COMPREHENSIVE TEEX ACTIVATED
SLUDGE TEST WITH CORRECT
SOLUTIONS
Following primary wastewater treatment, activated sludge treatment ,is used to remove:
- ANSWER-most of the remaining solids, and BOD
1. This describes healthy activated sludge ? - ANSWER-light to dark brown in color ,
earthy or musty odor
the number of mechanical systems required to operate an activated sludge system is -
ANSWER-5
Five important controls for activated sludge plants are: - ANSWER-dissolved oxygen, M
L S S concentration , solids quality, return sludge rate, and wasting rate.
DO levels will normally be kept between - ANSWER-2 and 3 , milligrams per liter
Advanced treatment reduces specific contaminants such as: - ANSWER-T S S ,
Ammonia, pH
The clarifier should concentrate the mixed liquor solids at least - ANSWER-Two times
Air requirements, in an activated sludge process ,are governed by the organic loading,
on the plant. - ANSWER-
Rising sludge, and gas bubbles, can be caused by denitrification, in the final clarifier. -
ANSWER-
The 30-minute settling test, gives the operator a visual check on sludge quality. -
ANSWER-
In the extended aeration process , air blowers , or aerators, normally run continuously,
to provide the oxygen needed ,unless? - ANSWER-the plant is small and underloaded
organically.
An advantage of the Sequential Batch Reactor, process is it - ANSWER-requires one
tank, and no separate clarifier, to perform its task.
What is the relationship between the F M ratio and the M.C.R.T for a particular plant,
when the aerator detention time, is a constant value? - ANSWER-When one increases,
the other decreases
, The activated sludge process parameters, which an operator can change directly, are
________.
a. aeration rates
b. waste rates
c. the ratio of free-swimming to stalked ciliates
d. return sludge rates
e. all the above except c - ANSWER-e. all the above except c
When the return sludge rate is too low, ________.
a. the aeration tank will not fill
b. there will be insufficient organisms to treat the waste load entering the aeration basin
c. the activated sludge in the aerator will starve
d. the sludge blanket in the secondary clarifier could become too high
e. b and d - ANSWER-e. b and d
Causes of sludge bulking include ________.
a. low DO and presence of sulfides
b. air supply too low
c. excessive organic loading
d. nutrient imbalance
e. all the above - ANSWER-e. all the above
Testing of mixed liquor indicates the MLSS is 2,000 mg/L, and the settling test shows
that a 1,000 mL sample settles to 250 mL after 30 minutes. What is the SVI and sludge
quality?
a. 80 and good
b. 125 and good
c. 400 and bulking
d. 50 and too compacting
e. 100 and bulking - ANSWER-b. 125 and good
An old, over-oxidized sludge, at an underloaded plant ,produces mixed liquor solids that
- ANSWER-settle rapidly , leaving a turbid supernatant
An anoxic zone, could promote the release of - ANSWER-nitrogen gas
Materials that increase the amount of fixed (inert) solids in mixed liquor are: - ANSWER-
sand, silt, clay particles, minerals
This type of floc, occurs ,when growth rates are high, due to high organic loadings, or
low solids. - ANSWER-straggler floc
SLUDGE TEST WITH CORRECT
SOLUTIONS
Following primary wastewater treatment, activated sludge treatment ,is used to remove:
- ANSWER-most of the remaining solids, and BOD
1. This describes healthy activated sludge ? - ANSWER-light to dark brown in color ,
earthy or musty odor
the number of mechanical systems required to operate an activated sludge system is -
ANSWER-5
Five important controls for activated sludge plants are: - ANSWER-dissolved oxygen, M
L S S concentration , solids quality, return sludge rate, and wasting rate.
DO levels will normally be kept between - ANSWER-2 and 3 , milligrams per liter
Advanced treatment reduces specific contaminants such as: - ANSWER-T S S ,
Ammonia, pH
The clarifier should concentrate the mixed liquor solids at least - ANSWER-Two times
Air requirements, in an activated sludge process ,are governed by the organic loading,
on the plant. - ANSWER-
Rising sludge, and gas bubbles, can be caused by denitrification, in the final clarifier. -
ANSWER-
The 30-minute settling test, gives the operator a visual check on sludge quality. -
ANSWER-
In the extended aeration process , air blowers , or aerators, normally run continuously,
to provide the oxygen needed ,unless? - ANSWER-the plant is small and underloaded
organically.
An advantage of the Sequential Batch Reactor, process is it - ANSWER-requires one
tank, and no separate clarifier, to perform its task.
What is the relationship between the F M ratio and the M.C.R.T for a particular plant,
when the aerator detention time, is a constant value? - ANSWER-When one increases,
the other decreases
, The activated sludge process parameters, which an operator can change directly, are
________.
a. aeration rates
b. waste rates
c. the ratio of free-swimming to stalked ciliates
d. return sludge rates
e. all the above except c - ANSWER-e. all the above except c
When the return sludge rate is too low, ________.
a. the aeration tank will not fill
b. there will be insufficient organisms to treat the waste load entering the aeration basin
c. the activated sludge in the aerator will starve
d. the sludge blanket in the secondary clarifier could become too high
e. b and d - ANSWER-e. b and d
Causes of sludge bulking include ________.
a. low DO and presence of sulfides
b. air supply too low
c. excessive organic loading
d. nutrient imbalance
e. all the above - ANSWER-e. all the above
Testing of mixed liquor indicates the MLSS is 2,000 mg/L, and the settling test shows
that a 1,000 mL sample settles to 250 mL after 30 minutes. What is the SVI and sludge
quality?
a. 80 and good
b. 125 and good
c. 400 and bulking
d. 50 and too compacting
e. 100 and bulking - ANSWER-b. 125 and good
An old, over-oxidized sludge, at an underloaded plant ,produces mixed liquor solids that
- ANSWER-settle rapidly , leaving a turbid supernatant
An anoxic zone, could promote the release of - ANSWER-nitrogen gas
Materials that increase the amount of fixed (inert) solids in mixed liquor are: - ANSWER-
sand, silt, clay particles, minerals
This type of floc, occurs ,when growth rates are high, due to high organic loadings, or
low solids. - ANSWER-straggler floc
