CWEA Environmental Compliance Inspector
Grade 1 Exam Guide 2026
1. Floatable solids are easy to measure. True or False? False
2. A well operated digester normally receives sludge at 70-75%, 25-30%
about % volatile solid and reduces it to about
% volatile solids.
3. According to OSHA, which of the following oxygen in 19.5% oxygen
air concentration is the lowest safe concentration for
humans to breathe in order to avoid the hazard of
oxygen deficiency?
4. The population equivalent factor for BOD is 0.17 lb/day/BOD/person
5. Which microorganisms are found in a good settling Rotifers, stalked ciliates,
mixed liquor? and free swimming ciliates
6. Which heavy metal is the most stringent for land appli- Mercury
cation?
7. Grit chambers that are designed to remove grit at a 0.5 to 1.0 ft/sec
velocity of
8. The purpose of adding sodium thiosulfate to a micro- Remove any chlorine
biological (such as fecal coliform) sample bottle is to residual present
9. Which of the following types of wastewater would set- Strong wastewater
tling occur most rapidly?
Cold wastewater
Old wastewater
Septic wastewater
Strong wastewater
10. The disadvantage of using a constant percentage re- Clarifier is subjected to
turn activated sludge flow control is maximum solids loading
, when it contains maximum
amount of sludge
11. Under which conditions should sludge wasting nor- A dark brown scummy
mally be increased? foam appears on the aer-
ation tank surface
12. The outlet of a forced ventilation system for a chlorina- Near the floor
tor room should be located
13. If packing is not maintained properly There will be a loss of
suction from air being al-
lowed to enter the pipe.
14. Turbidity in wastewater is caused by Finely divided suspended
material
15. One of the primary reasons why air should be excluded The entrance of air mixed
from the digester is that... with gas produced in the
digester could create an
explosive mixture
16. True or False: Barminutors and comminutors are in- False
stalled for different purposes
17. What are the end products of the aerobic biochemical H2O and CO2
reaction?
18. What does pump maintenance include? all of the above
a. Checking operating temperatures of bearings
b. checking packings glands
c. lubricating the impeller
d. all of the above
, 19. Pump packing should be Tightened down to a drip
20. The fusible plug that is in all chlorine containers? Should never be removed
or tampered with
a. May be used as a tap for the chlorine source
b. Should be removed after the cylinders are empty
c. Should never be removed or tampered with
d. Should be removed prior to withdrawing chlorine
from the container
21. A piston or diaphragm pump would be used for pump- Primary sludge
ing...
22. Collection system variables that could upset an activat- Activities of collection sys-
ed sludge process include... tem maintenance crew
23. What type of pump is not seriously damaged if the Centrifugal pump
discharge valve is closed for a short time, while the
pump is running?
24. Which of the following chemicals would be the most Soda ash
effective in achieving a pH adjustment of 8.4 so nitrifi-
cation can take place in an RBC?
25. Acids should never be added to chlorine solution be- Cause chlorine gas to be
cause they... released
26. Which of the following is a method for treating flow to Preaerate
the primary settling tank that would increase grease
removal, efficiency of that unit?
27. Name three waterborne diseases Typhoid fever, dysentery,
cholera
Grade 1 Exam Guide 2026
1. Floatable solids are easy to measure. True or False? False
2. A well operated digester normally receives sludge at 70-75%, 25-30%
about % volatile solid and reduces it to about
% volatile solids.
3. According to OSHA, which of the following oxygen in 19.5% oxygen
air concentration is the lowest safe concentration for
humans to breathe in order to avoid the hazard of
oxygen deficiency?
4. The population equivalent factor for BOD is 0.17 lb/day/BOD/person
5. Which microorganisms are found in a good settling Rotifers, stalked ciliates,
mixed liquor? and free swimming ciliates
6. Which heavy metal is the most stringent for land appli- Mercury
cation?
7. Grit chambers that are designed to remove grit at a 0.5 to 1.0 ft/sec
velocity of
8. The purpose of adding sodium thiosulfate to a micro- Remove any chlorine
biological (such as fecal coliform) sample bottle is to residual present
9. Which of the following types of wastewater would set- Strong wastewater
tling occur most rapidly?
Cold wastewater
Old wastewater
Septic wastewater
Strong wastewater
10. The disadvantage of using a constant percentage re- Clarifier is subjected to
turn activated sludge flow control is maximum solids loading
, when it contains maximum
amount of sludge
11. Under which conditions should sludge wasting nor- A dark brown scummy
mally be increased? foam appears on the aer-
ation tank surface
12. The outlet of a forced ventilation system for a chlorina- Near the floor
tor room should be located
13. If packing is not maintained properly There will be a loss of
suction from air being al-
lowed to enter the pipe.
14. Turbidity in wastewater is caused by Finely divided suspended
material
15. One of the primary reasons why air should be excluded The entrance of air mixed
from the digester is that... with gas produced in the
digester could create an
explosive mixture
16. True or False: Barminutors and comminutors are in- False
stalled for different purposes
17. What are the end products of the aerobic biochemical H2O and CO2
reaction?
18. What does pump maintenance include? all of the above
a. Checking operating temperatures of bearings
b. checking packings glands
c. lubricating the impeller
d. all of the above
, 19. Pump packing should be Tightened down to a drip
20. The fusible plug that is in all chlorine containers? Should never be removed
or tampered with
a. May be used as a tap for the chlorine source
b. Should be removed after the cylinders are empty
c. Should never be removed or tampered with
d. Should be removed prior to withdrawing chlorine
from the container
21. A piston or diaphragm pump would be used for pump- Primary sludge
ing...
22. Collection system variables that could upset an activat- Activities of collection sys-
ed sludge process include... tem maintenance crew
23. What type of pump is not seriously damaged if the Centrifugal pump
discharge valve is closed for a short time, while the
pump is running?
24. Which of the following chemicals would be the most Soda ash
effective in achieving a pH adjustment of 8.4 so nitrifi-
cation can take place in an RBC?
25. Acids should never be added to chlorine solution be- Cause chlorine gas to be
cause they... released
26. Which of the following is a method for treating flow to Preaerate
the primary settling tank that would increase grease
removal, efficiency of that unit?
27. Name three waterborne diseases Typhoid fever, dysentery,
cholera
