Dissolved Oxygen Flashcards

(35 cards)

1
Q

True/False

Higher DO indicates better water quality

A

True

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2
Q

It is characterized by the presence of DO. “Aerobic
” is also used to describe biological or chemical processes that occur in the
presence of oxygen.

A

Aerobic (oxic)

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3
Q

It is n environmental condition in which the concentration of DO is
low enough to have biological effects. According to the USEPA (2000b), water with oxygen concentrations of 2mg/L or less is of concern.

A

Hypoxia

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4
Q

It is used to
describe biological or chemical processes that occur in the absence of

A

Anaerobic (anoxic)

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5
Q

It is a DO level concentration that can suffocate sport fishes.

A

3-4 mg/L

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6
Q

Large and juvenile fish require higher DO
concentration, ranging from

A

5-8 mg/L

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7
Q

True/False

Adequate dissolved oxygen is necessary for good water
quality.

A

True

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8
Q

True /False

A

The energy from sunlight is used to split carbon dioxide and water into oxygen and sugar.

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9
Q

True/False

CO2 + H2O -> O2 + sugar

A

True

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10
Q

A process by which oxygen is transferred across the
atmosphere and waterbody.

A

Reaeration

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11
Q

True/False

Reaeration cannot produce dissolved
oxygen even in night.

A

False (can)

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12
Q

3 Dissolved Oxygen measurement methods

A

Colorimetric
Titrimetric
Polarographic

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13
Q

Best-known titrimetric method

A

Winkler method

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14
Q

It provide for rough
and rapid measurement: they are often used for screening for low-oxygen conditions and can be easily used by non-professional operators.

A

Colorimetric

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15
Q

A method for measuring DO where Chemical reagents added in excess interact with oxygen to form a product, and another chemical (the
“titrant”) is used quantitatively to neutralize that product.

A

Titrimetric

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16
Q

DO method where Electrodes measure the flux of oxygen across a membrane.
Oxygen is consumed in the
process, and the traditional
electrodes require flushing of measured liquid at the
membrane surface to constantly replace the oxygen consumed.

A

Polarographic

17
Q

It indicates the quantity of oxygen used by bacteria and other microorganisms during the aerobic (oxygen-containing) decomposition
of organic materials at a particular temperature.

A

Biochemical Oxygen Demand

18
Q

True/False

Higher BOD, more pure water

Lower BOD, more polluted

A

False (interchange description)

19
Q

True/False

Low concentration of DO in the water indicates contamination.

20
Q

True/false

The temperature and altitude of the water affect
the DO in a saturated solution.

21
Q

3 Major sources of DO

A

Reaeration
Photosynthesis
External loads

22
Q

5 Major sinks of DO

A

DOC Oxidation
Nitrification
Respiration
SOD
COD

23
Q

Consumes oxygen to oxidize NH4+ to NO2- and then to NO3-.

A

Nitrification

24
Q

Carbon dioxide and water is converted from organic carbon dioxide in the presence of oxygen

25
Represents oxygen depletion caused by benthic reactions. It it the rate of oxygen consumption exerted by the bottom sediment to the overlying water.
SOD
26
Chemicals such as Sulfide and Methane give rise to more oxygen demand. Stratification may intercept the DO from the surface to reach at the bottom.
COD
27
This model takes into account the DO contribution in the reaeration process as well as the consumption of DO by aerobic bacteria that oxidize organic materials.
DO Kinetic Equation
28
Used to show how surface waters' dissolved oxygen is affected by sewage and organic pollutants such as soils, sediments, garbage, sludg
BOD5 Test
29
An examination designed to quantify the oxygen needed for the chemical oxidation of both organic matter and inorganic nutrients like Ammonia or Nitrate found in water.
COD
30
True/False Higher COD, more polluted
True
31
3 Factors Affecting DO
Water temperature Salinity Pressure
32
True/False Cooler water has a greater capacity to retain dissolved oxygen compared to warmer water.
True
33
True/False Water with higher salinity retains a lower amount of oxygen compared to freshwater.
True
34
True/False Lowering the salt concentration results in a reduction in the solubility of oxygen.
False (Raising)
35
True/False Lower atmospheric pressure enables bodies of water to retain increased levels of dissolved oxygen.
False (Greater)