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NEW MEXICO WATER OPERATOR CERTIFICATION EXAM, STUDY
GUIDE AND PRACTICE EXAM LATEST 2025/2026 ACTUAL EXAM
WITH COMPLETE QUESTIONS AND CORRECT DETAILED ANSWERS
(100% VERIFIED ANSWERS) |ALREADY GRADED A+| ||PROFESSOR
VERIFIED|| ||BRANDNEW!!!||
Which of the following is the best process to remove lead?
A. activated alumina
B. anion exchange
C. chemical oxidation
D. lime softening - ANSWER-D. lime softening
The ion exchange softening process does not alter which
properties of water? - ANSWER-pH and alkalinity
What would be the most probable solution to control algae in the
water plant if the algae were clogging the filters? - ANSWER-Use
activated carbon
A flocculant is required for iron removal if most of the iron passes
through what size filter membrane? - ANSWER-5 micrometre
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Activated silica is prepared by the water treatment operator. What
is the actual chemical delivered to the water treatment plant? -
ANSWER-Na₂SiO₃
Raw water requires both lime and soda ash when there are
nominal amounts of what type of hardness in the water? -
ANSWER-Magnesium hardness
The double stage process in excess lime softening
accomplishes? - ANSWER-Greater removal of magnesium
The reaction CO₂ + Ca(OH)₂ → CaCO₃ + H₂O is complete when
the pH reaches? - ANSWER-8.3
Trihalomethanes can form along with other disinfectant by
products due to lime, excess lime, or soda ash softening of water
because of? - ANSWER-High pH that is required to operate the
process
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When backwashing an ion exchange unit, how much should the
bed expand from water introduced from the bottom of the ion
exchange column? - ANSWER-50 to 75%
What bed expansion during backwashing must be achieved for
filters using GAC? - ANSWER-50%
What type of aerator causes aeration to occur in splash areas and
can be used to oxidize iron and to partially reduce dissolved
gases? - ANSWER-Cascade aerator
What type of aerator is much more efficient in removing dissolved
gases and for oxidizing iron and manganese? - ANSWER-Draft
aerator
The lime soda ash softening process is enhanced best with what
other application? - ANSWER-Solids contact unit
After first stage recarbonation, what is almost completely
dissolved? - ANSWER-Calcium carbonate crystals
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What are the exchange capacities of natural zeolites? -
ANSWER-3 to 5 kilograins/ft³
What best describes the purpose of GAC? - ANSWER-Particulate
removal and particulate adsorption
What is the best process for removing trihalomethanes? -
ANSWER-Aeration and stripping
The most common cation exchange resins are? - ANSWER-
Strong acid resins
Sequestration of iron and manganese is usually not
recommended for waters where the concentration of iron,
manganese, or both exceeds? - ANSWER-1.0 mg/L
What coagulant aids use extremely small dosages? - ANSWER-
Polyelectrolytes
NEW MEXICO WATER OPERATOR CERTIFICATION EXAM, STUDY
GUIDE AND PRACTICE EXAM LATEST 2025/2026 ACTUAL EXAM
WITH COMPLETE QUESTIONS AND CORRECT DETAILED ANSWERS
(100% VERIFIED ANSWERS) |ALREADY GRADED A+| ||PROFESSOR
VERIFIED|| ||BRANDNEW!!!||
Which of the following is the best process to remove lead?
A. activated alumina
B. anion exchange
C. chemical oxidation
D. lime softening - ANSWER-D. lime softening
The ion exchange softening process does not alter which
properties of water? - ANSWER-pH and alkalinity
What would be the most probable solution to control algae in the
water plant if the algae were clogging the filters? - ANSWER-Use
activated carbon
A flocculant is required for iron removal if most of the iron passes
through what size filter membrane? - ANSWER-5 micrometre
,2|Page
Activated silica is prepared by the water treatment operator. What
is the actual chemical delivered to the water treatment plant? -
ANSWER-Na₂SiO₃
Raw water requires both lime and soda ash when there are
nominal amounts of what type of hardness in the water? -
ANSWER-Magnesium hardness
The double stage process in excess lime softening
accomplishes? - ANSWER-Greater removal of magnesium
The reaction CO₂ + Ca(OH)₂ → CaCO₃ + H₂O is complete when
the pH reaches? - ANSWER-8.3
Trihalomethanes can form along with other disinfectant by
products due to lime, excess lime, or soda ash softening of water
because of? - ANSWER-High pH that is required to operate the
process
,3|Page
When backwashing an ion exchange unit, how much should the
bed expand from water introduced from the bottom of the ion
exchange column? - ANSWER-50 to 75%
What bed expansion during backwashing must be achieved for
filters using GAC? - ANSWER-50%
What type of aerator causes aeration to occur in splash areas and
can be used to oxidize iron and to partially reduce dissolved
gases? - ANSWER-Cascade aerator
What type of aerator is much more efficient in removing dissolved
gases and for oxidizing iron and manganese? - ANSWER-Draft
aerator
The lime soda ash softening process is enhanced best with what
other application? - ANSWER-Solids contact unit
After first stage recarbonation, what is almost completely
dissolved? - ANSWER-Calcium carbonate crystals
, 4|Page
What are the exchange capacities of natural zeolites? -
ANSWER-3 to 5 kilograins/ft³
What best describes the purpose of GAC? - ANSWER-Particulate
removal and particulate adsorption
What is the best process for removing trihalomethanes? -
ANSWER-Aeration and stripping
The most common cation exchange resins are? - ANSWER-
Strong acid resins
Sequestration of iron and manganese is usually not
recommended for waters where the concentration of iron,
manganese, or both exceeds? - ANSWER-1.0 mg/L
What coagulant aids use extremely small dosages? - ANSWER-
Polyelectrolytes
