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Water Disinfection Chapter 6 > Questions > Flashcards

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1
Q

True/False

The presence of coliform bacteria is an indication that water is polluted and may contain disease-causing organisms.

A

True

2
Q

True/False

Disinfection removes toxic chemicals that could make water unsafe to drink

A

False

Disinfectionis the selective destruction or inactivation of pathogenic. organisms

3
Q

True/False
The Safe Drinking Water Act (SWDA) and its amendments contains specific maximum allowable levels of substance known to be hazardous to human health.

A

True

4
Q

True/False

Excessive turbidity will greatly increase the efficiency of the disinfecting chemical.

A

False

Excessive turbidity will greatly reduce the efficiency of the disinfecting chemical

5
Q

True/False
Organic reducing agents in water will react with chlorine and form chlorinated organic materials of potential Health significance.

A

True

6
Q

True/False

Free chlorine is the most commonly used distribution system disinfectant.

A

True

7
Q

True/False

The chlorine ion and hydrochloric acid both have strong disinfecting power and produce a lasting chlorine residual.

A

False

8
Q

True/False

Chlorine gas tends to increase the pH and hypochlorite tends to decrease the pH.

A

False ( Chlorine gas tends to decrease)…..

9
Q

True/False

Chlorine dioxide forms carcinogenic compounds similar to those formed by other chlorine compounds.

A

False

Chlorine dioxide does not form carcinogenic compounds ….

10
Q

True/False

The chlorine demand for groundwater changes rapidly.

A

False

11
Q

True/False

The lower the temperature, the more rapid the rate of disinfection.

A

False

The higher the temperature, the more efficiently it can be treated

12
Q

True/False
Once water from a well starts producing positive coliform results, it is very easy to correct the problem with chlorine disinfection.

A

False

13
Q

True/False

Never use water on a chlorine leak because the corrosive action of chlorine and water will always make the leak worse

A

True

14
Q

True/False

The chlorinator should operate only when the well pump is running.

A

True

15
Q

True/False

Always keep chlorine cylinders away from direct heat (steam pipes or radiators).

A

True

16
Q

True/False

Always add acid to water, never the reverse.

A

True

17
Q

True/False

Most chlorinators are more easily repaired on line then replaced

A

False

18
Q

True/False

Every good safety program begins with Corporation between the employee and the employer

A

True

19
Q

True/False

Chlorine gas can deaden your sense of smell and cause a false sense of security.

A

True

20
Q

True/False

Hypochlorite compounds can cause fires when they come in contact with Organics or other easily oxidizable substances.

A

True

21
Q

Best Answer
What are pathogenic organisms?
1. Organisms capable of causing disease.
2. Organisms known to reproduce rapidly.
3. Organisms that excite pity.
4. Organisms with the ability to degrade pollution

A
  1. Organisms capable of causing disease
22
Q

Best Answer
What is disinfection?
1. The degradation of organic matter by microorganisms.
2. The destruction of volatile organic matter.
3. The selection of a form of chlorine to treat water.
4. The selective destruction or inactivation of pathogenic organisms.

A
  1. The selective destruction or inactivation of pathogenic organisms.
23
Q
Best Answer
What is the purpose of the disinfection process?
1. To control corrosion
2. To destroy harmful organisms
3. To please consumer's
4. To reduce taste and odors
A
  1. To destroy harmful organisms
24
Q
Best Answer 
What is the term for the amount of chlorine added to water to disinfect it?
1. Chlorine breakpoint
2. Chlorine demand
3. Chlorine dose 
4. Chlorine residual
A
  1. Chlorine dose
25
Q

Best Answer
What is breakpoint chlorination? A process of adding chlorine
1. To the optimum economic point
2. To the point wherecarcinogins are formed
3. To water until the chlorine demand has been satisfied
4. Until chlorine breaks out of solution

A
  1. To water until the chlorine demand has been satisfied
26
Q
Best Answer 
What is the biofilm? The layer of microorganisms
1. Causing disease
2. On filter media
3. On pipeline walls
4. That plug filters
A
  1. On pipeline walls
27
Q

Best Answer
What is the danger in allowing nitrification episodes to occur in water storage or distribution systems?
1. Operators may be left with A very low or no total chlorine residual
2. Operator may discover increases in algal growths
3. Operator may have to increase leak detection program efforts
4. Operator may have to increase water production rates to compensate for unaccounted for water losses.

A
  1. Operators may be left with A very low or no total chlorine residual
28
Q
Best Answer 
How is the effectiveness of the chlorine dosage used to disinfect a well determined?
1. Test for chlorine residual
2. Test for the tightness of the seal
3. Test for total coliforms
4. Test for turbidity
A
  1. Test for total coliforms
29
Q

Best Answer
When storm sewers are used to dispose of water used to disinfect mains and the water has a high chlorine residual (greater than 1mg/L), what precaution should be taken?
1. Be sure the water does NOT erode away any soil
2. Be sure the water is NOT used for irrigation
3. Be sure there is NO chlorine residual remaining when the water reaches the receiving waters (creek, river, or lake)
4. Be sure to avoid body contact with the water

A
  1. Be sure there is NO chlorine residual remaining when the water reaches the receiving waters (creek, river, or lake)
30
Q

Best Answer
What is a hypochlorinator?
1. Equipment that feeds chlorine solutions at a high rate
2. Equipment that feeds gaseous chlorine solutions
3. Equipment that feeds liquid chlorine (bleach) solutions
4. Equipment that feeds solid (granular) chlorine solutions

A
  1. Equipment that feeds liquid chlorine (bleach) solutions
31
Q
Best Answer 
Why should the chlorine injection point never be located on the intake side of the pump?  Because it will cause
1. Cavitation problems
2. Corrosion problems
3. Taste and odor problems
4. Water hammer problems
A
  1. Corrosion problems
32
Q

Best Answer
Why should the yoke of the chlorinated on a chlorine cylinder NOT be overtightened?
1. Overtightening can break the wrench
2. Overtightening can damage the yoke of the chlorinated resulting in a leak
3. Overtightening can prevent the operator from removing the yoke
4. Overtightening can strip the threads

A
  1. Overtightening can damage the yoke of the chlorinated resulting in a leak
33
Q

Best Answer
What is a “False positive” Chlorine residual reading?
1. When a chlorine residual is present and the residual is measured as zero mg/L
2. When coliform test are positive and there is a chlorine residual present
3. When the lab reports NO residual and there is a chlorine residual
4. When turbidity produces a positive test result when there is NO chlorine present

A
  1. When turbidity produces a positive test result when there is NO chlorine present
34
Q
Best Answer 
Regular exposure to chlorine can produce what kind of chronic effect?
1. Cancerous tumors
2. Loss of hair
3. Mental deterioration
4. Permanent damage to lung tissue
A
  1. Permanent damage to lung tissue
35
Q
Best Answer
How can a chlorine leak be detected? By the use of
1. Ammonia
2. Caustic soda
3. Hydrochloric acid
4. Soda Ash
A
  1. Ammonia
36
Q
Which types of pathogenic organisms can be transmitted by water?
1 animals 
2 bacteria 
3 humans 
4 intestinal parasites 
5 viruses
A

2 bacteria
4 intestinal parasites
5 viruses

37
Q

Which diseases are transmitted by intestinal parasites in water?

  1. Cholera
  2. Cryptosporidiosis.
  3. Giardiasis
  4. Salmonellosis
  5. Typhoid fever
A
  1. Cryptosporidiosis.

3. Giardiasis

38
Q

What is organic matter undesirable in water being disinfected?

  1. Organics can consume great amounts of disinfectants.
  2. Organics can form trihalomethanes
  3. Organics can form unwanted compounds.
  4. Organics can provide nutrients for pathogens.
  5. Organics can provide substrate for pathogens
A
  1. Organics can consume great amounts of disinfectants.
  2. Organics can form trihalomethanes
  3. Organics can form unwanted compounds.
39
Q

What are possible sources of contaminants in water Distribution Systems?

  1. Cross connections.
  2. Main breaks.
  3. New main installations
  4. Sacrificial anodes.
  5. Sequestering agents.
A
  1. Cross connections.
  2. Main breaks.
  3. New main installations
40
Q

What are the advantages of using chlorine dioxide to disinfect drinking water?

  1. Controls phenolic taste and odors
  2. Does not form carcinogenic compounds
  3. Not affected by ammonia
  4. Reacts with sulfide compounds
  5. Very effective at higher pH levels.
A

All of the above

41
Q

And operators decision to use chloramines depends on which factors?
1. Ability of the treatment plant to meet various regulations.
2. Distribution system characteristics.
3. Form of chlorine available
4, Operational practices
5. Qualitiy of the raw water

A
  1. Ability of the treatment plant to meet various regulations.
  2. Distribution system characteristics.
    4, Operational practices
  3. Qualitiy of the raw water
42
Q

What are the early warning signs that can be used to detect that nitrification is beginning to occur?

  1. Decrease in ammonia.
  2. Decrease in PH.
  3. Decrease in total chlorine.
  4. Increase and heterotrophic plate count bacteria.
  5. Increase in nitrite
A

All of the above

43
Q

What are the benefits of maintaining a chlorine residual throughout the distribution system?

  1. Biological control and elimination of coliform bacteria that might reach the system through cross connections
  2. Biological control and elimination of coliform bacteria that might reach through leakage into the system
  3. Control of corrosion
  4. Control of microorganisms that could produce limes
  5. Control of microorganisms that could produce taste and odors
A
  1. Biological control and elimination of coliform bacteria that might reach the system through cross connections
  2. Biological control and elimination of coliform bacteria that might reach through leakage into the system
  3. Control of microorganisms that could produce limes
  4. Control of microorganisms that could produce taste and odors
44
Q

What a new well is completed, it is necessary to disinfect which items?

  1. The distribution system
  2. The pump
  3. The screen
  4. The storage tank
  5. The well
A
  1. The pump
  2. The screen
  3. The well
45
Q

Under what conditions should water storage tanks be thoroughly cleaned before disinfecting with tank?

  1. After construction
  2. After inspection
  3. After maintenance
  4. After repairs
  5. After visits
A
  1. After construction
  2. After maintenance
  3. After repairs
46
Q

Which items should be included in a hypochlorination normal operation checklist?

  1. Check chemical usage
  2. Check the building for any possible problems
  3. Clean up the area
  4. Determine if every piece of equipment is operating
  5. Inspect the lubrication of the equipment.
A

All of the above

47
Q

Which items of safety equipment are required and must be available outside the chlorinator room?

  1. Chlorine leak detector/warning device
  2. Chlorine residual analyzer
  3. Device to measure the chlorine solution level
  4. Protective clothing loves and rubber suit
  5. Self-contained positive pressure/demand air supply system
A
  1. Chlorine leak detector/warning device
  2. Protective clothing loves and rubber suit
  3. Self-contained positive pressure/demand air supply system
48
Q

What abnormal operating systems should be included in a direct-mount chlorinator troubleshooting guide?

  1. Indication on Flow meter but are present, NOT chlorine gas
  2. NO indication on a flow meter when vacuum is present
  3. Percent of hypochlorite solution
  4. Water in the chlorine meter tube
  5. Water venting to atmosphere
A
  1. Indication on Flow meter but are present, NOT chlorine gas
  2. NO indication on a flow meter when vacuum is present
  3. Water in the chlorine meter tube
  4. Water venting to atmosphere
49
Q

They should be on a chlorine emergency list?

  1. Chlorine many emergency Personnel
  2. Chlorine supplier
  3. Fire department
  4. Local media
  5. Police department
A
  1. Chlorine many emergency Personnel
  2. Chlorine supplier
  3. Fire department
  4. Police department
50
Q

First aid measures for persons exposed to chlorine include which items?

  1. If breathing is difficult, administer oxygen if equipment and trained Personnel are available
  2. If breathing seems to have stopped, begin artificial respiration immediately
  3. Keep patients warm and cover them with blankets, if necessary
  4. Place patients in a comfortable position on their backs.
  5. Remove contaminated clothes to prevent clothing giving out chlorine gas which would irritate the body
A

All of the above

51
Q

Why are nearly all new metal water mains line with cement mortar?

  1. Improve structural strength
  2. Increase carrying capacity
  3. Prevent corrosion
  4. Prevent release of corrosion products into water
  5. Reduce leakage through for joints.
A
  1. Increase carrying capacity
  2. Prevent corrosion
  3. Prevent release of corrosion products into water
  4. Reduce leakage through for joints.
52
Q

Which factors could cause deterioration in the quality of water traveling through a distribution system?

  1. Age of the facilities
  2. Cross connections
  3. High temperatures
  4. Pipe corrosion
  5. Time in the system.
A

All of the above