ENVE3503 – Environmental Engineering
Candidate Exam Questions for Section 5, Drinking Water Treatment
1. Define and contrast palatable and potable water.
2. List the five classes of materials regulated under National Primary Drinking Water Standards.
3. List the three classes of microorganisms and a disease caused by each class as regulated by National Primary Drinking Water Standards.
4. Explain what indicator organisms are and how they are applied in regulating drinking water supplies.
5. Explain what turbidity is and why it is regulated as part of the microorganism classification of the National Primary Drinking Water Standards.
6. Provide an example of an inorganic chemical contaminant, an organic chemical contaminant and a radionuclide contaminant.
7. Describe the objective of the National Secondary Drinking Water Standards and provide an example of one attribute that is regulated in this manner.
8. How do are Primary/Secondary and enforceable/non-enforceable standards and the palatable/potable question related.
9. What are MCLs and MCLGs and how do they differ?
10. Consider a ‘plain vanilla’ drinking water process train seeking to remove turbidity and microbial contaminants from raw water.
a. Illustrate and label the process train.
b. For each of the 5 processes utilized describe its objective and how that objective is achieved.
11. For disinfection with chlorine,
a. Write the equilibrium expression for dissolution of chlorine in water, identify the more potent disinfectant agent present and the pH range where that agent would be present in the greatest relative abundance.
b. Describe how (a) Chick’s Law and (b) the Ct/It approach are used to design a disinfection system.
c. Explain what residual chlorine is and describe its importance in drinking water treatment.
d. What are DBPs? THMs? How are they formed, what is their significance in drinking water supply and how can their formation be minimized.
12. What is hardness? What problems does it cause in a water supply? Describe the manner in which hardness is removed from water in (a) a municipal supply, (b) a home supply.
13. What contaminants are removed when an activated carbon unit is added to the drinking water process train? What is activated carbon and how does it work?
14. How are membrane processes used to remove contaminants from raw water? What is the design variable that determines which contaminants will be removed? What is the ‘consequence’ or expense of seeking to remove progressively smaller targets (e.g. salt ions)?
15. Describe the manner in which ion exchange is used to remove hardness from water. Explain the process of recharge in an ion exchange system.
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