Class A Water Operator Certification Exam 2026/2027 | 100 Verified
Questions & Answers | ADEM Water Treatment Prep | 9 Core Domains |
Instant Download
1. A raw water has an alkalinity of 36 mg/l (as HCO3). A dose of 52 mg/l of alum is needed
to reduce the turbidity from 75 NTU to lass than 0.5 NTU. At least 30 mg/l of alkalinity
is requires for complete precipitation of alum. What dose of Ch(OH)2 is needed to
complete the reaction? - ANSWERS-13.5 mg/l (insert math here)
2. Adsorbtion - ANSWERS-The gathering of a substance on the surface of the filtration
media
3. One gallon is how many cubic feet - ANSWERS-0.1337 ft3
4. Biological action - ANSWERS-The breakdown of a substance as a result of digestion
by microorganisms
5. Absorption - ANSWERS-Taking in or "soaking up" of a substance into themedia
6. Straining - ANSWERS-The removal of particles by passing the liquid through a filter
that has pores small enough to "catch" the particles to be removed
7. Simple Sedimentation - ANSWERS-Particles settling onto the media through the
forces of gravity
8. Rapid Gravity Filtration - ANSWERS-The most common type of filtration used in water
treatment
1. Single Media (Sand)
2. Dual Media (anthracite coal and sand)
3. Multimedia (anthracite coal, sand, and garnet)
9. Activated carbon - ANSWERS-A form of specially treated, porous carbon, used to
remove various odors and tastes as well as various types of organic substances.
10. Filter Breakthrough - ANSWERS-Turbidity will build up on the surface and inside the
media of the filter eventually causing clogging of the filter. This leads to breakthrough,
a condition in which solids are no longer being removed.
11. Filter Run - ANSWERS-The period of time between back washing.
12. Surface Wash - ANSWERS-A device that is activated sometime during the backwash
procedure that sprays water down onto the surface of the filter to break up solids that
have collected.
13. Backwash schedule - ANSWERS-It is a good practice to always backwash the filter
every 72 hours of operation, even if significant head loss has not yet developed.
, 14. Head Loss - ANSWERS-Clogging of a filter can be defined as a build-up of head loss
(pressure-drop) across the filter media. Design limits for head loss generally range
from about 6 to 10 feet depending mainly on the depth of the water over the media.
15. Backwash flow Rates - ANSWERS-Most filters utilize backwash flow rates of about 20
gpm/ft2 or other rates necessary to provide for 50% expansion of filter media. Typical
water plant will use approximately 2 to 4 percent of the water produced as the plant
for backwashing purposes.
16. Filter Rate - ANSWERS-The rate that water flows through the media and is expressed
in gpm per square foot (gpm/ft2)
17. Mudballs - ANSWERS-Pockets of sludge and other solids that build up in the filtration
media
18. Air Binding - ANSWERS-A situation where air enters the filter media as a result of
differences in pressure between water and the pressure in the filter. Dissolved air is
released from saturated cold water due to the decrease in pressure in the filter. Air
binding can prevent the passage of water during the filtration process and can cause
a loss of media during the backwash process.
19. Granular activated carbon (GAC) - ANSWERS-Sometimes utilized as an activated
carbon filtration media for removing taste and oder compounds in water. It is also
used for removing volatile organic compouncs (vocs) and synthetic organic
compounds (socs). Becomes "spent" over time and will need replaces or
"reactivation"
20. Ch 6 - The most common type of filter used by water plants in Oklahoma is the -
ANSWERS-rapid gravity sand filter
21. Ch 6 - The most important removal process that takes place during filtration is -
ANSWERS-Sedimentation
22. Ch 6 - The most important filter effluent water quality change is - ANSWERS-Turbidity
23. Ch 6 - A plant filter 2.2 MGD with a filter surface of 600 ft2. What is the filtrate rate in
gpm/ft2 - ANSWERS-
24. Disinfection - ANSWERS-The destruction of most of the pathogenic organisms
present in the water
25. Sterilization - ANSWERS-The complete destruction of all organisms present in the
water.
26. Calcium Hypochlorite (High Test Hypochlorite (HTH)) - ANSWERS-Calcium
hypochlorite Ca(ocl)2 is a disinfectant that can be purchased in tablet, powder or
granulated form. HTH has about 65% available chlorine
Questions & Answers | ADEM Water Treatment Prep | 9 Core Domains |
Instant Download
1. A raw water has an alkalinity of 36 mg/l (as HCO3). A dose of 52 mg/l of alum is needed
to reduce the turbidity from 75 NTU to lass than 0.5 NTU. At least 30 mg/l of alkalinity
is requires for complete precipitation of alum. What dose of Ch(OH)2 is needed to
complete the reaction? - ANSWERS-13.5 mg/l (insert math here)
2. Adsorbtion - ANSWERS-The gathering of a substance on the surface of the filtration
media
3. One gallon is how many cubic feet - ANSWERS-0.1337 ft3
4. Biological action - ANSWERS-The breakdown of a substance as a result of digestion
by microorganisms
5. Absorption - ANSWERS-Taking in or "soaking up" of a substance into themedia
6. Straining - ANSWERS-The removal of particles by passing the liquid through a filter
that has pores small enough to "catch" the particles to be removed
7. Simple Sedimentation - ANSWERS-Particles settling onto the media through the
forces of gravity
8. Rapid Gravity Filtration - ANSWERS-The most common type of filtration used in water
treatment
1. Single Media (Sand)
2. Dual Media (anthracite coal and sand)
3. Multimedia (anthracite coal, sand, and garnet)
9. Activated carbon - ANSWERS-A form of specially treated, porous carbon, used to
remove various odors and tastes as well as various types of organic substances.
10. Filter Breakthrough - ANSWERS-Turbidity will build up on the surface and inside the
media of the filter eventually causing clogging of the filter. This leads to breakthrough,
a condition in which solids are no longer being removed.
11. Filter Run - ANSWERS-The period of time between back washing.
12. Surface Wash - ANSWERS-A device that is activated sometime during the backwash
procedure that sprays water down onto the surface of the filter to break up solids that
have collected.
13. Backwash schedule - ANSWERS-It is a good practice to always backwash the filter
every 72 hours of operation, even if significant head loss has not yet developed.
, 14. Head Loss - ANSWERS-Clogging of a filter can be defined as a build-up of head loss
(pressure-drop) across the filter media. Design limits for head loss generally range
from about 6 to 10 feet depending mainly on the depth of the water over the media.
15. Backwash flow Rates - ANSWERS-Most filters utilize backwash flow rates of about 20
gpm/ft2 or other rates necessary to provide for 50% expansion of filter media. Typical
water plant will use approximately 2 to 4 percent of the water produced as the plant
for backwashing purposes.
16. Filter Rate - ANSWERS-The rate that water flows through the media and is expressed
in gpm per square foot (gpm/ft2)
17. Mudballs - ANSWERS-Pockets of sludge and other solids that build up in the filtration
media
18. Air Binding - ANSWERS-A situation where air enters the filter media as a result of
differences in pressure between water and the pressure in the filter. Dissolved air is
released from saturated cold water due to the decrease in pressure in the filter. Air
binding can prevent the passage of water during the filtration process and can cause
a loss of media during the backwash process.
19. Granular activated carbon (GAC) - ANSWERS-Sometimes utilized as an activated
carbon filtration media for removing taste and oder compounds in water. It is also
used for removing volatile organic compouncs (vocs) and synthetic organic
compounds (socs). Becomes "spent" over time and will need replaces or
"reactivation"
20. Ch 6 - The most common type of filter used by water plants in Oklahoma is the -
ANSWERS-rapid gravity sand filter
21. Ch 6 - The most important removal process that takes place during filtration is -
ANSWERS-Sedimentation
22. Ch 6 - The most important filter effluent water quality change is - ANSWERS-Turbidity
23. Ch 6 - A plant filter 2.2 MGD with a filter surface of 600 ft2. What is the filtrate rate in
gpm/ft2 - ANSWERS-
24. Disinfection - ANSWERS-The destruction of most of the pathogenic organisms
present in the water
25. Sterilization - ANSWERS-The complete destruction of all organisms present in the
water.
26. Calcium Hypochlorite (High Test Hypochlorite (HTH)) - ANSWERS-Calcium
hypochlorite Ca(ocl)2 is a disinfectant that can be purchased in tablet, powder or
granulated form. HTH has about 65% available chlorine
