Environmental Engineering

Name: _______________________________________

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Final Exam – CE 2633: Environmental Engineering Due December 11 noon, 2009

NO DISCUSSION, NO TEAM WORK Multiple Choice (50 points – 5 points per question, circle all that apply)

1. Which of the following statements are true concerning the Safe Drinking Water Act secondary standards?

a. They are enforceable. b. They are for compounds which make drinking water aesthetically pleasing

to consumers. c. They enable drinking water to be potable. d. They enable drinking water to be palatable. e. All of the above.

2. A pollutant which degrades according to the equation dC/dt = -kC is said to react

according to? a. Zero order kinetics. b. First order kinetics. c. Second order kinetics. d. None of above. e. All of the above.

3. Recarbonation is necessary in drinking water treatment because:

a. The chemicals added during water treatment reduce the pH. b. The chemicals added during water treatment increase the pH. c. The chemicals added during water treatment consume carbon dioxide. d. All of the above e. None of the above

4. If the current mineral reserve of iron is 65,400 Tg, the annual demand is 1060 Tg

and we assume the demand increases 1.2% annually, how long will the reserve last?

a. 62 years b. 73 years c. 55 years d. 46 years e. None of the above

5. A solution that has a [OH-] concentration of 10-3 M has a pH of

a. 11 b. 7 c. 3 d. 10 e. -3 f. 12

 

 

Name: _______________________________________

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6. A dual media rapid sand filter used what two types of porous media for screening

of small-sized particulate matter a. Anthracite coal b. Garnet c. Gravel d. Sand e. Clay

7. The unit process that is used primarily for the removal of settleable solids such as

coffee grinds and sand is: a. Comminutor b. Primary settling tank c. Grit chamber d. Secondary clarifier e. Bar screen

8. The hardness of water is most commonly due to the presence of

a. CO3 2-

b. HCO3 –

c. Ca2+ d. Mg2+ e. Cl- f. All of above g. None of the above

9. The single-most important purpose of secondary treatment is

a. Removal of suspended solids b. Removal of suspended BOD c. Removal of soluble BOD d. Denitrification e. Nitrification f. All of above

10. The purpose of disinfection in drinking water treatment is/are concentration of 10-

a. Kill pathogens b. Keep residual chlorine to the end point of the consumer c. More palatable water d. Prevent disinfection by-products e. Reduce the turbidity

 

 

 

Name ____________________________Student No. ____________________________

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Short Answers (10 points – 10 points per question) 1) Below (in problems I-VII) are listed the abbreviations for several of the major regulations discussed in CE 2633 and the major topics covered by these regulations. Match the regulation with its description.

___I. SARA A) established primary regulations for the protection of public

health and secondary regulations related to the esthetic properties of drinking water

___II. RCRA B) provides for liability, compensation, cleanup and emergency response for hazardous substances released into the environment and for the cleanup of inactive hazardous waste disposal sites

___III. HSWA C) control of waterborne toxic substances and formation of NPDES permits

___IV. CAA D) directed the US EPA to establish hazardous waste regulations which define, classify and regulate the generation and disposal of hazardous wastes

___V. SDWA E) created, in part, in response to concerns that existing methods of hazardous waste disposal were not safe; sets restrictions on the land disposal of specific wastes (commonly referred to as the “Land Ban”)

___VI. CERCLA F) reaffirmed previously enacted legislation; clearly a preference for remediation technologies that rendered a waste nonhazardous (rather than just transferring it from one disposal site to another or simple containment on site)

___VII. CWA G) established the NAAQS, required states to submit SIPs that would show how they would meet these standards; required NSPS to be established which would limit emissions from certain types of industrial facilities.

2) Define the following terms

 

a) Steady state condition b) Conservative pollutant

 

 

 

Name ____________________________Student No. ____________________________

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3) Draw a schematic of a typical secondary wastewater treatment plant using activated sludge treatment. Indicate where sludge are produced and where gases are added

4) What is “purple pipe”? (Guest speaker lecture) 5) What is nitrification and denitrification? (List chemical reactions too)

 

 

 

Name ____________________________Student No. ____________________________

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6) List five of six major air pollutants for which the US EPA has designated air quality standards.

7) Identify the water treatment process (from the list below) that is most likely to be used to (hint: you only need to pick 4 out of 12 choices):

i) protect the general public from dental caries _____ ii) remove turbidity _____ iii) protect the general public from waterborne diseases ____ iv) reduce the pH following softening ____

A) softening B) flocculation/ coagulation C) alkali addition D) recarbonation E) disinfection F) bar screens G) low-lift pumps H) high lift pumps I) fluoridation J) distribution K) filtration

L) activated sludge

8) There are two sludge treatment processes, one use sludge retention time of 3 days (θc=3 days), they other use sludge retention time of 10 days (θc=10 days), which process cost more for sludge proposal? And why?

 

 

 

Name ____________________________Student No. ____________________________

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9) If a hazard index is 0.001 (HI=0.001), what does this number mean to you as an environmental engineer? (For example, is there any potential healthy effect?)

10) Among alpha, beta, gamma and x-ray, what are the most dangerous internal radiation

hazards? Why?

 

 

Name ____________________________Student No. ____________________________

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Part III – Problems Problem 1 – Alkalinity (40 points) A water has a pH of 5.66 and the concentration of HCO3

– is 0.658 mg/L. What is the exact alkalinity of the water in units of mg/L as CaCO3?

 

 

Name ____________________________Student No. ____________________________

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Problem 2 – Water quality in river (60 points) Using the data given below: a) calculate the DO deficit just after mixing of the plant waste water with the water in the river. b) calculate the time (days) required for the deficit to reach its maximum value Deadly Chemical Plant Babbling Run (upstream from outfall) Flow, m3/s 0.33 5.67 ult-BOD at 20 oC, mg/L 450 1.05 DO, mg/L 0.0 8.3 kd, at 20

oC, day-1 N/A 0.22 kr, at 20

oC, day-1 N/A 0.78 speed, m/s N/A 0.55 T, oC 20 20 DOsat, mg/L, 20

oC N/A 9.17 N/A = not applicable