CWEA Environmental Compliance
Inspector Grade 1
1. Floatable solids are easy to measure.
o False
2. A well-operated digester normally receives sludge at about ___% volatile
solids and reduces it to about ___% volatile solids.
o 70-75%, 25-30%
3. According to OSHA, the lowest safe oxygen concentration for humans to
breathe is:
o 19.5% oxygen
4. The population equivalent factor for BOD is:
o 0.17 lb/day/BOD/person
5. Which microorganisms are found in good settling mixed liquor?
o Rotifers, stalked ciliates, and free-swimming ciliates
6. Which heavy metal is the most stringent for land application?
o Mercury
7. Grit chambers are designed to remove grit at a velocity of:
o 0.5 to 1.0 ft/sec
8. The purpose of sodium thiosulfate in a microbiological sample bottle is to:
o Remove any chlorine residual present
9. In which type of wastewater does settling occur most rapidly?
o Strong wastewater
10. The disadvantage of constant percentage return activated sludge flow
control is:
, o Clarifier is subjected to maximum solids loading when it contains
maximum sludge
11. When should sludge wasting normally be increased?
o A dark brown scummy foam appears on the aeration tank surface
12. The outlet of a forced ventilation system for a chlorinator room should be
located:
o Near the floor
13. If packing is not maintained properly:
o There will be a loss of suction from air entering the pipe
14. Turbidity in wastewater is caused by:
o Finely divided suspended material
15. Why should air be excluded from a digester?
o Air mixed with digester gas could create an explosive mixture
16. True or False: Barminutors and comminutors are installed for different
purposes.
o False
17. End products of aerobic biochemical reactions are:
o H₂O and CO₂
18. Pump maintenance includes:
o All of the above (bearing temps, packing glands, lubrication)
19. Pump packing should be:
o Tightened down to a drip
20. The fusible plug in chlorine containers:
o Should never be removed or tampered with
21. A piston or diaphragm pump is used for:
o Primary sludge
22. Collection system variables that could upset an activated sludge process
include:
Inspector Grade 1
1. Floatable solids are easy to measure.
o False
2. A well-operated digester normally receives sludge at about ___% volatile
solids and reduces it to about ___% volatile solids.
o 70-75%, 25-30%
3. According to OSHA, the lowest safe oxygen concentration for humans to
breathe is:
o 19.5% oxygen
4. The population equivalent factor for BOD is:
o 0.17 lb/day/BOD/person
5. Which microorganisms are found in good settling mixed liquor?
o Rotifers, stalked ciliates, and free-swimming ciliates
6. Which heavy metal is the most stringent for land application?
o Mercury
7. Grit chambers are designed to remove grit at a velocity of:
o 0.5 to 1.0 ft/sec
8. The purpose of sodium thiosulfate in a microbiological sample bottle is to:
o Remove any chlorine residual present
9. In which type of wastewater does settling occur most rapidly?
o Strong wastewater
10. The disadvantage of constant percentage return activated sludge flow
control is:
, o Clarifier is subjected to maximum solids loading when it contains
maximum sludge
11. When should sludge wasting normally be increased?
o A dark brown scummy foam appears on the aeration tank surface
12. The outlet of a forced ventilation system for a chlorinator room should be
located:
o Near the floor
13. If packing is not maintained properly:
o There will be a loss of suction from air entering the pipe
14. Turbidity in wastewater is caused by:
o Finely divided suspended material
15. Why should air be excluded from a digester?
o Air mixed with digester gas could create an explosive mixture
16. True or False: Barminutors and comminutors are installed for different
purposes.
o False
17. End products of aerobic biochemical reactions are:
o H₂O and CO₂
18. Pump maintenance includes:
o All of the above (bearing temps, packing glands, lubrication)
19. Pump packing should be:
o Tightened down to a drip
20. The fusible plug in chlorine containers:
o Should never be removed or tampered with
21. A piston or diaphragm pump is used for:
o Primary sludge
22. Collection system variables that could upset an activated sludge process
include:
