ABC Wastewater Treatment Grade 3 Exam Questions with Verified Answers| Latest Update
Graded A+
Secondary clarifier sludge is rising, do what 2 steps? Increase RAS, Increase DO
Type of breathing apparatus used in oxygen deficient zones? Positive charged breathing
apparatus
2700 ppl send BOD, industry sends 300 BOD, what % is industry? 40%
Pressure reducing valve is located where on a chlorine injection line? Up the stream
Solids testing accurate weight time is 1 hour cook, 15 minute desiccator
When carbon dioxide is present, the pH goes down
How to get bigger floculation? Flash Mixing
Practical suction lift cannot exceed how many ft? 34 ft
Backflow prevention devices installed above ground level to prevent the relief port from
being submerged
Manholes are considered a Liability
Headworks barscreen won't move? Check for a broken Shear Pin
Gas + water pump Diaphram pump
, Batch Reactor 3 steps: mixed fill, static settle, draw
18 gal/1 cubic ft 199.5gpm
What transfers O2 better? MLSS
Effluent in system PH drops to 6.6 Nitrification leads to lower pH
Digester PH very low, chemical to add Sodium Hydroxide
MLSS goes up one day and higher the next from a settleability test, you increase WAS
COD holding time in fridge? 28 days
Time taken to seed a digester A and AN A 1 week, AN 2-4 weeks
BOD incubation period and temperature 5 days at 20 C
Time to hold BOD sample in fridge 48 hours 4 C
What preservative do you add to store COD samples? Sulfuric Acid H2SO4
Ammonia incubation period and temperature 28 days at 4 C
What preservative do you add to store Ammonia Sulfuric Acid H2SO4
Graded A+
Secondary clarifier sludge is rising, do what 2 steps? Increase RAS, Increase DO
Type of breathing apparatus used in oxygen deficient zones? Positive charged breathing
apparatus
2700 ppl send BOD, industry sends 300 BOD, what % is industry? 40%
Pressure reducing valve is located where on a chlorine injection line? Up the stream
Solids testing accurate weight time is 1 hour cook, 15 minute desiccator
When carbon dioxide is present, the pH goes down
How to get bigger floculation? Flash Mixing
Practical suction lift cannot exceed how many ft? 34 ft
Backflow prevention devices installed above ground level to prevent the relief port from
being submerged
Manholes are considered a Liability
Headworks barscreen won't move? Check for a broken Shear Pin
Gas + water pump Diaphram pump
, Batch Reactor 3 steps: mixed fill, static settle, draw
18 gal/1 cubic ft 199.5gpm
What transfers O2 better? MLSS
Effluent in system PH drops to 6.6 Nitrification leads to lower pH
Digester PH very low, chemical to add Sodium Hydroxide
MLSS goes up one day and higher the next from a settleability test, you increase WAS
COD holding time in fridge? 28 days
Time taken to seed a digester A and AN A 1 week, AN 2-4 weeks
BOD incubation period and temperature 5 days at 20 C
Time to hold BOD sample in fridge 48 hours 4 C
What preservative do you add to store COD samples? Sulfuric Acid H2SO4
Ammonia incubation period and temperature 28 days at 4 C
What preservative do you add to store Ammonia Sulfuric Acid H2SO4
