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45 terms

Wastewater/Practice exam

Questions from WEF/ABC practice test (KF)
STUDY
PLAY
When organic wastes are discharged to receiving waters, O2 is depleted by _____.
bacteria
Hydrogen sulfide gives off an odor similar to____.
rotten eggs
3 diseases potentially carried by wastewater are _____.
typhoid fever, disentery, cholera
Immediate first aid for butrns is to ____.
flood with cold water
What most likely causes an electic motor failure?
mopisture
What mixed liquor characteristics indicate a healthy activated sludge process?
brown color, frothy appearance, and musty odor
T/F: Algae is a plant life necessary for the proper functioning of a stabilization or oxidation pond.
True
Chlorine gas is ?
heavier than air
T/F: The highest concentration of algae growth in a facultative lagoon is usually observed near the top.
True
Common hydraulic detention times for primary clarifiers range from ____ hours
2 - 3 hours
T/F: Methane is produced in an anaeroibic digester and can be used as a fuel?
True
T/F: The rock in a trickling filter is usually placed on a tile underdrain system.
True
What is the purpose of heating and mixing a primary anaeroibic digester?
to increase the digestion rate
T/F: Exhaust from a chlorinator room should be taken form floor level.
True
T/F: Chlorine residual may be determined using the reagent _____
diethyl-p-phenylene diamine (DPD)
What test is typically never performed on wastewater influent?
fecal coliform
Considering the layout and flow diagram for the complete treament plant, oxidation ditch plants would be most similar to _____?
extended aeration
The pressure against which a pump must operate is measured in terms of _____
kPA (psi)
T/F: Assuming aa constant suction head, the discharge of a centrifugal pump decreases with an increase in discharge head.
True
T/F: The addition of chlorine, acid, carbon dioxide, or sulfuric acid will "lower" the pH of wastewater?
True
T/F: Activated sludge generally "settle more slowly" than raw sludge.
True
T/F: Controlling the sludge wasting rate by constant MLSS concentration involves maintaining a certain concentration of "volatile suspended solids in the reactor(aeration tanks)
True
T/F: "Fungi" organisms should mot be present in a healthy lagoon treament system
True
T/F: Under ice and snow cover, the BOD level in poinds will mormally "increase slowly".
True
T/F: The rotational speed of the air-driven rotating biological contactor (RBC) is controlled by "air volume".
True
T/F: chloramines are "combined chlorine."
True
T/F: An "increase in organic matter" increases chlorine demand.
True
When a high organic waste load reaches an activated sludge plant, the operator's first indicator is a decrease in
DO residual in the reactors (aeration tanks)
Disaster planning is ____
useful in reducing confusion in the event of a disaster.
The gas most commonly associated with septic wastewater is
hydogen sulfide
In electrical circuits, a ______ is used to reduce the voltage where necessary.
transformer
What causes the greatest pipe friction loss?
Increasing the velocity of wastewater
T/F: Denitrification is the most likely cause of rising sludge in clarifiers.
True
The amount of BOD in sludge entering a digester is an indirect measure of the
"food" available for bacteria in the digester.
Chemical coagulation doses can be initially estimated by
jar tests.
An incubator for the BOD test should be controlled at ____C.
30 degrees
In certain situations, a supervisor encourages the employees to make their own decisions. This is considered to be ______
highly desirable because it encourages employee growth and frees the supervisor for other tasks
What peeice of lab equipment should be calibrated daily at a treament plant?
portable dissoved oxygen probe
The ask content remaining at the end of a VSS test is the same as the ____.
inorganic solids
A chlorine demand test will show the ______.
amount of chlorine required to give a desired residual after a given time.
Jar tests may be used to determine the optimum dosage of ______.
polymer
Which activated sludge process ccould handle shock loads of dairy waste most effectively?
a tapered aeration system
When chlorine reacts with hydrogen sulfide gas, the hydrogen sulfide is ______.
oxidized and made odorless
T/F: in the membrane filter method, the number of coliforms is estimated by the _____.
number of coloniew grown
Decentralized authority describes the process of _______.
delegating power for decisions to lower levels