Lesson 5: Part 1 Flashcards
(174 cards)
1
Q
The transmission of disease by pathogenic organisms in polluted water was not recognized until the ____________________________ century.
A
middle of the nineteenth
2
Q
People intuitively relate filth to __________
A
disease
3
Q
the ____________________ by _____________ in polluted water was not recognized until the middle of the nineteenth century.
A
transmission of disease ; pathogenic
organisms
4
Q
___________ was viewed primarily as a threat to human health because of the transmission of bacterial and viral waterborne diseases.
A
water pollution
5
Q
Water pollution was viewed primarily as a threat to human health because of the_______________ and _______________________
A
transmission of bacterial ; viral waterborne diseases.
6
Q
water pollution was viewed primarily as a threat to ____________ because of the transmission of bacterial and viral waterborne diseases.
A
human health
7
Q
In _______________ countries, and in almost ________________, waterborne diseases remain a major public health threat.
A
less developed ; any country in time of war
8
Q
In less developed countries, and in almost any country in time of war, _____________ remain a major public health threat.
A
waterborne diseases
9
Q
In less developed countries, and in almost any country in time of war, waterborne diseases remain a ________________
A
major public health threat.
10
Q
Two general sources of water pollutants
A
Point Sources and Non-Point Sources
11
Q
Point sources of pollution occur when harmful substances are emitted _______________________ from _________________
A
directly into a body of water; a pipeline or sewer
12
Q
They occur when harmful substances are emitted directly into a body of water from a pipeline or sewer.
A
Point sources of pollution
13
Q
Point sources of pollution occur when ______________ are emitted directly into a body of water from a pipeline or sewer.
A
harmful substances
14
Q
POINT SOURCES
Domestic sewage consists of wastes from __________, _______, ___________, and ______________.
A
homes, schools, office buildings, and stores.
15
Q
It consists of wastes from homes, schools, office buildings, and stores.
A
Domestic sewage
16
Q
POINT SOURCES
_______________ means process and non-process wastewater from manufacturing, commercial, mining, and silvicultural facilities, or activities, including the runoff and leachate from areas that receive pollutants associated with industrial or commercial storage, handling or processing, and all other wastewater not otherwise defined as ________________.
A
Industrial wastewater ; domestic wastewater
17
Q
POINT SOURCES
TRUE OR FALSE
Industrial wastewater means process and non-process wastewater from manufacturing,
commercial, mining, and silvicultural facilities, or activities, including the runoff and leachate
from areas that DO NOT RECEIVE pollutants associated with industrial or commercial storage, handling
or processing, and all other wastewater not otherwise defined as domestic wastewater.
A
FALSE
industrial wastewater means process and non-process wastewater from manufacturing,
commercial, mining, and silvicultural facilities, or activities, including the runoff and leachate
from areas that RECEIVE pollutants associated with industrial or commercial storage, handling
or processing, and all other wastewater not otherwise defined as domestic wastewater.
18
Q
POINT SOURCES
It includes domestic sewage along with any industrial wastes that are permitted to be discharged into the sanitary sewers.
A
Municipal sewage
19
Q
POINT SOURCES
Municipal sewage includes ____________ along with any _________________ that are permitted to be discharged into the sanitary sewers.
A
domestic sewage ; industrial wastes
20
Q
POINT SOURCES
Municipal sewage includes domestic sewage along with any industrial wastes that are permitted to be _______________ ____________.
A
discharged into the sanitary sewers.
21
Q
____________ can be reduced or eliminated through waste minimization and proper wastewater treatment prior to discharge to a natural water body.
A
Point source pollution
22
Q
Point source pollution can be _________or ___________ through waste minimization and proper wastewater treatment prior to discharge to a natural water body.
A
reduced ; eliminated
23
Q
Point source pollution can be reduced or eliminated through ________________ and ____________________ prior to discharge to a natural water body.
A
waste minimization; proper wastewater treatment
24
Q
Point source pollution can be reduced or eliminated through waste minimization and proper wastewater treatment prior to discharge to a ___________________.
A
natural water body
25
delivers pollutants indirectly by passing through the continents.
Nonpoint source
26
Nonpoint source delivers ________ indirectly by passing through the continents.
pollutants
27
TRUE OR FALSE
Nonpoint source delivers pollutants indirectly by PASSING through the CONTINENTS.
TRUE
28
Much of ______________ occurs during rainstorms, resulting in large flow rates that make treatment even more difficult.
nonpoint source
29
Much of nonpoint source occurs during __________, resulting in large flow rates that make treatment even more difficult.
rainstorms
30
Much of nonpoint source occurs during rainstorms, resulting in _________________ that make __________ even more difficult.
large flow rates ; treatment
31
TWO RUNOFF IN NONPOINT SOURCES
Agricultural runoff
Urban runoff
32
Non-Point Sources
____________________ (including that from streets, parking lots, golf courses, and lawns) can transport pollutants such as nitrogen, phosphorus from fertilizers, herbicides applied to lawns and golf courses, oil, greases, ethylene glycol (used in antifreeze), and cut grass and other organic debris.
Urban storm water runoff
33
Non-Point Sources
Urban storm water runoff (including that from streets, parking lots, golf courses, and lawns) can _________ pollutants such as nitrogen, phosphorus from fertilizers, herbicides applied to lawns and golf courses, oil, greases, ethylene glycol (used in antifreeze), and cut grass and
other organic debris.
transport
34
Non-Point Sources
Urban storm water runoff (including that from streets, parking lots, golf courses, and lawns) can transport pollutants such as _____________________ from ________________ applied to ________________________________, and cut grass and other organic debris.
nitrogen ; phosphorus
fertilizers, herbicides
lawns and golf courses, oil, greases, ethylene glycol (used in antifreeze),
35
cuts grass and
other organic debris.
Urban storm water runoff
36
ethylene glycol is used in?
antifreeze
37
Types of Water Pollutants (SENUSYA ACOH M)
SEdiments
NUtrients
SYnthetic Organics and Pesticides
Agricultural Wastes
ACids and Bases
Oxygen-Demanding Materials
Heat
Municipal Wastewater
38
Anything that can be oxidized in the receiving water resulting in the consumption of dissolved molecular oxygen is termed ________________
oxygen-demanding material.
39
Anything that can be ______ in the receiving water resulting in the ____________________ is termed oxygen-demanding material.
oxidized ; consumption of dissolved
molecular oxygen
40
This material is usually biodegradable organic matter but also includes inorganic compounds.
oxygen-demanding material.
41
oxygen-demanding material is usually biodegradable ____________ but also includes _____________
organic matter ; inorganic compounds
42
oxygen-demanding material is usually __________ organic ________ but also includes inorganic ____________
biodegradable ; matter ; compounds
43
TRUE OR FALSE
The consumption of CONDENSED oxygen (CO) poses a threat to fish and other higher forms of aquatic life that must have oxygen to live.
FALSE
The consumption of DISSOLVED OXYGEN (DO) poses a threat to fish and other higher forms of
aquatic life that must have oxygen to live.
44
The consumption of DISSOLVED OXYGEN (DO) poses a threat to _____ and other higher forms of
_________ that must have oxygen to live.
fish ; aquatic life
45
OXYGEN DEMANDING MATERIAL
______________ – human wastes and food residue
Domestic sewage
46
OXYGEN DEMANDING MATERIAL
Domestic sewage – human _________ and food _______
wastes ; residue
47
OXYGEN DEMANDING MATERIAL
___________ – food processing and paper industries
Industrial sewage
48
TRUE OR FALSE
Maximum amount in CLEAN water is ABOUT 9 MG/L
TRUE
49
OXYGEN DEMANDING MATERIAL
Dissolved Oxygen varies with _______, _______, _________, and ______________.
temperature, salinity, elevation, and turbulence (mixing).
50
_______________ varies with temperature, salinity, elevation, and turbulence (mixing).
Dissolved Oxygen
51
__________ such as might be discharged from milk processing plants, breweries, or paper mills, as well as municipal wastewater treatment plants, compose one of the most important types of pollutants because these materials decompose in the watercourse and can deplete the water of dissolved oxygen.
Oxygen demanding substances
52
Oxygen-demanding substances might be discharged from _________,
____________, or____________, _______________, compose one of the most important types of pollutants because these materials decompose in the
watercourse and can deplete the water of dissolved oxygen.
milk processing plants, breweries, or paper mills, as well as municipal wastewater treatment plants
53
Oxygen-demanding substances might be discharged from milk processing plants, breweries, or paper mills, as well as municipal wastewater treatment plants, compose one of the ____________ because these materials decompose in the watercourse and can deplete the water of dissolved oxygen.
most important types of pollutants
54
Oxygen demanding substances such as might be discharged from milk processing plants,
breweries, or paper mills, as well as municipal wastewater treatment plants, compose one of
the most important types of pollutants because these materials decompose in the
__________ and can deplete __________.
watercourse ; the water of dissolved oxygen.
55
Sediments and suspended solids may also be classified as a ___________.
pollutant
56
It consists of mostly inorganic material washed into a stream because of land cultivation, construction, demolition, and mining operations.
Sediments
57
SEDIMENTS
Sediments interfere with ________ because they can cover gravel beds and block light penetration, making food harder to find.
fish spawning
58
Sediments interfere with fish spawning because they can ___________ and _____________, making food harder to find.
cover gravel beds ; block light penetration
59
TRUE OR FALSE
Sediments can also DAMAGE gill structures
directly, smothering aquatic INSECTS and fishes.
TRUE
60
It may create unsightly conditions and
cause unpleasant odors.
Organic sediments
61
Organic sediments can ___________ of oxygen, ___________________ conditions
deplete the water ; anaerobic (without oxygen)
62
______________ can deplete the water of oxygen, creating anaerobic (without oxygen) conditions
Organic sediments
63
Nutrients, mainly ___________ and __________, can promote accelerated eutrophication, or the rapid
biological ―aging‖ of lakes, streams, and estuaries.
nitrogen ; phosphorus
64
Nutrients, mainly nitrogen and phosphorus, can promote accelerated ___________, or the rapid
biological aging of lakes, streams, and estuaries.
eutrophication
65
eutrophication, or ____________, _____________, and ____________.
rapid biological aging of lakes ; streams ; estuaries
66
Phosphorus and nitrogen are common pollutants in _____ and __________, and are usually associated with plant debris, animal wastes, or fertilizer.
residential ; agricultural runoff
67
Phosphorus and nitrogen are also common pollutants in ______________, even if the wastewater has received conventional treatment.
municipal wastewater discharges
68
Phosphorus adheres to
_______________ and is transported with sediments in ____________.
inorganic sediments ; storm runoff
69
Nitrogen tends to move
with _________ or is leached from soils and moves with _______________.
organic matter ; groundwater
70
It may be classified as a water pollutant when it is caused by heated industrial effluents or from anthropogenic alterations of stream bank vegetation that increase the stream temperatures due to solar radiation.
Heat
71
Heat may be classified as a ______________ when it is caused by heated industrial effluents or from
anthropogenic alterations of stream bank vegetation that increase the stream temperatures due to
solar radiation.
water pollutant
72
Heat may be classified as a water pollutant when it is caused by __________________ or from
___________ _____________ that increase the ______________ due to
solar radiation.
heated industrial effluents; anthropogenic alterations of stream bank vegetation ; stream temperatures
73
_______________ may drastically alter the ecology of a stream or lake. Although localized heating can have beneficial effects like freeing harbors from ice, the ecological effects are generally deleterious.
Heated discharges
74
Heated discharges may drastically alter ___________________
the ecology of a stream or lake
75
Although localized heating can have beneficial effects like _________________________, the ecological effects are
generally _____________.
freeing harbors from ice ; deleterious
76
______ lower the solubility of oxygen in the water because gas solubility in water is inversely proportional to temperature, thereby reducing the amount of dissolved oxygen available to aerobic (oxygen-dependent) species.
Heated effluents
77
Heated effluents lower the ________ in the water because gas solubility in water is inversely proportional to temperature, thereby reducing the amount of dissolved oxygen available to aerobic (oxygen-dependent) species.
solubility of oxygen
78
Heated effluents lower the solubility of oxygen in the water because ____________ in water is inversely proportional to temperature, thereby reducing the amount of ____________ available to ____________________
gas solubility ; dissolved oxygen ; aerobic (oxygen-dependent) species.
79
TRUE OR FALSE
gas solubility in water is INVERSELY proportional to temperature
TRUE
80
_________ also increases the metabolic rate of aquatic organisms (unless the water temperature gets too high and kills the organism), which further reduces the amount of dissolved oxygen because respiration increases.
Heat
81
Heat also increases the______________ of aquatic organisms (unless the water temperature gets too high and kills the organism), which further reduces the amount of dissolved oxygen because respiration increases.
metabolic rate
82
Heat also increases the metabolic rate of aquatic organisms (unless the water temperature gets too high and kills the organism), which further reduces the amount of dissolved oxygen because _____________.
respiration increases
83
______________ often contains high concentrations of organic carbon, phosphorus, and nitrogen, and may contain pesticides, toxic chemicals, salts, inorganic solids (e.g., silt), and pathogenic bacteria and viruses.
Municipal wastewater
84
________________, most discharges from municipalities received no treatment whatsoever. Since that time, the population and the pollution contributed by municipal
discharge have both increased, but treatment has increased also.
A century ago
85
A century ago, most discharges from municipalities received _____________ whatsoever. Since that time, the population and the pollution contributed by municipal
discharge have both increased, but treatment has increased also.
no treatment
86
TRUE OR FALSE
A century ago, most discharges from municipalities received no treatment whatsoever. Since that time, the population and the pollution contributed by municipal
discharge have both INCREASED, but treatment has INCREASED also.
TRUE
87
We define a population equivalent of _______________ as equivalent of the amount of
_______________ contributed by a given number of people.
municipal discharge ; untreated discharge
88
The current estimate of the population equivalent of municipal discharges into U.S. surface water is
about _____________, for a population of nearly 300 million.
100 million
89
TRUE OR FALSE
The contribution of municipal discharges
to water pollution HAS NOT decreased significantly in the past several decades, nor has it
SIGNIFICANTLY INCREASED; at least WE ARE NOT FALLING behind.
TRUE
90
TRUE OR FALSE
Agricultural wastes that flow directly into surface waters have a collective population equivalent of
about THREE BILLION
FALSE
Agricultural wastes that flow directly into surface waters have a collective population equivalent of
about TWO BILLION
91
Agricultural wastes are typically high in__________(phosphorus and nitrogen), __________________, _______________, and ___________________
nutrients ; biodegradable organic carbon ; pesticide residues ; fecal coliform bacteria
92
bacteria that normally live in the intestinal tract of warm-blooded animals and indicate contamination by animal
wastes
fecal coliform bacteria
93
_____________ where large numbers of animals are penned into relatively small spaces provide
an efficient way to raise animals for food.
Feedlots
94
They are usually located near slaughterhouses, and thus
near cities.
Feedlots
95
creates an extremely
high potential for water pollution.
Feedlot drainage
96
Aquaculture has a similar problem because wastes are
concentrated in a _________________
relatively small space.
97
______________ has a similar problem because wastes are
concentrated in a relatively small space.
Aquaculture
98
Even relatively ________________ can significantly
degrade water quality if the animals can trample the stream bank, or runoff from manure-holding
ponds is allowed to overflow into nearby waterways.
low densities of animals
99
Even relatively low densities of animals can significantly
________________ if the animals can trample the stream bank, or runoff from manure-holding ponds is allowed to overflow into nearby waterways.
degrade water quality
100
Both ________ and ________ pollution are common in agricultural regions because of the extensiveness of fertilizer and pesticide application.
surface ; groundwater
101
Both surface and groundwater pollution are
common in agricultural regions because of the _______________ and _____________.
extensiveness of fertilizer ; pesticide application
102
Both surface and groundwater pollution are common in _________ because of the extensiveness of fertilizer and pesticide application.
agricultural regions
103
________ and _____ from industrial and mining activities can alter the water quality in a stream or lake to the extent that it kills the aquatic organisms living there or prevents them from reproducing.
Acids ; bases
104
Acids and bases from industrial and mining activities can _____________ in a stream or lake to the extent that it kills the aquatic organisms living there or prevents them from reproducing.
alter the water quality
105
TRUE OR FALSE
Acids and bases from industrial and mining activities can alter the water quality in a stream or lake
to THE EXTENT that IT KILLS THE AQUATIC organisms living there or prevents them from REPRODUCING.
TRUE
106
______________ has polluted surface waters since the beginning of ore mining.
Acid mine drainage
107
Acid mine drainage has polluted surface waters since the beginning of ___________
ore mining.
108
__________________ leached from mines, including old and abandoned mines as well as active ones, contains
compounds that oxidize to sulfuric acid in contact with air.
Sulfur-laden water
109
Sulfur-laden water leached from mines, including old and abandoned mines as well as active ones, contains
______________ that ___________________ in contact with air.
compounds ; oxidize to sulfuric acid
110
_______________________
originating in industrial regions has caused lake acidification throughout vast areas of Canada,
Europe, and Scandinavia.
Deposition of atmospheric acids
111
Deposition of atmospheric acids originating in industrial regions has caused _______________ throughout vast areas of Canada, Europe, and Scandinavia.
lake acidification
112
TRUE OR FALSE
Deposition of atmospheric acids
originating in industrial regions has caused lake acidification throughout vast areas of Canada,
Philippines, and Scandinavia.
False
Deposition of atmospheric acids
originating in industrial regions has caused lake acidification throughout vast areas of Canada,
EUROPE, and Scandinavia.
113
_________________ can adversely affect aquatic ecosystems as well as making the water unusable for human contact or consumption.
Synthetic organics and pesticides
114
These compounds may come from point source industrial effluents or from nonpoint source agricultural and urban runoff.
Synthetic Organics and Pesticides
115
The effects of water pollution can be best understood in the context of an ________________, by studying one or more specific interactions of pollutants with that ecosystem.
aquatic ecosystem
116
Surface water is obviously highly susceptible to _________________.
contamination
117
__________________ is obviously highly susceptible to contamination.
Surface water
118
Surface water has historically been the most
convenient sewer for industry and municipalities alike, while at the same time, it is the source of
the _______________________________
majority of our water for all purposes.
119
These has been such a pervasive surface-water problem, affecting both moving water and still water
oxygen- demanding wastes
120
When biodegradable organic matter is released into a body of water, ______________, especially bacteria, feed on the wastes, breaking them down into simpler organic and inorganic substances.
microorganisms
121
When biodegradable organic matter is released into a body of water, microorganisms, especially bacteria, ________________, breaking them down into ______________ and ____________
feed on the wastes; simpler organic ; inorganic
substances.
122
When biodegradable organic matter is released into a body of water, microorganisms, especially bacteria, feed on the wastes, breaking them down into simpler organic and inorganic substances.
When this decomposition takes place in an aerobic environment that is, in the presence of oxygen the process produces non objectionable, stable end products such as ______, ___________, ___, and _____ .
carbon dioxide, sulfate, orthophosphate, and nitrate .
123
TRUE OR FALSE
When insufficient oxygen is available, the resulting ANAEROBIC decomposition is performed by completely DIFFERENT MICROORGANISMS.
TRUE
124
When insufficient oxygen is available, the resulting anaerobic decomposition is performed by completely different microorganisms. They produce end products that can be highly objectionable, including ___________, _____________ and __________
hydrogen sulfide ; ammonia ; methane
125
ANAEROBIC DECOMPOSITION can be represented by
module - page 3
126
The methane produced is physically stable, biologically degradable, and a potent greenhouse gas. When emitted from bodies of water, it is often called _____________.
swamp gas
127
The methane produced is ____________,___________, and a ______________. When emitted from bodies of water, it is often called swamp gas.
physically stable ; biologically degradable ; a potent greenhouse gas
128
Biochemical Oxygen Demand (BOD)
It is also generated in the anaerobic environment of landfills, where it is sometimes collected and used as an ________________.
energy source.
129
The amount of oxygen required by microorganisms to oxidize organic wastes aerobically is
called the_______________________
biochemical oxygen demand
130
TRUE OR FALSE
biochemical oxygen demand is most often expressed in MILLIGRAMS of OXYGEN required per liter of wastewater (MG/L).
TRUE
131
TWO PARTS OF BOD (biochemical oxygen demand)
the carbonaceous oxygen demand (CBOD) and the nitrogenous oxygen demand (NBOD).
132
The __________ that will be required for biodegradation is an important measure of the impact that a given waste will have on the receiving body of water.
total amount of oxygen
133
it has become standard practice simply to
measure and report the oxygen demand over a shorter, restricted period of ______,
realizing that the ultimate demand may be considerably higher.
five days
134
_______________ is the total amount of oxygen consumed by microorganisms during the first five days of biodegradation.
The five-day BOD
135
The five-day BOD, or (BOD5 ), is the total amount of ___________ consumed by microorganisms
during the _________________________
oxygen ; first five days of biodegradation.
136
It would involve putting a sample of waste into a stoppered bottle and measuring the concentration of dissolved oxygen (DO) in the sample at the beginning of the test and again five days later.
BOD5 TEST
137
The difference in DO divided by the ___________________ would be the five-day BOD.
volume of waste
138
TRUE OR FALSE
LIGHT must be kept out of the bottle to keep algae from adding oxygen by photosynthesis, and the bottle is sealed to keep air from replenishing DO that has been removed by biodegradation.
true
139
To standardize the procedure of BOD5, the test is run at a fixed temperature of _____________
20°C.
140
Since the oxygen demand of typical waste is several hundred milligrams per liter, and the saturated value of DO for water at 20°C is only 9.1 mg/L, it is usually necessary to dilute the sample to keep the final DO _______________.
above zero
141
If during the five days, the DO drops to zero, the test is _________________ because more oxygen would have been removed had more been available.
invalid
142
The five-day BOD of a diluted sample is given by:
BOD5 = (DOi - DOf) / P
143
Dillution fraction ( P) formula:
volume of wastewater divided by the summation of the volume of wastewater and volume of dillution water
144
TRUE OR FALSE
A standard BOD bottle holds 300 mL, so is just the volume of wastewater divided by 300
mL.
TRUE
145
Suppose we imagine a flask with some biodegradable organic waste in it. As bacteria _________, the amount of organic matter remaining in the flask will decrease with time until eventually it all disappears.
oxidize the waste
146
Suppose we imagine a flask with some biodegradable organic waste in it. As bacteria oxidize the waste, the amount of organic matter remaining in the flask will __________ with time until eventually it all ______________.
decrease ; disappears
147
true or false
Another way to describe the organic matter in the flask is to say as time goes on, the amount of organic matter already OXIDIZED goes UP until finally all the
original organic matter has been OXIDIZED.
TRUE
148
We could say that the remaining demand for oxygen to decompose the wastes ________ with time until there is no more demand, or we could say the amount of oxygen demand already exerted, or utilized, starts at zero and rises until all of the original oxygen demand has been satisfied.
decreases
149
We could say that the remaining demand for oxygen to decompose the wastes decreases with time until there is no more demand, or we could say the amount of oxygen demand already exerted, or utilized, starts at ___________ and rises until ____________ has been satisfied.
zero ; all of the original oxygen demand
150
it is assumed that the rate of decomposition of organic wastes is________ to the amount of waste that is left in the flask.
proportional
151
It is assumed that the _____________________________ is proportional to the _______________ that is left in the flask.
rate of decomposition of organic wastes ; amount of waste
152
BODt Formula
BODt = Lo (1-e ^ -kt)
153
graph of Lt Formula
Lt = Loe^-kt
(That is where is the ultimate carbonaceous oxygen demand. It is the total amount of oxygen required
by microorganisms to oxidize the carbonaceous portion of the waste to simple carbon dioxide
and water. The ultimate carbonaceous oxygen demand is the sum of the amount of oxygen
already consumed by the waste in the first days (BODt) plus the amount of oxygen remaining to be consumed after time t )
154
Notice that oxygen demand can be described by the _______________ (you might want to think
of as how much oxygen demand is left at time t )
BOD remaining
155
The _________________ is a factor that indicates the rate of biodegradation of wastes.
BOD reaction rate constant k
156
The BOD reaction rate constant k is a factor that indicates the _____________________ of wastes.
rate of biodegradation
157
BOD reaction rate constant k
As k ________, the rate at which dissolved oxygen is used ________, although the ultimate amount required, Lo , does not change. The reaction rate will depend on a number of factors, including the nature of the waste itself
increases ; increases
158
BOD reaction rate constant k
As increases, the rate at which dissolved oxygen is used increases, although the ultimate amount required, Lo, does not change. The ____________ will depend on a number of factors, including the ___________
The reaction rate ; nature of the waste itself
159
BOD reaction rate constant k
TRUE OR FALSE
(as temperatures INCREASE, SO DOES the rate of biodegradation).
TRUE
160
Some typical values of the BOD reaction rate constant, at 20°C,
Raw Sewage = ____________
Well-treated Sewage = __________
Polluted River Water= ___________
0.35—0.70
0.12—0.23
0.12—0.23
161
Why does raw sewage have a higher rate constant than either well-treated sewage or polluted river water?
because raw sewage contains a larger proportion of easily degradable organics that exert their oxygen demand quite quickly, leaving a remainder that decays more
slowly.
162
TRUE OR FALSE
RAW SEWAGE has a HIGHER rate constant than either well-treated sewage or polluted river water.
TRUE
Raw Sewage 0.35—0.70
Well-treated Sewage 0.12—0.23
Polluted River Water 0.12—0.23
HENCE, Raw Sewage > WTS AND PRW
163
Two other indicators that are sometimes used to describe the oxygen demand of wastes:
1. theoretical oxygen demand (ThOD) and
2. chemical oxygen demand (COD).
164
The ____________________ is the amount of oxygen required to oxidize completely a particular organic substance, as calculated from simple stoichiometric considerations.
theoretical oxygen demand
165
It tends to overestimate the amount of oxygen actually consumed during decomposition for both the carbonaceous and nitrogenous components
Stoichiometric analysis
166
These are organic matters that resist biodegradation.
cellulose, phenols, benzene, and tannic acid,
167
TRUE OR FALSE
Other types of organic matter, such as pesticides and various industrial chemicals, are NONBIODEGRADABLE because they are TOXIC to microorganisms.
TRUE
168
It is a measured quantity that does not depend either on the ability of microorganisms to degrade the waste or on knowledge of the particular substances in question.
The chemical
oxygen demand (COD)
169
In a COD test, a strong ________________ is used to oxidize the organics rather than relying on _______________ to do the job.
chemical oxidizing agent ; microorganisms
170
true or false
The COD test is much QUICKER than a BOD test
TRUE
The COD test is much quicker than a BOD test, taking only a matter of hours.
171
TRUE OR FALSE
You CANNOT USE the COD test as a way to estimate the ultimate BOD.
false
the COD test is SOMETIMES USED as a way to estimate the ultimate BOD.
172
It does not provide any information on the rate at which actual biodegradation will take place.
The chemical
oxygen demand (COD)
173
It does not distinguish between the oxygen demand that will actually be felt in a natural environment due to biodegradation and the chemical oxidation of inert organic matter.
The chemical
oxygen demand (COD
174
TRUE OR FALSE
The measured value of COD is HIGHER than BOD, though for easily biodegradable matter, the two will be similar.
true
