Water Distribution manager Flashcards
Tastes and odors in water are not as noticeable when the water is:
Cold
The continuous natural recycling of water is called?
Hydrologic cycle
The concentration of _______ ions in a water supply determines whether the water will act as an acid or a base.
Hydrogen
Calcium and/or magnesium compounds cause ________ in water.
Hardness
When the iron content is over 0.3 mg/L what problems could you expect?
Staining and taste
The weight of one cubic foot of water is:
62.4 lbs
One cubic foot of water contains:
7.48 gallons
Temporary cloudiness in a freshly drawn sample of tap water may be caused by:
Air
What chemical is added to coliform sample bottles to remove residual chlorine from the potable water being sampled?
Sodium thiosulfate
The pH scale is used to measure the concentration of:
Hydrogen ions
A particular electric motor is wound for 3-phase current. If one phase cuts out while It is in operation, the motor will:
Heat and be damaged unless it is stopped by a control device.
The term “air-gap separation” means:
A physical break between the water supply line and the receiving vessel.
Which of the following backflow prevention measures would normally be required on the feed water line connected directly to a low pressure boiler which utilized chemical-feed water treatment?
Reduced pressure principle device.
A covered roof tank holding domestic water for a building has a low inlet full line. This inlet requires:
No change or correction
Chlorine cylinders should be kept ________than the temperature of the chlorinator to prevent chlorine gas from condensing in the transfer line or in the feed operation.
Cooler
All of the following are types of starters for electrical motors except:
Across the line
Actuator
Reduced voltage
Capacitor
Actuator
The current rating of the time-lag fuse placed in an electrical circuit for a motor should be at least:
The same as that of the motor.
Which of the following should be used by an operator to test for residual chlorine?
DPD
A pitot tube is used to measure:
Velocity head
How often should a reduced pressure backflow prevention assembly be tested?
Once per year
As the temperature of the water increases, the disinfecting action of the chlorine is:
More effective
After chlorination, the free chlorine residual includes:
OCl- and HOCl
Hypochlorite and Hypochlorus acid
If a chlorinator is connected to the bottom valve of a half full one ton cylinder, the chlorinator is withdrawing:
Liquid
Top connection is gas, bottom is liquid
What type of rupture or breakage may occur when a pipe is unevenly supported along its length?
Beam breakage
What color does DPD produce when reacted with a water that contains residual chlorine?
Pink
What is the purpose of a hydrostatic test?
To measure leakage in a pipe section
To test the thrust restraints
To test the integrity of assembled valves and fittings
Cathodic protection of elevated steel water tanks is:
A protective deposit of metal molecules laid down on the inside of the tank through action of a small electric current.
Which of the following is the most likely to cause corrosion?
Pressure
Dissolved oxygen
Temperature
Velocity of flow
Dissolved oxygen
When found in a water supply, which of the following conditions tend to increase the corrosiveness of the water on metals?
High alkalinity
High dissolved carbon dioxide
High pH
Low dissolved oxygen content
High dissolved carbon dioxide
What type of meter would be the most appropriate for a manufacturing plant needing a steady flow of 200 gal/min?
3” turbine meter
Disease producing microorganisms are commonly called:
Pathogens
How will water demand be affected when a utility charges users based on consumption?
Lower per capita use than flat-rate water systems
A chlorine taste is reported by two or more customers in a given section of town some distance from the plant. If you are required to handle all complaints and you receive this complaint, how should it be handled?
Inform the plant that a chlorine-taste problem exists and that they need to add more chlorine.
What should a supervisor do if an employee is performing work in an unsafe manner?
Stop the work immediately and train the employee to perform the work safely
What would not be considered and acceptable standby arrangement for times of power outage at the pumping station?
Another large pump and motor ready to put into place.
Regulations promulgated under the “Safe Water Drinking Act” require utilities do all the the following except:
To maintain records of water quality tests, and establishes maximum contaminate levels for chemical, physical and bacteriological contaminants.
requires public notification in the event of a violation of a water quality standard.
Requires routine chemical and bacteriological testing.
Requires the utility to have a source of water from wells
Requires the utility to have a source of water from wells
When obtaining a pipeline right-of-way, which factor does NOT need to be considered.
Access for repai and replacement Areas of unstable earth Ease of installation Restoration costs following installation and repair Velocity in pipeline
Velocity in pipeline
If an underground utility map shows at Station 180+20 there is a valve, and at Station 220+10 there is another valve, the distance between the valves would be:
3,990 ft.
At the time that new service connections are made, detailed records should be kept to allow future location with minimum effort. These maps should include:
Applicants name and address
Date of installing
Detailed measurements and depths
Size and kind of materials used
What is the secondary MCL for chloride?
250 mg/L
Which of the following is the most effective disinfectant compound?
Dichloramine
Hypochlorus Acid
Monochloramine
Nitrogen Trichloride
Hypochlorous Acid
Scale in a pipeline is caused by:
Insoluble carbonate compounds
The type of corrosion caused by the use of dissimilar metals in water systems is known as:
Galvanic corrosion
How many amperes of electricity (110-115 volts) will it take to injure or kill a person?
1/3 amperes
If the horizontal scale on a plan is 1” = 100’ and the vertical scale is 1” =10’ , how long a line would represent a level length of pipeline 175’ long?
1.75”
Hydrants in the distribution system should be:
Placed according to the fire flow requirements for a given area
What type of valve should be installed between fire hydrants and mains?
Auxiliary valves
In any locality the amount of water that a water bearing formation will yield depends on the:
Thickness and permeability of the formation
Static head is the:
Pressure due to the depth or elevation of water
If any foreign material such as sand, gravel, and tar is present when a joint is made up, it is likely the joint will:
Leak
A master meter on the water supply source is required to:
Comply with water right requirements
Determine unaccounted for water
Determine chemical dosages
Rate of flow from a large pumping station could be measured by:
Turbine meter and Venturi meter
The type of meter to be used in any given installation should be determined by the:
Amount of sand scale or other foreign matter that may be present in the water supply.
Range of flow rates, plus allowable pressure loss
Type of service (domestic, commercial, or irrigation etc)
Measuring the flow of water can be done by a weir, pitot tube, orifice, and by what method?
Volume measurement for a given period of time
Which of the following service line materials is not flexible?
Lead
Copper
High Density Polyethylene
Galvanized iron
Galvanized Iron
The theoretical possible suction list of a pump at sea level (14.7 atmospheric pressure) capable of pulling a complete vacuum is:
34 ft. of water
A characteristic of the plunger or piston-type pump is that within the limits of design…
A fixed rate of flow can be continuously delivered against a variable head.
What information is required on the tag during a switch lock-out?
Name of person who locked out the switch.
Which would not be acceptable as a coating inside a water storage tank?
Alkyd enamel
The main purpose of a distribution system reservoir is to:
Provide storage to meet peak demands
In instances where potentially non-potable water is connected directly with a potable water system, one method of eliminating such a cross connection is:
Providing an air gap between the two systems