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WASTEWATER GRADE III PRACTICE TEST
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WASTEWATER GRADE III PRACTICE TEST
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WASTEWATER GRADE III PRACTICE TESTA properly functioning anaerobic digester will achieve a reduction in volatile solids of
greater than
50%.
( )True
( )False - Answers -True
Explanation:
A properly functioning anaerobic digester will achieve a reduction in volatile solids of
greater than
50%.
You are operating a belt press to dewater anaerobically digested sludge. The
conditioned feed solids
concentration today is 4.2%. You have operated for 7 hours at an average of 60 gpm.
You have
produced 22.4 wet weight tons of filter cake with an average solids concentration of
19%. Determine
the percent solids recovery for today's operation.
( )93.3%
( )99.5%
( )91.5%
( )96.4%
( )94.1% - Answers -96.4%
What is a likely result if the overflow rate is too low in a primary clarifier?
( )Primary sludge that is too thick to pump
( )Excessive scum
( )Floating sludge near the inlet end of the clarifier
( )Septic odors
( )Excessive load on the sludge cross collectors - Answers -Septic odors
Explanation:
Septic odors will occur if the overflow rate is too low in a primary clarifier.
Which of the following is not true regarding chlorine or chlorination equipment?
( ) Due to the high vapor pressure of liquid chlorine, it may be withdrawn from a 1 ton
container
without pressurization
( )Chlorine gas may lower the pH of the secondary effluent
( )When taking a chlorinator out of service, the chlorine valve at the cylinder is shut and
the
chlorine ejector is operated for a time to remove the gas remaining in the line
( )The vacuum in a vacuum chlorinator is created when chlorine gas moves rapidly
through a
, restriction in the line
( )The withdraw rate is limited because freezing in the line can occur if chlorine gas is
removed too
fast - Answers -The vacuum in a vacuum chlorinator is created when chlorine gas
moves rapidly through a restriction in the line
Explanation:
The vacuum in a vacuum chlorinator is created by the use of carrier water flowing
through the nozzles of an eductor.
Which of the following will hinder photosynthesis?
( )Duckweed
( )Phosphorous
( )Nitrogen
( )Chlorophyll
( ) Sunlight - Answers -Duckweed
Explanation:
Duckweed will block sunlight from penetrating the surface of the pond and will thus
hinder photosynthesis. Photosynthesis is a vital process in successful pond treatment.
Two toxic gases that have a noxious odor and are commonly found in confined spaces
are Carbon
Dioxide and Ferrous Sulfide.
( )True
( )False - Answers -False
Explanation:
Carbon dioxide has no odor. The toxic gas with a distinct noxious odor is Hydrogen
Sulfide.
Which one of the following is true regarding the complete mix activated sludge
treatment plant?
( )The rate of Oxygen uptake per pound of activated sludge is the same throughout the
aeration
basin
( )It uses bubble dome diffusers to ensure adequate DO for microorganisms
( )It is not possible to calculate MCRT for the system
( )Complete mixing is not desirable
( )Complete mix processes usually have 18-24 hour detention time in the aeration basin
- Answers -The rate of Oxygen uptake per pound of activated sludge is the same
throughout the aeration
basin
Explanation:
With a complete mix system, the rate of oxygen uptake per pound of sludge is
consistent throughout
the aeration basin.
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