Deck 22: Microbiology of the Built Environment

Question 1

The goal of wastewater treatment is to

A) produce potable water.
B) remove pathogens from wastewater before it is released.
C) reduce organic and inorganic materials in wastewater to a level that no longer supports microbial growth.
D) remove pathogens from wastewater to produce potable water.

Answer 1

C

Question 2

The use of ________ to treat drinking water, which began in 1913, reduces the incidence of waterborne diseases.

A) coagulation
B) chlorination
C) filtration
D) UV irradiation

Answer 2

B

Question 3

Effluent water is wastewater

A) discharged from the pharmaceutical, plastics, and petrochemical industries.
B) discharged from the wastewater treatment facility.
C) that has undergone anoxic secondary wastewater treatment.
D) that is imported to the wastewater treatment facility for treatment.

Answer 3

B

Question 4

Microbes are involved in which step(s) of wastewater treatment?

A) primary only
B) secondary and tertiary
C) secondary only
D) primary and secondary

Question 5

Which of the following bacterial pathogens is found in water distribution systems?

A) Enterobacter aerogenes
B) Klebsiella pneumoniae
C) Legionella pneumophila
D) Vibrio cholerae

Question 6

With increased levels of oxidizable materials, the biochemical oxygen demand (BOD) will

A) increase.
B) decrease.
C) remain the same.
D) increase or decrease depending on the nature of the materials involved.

Question 7

Which process produces a gaseous product that can be used as fuel to provide heat or power for a wastewater treatment plant?

A) trickling filter secondary wastewater treatment
B) aerobic secondary wastewater treatment
C) anaerobic secondary wastewater treatment
D) primary wastewater treatment

Question 8

Water distribution systems contain

A) very few bacteria or other microorganisms.
B) biofilms that may harbor opportunistic pathogens.
C) numerous grazing protists that consume bacteria.
D) biofilms that may harbor opportunistic pathogens and numerous grazing protists that consume bacteria.

Question 9

Opportunistic pathogens such as Legionella, Pseudomonas, and Mycobacterium species have the ability to grow within ________, which may enhance their ability to survive in water distribution systems.

A) human saliva
B) fish
C) protists
D) UV irradiated water

Question 10

Water leaving an efficient wastewater treatment facility ideally has a biochemical oxygen demand (BOD) between ________ units.

A) 50 and 100
B) 25 and 50
C) 5 and 25
D) 0 and 5

Question 11

What is the advantage of enhanced biological phosphorus removal (EBPR) over chemical precipitation?

A) Chemical precipitation produces sludge containing arsenic.
B) EBPR removes significantly more phosphorus than chemical precipitation.
C) Significantly less sludge is produced by EBPR compared to chemical precipitation.
D) EBPR is a more stable process.

Question 12

Secondary disinfection of drinking water is necessary to

A) maintain sufficient residual in the water distribution system to inhibit microbial growth.
B) prevent the formation of biofilms on pipes in the water distribution system.
C) neutralize taste- and odor-producing organic compounds.
D) kill Cryptosporidium and other resistant pathogens.

Question 13

Microbes are sometimes used in secondary treatment of wastewater to

A) convert heavy metals into carbon dioxide.
B) remove organic matter.
C) remove large particles.
D) convert heavy metals into carbon dioxide, remove organic matter, and remove large particles.

Question 14

Aerobic secondary treatment is usually best for ________ wastewater.

A) industrial
B) agricultural
C) residential
D) chemical

Question 15

To further reduce the possibility of biological contamination, most treatment plants treat the effluent with

A) fluorine.
B) chlorine.
C) ozone.
D) extreme heat.

Question 16

While wastewater is in an activated sludge tank, much of the organic matter is

A) oxidized.
B) adsorbed to the floc.
C) incorporated into microbial cells.
D) oxidized, adsorbed to the floc, and incorporated into microbial cells.

Question 17

Which product of anoxic sewage treatment can be used to heat and power an entire water treatment facility?

A) CO₂
B) H₂
C) CH₄
D) O₂

Question 18

Which statement BEST describes sewage and wastewater?

A) Wastewater is a subset of sewage.
B) Sewage is a subset of wastewater.
C) Wastewater and sewage are virtually synonymous.
D) Wastewater and sewage are both subsets of all liquid effluents from domestic and industrial sources.

Question 19

Which treatment method(s) are used in primary wastewater treatment?

A) biological
B) chemical
C) physical separation
D) biological, chemical, and physical separation

Question 20

During secondary aerobic wastewater treatment, some of the activated sludge goes ________ while the rest goes ________.

A) back to the aerator / to the anoxic sludge digester
B) back to the primary system / to the aerator
C) to the anoxic digester / back to the primary system
D) back to the primary system / to the tertiary digester

Question 21

Which group of organisms is thought to be responsible for the corrosion of submerged metal structures and pipelines?

A) fermentative microorganisms
B) acidophilic iron-oxidizers
C) sulfate reducers
D) hydrocarbon-degrading anaerobes

Question 22

The goal of tertiary wastewater treatment is to sharply reduce the levels of ________ from the final effluent.

A) organic compounds
B) heavy metals
C) methane
D) inorganic nutrients

Question 23

Microbial immobilization is the best strategy for uranium bioremediation, because

A) uranium is difficult to chemically oxidize.
B) uranium contamination is widespread and thus difficult to physically remove.
C) the by-products of chemical immobilization are toxic.
D) immobilization may only be temporary.

Question 24

To prevent the souring of crude oil, ________ is added to oil well injection water to encourage ________ instead of ________.

A) oxygen / aerobic respiration / sulfate reduction
B) sulfate / sulfate reduction / fermentation
C) sulfate / sulfate reduction / nitrate reduction
D) nitrate / nitrate reduction / sulfate reduction

Question 25

Treatment of drinking water by UV irradiation is effective at ________, but is less effective at ________.

A) killing bacteria and some cysts / killing iruses
B) killing viruses / killing bacteria and eukaryotic pathogens
C) removing order- and taste-altering organic compounds / killing bacteria
D) killing bacteria and viruses / killing eukaryotic pathogens

Question 26

Which of the following hydrocarbon compounds are most recalcitrant to degradation during bioremediation, meaning that they stay in the environment longer than the others?

A) straight-chain hydrocarbons
B) methane
C) polycyclic hydrocarbons
D) natural gases such as ethane and propane

Question 27

Crown corrosion of concrete wastewater distribution systems is the result of

A) acidic fermentation products reacting with the gypsum in the concrete.
B) sulfate reduction in the sewage and sulfide oxidation in the oxic headspace above.
C) fungal growth in the concrete.
D) rapid iron reduction coupled to pyrite dissolution.

Question 28

Which of the following can be completely degraded to carbon dioxide by microorganisms?

A) petroleum
B) uranium
C) chlorinated organics
D) petroleum and chlorinated organics

Question 29

The propagation cycle that occurs in acid mine drainage is caused by

A) reduction of Fe³⁺ by sulfuric acid.
B) the oxidation of sulfide to sulfuric acid by microbial oxidation of iron (Fe³⁺).
C) microbial sulfate reduction.
D) low pH and high oxygen concentrations.

Question 30

Synthetic plastics are

A) oxidized completely to carbon dioxide after a few years under aerobic conditions.
B) slower to degrade than microbial plastics.
C) constructed from PHAs.
D) more expensive than microbial plastics.

Question 31

Microbial plastics are composed of

A) polysaccharides.
B) Polyhydroxyalkanoates (PAHs).
C) polyaromatic hydrocarbons.
D) xenobiotics.

Question 32

Why are some xenobiotics biodegraded slower than crude oil and petroleum products?

A) Xenobiotics were designed to inhibit microbial growth.
B) Some xenobiotics are novel compounds that differ from naturally occurring chemicals, thus microorganisms have not yet evolved to effectively degrade them.
C) Only cometabolic microbial processes degrade xenobiotics.
D) Chlorinated compounds are so toxic that biodegradation is not possible.

Question 33

What chemical initiates the formation of acid mine drainage when pyrite is not disposed of properly?

A) O₂
B) Fe²⁺
C) HS⁻
D) SO₄²⁻

Question 34

What role does Acidithiobacillus ferrooxidans play in the copper leaching process?

A) oxidation of sulfide to sulfate
B) reduction of oxidized iron (Fe³⁺) to reduced iron (Fe²⁺)
C) oxidation of reduced iron (Fe²⁺) to oxidized iron (Fe³⁺)
D) reduction of sulfate to sulfide

Question 35

Bioremediation of uranium depends on

A) fermentation and oxidation.
B) methanogens.
C) metal-reducing bacteria.
D) sulfur-oxidizing bacteria.

Question 36

Reductive dechlorination is important in the breakdown of chlorinated xenobiotics because

A) anoxic conditions develop rapidly in polluted habitats and reductive dechlorination can take place in these conditions.
B) reductive dechlorination breaks down all halogen compounds.
C) aerobic breakdown of xenobiotics is not possible under any circumstances.
D) these compounds do not leach into groundwater or sediment.

Question 37

Which of the following is the first, or initiator, reaction in acid mine drainage and leaching?

A) oxidation of reduced sulfides to sulfate and the release of reduced iron (Fe²⁺)
B) rapid spontaneous reduction of oxidized iron (Fe³⁺)
C) rapid oxidation of sulfides to sulfate by oxidized iron (Fe³⁺)
D) microbial sulfate reduction

Question 38

The production of ________ by ________ is thought to be a major contributor to the biodeterioration of stone building materials.

A) oxalic acid / fungi
B) sulfuric acid / sulfate reducers
C) nitric acid / nitrate reducers
D) carbonic acid / lichens

Question 39

Based on your knowledge of hydrocarbon degradation, what factors most likely limited the rate of petroleum degradation after the Exxon Valdez oil spill off the coast of Alaska?

A) salt concentration
B) temperature
C) inorganic nutrient concentrations
D) temperature and inorganic nutrient concentrations

Question 40

Reductive dechlorination is a process in which

A) oxygenase enzymes are used to add oxygen to chlorinated compounds.
B) chlorinated organics are used as terminal electron acceptors in anaerobic respiration, releasing chloride.
C) carbon dioxide is the primary end product.
D) only dichlorocompounds can be degraded.

Question 41

Chlorinated xenobiotics can ONLY be degraded aerobically, thus making them very recalcitrant if they accumulate in anoxic environments.

Question 42

Inorganic pollutants such as metals and radionuclides can be completely destroyed through bioremediation.

Question 43

Subway air and water distribution systems harbor dangerous levels of pathogenic microorganisms.

Question 44

BOTH physical and chemical methods are used to treat and purify drinking water.

Question 45

Wastewater plants are usually constructed to handle both domestic and industrial wastes.

Question 46

Secondary treatment may be aerobic or anoxic.

Question 47

Metal-reducing Geobacter and Shewanella species are important in the microbial mining of metals.

Question 48

Although the sulfate-reducing bacteria are thought to be critical in the corrosion of metal structures, the mechanism of metal corrosion is not well understood.

Question 49

It is possible to completely eliminate pathogens from water if sufficient amounts of chlorine are used.

Question 50

Organisms that degrade hydrocarbons in crude oil are ubiquitous in the environment and have evolved special strategies, such as surfactant production, that allow them to readily use hydrocarbons as electron donors and carbon sources.

Question 51

most wastewater treatment facilities employ methods designed to detect each pathogenic organism that may be present in a given sample.

Question 52

Natural underground pyritic deposits that are not disturbed by mining activities do not form acidic drainage waters. Why not? Explain the critical steps in the formation of acid mine drainage in your answer.

Question 53

Potable water is NOT safe for human consumption.

Question 54

In water, most taste- and odor-producing compounds are inorganic in nature.

Question 55

Fungi are the main contributor to the biodeterioration of stone building materials and concrete wastewater distribution systems.

Question 56

What microbial processes are involved in the bioremediation of organic pollutants such as hydrocarbons and the bioremediation of inorganic pollutants such as uranium? What are the end products of bioremediation for hydrocarbons and uranium?

Question 57

Water disinfection agents such as chlorine can easily kill Cryptosporidium.

Question 58

Chlorine is consumed when it reacts with organic materials.

Question 59

Bioremediation of uranium depends on metal-reducing bacteria to change the oxidation state of the uranium to form insoluble uranium compounds.

Question 60

Pyrite (FeS₂) is common in bituminous coal and metal ores and is a critical component of the microbial leaching of ores and acid mine drainage.

Question 61

If you were in charge of preserving ancient stone ruins and sculptures in an outdoor environment, what strategies would you use to prevent deterioration of the stone?

Question 62

Describe floc formation in the activated sludge process.

Question 63

What is souring of crude oil and how does the petroleum industry control it?

Question 64

Describe the general processes that occur in a sludge digester. What is an advantage of sludge digestion over activated sludge?

Question 65

Compare the operation and function of a trickling filter system and activated sludge.

Question 66

Which microorganisms commonly thrive in drinking water distribution systems and how might they impact human health?