Environmental Engineering - 2 - May 2014

MU Civil Engineering (Semester 7)

Total marks: --
Total time: -- INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

Answer any four

1 (2) State the significance of BOD in waste water treatment. 4 marks

1 (3) Name the two factors used as criteria for selection of pipe diameter and slope in design of sewer. 4 marks

1 (4) Define Noise and explain why it should be regarded as an environmental pollutant. 4 marks

1 (5) Enumerate the various sources of air pollution. 4 marks

2 (1) What are traps, and why are they provided? How can the water seal in traps be broken? What methods are to be employed to maintain the seal? 4 marks

2 (2) Explain the various sewer appurtenances used in the sewerage system. 4 marks

3 (1) Explain in detail the dilution method of disposal of sewage. State the oxygen sag curve. 4 marks

3 (2) Differentiate between aerobic and anaerobic treatment of sewage giving major end products. Name one treatment method in each category. 4 marks

4 (1) Calculate the discharge of 1.25m circular sewer laid at a slope of 1 in 360, when it is running half full. Assume n in Manning's formula as 0.011. 4 marks

4 (2) Draw a flow diagram of an activated sludge plant for the treatment of sewage. Discuss the role of return sludge. 4 marks

5 (1) Design a septic tank for a hostel of 250 inmates with average daily sewage flow of 120 liters per head. Detention period is 30 hours. Cleaning interval is 6 months. Draw a neat sectional sketch showing all details. 4 marks

5 (2) Discuss the stage of biological action constituting sludge digestion. 4 marks

6 (1) Define sludge bulking and explain causes of sludge bulking. 4 marks

6 (2) Determine the size of a high rate trickling filter for the following data
sewage flow =4 MLD . Recirulation ration=1.3 BOD of raw sewage=300 mg/l
BOD removal in Primary tank=25% final effluent BOD desired=30 mg/l 4 marks

7 (1) Explain the causes, effects and control measures of Air pollution. 4 marks

7 (2) Explain factors affecting self purification of stream. 4 marks