Q: Which of the following equations best represents the aerobic degradation of organic matter during secondary treatment?

$$\mathrm{C_6H_{12}O_6$} + 6\,O_2$ \rightarrow 6\,CO_2$ + 6\,H_2O + \text{energy}$$

Question 1

Which of the following best describes the primary goal of the coagulation step in water purification?

Accepted Answer

To aggregate suspended particles into larger flocs for easier removal

Question 2

A water sample is tested for coliforms as an indicator organism. Why are coliforms used for this purpose?

Accepted Answer

They are commonly found in the human gut and persist in water longer than many pathogens

Question 3

Which of the following contaminants is most likely to cause eutrophication if not removed during wastewater treatment?

Accepted Answer

Inorganic nutrients such as nitrogen and phosphorus

Question 4

During secondary wastewater treatment, which process is responsible for the biological removal of dissolved organic matter?

Accepted Answer

Trickling filters

Question 5

Which of the following equations best represents the aerobic degradation of organic matter during secondary treatment?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + 6\,O_2$ ightarrow 6\,CO_2$ + 6\,H_2O + 	ext{energy}$$

Question 6

A patient develops severe gastrointestinal illness after drinking contaminated water. Which EPA-listed microbial contaminant is most likely responsible if the patient also develops kidney failure?

Accepted Answer

E. coli O157:H7

Question 7

Which step in municipal water treatment is primarily responsible for removing 99% of bacteria?

Accepted Answer

Rapid sand filtration

Question 8

A trickling filter in a wastewater treatment plant is malfunctioning. Which of the following is the most likely consequence?

Accepted Answer

Increased levels of dissolved organic matter in the effluent

Question 9

Which of the following best explains why anaerobic digestion is used in wastewater treatment?

Accepted Answer

It stabilizes sludge and produces methane for energy

Question 10

A city is experiencing groundwater contamination due to failing home treatment systems. Which system is most likely responsible?

Accepted Answer

Septic tanks

Question 11

Which of the following is a major challenge for future water purification efforts as described in the study materials?

Accepted Answer

Providing clean water and wastewater treatment for a growing global population

Question 12

Which of the following is NOT a typical process in tertiary wastewater treatment?

Accepted Answer

Physical removal of large solids

Question 13

Which contaminant is most likely to cause toxic effects to all trophic levels if discharged into rivers and streams?

Accepted Answer

Heavy metals

Question 14

Which of the following best describes the function of biofilms in a trickling filter system?

Accepted Answer

They degrade organic waste as water passes over them

Question 15

Which process is most effective at removing viruses from wastewater?

Accepted Answer

Tertiary treatment with chemical or physical inactivation

Question 16

A water sample passes through the following steps: settling, coagulation, sedimentation, filtration, and disinfection. Which step is most responsible for the removal of protozoan cysts?

Accepted Answer

Filtration

Question 17

Which of the following is a correct sequence of steps in municipal water purification, as shown in the provided diagram?

Accepted Answer

Coagulation → Sedimentation → Filtration → Disinfection

Question 18

Which of the following best explains why granular sludge is important in wastewater treatment?

Accepted Answer

It increases the rate of flocculation and reduces the space required for sludge processing

Question 19

Which EPA-listed waterborne pathogen is most likely to cause primary amoebic meningoencephalitis?

Accepted Answer

Naegleria fowleri

Question 20

Which of the following best describes the main function of secondary treatment in wastewater processing?

Accepted Answer

Biological conversion of dissolved organic matter into microbial biomass and carbon dioxide

Water Purification and Wastewater Treatment in Microbiology

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