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69 Cards in this Set
- Front
- Back
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Which organisms are responsible for organic taste orders? |
Algae |
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Which chemicals create inorganic taste and odors? |
Iron and manganese |
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Which chemical is responsible for rotten egg holders? |
Hydrogen sulfide |
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What causes color in surface water supplies? |
Organic compounds decaying vegetation cause true colors |
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What is GAC? |
Granulated activated carbon (absorb organics filtered water) |
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What is the best way to remove organic taste and odors ? |
Activated carbon, chlorine, aeration. |
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What types of types of taste and odors can be removed by aeration? |
Iron or hydrogen sulphide |
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Which kinds of algae cause most of the organic taste and odors ? |
Blue green algae |
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Which chemical can be used to kill algae in a lake? |
Copper sulfate |
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Where should activated carbon be added in a surface water treatment plant? |
As far upstream as possible |
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What is a coagulant chemical used for? |
To bring negatively charged particles together |
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What is hydraulic shear in a flocculator? |
When a mixer is moving too fast “cuts” floc into pieces. |
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Where does rapid mixing occur in a surface water treatment plant? |
At the head of the plant/intake |
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Which to chemicals are commonly used to remove turbidity? |
Alum or Lime |
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List three substances that would be considered to be a coagulant aids. |
Alum, Ferric, ferrous |
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Which insoluble form of aluminum precipitated as a floc particle? |
Alum which forms aluminum hydroxide |
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What is the detention time for a rapid mixer? |
1 to 3 minutes velocity of 5-7 |
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What type of polymer will attract negatively charged turbidity particles? |
Catatonic polymers |
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What is the pH range for alum precipitation? |
5.5 through 6.5 |
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What happens to the pH when iron and aluminum are added to the water? |
Forms aluminum hydroxide which raises ph |
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What is the PH range for precipitation of color? |
3.5 through 5.5 |
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What color is associated with manganese problems? |
Black |
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What color is associated with manganese problems? |
Black |
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Red water problems occur when iron concentrations exceed _____ mg/l. |
.03 |
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What other treatment process is required if iron is removed by aeration? |
Sedimentation tanks |
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What is a sequestering agent? |
Surrounds ions and keeps them in solution |
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What is the common name of the chemical used to sequester iron? |
Polyphosphate & sodium hexametaphoshates also known as calgon |
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Why are baffles important in a sedimentation basin? |
Prevents short circuiting |
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Why are baffles important in a sedimentation basin? |
Prevents short circuiting |
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What is the notched plate used to remove water from the basin called? |
v notch weir |
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Why are baffles important in a sedimentation basin? |
Prevents short circuiting |
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What is the notched plate used to remove water from the basin called? |
v notch weir |
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What is the detention time for a sedimentation basin? |
4 to 6 hours |
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What can happen when sludge is not removed often enough? |
Bulking |
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Why is the weir over flow rate important? |
Determines how many gallons pass over each foot/day. |
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Why is the weir over flow rate important? |
Determines how many gallons pass over each foot/day. |
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What type of device protects the sludge removal equipment in a sedimentation basin? |
Shear pin |
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An upflow clarifier will contain which of the conventional treatment processes? |
Coagulation, flocculation, sedimentation |
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Pin floc leaving a sedimentation basin may indicate a problem with which part of the process? |
Flocculation basin |
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What are the three kinds of gravity filters? |
Slow sand, rapid sand, and high rate |
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What is the primary function of the filter under drain? |
Evenly distribute the backwash |
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What does loss of head mean in a filter? |
Indicates the filter is in need of backwashing |
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What is freeboard in a filter? |
Area 24 to 28 inches above filter media to prevent media lost. |
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What two chemicals are used for Turbidity removal? |
Alum and lime |
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True or False Hardness compounds become insoluble at a high pH. |
False |
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Lime, Polymer, bentonite clay are |
Coagulant aids for turbidity removal |
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Alum works best with the PH is. |
6.5 through 7.0 |
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Powder activated carbon is not: |
Used for turbidity removal |
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All kinds of taste and odors can be removed using: |
Activated carbon |
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Which two chemicals are used for non-carbonate sofenting? |
Soda ash and caustic soda |
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Which two chemicals are used for non-carbonate sofenting? |
Soda ash and caustic soda |
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Carbonate hardness compounds become insoluble at what pH. |
9.0 through 10.5 |
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Which of the following is a coagulant aid for turbidity removal? |
Polymer |
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Color can be removed by lowering the pH to |
3.5 through 5.5 |
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Chemical precipitation of arsenic is accomplished using; |
Ferric chloride |
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Alum can be used to precipitate organic compounds at a pH of: |
6.0 |
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Alum can be used to precipitate organic compounds at a pH of: |
6.0 |
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Daily fluctuations in the pH in a Reservoir Could mean: |
Taste and older problems coming |
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Alum can be used to precipitate organic compounds at a pH of: |
6.0 |
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Daily fluctuations in the pH in a Reservoir Could mean: |
Taste and older problems coming |
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Recarbonation is used to prevent: |
Scaling in the distribution system |
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The detention time in a coagulation basin should be: |
1 to 3 minutes |
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The detention time in a coagulation basin should be: |
1 to 3 minutes |
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Sludge that rises to the surface of a sedimentation basin is caused by |
Not removing sludge often enough |
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The detention time in a coagulation basin should be: |
1 to 3 minutes |
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Sludge that rises to the surface of a sedimentation basin is caused by |
Not removing sludge often enough |
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What should the detention be in a sedimentation basin? |
4 to 6 hours |
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True or False Always add the coagulant aids first in a coagulation basin? |
True |
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The Langlier index is used for: |
Corrosion control |
