Class D Water Operator License Test with Questions & Answers
What are some physical characteristics of water?
Temperature, turbidity, color, taste, odor
What are some chemical characteristics of water?
Hardness, pH, solids, and gases
What is turbidity?
the amount of suspended matter, such as clay, silt, organic matter, and microorganisms in water
T/F Water is never found pure in nature.
True
Is turbidity more of a problem in groundwater or surface water?
Surface water
A system's filtered water must be _______ Nephelometric Turbidity Units (NTU) or less in at
least 95% of the measurements taken each month, and no sample can exceed _____ NTU.
0.3
1
T/F True color is dissolved in water (in solution) and cannot be removed by filtering.
True. Tea in water is an example of true color.
Suspended color is called _______ color.
apparent
Color above ______ units is objectionable in a public water supply.
15 units
A scale called the ________ measures odor.
Threshold Odor Number (TON)
Odor greater than a scale of _______ is undesirable.
3
Taste and odors in water result from _______, bacteria, decaying organic matter, gases, and
chemicals such as manganese, zinc, copper, iron, magnesium, sodium, and potassium.
,algae
Chemical characteristics of water generally cannot be detected by sight, smell, or taste and must
be determined by __________.
laboratory analysis
Chemical laboratory analysis must be sampled _______ per year for surface water and normally
_______ for groundwater.
once/year for surface water
once every three years for groundwater
Water weighs ______ lbs/gal.
8.34 lbs/gal
T/F
For water, 1 mg/L is equal to 1 part per million (ppm) by weight.
True
Which two minerals mainly cause hardness in water?
Calcium and magnesium
Is hardness more of a problem in groundwater or surface water?
Groundwater
Water is considered hard when it exceeds _______.
100 mg/L of calcium carbonate
The pH scale ranges from _____ to _____.
0 to 14
On the pH scale:
0 to <7 is ______.
7 is _______.
>7 to 14 is ______.
Acidic
Neutral
Basic or alkaline
Sulfuric, hydrochloric, and nitric acids can be used to ______ pH.
Caustic, lime, or soda ash can be used to ______ pH.
, Lower
Raise
Suspended solids can be removed by ________.
Filtration
Can dissolved solids be removed by filtration?
No
Total dissolved solids should not exceed________.
1000 mg/L
What are three common gasses found in water?
Hydrogen sulfide, carbon dioxide, and methane
Excess ________ can cause blue baby syndrome.
Nitrogen or Nitrates
What is the major source of nitrogen into drinking water?
Fertilizer and animal waste carried by rainwater runoff
What is the EPA primary MCL (maximum contaminant level) for fluoride?
4.0 mg/L
At what level will fluoride cause mottling of teeth, a condition known as fluorosis?
4.0 mg/L
What is the state of Texas secondary standard for fluoride?
2.0 mg/L
Trihalomethanes (THM) and Haloacetic Acids (HAA) are byproducts of drinking water
________.
chlorination
THM's and HAA's are byproducts formed when chlorine reacts with dissolved _________.
natural organic matter, mostly plant life
Combining chlorine with _______ greatly reduces THM and HAA formation.
ammonia
Is surface water or groundwater more likely to contain natural organic matter?
What are some physical characteristics of water?
Temperature, turbidity, color, taste, odor
What are some chemical characteristics of water?
Hardness, pH, solids, and gases
What is turbidity?
the amount of suspended matter, such as clay, silt, organic matter, and microorganisms in water
T/F Water is never found pure in nature.
True
Is turbidity more of a problem in groundwater or surface water?
Surface water
A system's filtered water must be _______ Nephelometric Turbidity Units (NTU) or less in at
least 95% of the measurements taken each month, and no sample can exceed _____ NTU.
0.3
1
T/F True color is dissolved in water (in solution) and cannot be removed by filtering.
True. Tea in water is an example of true color.
Suspended color is called _______ color.
apparent
Color above ______ units is objectionable in a public water supply.
15 units
A scale called the ________ measures odor.
Threshold Odor Number (TON)
Odor greater than a scale of _______ is undesirable.
3
Taste and odors in water result from _______, bacteria, decaying organic matter, gases, and
chemicals such as manganese, zinc, copper, iron, magnesium, sodium, and potassium.
,algae
Chemical characteristics of water generally cannot be detected by sight, smell, or taste and must
be determined by __________.
laboratory analysis
Chemical laboratory analysis must be sampled _______ per year for surface water and normally
_______ for groundwater.
once/year for surface water
once every three years for groundwater
Water weighs ______ lbs/gal.
8.34 lbs/gal
T/F
For water, 1 mg/L is equal to 1 part per million (ppm) by weight.
True
Which two minerals mainly cause hardness in water?
Calcium and magnesium
Is hardness more of a problem in groundwater or surface water?
Groundwater
Water is considered hard when it exceeds _______.
100 mg/L of calcium carbonate
The pH scale ranges from _____ to _____.
0 to 14
On the pH scale:
0 to <7 is ______.
7 is _______.
>7 to 14 is ______.
Acidic
Neutral
Basic or alkaline
Sulfuric, hydrochloric, and nitric acids can be used to ______ pH.
Caustic, lime, or soda ash can be used to ______ pH.
, Lower
Raise
Suspended solids can be removed by ________.
Filtration
Can dissolved solids be removed by filtration?
No
Total dissolved solids should not exceed________.
1000 mg/L
What are three common gasses found in water?
Hydrogen sulfide, carbon dioxide, and methane
Excess ________ can cause blue baby syndrome.
Nitrogen or Nitrates
What is the major source of nitrogen into drinking water?
Fertilizer and animal waste carried by rainwater runoff
What is the EPA primary MCL (maximum contaminant level) for fluoride?
4.0 mg/L
At what level will fluoride cause mottling of teeth, a condition known as fluorosis?
4.0 mg/L
What is the state of Texas secondary standard for fluoride?
2.0 mg/L
Trihalomethanes (THM) and Haloacetic Acids (HAA) are byproducts of drinking water
________.
chlorination
THM's and HAA's are byproducts formed when chlorine reacts with dissolved _________.
natural organic matter, mostly plant life
Combining chlorine with _______ greatly reduces THM and HAA formation.
ammonia
Is surface water or groundwater more likely to contain natural organic matter?
