Pune University BE Civil Environmental Engineering-II Question Papers

Pune University BE Civil Environmental Engineering-II Question

Papers

B.E. (Civil) ENVIRONMENTAL ENGINEERING – II (2008 Pattern) (Sem. – I)

Time :3 Hours]                                                                           [Max. Marks :100

Instructions to the candidates:-

1)             Solve Q.1 or 2, Q.3 or 4, Q.5 or 6 from Section -1 and Q.7 or 8, Q.9 or 10, Q.II or 12 from Section – II.

2)            Answer to the two sections should be written in separate answer books.

3)             Neat diagrams must be drawn wherever necessary.

4)             Pigures to the right indicate full marks.

5)             Use of logarithmic tables, slide rule, Mollier charts, electronic pocket calculator and steam tables is allowed.

6)            Assume suitable data, if necessary.

SECTION – I

QIA a) Specify the qualities of a good material for constructing sewers. Judging from these requirements,discuss the suitability of:                                                          [8]

i) Bricks      ii) Cement concrete

i)              Stone ware for sewers.

b) Calculate the velocity of flow and corresponding discharge in a sewer of circular section having diameter equal to I m, laid at a gradient of I in 500. The sewer runs at 0.6 depth. Use Mannings formula taking N = 0.012.                                                      [8]

OR

Q2) a) Differentiate between ‘Oxygen Demand’ and ‘Biochemical Oxygen Demand’? How do you determine BOD? What are the limitations of BOD test?                            [8]

b)            The BOD of sewage incubated for one day at 30°C has been found to be 100mg/l. What will be the 5-day 20°C BOD. Assume K = 0.12 (Base 10) at 20°C. [4]

c)             Give relationship between TOC, COD and BOD.                              [4]

Q3) a) Discuss fully the process of self purification of natural water.                         [6]

b)            The sewage of a town is to be discharged into a river stream. The quantity of sewage produced per day is 8 million liters, and its BOD is 250 mg/l. If the discharge in the river is 200 l/s and if its BOD is 6 mg/l, find out the BOD of the diluted water.                                                                                 [4]

c)             What do you understand by preliminary treatment of wastewater? Enumerate various unit operations falling under this. Also draw flow diagrams for possible arrangements of various units falling under preliminary treatment.                                       [6]

OR

Q4) a) What do you understand by grit chambers? Why it is necessary to provide a grit chamber? Explain the configuration of a grit chamber with the help of neat sketches.     [6]

b)            Design a primary settling tank of rectangular shape for a town having a population of 50,000 with a water supply of 180 liters per capita per day.

[4]

c)            What is the difference between BOD and COD and Give effluent discharge standards as per BIS 2490 for BOD, COD and TS.                                                            [6]

Q5) a) Give the classification of microorganisms based upon

i) Nutritional Requirements ii) Energy Requirements

i) Temperature Range      iv) Oxygen Requirements [4]

b)            Write notes on

i) SVI                                                       ii) F/M ratio

i)   Recirculation     [6]

c)            Design a high rate single stage trickling filter for treating the following wastewater of a town having population of 4000 persons:                                                      [8]

i)             Domestic sewage @ 150 lpcd having 200mg/l of BOD.

ii)           Industrial wastewater @0.25 million litres per day having 600mg/l of BOD.

Assume the following

1)          BOD removal in primary clarifier = 35%

2)           Permissible organic loading of filter = 8000 kg/ hec-m/day (Excluding recirculated sewage)

3)           Recirculation ratio = 1.0

4)           Permissible surface loading = 160mL/hec/day (including recirculated sewage)

Also determine the efficiency of the filter and BOD of the effluent.

OR

Q6) a) State the advantages and disadvantages of a conventional trickling filter. [4]

b)            Explain with neat graph ‘Growth Pattern of microorganisms’                           [6]

c) An average operating data for conventional activated sludge treatment plant is as follows:                                                                                           [8]

i)

Wastewater flow

= 50000 cum/d

ii)

Volume of aeration tank

= 15500 cum

iii)

Influent BOD

= 200mg/l

iv)

Effluent BOD

= 25mg/l

v)

MLSS

= 3000mg/l

vi)

Effluent Suspended solids

= 40mg/l

vii)

Watse sludge suspended solids

= 12000mg/l

viii)

Quantity of waste sludge

= 250cum/d

Based on the information above, determine

1)           Aeration Period (hours)

2)           F/M ratio (kg BOD per day/kg MLSS)

3)           Percentage efficiency of BOD removal

4)            Sludge age (days)

 

SECTION – II

Q7) a) Explain with the help of neat sketch the working of an oxidation ditch.

Distinguish clearly between an intermittent type and a continuous flow type oxidation ditch.                                                                                                                   2[6]

b)            Give advantages 8 disadvantages of oxidation ponds.                       [5]

c)            Distinguish clearly between the working of an ‘oxidation ditch’ and ‘oxidation pond’                                                                                                                     [5]

OR

Q8) a) What do you understand by ‘stabilization Ponds’? Give classification of stabilization ponds.                                                                                                                               [6]

b)            Explain the mechanism of purification in facultative ponds.           [5]

c)            Explain briefly root zone cleaning system.                                          [5]

Q9) a) What do you understand by ‘digestion of sludge’? Differentiate between anaerobic and aerobic digestion, Explain the mechanism of anaerobic digestion.          [8]

b)            Design a septic tank for a hostel housing 125 persons. Also design the soil absorption system for the disposal of the septic tank effluent, assuming the percolation rate as 20 min. per cm. Desludging period once in a year.

[8]

OR

Q10)a) What do you understand by sludge thickening? Enumerate various methods. Describe with the help of sketch gravity sludge thickener. [8]

b) Draw a neat sketch of Up flow Anaerobic Sludge Blanket Reactor (UASBR). Explain the principal of working and comment on its suitability for the treatment of Industrial wastewater.                                                                                                          [8]

QII)Write short note on the following chemical treatments of Industrial wastewaters.

[18]

a)            Reverse osmosis.

b)            Electrodialysis

c)            Chemical Oxidation

d)            Chemical Coagulation

e)            Adsorption

f)             Air – stripping

OR

Q12)Give the range of important characteristics of wastewater from the following industries and draw a suitable flow diagram for treatment of each industry. [18]

a)            Distillery Industry

b)            Sugar Industry

c)            Pulp and paper Industry.

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