Basic Wastewater Operator Practice Exam
Questions and Correct Answers Updated
Question 1
If you are collecting a manual flow proportional composite sample with the following
flows, and you want to collect a total of 1000 mL, how much sample would be needed
for sample #4?
Flow #1: 12367
Flow #2: 12452
Flow #3: 12511
Flow #4: 12612
Flow #5: 12710
a. 246 mL
b. 171 mL
c. 293 mL
d. 284 mL
Correct Answer
d. 284 mL
Question 2
Name a device which is used to measure the flow of wastewater?
a. rotometer
b. ruler
c. parshall flume
d. sight glass
Correct Answer
c. parshall flume
Page 1 of 42
,Question 3
How do you calibrate a chemical feed pump?
A. by measuring the pump output
B. using the SWAG method
C. jar test
D. with a microscope
Correct Answer
A. by measuring the pump output
Question 4
What is one component of a centrifugal pump?
a. impeller
b. primer
c. hose bib
d. piston
Correct Answer
a. impeller
Question 5
What type of supply pipe is recommended for gaseous chlorine & water?
a. galvanized steel
b. polyvinyl chloride
c. rubber
d. stainless steel
Correct Answer
b. polyvinyl chlorine (PVC)
Page 2 of 42
,Question 6
What factors control the throat size in a chlorinator?
a. chlorine pressure
b. type of chlorine used
c. water pressure
d. distance to injection point
Correct Answer
c. water pressure
Question 7
What condition increases chlorine demand?
a. low flow
b. high flow
c. an increase in organic matter
d. a decrease in organic matter
Correct Answer
c. an increase in organic matter
Question 8
Calculate the pounds per day of chemical dosage with a flow of 5 MGD doing at a
rate of 218 ppm.
a. 1090 lbs/day
b. 9090 lbs/day
c. 8153.2 lbs/day
d. 1818 lbs/day
Correct Answer
b. 9090 lbs.day
Page 3 of 42
, Question 9
Considering the layout and flow diagram for the complete treatment plant, oxidation
ditch plants would be most similar to which of the following?
a. SBR
b. plug flow
c. Extended aeration
d. contact stabilization
Correct Answer
c. extended aeration
Question 10
What type of flow meters are used during normal operations of the sludge removal?
a. turbine
b. magnetic
c. TDR
d. paddle wheel
Correct Answer
b. magnetic
Question 11
How is an air-gap used?
a. it takes the gap of air and creates space for more bugs
b. to prevent contamination of potable water systems
c. to allow for less air to enter the system
d. to discharge excess air in the pressure line
Correct Answer
b. to prevent contamination of potable water systems
Page 4 of 42
Questions and Correct Answers Updated
Question 1
If you are collecting a manual flow proportional composite sample with the following
flows, and you want to collect a total of 1000 mL, how much sample would be needed
for sample #4?
Flow #1: 12367
Flow #2: 12452
Flow #3: 12511
Flow #4: 12612
Flow #5: 12710
a. 246 mL
b. 171 mL
c. 293 mL
d. 284 mL
Correct Answer
d. 284 mL
Question 2
Name a device which is used to measure the flow of wastewater?
a. rotometer
b. ruler
c. parshall flume
d. sight glass
Correct Answer
c. parshall flume
Page 1 of 42
,Question 3
How do you calibrate a chemical feed pump?
A. by measuring the pump output
B. using the SWAG method
C. jar test
D. with a microscope
Correct Answer
A. by measuring the pump output
Question 4
What is one component of a centrifugal pump?
a. impeller
b. primer
c. hose bib
d. piston
Correct Answer
a. impeller
Question 5
What type of supply pipe is recommended for gaseous chlorine & water?
a. galvanized steel
b. polyvinyl chloride
c. rubber
d. stainless steel
Correct Answer
b. polyvinyl chlorine (PVC)
Page 2 of 42
,Question 6
What factors control the throat size in a chlorinator?
a. chlorine pressure
b. type of chlorine used
c. water pressure
d. distance to injection point
Correct Answer
c. water pressure
Question 7
What condition increases chlorine demand?
a. low flow
b. high flow
c. an increase in organic matter
d. a decrease in organic matter
Correct Answer
c. an increase in organic matter
Question 8
Calculate the pounds per day of chemical dosage with a flow of 5 MGD doing at a
rate of 218 ppm.
a. 1090 lbs/day
b. 9090 lbs/day
c. 8153.2 lbs/day
d. 1818 lbs/day
Correct Answer
b. 9090 lbs.day
Page 3 of 42
, Question 9
Considering the layout and flow diagram for the complete treatment plant, oxidation
ditch plants would be most similar to which of the following?
a. SBR
b. plug flow
c. Extended aeration
d. contact stabilization
Correct Answer
c. extended aeration
Question 10
What type of flow meters are used during normal operations of the sludge removal?
a. turbine
b. magnetic
c. TDR
d. paddle wheel
Correct Answer
b. magnetic
Question 11
How is an air-gap used?
a. it takes the gap of air and creates space for more bugs
b. to prevent contamination of potable water systems
c. to allow for less air to enter the system
d. to discharge excess air in the pressure line
Correct Answer
b. to prevent contamination of potable water systems
Page 4 of 42
