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