Statistics for Texas Waste Water Treatment Ch#05 Preliminary & Primary Treatment

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Question	Answer	% Correct
Conditions influencing settling of solids include which of the following?	All of the above	100%
Too high a velocity in a grit chamber can result in ________.	excess grit in primary clarifier	100%
Raw sludge should be pumped to a digester ________.	slowly when it is adequately thickened	100%
Grit should be removed to prevent which of the following?	All of the above	92%
Grease may be removed before sedimentation by which of the following?	All of the above	92%
When should sludge be pumped from a primary clarifier?	None of the above	92%
Flow equalization is used to ________.	reduce excessive flows or organic loads	92%
A primary clarifier should remove most of the ________.	settleable solids	92%
Sludge from a primary clarifier should have a moisture content of ________.	94% to 96%	85%
Short-circuiting in a clarifier is ________.	a flow problem	85%
As its temperature increases, water becomes ________.	less dense	85%
Why does grit need to be washed?	Organic matter clings to it.	85%
By performing Imhoff cone tests on the clarifier inlet and outlet, the operator can determine which of the following?	The efficiency AND depth of sludge in the clarifier	85%
The upper compartment of an Imhoff tank serves as the ________ and the lower compartment provides space for ________.	clarifier/digester	69%
One of the benefits of pre-aeration is ________.	gas and grease removal	69%