Q: Which equation best represents the calculation of biochemical oxygen demand (BOD) in a water sample?

$$\text{BOD} = \text{Initial DO} - \text{Final DO}$$

Question 1

Which process in wastewater treatment primarily relies on physical separation to remove solid and particulate organic and inorganic materials from wastewater?

Accepted Answer

Primary treatment

Question 2

What is the main goal of reducing the biochemical oxygen demand (BOD) in wastewater treatment?

Accepted Answer

To lower organic and inorganic materials so microbial growth and toxic materials are minimized

Question 3

During secondary aerobic wastewater treatment, which process is most commonly used to decompose organic matter?

Accepted Answer

Activated sludge and trickling filter

Question 4

Which microorganism is specifically noted for its role in bioremediation of chlorinated solvents in groundwater for up to 4 years?

Accepted Answer

Dehalococcoides

Question 5

In the activated sludge process, what is the function of slime-forming bacteria such as Zoogloea ramigera?

Accepted Answer

They form flocs that aggregate organic matter for easier removal

Question 6

Which of the following is NOT a step in typical drinking water purification?

Accepted Answer

Anaerobic digestion

Question 7

Why is tertiary wastewater treatment not widely adopted despite being the most complete method?

Accepted Answer

It is costly compared to other methods

Question 8

Which equation best represents the calculation of biochemical oxygen demand (BOD) in a water sample?

Accepted Answer

$$	ext{BOD} = 	ext{Initial DO} - 	ext{Final DO}$$

Question 9

Which of the following is a major problem associated with water distribution systems?

Accepted Answer

Promotion of growth of opportunistic pathogens

Question 10

What is the primary reason sexually transmitted diseases are unlikely to be transmitted via toilet aerosols?

Accepted Answer

They are sensitive to drying and die before transmission

Question 11

Which process uses phosphorus-accumulating organisms and sequential passage through anaerobic and aerobic bioreactors for phosphorus removal?

Accepted Answer

Enhanced biological phosphorus removal (EBPR)

Question 12

Which of the following is a contaminant of emerging concern in wastewater treatment?

Accepted Answer

Pharmaceuticals and personal care products

Question 13

Why is it impossible to completely eliminate microbial growth in water distribution systems?

Accepted Answer

Complete nutrient removal and perfect chlorine maintenance cannot be achieved

Question 14

Which opportunistic pathogen is commonly found surviving and growing within protists in water distribution systems?

Accepted Answer

Legionella pneumophila

Question 15

What is the role of biostimulation in bioremediation of contaminated groundwater?

Accepted Answer

Using molasses to trigger growth of native microorganisms

Question 16

Which of the following best describes 'gray water'?

Accepted Answer

Water resulting from washing, bathing, and cooking

Question 17

Which step in drinking water purification is responsible for removing aggregates formed during coagulation?

Accepted Answer

Sedimentation

Question 18

What is the main reason wastewater treated by secondary methods is not yet potable?

Accepted Answer

It may still contain pathogens and chemicals unsafe for human consumption

Question 19

Which of the following is a real-world consequence of the microbiota inhabiting homes and public spaces?

Accepted Answer

Potential for increased exposure to pathogens and decreased overall exposure leading to allergies

Question 20

Which of the following is a plausible reason for the selection of more pathogenic or resistant bacteria in water distribution systems?

Accepted Answer

Incomplete nutrient removal and suboptimal chlorine levels

Microbiology of the Built Environment: Wastewater, Water Treatment, and Indoor Microbiota

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