Bengal Engineering and Science University 2007 B.E Civil Engineering Environmental Engineering-I - Question Paper
the ques. paper is with the attachment.
Ex/BESUS/ CE- 606/07 B.E. (CE) Part-Ill 6th Semester Examination, 2007
Environmental Engineering-I (CE-606)
Full Marks : 100
Time : 3 hours
Use separate answerscript for each half.
Answer SEX questions, taking THREE from each half.
Two marks in First half & Half Mark in Second half are reserved for neatness. Assume any data, if required. reasonably.
1. a) What is prms for sound? What is sound pressure level? What is the sound pressure level generated by a sound source with intensity of 9.9 x 10-9 W/m ? If five similar sources generate sound generate simultaneous sound
o 2
with same intensity of 9.9 x 10~ W/m , find the resultant sound level.
b) What are dbA and dbC for noise level measurement?
c) What is Leq in connection with noise level measurement? The following noise level measurements were taken in a locality.
| ||||||||||||||
|
eq- |
Calculate the L
(8+3+5)
2. a) In which layer of the earth's atmosphere is the ozone layer found? How the ozone layer acts as a shield against solar UV radiation? Why the chlorofluorocarbons are considered to be damaging for the ozone layer?
-j b) How acid rain is caused? Why acid rain is a cause for concern?
c) Name at least four gases that are responsible for global warming. (6+6+4)
a) If the biomass of each trophic level is put together, it assumes the form of a pyramid; i.e. biomass decreases as we go up the food chain. Explain the reason.
b) In any ecosystem, the food chain is normally limited within few trophic levels. Why there cannot be too many trophic levels in any ecosystem?
c) Write a scenario of what would happen to an ecosystem or to the human system in the event of all decomposers and detritus feeders are eliminated.
(6+6+4)
4. a) A large number of fish are suddenly found floating dead on a lake. You are
called to investigate the problem. You find an abundance of phytoplankton and no evidence of toxic dumping. Suggest a reason for the fish kill.
b) Why is it important to preserve biodiversity?
c) Explain bioaccumulation and biomagnification as related to chemical pesticides.
(5+5+6)
5. a) What is adiabatic lapse rate? If the environmental (ambient) lapse rate is
6C per km, how is the stability of the environment characterised? What is inversion in the context of environmental lapse rate?
b) Scrubbers can be used for removal of S02. Name a suitable chemical that can be used for this purpose. Also write pertinent chemical equation.
c) Show a schematic sketch of a cyclone separator and briefly explain its operation.
(6+4+6)
SECOND HALF
6. a) What are the quality parameters for drinking water? What is their significance
as drinking water quality standards?
b) Tests for common ions are run on a sample of water and the results are shown below. Draw the bar diagram and calculate total hardness, calcium hardness, magnesium hardness, temporary hardness, permanent hardness, carbonate hardness, non-carbonate hardness, sulfate hardness and chloride hardness. Constituents : Ca2+= 60 mg/L; HC03-= 180 mg/L; Mg2+=24 mg/L; S042' = 63 mg/L; Na+ = 65 mg/L; Cl = 91.5 mg/L. And concentration of C02 (g) = 20 mg/L. J8*/2+8J
7. a) What are the different types of solids that may present in water? How they
are related to turbidity.
b) What are the alpha and beta particles? What are their units of measurements? What are their impacts on environment?
c) If 5 gram of acetic acid (CH3COOH) is added to enough distilled water to make 1 liter of solution, what will be the acetate ion concentration and pH of the solution? KA = 1.75 x 10-5. \4'A+6+6\
8. a) Write short notes on Arsenic problem in India and Bangladesh.
b) A sample of water from the overflow of the recarbonation basin that follows a precipitation/softening process has a pH of 9.0; 200 mL of the water require
3.1 mL of 0.02 N H2S04 to titrate it to the phenolphthalein endpoint and additional 22.9 mL of 0.02 N H2S04 to titrate it further to the orange endpoint. Asuming the sample contains no calcite particles, what are phenolphthalein alkalinity and the total alkalinity in mg/L as CaC03? At what concentration of different 'alkalinity causing species' are present in the sample?
c) What is Kjeldahl nitrogen? Why nitrite and nitrate tests are important in a waste water treatment plant? |5+6'/2+5|
9. a) What are basic diferences between BOD and COD? Explain with diagram
the 1st stage and 2nd stage BOD. Why usually 5 day BOD at 20C is considered as standard?
b) Describe the different zones of DO sag curve.
c) The BODs at 27C of a waste has been measured as 600 mg/1. If k = 0.23/day at 20C, what is the ultimate BOD of the waste. What proportion of the ultimate BOD would remain unoxidised after 17 days? Given Temperature of waste is 30C. [6V4+4-t-6l
10. a) What are the management procedure of Bio-medical waste and Industrial
solid waste?
b) Draw a flow-chart of the modern management system (treatment and disposal only) of Municipal Solid Waste.
c) Estimate the moisture content, density and energy content (as discarded and dry) of a solid waste sample that has following components.
|
Component |
% by mass |
Moisture content (%) |
Typical Density (kg/m3) |
Energy content (kJ/Kg) |
|
Food waste |
50 |
70 |
290 |
4650 |
|
Paper |
30 |
6 |
85 |
16750 |
|
Plastics |
8 |
3 |
65 |
32600 |
|
Yard waste e*-1 |
12 |
60 |
105 |
6500 |
8. a) Write short notes on Arsenic problem in India and Bangladesh.
b) A sample of water from the overflow of the recarbonation basin that follows a precipitation/softening process has a pH of 9.0; 200 mL of the water require
3.1 mL of 0.02 N H2S04 to titrate it to the phenolphthalein endpoint and additional 22.9 mL of 0.02 N H2S04 to titrate it further to the orange endpoint. Asuming the sample contains no calcite particles, what are phenolphthalein alkalinity and the total alkalinity in mg/L as CaC03? At what concentration of different 'alkalinity causing species' are present in the sample?
c) What is Kjeldahl nitrogen? Why nitrite and nitrate tests are important in a waste water treatment plant? |5+6'/2+5|
9. a) What are basic diferences between BOD and COD? Explain with diagram
the 1st stage and 2nd stage BOD. Why usually 5 day BOD at 20C is considered as standard?
b) Describe the different zones of DO sag curve.
c) The BOD5 at 27C of a waste has been measured as 600 mg/1. If k = 0.23/day at 20C, what is the ultimate BOD of the waste. What proportion of the ultimate BOD would remain unoxidised after 17 days? Given Temperature of waste is 30C. [6'/i+4+6|
10. a) What are the management procedure of Bio-medical waste and Industrial
solid waste?
b) Draw a flow-chart of the modern management system (treatment and disposal only) of Municipal Solid Waste.
c) Estimate the moisture content, density and energy content (as discarded and dry) of a solid waste sample that has following components.
|
Component |
% by mass |
Moisture content (%) |
Typical Density (kg/m3) |
Energy content (kJ/Kg) |
|
Food waste |
50 |
70 |
290 |
4650 |
|
Paper |
30 |
6 |
85 |
16750 |
|
Plastics |
8 |
3 |
65 |
32600 |
|
Yard waste e*-1 |
12 |
60 |
105 |
6500 |
[6+5'/2+51
|
Attachment: |
| Earning: Approval pending. |
