Intro to Water Distribution Flashcards
True or False? Chlorination is the most common means of disinfection used today to protect the public’s health.
True
True or False? As water mains and reservoirs become older, they require less and less maintenance.
False. They require more
True or False? Routine water quality monitoring consists of collecting samples at remote locations in the system and testing for chlorine residual and coliforms
True
True or False? Existing contaminant limits may be modified if EPA’s ongoing research reveals new information about the effects of a particular substance.
True
True or False? Reservoirs that are not heavily used can be a source of taste, odor, and contamination problems.
True
True or False? When someone contacts you complaining that their drinking water looks muddy, tastes bad, or smells bad, you need not be concerned.
False. You may have a serious problem
True or False? Lack of circulation in a dead end creates nearly ideal conditions for degrading water quality.
True
Are groundwaters less or more susceptible to contamination than surface water?
Less
True or False? A water supply that is satisfactory in quality for one purpose might be entirely unsatisfactory for another.
True
Which is considered a more powerful disinfectant? Chloramines or chlorine?
Chlorine
Under what conditions may water mains be located adjacent to sewer lines?
When physical conditions or soil conditions prevent minimum separation distances from being met
How can corrosion be prevented on the insides of cement or metal pipes?
Line with asphalt or coal tar coatings
The knowledge and skills required to work as a water distribution system operator in a given system depend on:
the size and type of water distribution system
What are organics?
chemical substances that are based on the element carbon
Why are cloramines more effective against biofilms than chlorine?
They are more persistent
Why have drinking water quality standards been prepared and used?
To provide the needed quality control and ensure the acceptability of the product
Why is water quality monitoring of distribution systems important?
To identify when and where water quality changes occur in the system
When water lines are being repaired, how can possible contamination of the water be prevented?
Keep the hole dewatered
What are pathogens?
disease causing organisms
What is the primary responsibility of a water treatment plant?
To produce a safe and palatable water
Perhaps the greatest water quality nuisance is:
Corrosion and precipitation of iron
What types of consumer complaints can result from hydrant testing and flushing programs?
Dirty water complaints
What is the purpose of adequate and reliable records?
To document the effectiveness of the operation
Every operator’s responsibility with regard to safety is:
Be sure that the facilities are a safe place to work and that everyone follows safe procedures
What should you do after investigating a drinking water complaint?
Notify the person who complained of the results and what corrective action was or will be taken
Treated water storage facilities at water treatment plants are called:
Clear wells
What does the term water quality describe?
The composite chemical, physical, and biological characteristics of a water supply.
One of the best results from a well-guided tour of water system facilities is:
gaining support to obtain the funds necessary to run a good operation
What conditions in water main dead ends can produce carbon dioxide, methane, and sulfide odors?
Anaerobic
What is backsiphonage?
form of backflow caused by a negative or below atmospheric pressure within the water supply piping
What could be the cause of milky water?
Air
The water supply system’s ultimate consumers:
- Homes
- Industrial water users
- Businesses
Groundwater may require treatment to remove:
- excessive hardness
- iron and manganese
- dissolved gases
- taste- and odor-causing substances
What are the possible causes of water quality degradation in water storage facilities?
- Contamination entering through improperly maintained covers
- Small animals that gain access through improperly screened overflows
- Inadequate disinfection of reservoirs after construction or repairs
- Failure of side walls of below-ground reservoirs
- Materials introduced to uncovered reservoirs
How may large variations in flow through a distribution system adversely affect water quality?
- Low circulation and stagnant water can result in the growth of organisms, formations of sediments and corrosion products, depletion of oxygen, and increased tastes and odors
- Turbulence can entrain air into the supply causing milky water, which is objectionable to consumers
- Changes in water velocity and flow reversals can result in sediments being stirred up and carried along until they reach the consumer
Typical duties of a water distribution system operator:
- Place barricades, signs, and traffic cones around work sites to protect operators and the public
- Excavate trenches and install shoring
- Lay, connect, test, and disinfect water mains
- Tap into water mains
- Flush and clean water mains
Which diseases are transmitted by internal parasites in water?
- Cryptosporidiosis
- Giardiasis
Which types of constituents have limits under primary drinking water standards?
- Organic chemicals
- Inorganic chemicals
- Microorganisms
- Disinfection byproducts
Factors that may cause water quality degradation include:
- Cross-connections
- Corrosion
- Biological growth and activity
- Time in the system
- Dead ends
Which supervision and administration tasks might be included in a water distribution system operator’s duties?
- Giving advice on future planning
- keeping adequate reliable records
- giving advice on budget requirements
- training new operators
- encouraging operators to strive for higher levels of certification
Potential safety hazards for water distribution system operators:
Working in traffic
Excavating for the installation or repair of pipes
Painting facilities without adequate ventilation
Some components of the water distribution system:
- Network of pipes
- Valves
- Fire hydrants
- Service lines
- Meters,
Which items are possible contamination sources for open reservoirs?
- Atmospheric contaminants
- Animals, including birds and rodents
- Vandalism
- Illegal bathing and fishing
- Windblown contaminants
Which operating procedures can result in water quality degradation in a distribution system?
- Poorly performed water quality monitoring and flushing programs
- Inadequate cross-connection control
- Insufficient surveillance to determine whether the protective features for storage facilities and mains are still adequate
- Tolerance of low or negative pressures in the distribution system
- Inadequate disinfection after repair or installation of new facilities
Why is the iron precipitated by the iron bacteria, Crenothrix, of special concern in water distribution systems?
- reduces pipe carrying capacity
- produces color in water
- forms deposits in pipes
How can chemicals used at water treatment facilities cause water quality problems?
- Excessive use of manganese compounds for taste and odor control results in a colored water
- Overdosing alum during coagulation treatment results in turbidity and deposits
- Chlorinating water containing organic materials results in the formation of THMs
- Improper chlorination causes objectionable tastes and odors
Which criteria must a domestic water supply meet to be considered of good quality?
- Free of toxic chemicals
- free of disease-causing organisms
- will satisfy to a maximum degree the requirements of domestic and industrial consumers
- of such a chemical composition that it may be distributed without undue corrosive or scale-forming effects on the water distribution system
- attractive in taste and appearance
Under what conditions would water quality not change in the distribution system?
- If the water were completely stable
- if the system were completely sealed off from any intrusion
- if the water were biologically sterile
- if the system were inert to water
How can water in below-ground reservoirs be subject to contamination?
- From flooding by surface stormwaters
- from windblown contamination
- from materials that enter through failures in the side walls
- from vandalism
