LEVEL II WASTEWATER TREATMENT
PRACTICE TEST STUDY GUIDE 2026
QUESTIONS WITH ANSWERS GRADED A+
◉ Primary treatment process of a trickling filter Answer: Bacterial
decomposition
◉ Example of an activated sludge process Answer: Sequencing Batch
Reactor (SBR)
◉ Prevent excessive solids buildup in activated sludge Answer: Send
solids to secondary clarifier and treat
◉ Cause of white biomass on RBC discs Answer: High sulfur content in
influent
◉ Result of sludge layer too deep in sedimentation tank Answer:
Bulking and septic conditions
◉ Typical depth of synthetic media trickling filter Answer: 15-30 feet
◉ First sign of high organic load in activated sludge Answer: Decrease
in dissolved oxygen
, ◉ Reddish-brown or golden zoogleal film indicates Answer:
Nitrification
◉ Main workers in activated sludge treatment Answer: Microorganisms
◉ Proper grit channel velocity results in Answer: Grit with small
amount of organic material
◉ Food-to-microorganism ratio measures Answer: BOD loading divided
by microorganisms
◉ Optimal RBC operating temperature Answer: Above 55°F
◉ Minimum depth for wastewater pond treatment Answer: 3 feet
◉ Bulking is defined as Answer: Floating sludge that did not settle in
clarifier
◉ Mixing is important in digesters because it Answer: Speeds up
digestion
◉ pH in wastewater pond is highest at midday Answer: True
◉ Best protection against infectious diseases Answer: Immunizations
PRACTICE TEST STUDY GUIDE 2026
QUESTIONS WITH ANSWERS GRADED A+
◉ Primary treatment process of a trickling filter Answer: Bacterial
decomposition
◉ Example of an activated sludge process Answer: Sequencing Batch
Reactor (SBR)
◉ Prevent excessive solids buildup in activated sludge Answer: Send
solids to secondary clarifier and treat
◉ Cause of white biomass on RBC discs Answer: High sulfur content in
influent
◉ Result of sludge layer too deep in sedimentation tank Answer:
Bulking and septic conditions
◉ Typical depth of synthetic media trickling filter Answer: 15-30 feet
◉ First sign of high organic load in activated sludge Answer: Decrease
in dissolved oxygen
, ◉ Reddish-brown or golden zoogleal film indicates Answer:
Nitrification
◉ Main workers in activated sludge treatment Answer: Microorganisms
◉ Proper grit channel velocity results in Answer: Grit with small
amount of organic material
◉ Food-to-microorganism ratio measures Answer: BOD loading divided
by microorganisms
◉ Optimal RBC operating temperature Answer: Above 55°F
◉ Minimum depth for wastewater pond treatment Answer: 3 feet
◉ Bulking is defined as Answer: Floating sludge that did not settle in
clarifier
◉ Mixing is important in digesters because it Answer: Speeds up
digestion
◉ pH in wastewater pond is highest at midday Answer: True
◉ Best protection against infectious diseases Answer: Immunizations
