BASIC WASTEWATER OPERATOR PRACTICE EXAM
A composite sample must be? Correct answers representative
and sub-samples times spaced over 15 minutes apart
A horizontal centrifugal pump has "rope" packing. When the
pump is in operation, water slowly drips from the packing gland.
What does this indicate? Correct answers the packing bolts or
nuts on the packing gland are properly adjusted
A local college has an outbreak of giardia in the water system, a
hose that was connected to a spigot was found in a grease trap
was determined to be where the bacteria entered the system.
What is this an example of? Correct answers cross-connection
by back siphonage
A positive displacement sludge pump should never be placed
into operation ___ correct answers with the discharge valve
closed
A trickling filter arm is moving slow, how do you speed it up?
Correct answers close orifices on the distribution arms
A wwtp flow is 5.0 mgd, how many gallons per minute is this?
Correct answers 3472 gpm
An equipment failure warning light did not turn on, but a failure
was reported and repaired. What is the first thing the operator
needs to do? Correct answers check/replace the bulb in the
indicator light
, An operator notices a portion of the aeration tank with large
bubbles rising up.
What is the most likely problem? Correct answers unequal air
distribution caused by a blown diffuser
Assuming a constant suction head, the discharge of a centrifugal
pump ___ correct answers will increase with a decrease in
discharge head
Calculate f:m ratio
Given: influent bod5= 290 mg/l
Influent flow= 5.0 mgd
Aeration basin mlss= 2650 mg/l
Aeration basin volume= 0.8 mg correct answers 0
Calculate srt
Given: mixed liquor suspended solids (mlss)= 2400 mg/l
Aeration basin volume= 35,000 gallons= 0.0350 million gallons
(mg)
Wasted activated sludge (was) concentration 3500 mg/l
Wasted activated sludge (was) flowrate= 0.001 mgd correct
answers 24 days
Calculate svi
Given: 30 minute settling test= 1800 ml in a 2000 ml container
Mlss= 4000 mg/l correct answers 450
Calculate the bod using the given information:
Initial do: 8.3
Final do: 5.9
Milliliters of sample: 2 correct answers 360 mg/l
A composite sample must be? Correct answers representative
and sub-samples times spaced over 15 minutes apart
A horizontal centrifugal pump has "rope" packing. When the
pump is in operation, water slowly drips from the packing gland.
What does this indicate? Correct answers the packing bolts or
nuts on the packing gland are properly adjusted
A local college has an outbreak of giardia in the water system, a
hose that was connected to a spigot was found in a grease trap
was determined to be where the bacteria entered the system.
What is this an example of? Correct answers cross-connection
by back siphonage
A positive displacement sludge pump should never be placed
into operation ___ correct answers with the discharge valve
closed
A trickling filter arm is moving slow, how do you speed it up?
Correct answers close orifices on the distribution arms
A wwtp flow is 5.0 mgd, how many gallons per minute is this?
Correct answers 3472 gpm
An equipment failure warning light did not turn on, but a failure
was reported and repaired. What is the first thing the operator
needs to do? Correct answers check/replace the bulb in the
indicator light
, An operator notices a portion of the aeration tank with large
bubbles rising up.
What is the most likely problem? Correct answers unequal air
distribution caused by a blown diffuser
Assuming a constant suction head, the discharge of a centrifugal
pump ___ correct answers will increase with a decrease in
discharge head
Calculate f:m ratio
Given: influent bod5= 290 mg/l
Influent flow= 5.0 mgd
Aeration basin mlss= 2650 mg/l
Aeration basin volume= 0.8 mg correct answers 0
Calculate srt
Given: mixed liquor suspended solids (mlss)= 2400 mg/l
Aeration basin volume= 35,000 gallons= 0.0350 million gallons
(mg)
Wasted activated sludge (was) concentration 3500 mg/l
Wasted activated sludge (was) flowrate= 0.001 mgd correct
answers 24 days
Calculate svi
Given: 30 minute settling test= 1800 ml in a 2000 ml container
Mlss= 4000 mg/l correct answers 450
Calculate the bod using the given information:
Initial do: 8.3
Final do: 5.9
Milliliters of sample: 2 correct answers 360 mg/l
