Secondary treatment typically removes ______ of the BOD and suspended
solids.
a) 20-39%
b) 40-59%
c) 60-79%
d) 80-99% ---------CORRECT ANSWER-----------------d) 80-99%
Water entering a wastewater treatment plant will pass through a bar
screen. The bar screen is designed to remove which of the following items?
a) dissolved solids
b) grit and sand
c) large objects
,d) nutrients ---------CORRECT ANSWER-----------------c) large objects
Define the term 'supernatant'
a) a solution which is supersaturated
b) a substance used to reduce odour in polluted waters
c) the liquid located above a sediment or precipitate
d) an operator who is extremely proficient in fulfilling their duties ---------
CORRECT ANSWER-----------------c) the liquid located above a sediment or
precipitate
A __________ is used to move wastewater from a wastewater lift station to
an elevated gravity sewer:
a) sewer lateral
b) force main
c) sanitary trunk main
d) transmission main ---------CORRECT ANSWER-----------------b) force
main
What happens when a sewer is surcharged?
a) infiltration of ground water into sewers
b) flushing a sewer with clean water to clean debris away
c) hydraulically overloading a sewer
d) taxing a customer's water bill to pay for collection devices ---------
CORRECT ANSWER-----------------c) hydraulically overloading a sewer
Which of the following infectious diseases can be transmitted through
domestic wastewater?
a) hepatitis
,b) giardiasis
c) cryptosporidiosis
d) all of the above ---------CORRECT ANSWER-----------------d) all of the
above
What is meant by the term "combined sewers"?
a) industrial sewage and domestic sewage are collected in the same
sewers
b) stormwater and sewage are collected in the same sewers
c) the main sewer line which takes all of a city's sewage to the treatment
plant
d) a sewer which contains both gravity sewers and force mains ---------
CORRECT ANSWER-----------------b) stormwater and sewage are collected
in the same sewers
Why is hydrogen sulphide gas a problem in sewers?
a) results in an increase in rodent populations
b) the gas can block the flow of sewage
c) since it is odourless, workers will not know when they are exposed
d) leads to corrosion of certain types of sewers ---------CORRECT
ANSWER-----------------d) leads to corrosion of certain types of sewers
Why is a minimum wastewater velocity of 0.6 m (2.0 feet) per second
necessary in a gravity sewer?
a) it will ensure that sewage has enough velocity to go up minor increases
in sewer elevation
b) it will prevent the growth of roots in sewers
c) it will prevent the erosion of the bottom of the sewer
d) it will prevent the build up of solids in the sewer ---------CORRECT
ANSWER-----------------d) it will prevent the build up of solids in the sewer
, What units are used to measure water pressure?
a) Kilowatts
b) Kilopascals
c) Horsepower
d) Head units ---------CORRECT ANSWER-----------------b) Kilopascals
Which of the following is NOT an example of PPE (Personal Protective
Equipment)?
a) Exhaust fan
b) SCBA
c) Face shield
d) Traffic vest ---------CORRECT ANSWER-----------------a) Exhaust fan
Which of the following are operators-in-training NOT allowed to do?
a) There are no restrictions on the duties of an operator-in-training
b) Any operational duties if not in the presence of another operator
c) Anything which could effect the quality of the water/wastewater
d) Be the operator with overall operational responsibility of the system ------
---CORRECT ANSWER-----------------d) Be the operator with overall
operational responsibility of the system
Define the term "head" as used in hydraulic systems.
a) The block of an internal combustions engine
b) The ability of a piston pump to overcome the force of gravity
c) The height or energy of water above a specified point
d) The distance between the liquid level and the cover of a well ---------
CORRECT ANSWER-----------------c) The height or energy of water above a
specified point
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