chlorine cylinder and treating 5,000,000 gallons
per day. At
a dosage of 1.5 mg/L, is the safe withdrawal rate (vacuum transmission) exceeded if
the chlorinator room is 75° F? - ANSWER
8. How many pounds of fluorosilic acid are used daily at a dose of 1 mg/L if a
well produces 500
gallons per minute? - ANSWER
9. Lime is used in a surface water treatment plant at the rate of 480 pounds per day. If
the plant
produces 2,400,000 gallons daily, what is the mg/L dosage? - ANSWER
10. If a well pumps 650 gpm and uses 1.5 pounds of chlorine per hour, what is the mg/L
dosage
per day? - ANSWER
11. A water system uses 50 pounds of chlorine per day, but runs out a day before
a delivery is
made. If calcium hypochlorite (65%) is substituted, will 100 pounds last until
delivery? Calculate the answer 2 ways. - ANSWER
1. How many minutes will it take to fill a 4,000-gallon tank at 400 gpm? - ANSWER
2. How many hours will it take to empty a 20,000-gallon tank at 60 gpm? - ANSWER
License D Questions and Answers
Verified 100% Correct
1. A sample of treated surface water has a chlorine demand of 3.5 mg/L. If the operator
wants a
residual of 1 mg/L in the clear well, what dosage must the operator apply? - ANSWER
2. If an operator applies a chlorine dosage of 2.75 mg/L to 5000 gallons of well water
and the
chlorine demand of the water is 1.25 mg/L, what will be the mg/L residual? - ANSWER
3. An operator applies 7 mg/L of chlorine to well water containing hydrogen sulfide. The
hydrogen sulfide reacts with all but 2.5 mg/L of the chlorine. What was the chlorine
demand? - ANSWER
4. After flushing a fire hydrant for 10 minutes at 200 gpm, a water sample shows a
chlorine
residual of 4.8 mg/L. If the chlorine demand is 2.2, what is the dosage? - ANSWER
5. The following alum dosages were applied during surface water treatment: - ANSWER
6. A surface water treatment plant produces 1,600,000 gallons per day using alum at 9
mg/L
, dosage. How many pounds of alum are used per day, per hour and per 30-day month?
- ANSWER
7. An operator is using a 150-pound chlorine cylinder and treating 5,000,000 gallons
per day. At
a dosage of 1.5 mg/L, is the safe withdrawal rate (vacuum transmission) exceeded if
the chlorinator room is 75° F? - ANSWER
8. How many pounds of fluorosilic acid are used daily at a dose of 1 mg/L if a
well produces 500
gallons per minute? - ANSWER
9. Lime is used in a surface water treatment plant at the rate of 480 pounds per day. If
the plant
produces 2,400,000 gallons daily, what is the mg/L dosage? - ANSWER
10. If a well pumps 650 gpm and uses 1.5 pounds of chlorine per hour, what is the mg/L
dosage
per day? - ANSWER
11. A water system uses 50 pounds of chlorine per day, but runs out a day before
a delivery is
made. If calcium hypochlorite (65%) is substituted, will 100 pounds last until
delivery? Calculate the answer 2 ways. - ANSWER
1. How many minutes will it take to fill a 4,000-gallon tank at 400 gpm? - ANSWER
2. How many hours will it take to empty a 20,000-gallon tank at 60 gpm? - ANSWER
