Water Treatment Operator Certification Class a,b,c,d
Comprehensive Resource To Help You Ace 2026-2027
Includes Frequently Tested Questions With ELABORATED
100% Correct COMPLETE SOLUTIONS
Guaranteed Pass First Attempt!!
Current Update!!
1. What is the most common disinfection by product when adding chlorine to
water containing natural and inorganic matter? - Correct Answer: a.
Chloroform *
b. bromodichloromethane
c. monochloroacetic acid
d. dichloroacetic acid
2. What will most probably cause taste and odors, slime, and filter clogging?
a. decaying plant material
b. filamentous fungi
d. some species of ciliated protozoa
- Correct Answer: c. blue-green algae *
3. Why can rapid sand filters handle higher filtration rate compared to slow sand
filters?
a. finer sand
,b. coarser sand *
c. much higher water level above the filter's media, thus higher head pressure
d. media not as thick- Correct Answer: b. coarser sand *
4. Iron bacteria can interfere with ________ because the bacteria produce
________ that prevents the stabilization chemicals from reaching the pipe
surface. - Correct Answer: a. stabilization, a slime layer *
b. polyphosphates, an acid
c. polyphosphates, numerous massive bacterial colonies
d. stabilization, numerous massive bacterial colonies
Hypochlorous acid is favored over hypochlorite ion when the pH is ____________
and the temperature is _____________.
a. low, high
b. high, high
c. low, low *
d. high, low
- Correct Answer: c. low, low *
What filter has an unstratified media distribution? - Correct Answer: a. slow
sand filters *
b. rapid sand filters
c. high-rate filters
c. dual-media filters
,What is (are) the combined chlorine residuals(s) at pH values ranging from 6.5 to
8.5?
a. monochloramine
b. dichloramine
c. monochloramine and dichloramine *
d. dichloramine and trichloramine
- Correct Answer: c. monochloramine and dichloramine *
When iron alone is treated using manganese greensand filters, the chlorine feed
rate should be about ____________. - Correct Answer: a. 1.0 to 1.2 times the
iron concentration *
b. 1.2 to 1.5 times the iron concentration
c. 1.5 to 1.8 times the iron concentration
d. 1.5 to 2.0 times the iron concentration
Chlorination of water that has high concentrations of natural organic matter will
produce?
a. PCBs
b. BTEX
c. MTBX
d. THMs *
- Correct Answer: d. THMs *
, When disinfecting with chloramine, when can the ammonia be added to the
process?
a. Before the chlorine
b. Same time as the chlorine
c. after the chlorine
d. all of the above * - Correct Answer: d. all of the above *
What will settle out of the water in a short period of time?
a. protozoans
b. organic matter
c. very fine silt *
d. bacteria
- Correct Answer: c. very fine silt *
Point-of-use activated carbon filters are most effective for removing _________.
a. volatile organic chemicals
b. microorganisms
c. radon
d. chlorine *
- Correct Answer: d. chlorine *-
potassium permanganate is used as an oxidant for control of _______________.
Comprehensive Resource To Help You Ace 2026-2027
Includes Frequently Tested Questions With ELABORATED
100% Correct COMPLETE SOLUTIONS
Guaranteed Pass First Attempt!!
Current Update!!
1. What is the most common disinfection by product when adding chlorine to
water containing natural and inorganic matter? - Correct Answer: a.
Chloroform *
b. bromodichloromethane
c. monochloroacetic acid
d. dichloroacetic acid
2. What will most probably cause taste and odors, slime, and filter clogging?
a. decaying plant material
b. filamentous fungi
d. some species of ciliated protozoa
- Correct Answer: c. blue-green algae *
3. Why can rapid sand filters handle higher filtration rate compared to slow sand
filters?
a. finer sand
,b. coarser sand *
c. much higher water level above the filter's media, thus higher head pressure
d. media not as thick- Correct Answer: b. coarser sand *
4. Iron bacteria can interfere with ________ because the bacteria produce
________ that prevents the stabilization chemicals from reaching the pipe
surface. - Correct Answer: a. stabilization, a slime layer *
b. polyphosphates, an acid
c. polyphosphates, numerous massive bacterial colonies
d. stabilization, numerous massive bacterial colonies
Hypochlorous acid is favored over hypochlorite ion when the pH is ____________
and the temperature is _____________.
a. low, high
b. high, high
c. low, low *
d. high, low
- Correct Answer: c. low, low *
What filter has an unstratified media distribution? - Correct Answer: a. slow
sand filters *
b. rapid sand filters
c. high-rate filters
c. dual-media filters
,What is (are) the combined chlorine residuals(s) at pH values ranging from 6.5 to
8.5?
a. monochloramine
b. dichloramine
c. monochloramine and dichloramine *
d. dichloramine and trichloramine
- Correct Answer: c. monochloramine and dichloramine *
When iron alone is treated using manganese greensand filters, the chlorine feed
rate should be about ____________. - Correct Answer: a. 1.0 to 1.2 times the
iron concentration *
b. 1.2 to 1.5 times the iron concentration
c. 1.5 to 1.8 times the iron concentration
d. 1.5 to 2.0 times the iron concentration
Chlorination of water that has high concentrations of natural organic matter will
produce?
a. PCBs
b. BTEX
c. MTBX
d. THMs *
- Correct Answer: d. THMs *
, When disinfecting with chloramine, when can the ammonia be added to the
process?
a. Before the chlorine
b. Same time as the chlorine
c. after the chlorine
d. all of the above * - Correct Answer: d. all of the above *
What will settle out of the water in a short period of time?
a. protozoans
b. organic matter
c. very fine silt *
d. bacteria
- Correct Answer: c. very fine silt *
Point-of-use activated carbon filters are most effective for removing _________.
a. volatile organic chemicals
b. microorganisms
c. radon
d. chlorine *
- Correct Answer: d. chlorine *-
potassium permanganate is used as an oxidant for control of _______________.
