2025 IL Class B Water Operator Test UPDATED ACTUAL Questions and
CORRECT Answers
1. Common Types Of Underdrain Sys- Pipe Lateral Collectors
tems are? Perforated Tile Bottoms
Wheeler Filter Bottoms
Porous Plate Bottoms
False Floor Underdrain Systems
2. What filter sytems require a gravel Pipe Lateral Collectors
support bed to prevent sand and an- Perforated Tile Bottoms
thracite from flowing into the under- Wheeler Filter Bottoms
drains?
3. What is wash water through? A through placed above the filter media to collect
the backwash water and carry it to the drainage
system.
4. Air scouring works particulary well for Monomedium beds.
what type of filter bed?
5. Why is a rate of flow controller needed Without the controller flow surges could force sus-
for backwashing? pended particles through the filter.
6. Why are loss of head indicators used Are required to monitor the status of resistance to
on filters? flow in the filter as susupened matter builds up in
the media.
7. A sudden incrase in efflunet turbidity Filter Breakthrough
indicates what?
8. If filter run times between backwash- Floc Breakthrough
es are long, for example one week, be-
cause high quality (low turbidity) wa-
ter is being applied to the filters, which
problem could still arise?
, a. Mudball formation
b. Air binding and formation of mud-
balls
c. Extended backwashing due to me-
dia becoming too compacted
d. Floc breakthrough
9. Gravel displacement in a filter bed C. A sand Boil
from backwash rates with too high of
a velocity could eventually cause
a. compaction of the filter media.
b. loss of media into the backwash
troughs.
c. a sand boil.
d. bed shrinkage.
10. Which conventional treatment step is Sedimentation
eliminated by direct filtration.
11. Which of the following is the layer Schmutzdecke
of solids and biological growth that
forms on the top of a slow sand filter?
12. Filter tanks are generlly made? Rectangular and constructed of concrete
13. In a typical air scour sequence, air is Before
applied backwash water is intro-
duced?
14. What is the filtration flow rate through 3-8 gpm/ft2
a high rate mixed media filter?
15. Pipe lateral Collectors
CORRECT Answers
1. Common Types Of Underdrain Sys- Pipe Lateral Collectors
tems are? Perforated Tile Bottoms
Wheeler Filter Bottoms
Porous Plate Bottoms
False Floor Underdrain Systems
2. What filter sytems require a gravel Pipe Lateral Collectors
support bed to prevent sand and an- Perforated Tile Bottoms
thracite from flowing into the under- Wheeler Filter Bottoms
drains?
3. What is wash water through? A through placed above the filter media to collect
the backwash water and carry it to the drainage
system.
4. Air scouring works particulary well for Monomedium beds.
what type of filter bed?
5. Why is a rate of flow controller needed Without the controller flow surges could force sus-
for backwashing? pended particles through the filter.
6. Why are loss of head indicators used Are required to monitor the status of resistance to
on filters? flow in the filter as susupened matter builds up in
the media.
7. A sudden incrase in efflunet turbidity Filter Breakthrough
indicates what?
8. If filter run times between backwash- Floc Breakthrough
es are long, for example one week, be-
cause high quality (low turbidity) wa-
ter is being applied to the filters, which
problem could still arise?
, a. Mudball formation
b. Air binding and formation of mud-
balls
c. Extended backwashing due to me-
dia becoming too compacted
d. Floc breakthrough
9. Gravel displacement in a filter bed C. A sand Boil
from backwash rates with too high of
a velocity could eventually cause
a. compaction of the filter media.
b. loss of media into the backwash
troughs.
c. a sand boil.
d. bed shrinkage.
10. Which conventional treatment step is Sedimentation
eliminated by direct filtration.
11. Which of the following is the layer Schmutzdecke
of solids and biological growth that
forms on the top of a slow sand filter?
12. Filter tanks are generlly made? Rectangular and constructed of concrete
13. In a typical air scour sequence, air is Before
applied backwash water is intro-
duced?
14. What is the filtration flow rate through 3-8 gpm/ft2
a high rate mixed media filter?
15. Pipe lateral Collectors
