WASTEWATER CLASS 2 LATEST
OHIO ABC PART 1
Wastewater entering a plant is typically - ANSWERS-somewhat warmer
than unheated tap water
What's the best flow velocity to settle out grit? - ANSWERS-.7-1.4
ft/sec
Short circuiting of grit through an aerated grit chamber can be
minimized or eliminated entirely by - ANSWERS-installing a
submerged transverse baffle along the wall opposite the diffusers
If there is a high head loss across a microscreen, the most probable cause
could be - ANSWERS-a plugged screen
Which type of pump should be used to transfer a 5% solids primary
sludge to a digester? - ANSWERS-positive-displacement pump
Primary clarifiers are typically designed to remove____of the settleable
solids and ___of the BOD. - ANSWERS-95-99% and 20-50%
What flow device typically measures flow of primary sludge flow? -
ANSWERS-magnetic flow meter
END OF
PAGE
1
, WASTEWATER CLASS 2 LATEST
OHIO ABC PART 1
Worn wearing shoes are often found on - ANSWERS-the flights of a
rectangular clarifier
The withdrawal of sludge from a clarifier should be slow in order to -
ANSWERS-prevent the pulling of too much water with the sludge
What should an operator do to increase MCRT? - ANSWERS-Decrease
the waste rate
What effect does pre-aeration have on downstream secondary plant
processes - ANSWERS-it tends to improve the overall efficiency of
solids and cbod removal.
For a particular plant there is an optimum range in which the mixed
liquid solids concentration must be maintained. What could happen if
the concentration were allowed to exceed the range - ANSWERS-A
cloudy, turbid effluent would result.
The process of nitrification - ANSWERS-Consumes about 7.1 lbs of
alkalinity to oxidize 1 lb. of ammonia to nitrate
END OF
PAGE
2
, WASTEWATER CLASS 2 LATEST
OHIO ABC PART 1
what type of activated sludge process has a detention time of 3 to 24
hours and a design F/M ratio of .03-.1? - ANSWERS-Oxidation ditch
When is increased wasting of activated sludge and increasing the
aeration tank f/m practiced? - ANSWERS-Denitrication is occurring in
the final settling tank causing rising sludge
How can an operator decrease the SRT and the MLSS concentration in
an activated sludge plant? - ANSWERS-Decrease RAS rate and increase
the waste rate
Most important factor in preventing accidents at a wastewater plant? -
ANSWERS-Attitude of the employees.
Plant influent appears black and has a foul odor each morning. The
cause is traced to a pump station at a subdivision which is oversized for
the current number of homes in the subdivision. What corrective action
can you take? - ANSWERS-Decrease the distance between the on and
off probes in the wet well.
END OF
PAGE
3
OHIO ABC PART 1
Wastewater entering a plant is typically - ANSWERS-somewhat warmer
than unheated tap water
What's the best flow velocity to settle out grit? - ANSWERS-.7-1.4
ft/sec
Short circuiting of grit through an aerated grit chamber can be
minimized or eliminated entirely by - ANSWERS-installing a
submerged transverse baffle along the wall opposite the diffusers
If there is a high head loss across a microscreen, the most probable cause
could be - ANSWERS-a plugged screen
Which type of pump should be used to transfer a 5% solids primary
sludge to a digester? - ANSWERS-positive-displacement pump
Primary clarifiers are typically designed to remove____of the settleable
solids and ___of the BOD. - ANSWERS-95-99% and 20-50%
What flow device typically measures flow of primary sludge flow? -
ANSWERS-magnetic flow meter
END OF
PAGE
1
, WASTEWATER CLASS 2 LATEST
OHIO ABC PART 1
Worn wearing shoes are often found on - ANSWERS-the flights of a
rectangular clarifier
The withdrawal of sludge from a clarifier should be slow in order to -
ANSWERS-prevent the pulling of too much water with the sludge
What should an operator do to increase MCRT? - ANSWERS-Decrease
the waste rate
What effect does pre-aeration have on downstream secondary plant
processes - ANSWERS-it tends to improve the overall efficiency of
solids and cbod removal.
For a particular plant there is an optimum range in which the mixed
liquid solids concentration must be maintained. What could happen if
the concentration were allowed to exceed the range - ANSWERS-A
cloudy, turbid effluent would result.
The process of nitrification - ANSWERS-Consumes about 7.1 lbs of
alkalinity to oxidize 1 lb. of ammonia to nitrate
END OF
PAGE
2
, WASTEWATER CLASS 2 LATEST
OHIO ABC PART 1
what type of activated sludge process has a detention time of 3 to 24
hours and a design F/M ratio of .03-.1? - ANSWERS-Oxidation ditch
When is increased wasting of activated sludge and increasing the
aeration tank f/m practiced? - ANSWERS-Denitrication is occurring in
the final settling tank causing rising sludge
How can an operator decrease the SRT and the MLSS concentration in
an activated sludge plant? - ANSWERS-Decrease RAS rate and increase
the waste rate
Most important factor in preventing accidents at a wastewater plant? -
ANSWERS-Attitude of the employees.
Plant influent appears black and has a foul odor each morning. The
cause is traced to a pump station at a subdivision which is oversized for
the current number of homes in the subdivision. What corrective action
can you take? - ANSWERS-Decrease the distance between the on and
off probes in the wet well.
END OF
PAGE
3
