Texas Basic Waste Water Operations Ch#07 Sedimentation - Statistics

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  • The average score is 14 of 21
Answer Stats
Question Answer % Correct
Imhoff tanks are ________ story units with ________ compartments. 2/3
100%
Common design features of a sedimentation tank include baffles, a skimmer, a grease ring, and a sludge rake. True
100%
Withdraw sludge slowly or water will break through the sludge layer, ________ the sludge. diluting
80%
Floating sludge or excessive gas bubbles indicate a failure of the return sludge pump, sludge rake, or poor ________ schedule. pumping
80%
If the skimmer fails, the sludge ________ fails. rake
80%
The four settling zones in a sedimentation tank are the inlet zone, settling zone, sludge zone, and the outlet zone. True
80%
Short-circuiting is the uneven flow of water through a tank. True
80%
Secondary sludge contains more water than primary sludge. True
80%
Control foaming by controlling industrial waste, ________, and controlling pH with lime. wasting small amounts of sludge
80%
Usual blanket depth in a secondary clarifier is no more than ________ of the sidewall depth. 1/4
60%
When sludge in an Imhoff tank is near ________ inches of the slot, withdraw sludge. 18
60%
________ prevents septic solids from collecting and rising in the settling chamber. Chaining
60%
A primary clarifier settles biological sludge, and a secondary clarifier settles raw sludge. False
60%
Primary clarifiers should remove 90–95% of the BOD and 35% of the settleable solids. False
60%
A trapped slot in the bottom of the settling compartment permits ________ solids to pass into the digester, but prevents septic solids from ________ into the settling compartment. settled/rising
60%
Gas vents alongside the settling tank are the ________ compartment. third
60%
The ________ compartment of an Imhoff tank is the settling tank, and the ________ compartment is the sludge digester. upper/lower
60%
The settling compartment provides a detention time of about ________ hour(s). 2
40%
Foaming can be caused by industrial waste, drawing too much sludge, low pH, and restricted ________. gas vents
40%
Sedimentation is the process of separating a suspended solid from water by atmospheric pressure. False
20%
Factors affecting settling include solid weight, water temperature, detention time, velocity, surface loading, wastewater condition, and short-cutting. False
20%
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