Water distribution practice exam #2
(D1-D2) Questions and Answers 100%
Correct
Which process converts ammonia to nitrite and nitrate? - ANSWER-Nitrification
What is the maximum advisable rate of chlorine gas removal from a 150- pound
cylinder? - ANSWER-40 pounds per day
What is a type of positive displacement water meter? - ANSWER-Nutating- disk
meter
What is a power-operated mechanism for opening and closing a valve? - ANSWER-
Actuator
What is required if a routine sample test positive for total coliform bacteria? -
ANSWER-Take repeat samples
Why is a grid layout better than a tree layout for a water distribution system? -
ANSWER-Less dead-end mains
What is the purpose of a reduced pressure principle assembly? - ANSWER-Prevents
back-pressure and back-siphonage
In general, at what depths is shoring required for a trench, if you're excavating in
soil? - ANSWER-5 feet or deeper
What occurs after breakpoint chlorination is achieved? - ANSWER-Free available
chlorine residual is directly proportional to the amount of chlorine added
What is used to automatically shut-off the flow into a tank when the water level
reaches a pre-determined level? - ANSWER-Altitude valve
What would be used to find a chlorine gas leak, which produces white smoke when it
reacts with this substance? - ANSWER-Spray ammonia solution vapor near leak
What causes staining of plumbing fixtures? - ANSWER-Iron & manganese
How long should you flush water before you collect a bacteriological sample? -
ANSWER-As long as necessary to flush stagnant water from the service pipe
What is the purpose of a surge tank? - ANSWER-Protect pipelines from sudden high
pressure
, What is recommended if a chlorine gas cylinder is leaking? - ANSWER-Rotate the
cylinder and turn the leak upwards
What is the purpose of primary MCL? - ANSWER-To protect human health
What problem could be used by water with a pH of 5.3? - ANSWER-Corrosión
What is a common way to connect a new pipe to an existing pipe, while the latter is
pressurized and in-service? - ANSWER-Wet tap or hot tap
What impact would organics have on chlorine demand? - ANSWER-Increase
chlorine demand
What is dichloramine? - ANSWER-Combined chlorine residual
What impact does tuberculation have on the interior of a water main? - ANSWER-
Causes rough interior of the water due to corrosion
What is used to neutralize chlorine residuals when collecting a water sample for
bacteriological analysis? - ANSWER-Sodium thiosulfate
What are electrodes and ultrasonic signals used for in a tank? - ANSWER-Monitor
water level
Which part of the water main should a new service tap be installed? - ANSWER-45
degrees from the top of the water main
What is the purpose of a vacuumed breaker? - ANSWER-Prevent back siphonage
Which type of valve is commonly used to isolate water mains during repairs to
minimize service outages? - ANSWER-Gate valve
Pumping water level - static water level = - ANSWER-Drawdown
What is purple pipe used for? - ANSWER-Reclaimed water
Where is the correct location to install an air release valve - ANSWER-Top of pipe
What must be performed prior to entering a confined space? - ANSWER-Test for
oxygen deficiency/enrichment, combustible gases, and toxic gases
What does the C- factor of a pipe represent? - ANSWER-Roughness of pipe interior
Why should you never empty an underground storage tank when the groundwater
level is high? - ANSWER-It may float the tank and cause damage to the facility
What is used to determine the bacteriological quality of a water supply? - ANSWER-
Presence-absence of coliform bacteria
(D1-D2) Questions and Answers 100%
Correct
Which process converts ammonia to nitrite and nitrate? - ANSWER-Nitrification
What is the maximum advisable rate of chlorine gas removal from a 150- pound
cylinder? - ANSWER-40 pounds per day
What is a type of positive displacement water meter? - ANSWER-Nutating- disk
meter
What is a power-operated mechanism for opening and closing a valve? - ANSWER-
Actuator
What is required if a routine sample test positive for total coliform bacteria? -
ANSWER-Take repeat samples
Why is a grid layout better than a tree layout for a water distribution system? -
ANSWER-Less dead-end mains
What is the purpose of a reduced pressure principle assembly? - ANSWER-Prevents
back-pressure and back-siphonage
In general, at what depths is shoring required for a trench, if you're excavating in
soil? - ANSWER-5 feet or deeper
What occurs after breakpoint chlorination is achieved? - ANSWER-Free available
chlorine residual is directly proportional to the amount of chlorine added
What is used to automatically shut-off the flow into a tank when the water level
reaches a pre-determined level? - ANSWER-Altitude valve
What would be used to find a chlorine gas leak, which produces white smoke when it
reacts with this substance? - ANSWER-Spray ammonia solution vapor near leak
What causes staining of plumbing fixtures? - ANSWER-Iron & manganese
How long should you flush water before you collect a bacteriological sample? -
ANSWER-As long as necessary to flush stagnant water from the service pipe
What is the purpose of a surge tank? - ANSWER-Protect pipelines from sudden high
pressure
, What is recommended if a chlorine gas cylinder is leaking? - ANSWER-Rotate the
cylinder and turn the leak upwards
What is the purpose of primary MCL? - ANSWER-To protect human health
What problem could be used by water with a pH of 5.3? - ANSWER-Corrosión
What is a common way to connect a new pipe to an existing pipe, while the latter is
pressurized and in-service? - ANSWER-Wet tap or hot tap
What impact would organics have on chlorine demand? - ANSWER-Increase
chlorine demand
What is dichloramine? - ANSWER-Combined chlorine residual
What impact does tuberculation have on the interior of a water main? - ANSWER-
Causes rough interior of the water due to corrosion
What is used to neutralize chlorine residuals when collecting a water sample for
bacteriological analysis? - ANSWER-Sodium thiosulfate
What are electrodes and ultrasonic signals used for in a tank? - ANSWER-Monitor
water level
Which part of the water main should a new service tap be installed? - ANSWER-45
degrees from the top of the water main
What is the purpose of a vacuumed breaker? - ANSWER-Prevent back siphonage
Which type of valve is commonly used to isolate water mains during repairs to
minimize service outages? - ANSWER-Gate valve
Pumping water level - static water level = - ANSWER-Drawdown
What is purple pipe used for? - ANSWER-Reclaimed water
Where is the correct location to install an air release valve - ANSWER-Top of pipe
What must be performed prior to entering a confined space? - ANSWER-Test for
oxygen deficiency/enrichment, combustible gases, and toxic gases
What does the C- factor of a pipe represent? - ANSWER-Roughness of pipe interior
Why should you never empty an underground storage tank when the groundwater
level is high? - ANSWER-It may float the tank and cause damage to the facility
What is used to determine the bacteriological quality of a water supply? - ANSWER-
Presence-absence of coliform bacteria
