Statistics for Texas Basic Waste Water Operations Ch#03 Waste Water Characteristics

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This quiz has been taken 8 times
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Answer Stats

Question	Answer	% Correct
Each person contributes about ________ lbs of BOD daily.	0.17	100%
Good sampling results depend on ________.	all of the above	100%
A ________ sample is collected at any point, at any time.	grab	100%
Dangerous gases produced during the breakdown of organics in wastewater are hydrogen sulfide, carbon dioxide, and ________.	methane	100%
Hydrogen sulfide has a ________ odor, is combustible in air, and is very toxic.	rotten egg	100%
Two other classifications of solids are inorganic (ash) and organic (volatile).	True	100%
Because wastewater is mostly water, it weighs 8.34 lbs/gal.	True	100%
Fresh domestic wastewater contains dissolved oxygen.	True	100%
Some bacteria cause disease and are called pathogens.	True	100%
Some chemical characteristics of wastewater include solids, grease, DO, pH, and gases.	True	100%
The ________ test measures the oxygen depleting effect of the wastewater upon the receiving stream.	BOD	80%
The three primary types of organics are ________, proteins, and grease.	carbohydrates	80%
________ is odorless, colorless, heavier than air, and not combustible.	Carbon dioxide	80%
Facultative bacteria live with free oxygen or chemically combined oxygen.	True	80%
One way to classify bacteria is by their oxygen use: aerobic, facultative, and anaerobic.	True	80%
Wastewater characteristics are divided into 3 primary groups: bacteriological, physical, and chemical.	True	80%
The pH scale ranges from ________ to ________, with 7 being neutral.	0/14	60%
________ water has a pH below 7.0, while ________ water has a pH above 7.0.	Acidic/basic	60%
A ________ sample consists of several portions collected at intervals, then mixed together.	composite	60%
Septic wastewater is dark, has agreeable odor, and contains dissolved oxygen.	False	60%
The dissolved oxygen test must be performed as soon as a sample is taken because oxygen levels can ________ change.	quickly	60%
When a sample of a plant unit influent is collected at any time, and a sample of the effluent is collected corresponding to the unit’s detention time, the sample is a ________.	timed grab	60%
Organic solids are volatile, combustible solids found by burning the residue from the total solid test or the filter from the TSS test.	True	60%
Select a point where ________ is thorough and the wastewater quality is uniform.	mixing	40%
The ash (fixed solids) left after burning consists of inorganic solids.	True	40%
Suspended solids can be filtered out, and dissolved solids pass through a filter.	True	40%
The BOD test measures oxygen consumed as organics are oxidized by biological and chemical action during incubation for ________ days at ________°C.	5/20	20%
The ________ decomposition of organic matter produces methane which is colorless, odorless, and explosive.	anaerobic	20%
As the water temperature rises, the DO saturation level will ________.	decrease	20%
Settleable solids are dissolved solids of sufficient weight to settle when left standing for a time.	False	20%
When dissolved oxygen is present, it indicates the wastewater is ________.	fresh	20%
Labs report many characteristics of wastewater as milliliters per liter (ml/L).	False	0%
Anaerobic bacteria cannot live when chemically combined oxygen is present.	False	0%
________ in raw wastewater comes from the water supply.	Organic solids	0%