Test Papers / Previous Question Papers of IGNOU ET507B Waste Water Treatment December 2005

B.Tech. Civil (Construction Management) / B.Tech. Civil (Water Resources Engineering)
Term-End Examination

December, 2005

ET-507(B) : WASTE WATER TREATMENT

Time: 3 hours
Maximum Marks: 70

1. (a) Name the types of solids present in waste water. How would you determine the amount of suspended solids present in waste water ? (7)

(b) Differentiate between B.O.D. and C.O.D. Why is C.O.D. of sewage sample always higher than its B.O.D. ? (7)

2. (a) Describe the various tests normally conducted to ascertain the soundness of house drains. (5)

(b) A certain low lying area has a population of 4000 persons, who are being supplied water at the rate of 135 litres per capita per day. Design an air-ejector as a composite unit for the area, assuming following data : (9)

(i) Velocity of compressed air that is supplied = 6 m/s
(ii) Velocity in the main sewer = 0 9 m/sec
(iii) Time required to fill the ejector = 10 minutes
(iv) Height of the ejector = 2.0 m
(v) The entire water that is supplied appears as sewage.

3. (a) With the help of a neat sketch, discuss the working of a Grit chamber. (7)

(b) Design a detritus tank for an average flow of 300 litres per second. Make suitable assumptions wherever necessary. (7)

4. (a) Differentiate between Activated sludge process and Trickling filter process. (4)

(b) Design an oxidation pond for treating sewage from hot climate residential colony with 600 persons contributing sewage @ 100 litres per capita per day. The 5 day BOD of sewage is 275 mg/litre. (10)

5. Discuss in detail the various criteria normally used in selecting sludge treatment/disposal options. (14)

6. "Regular monitoring and evaluation of waste water re-use project is essential." Discuss this statement in detail. (14)

7. Write short notes on any four of the following : (4x3.5=14)

(a) Estimation of storm water run-off
(b) Water closet
(c) Self cleaning velocity
(d) Grease and oil traps
(e) Anaerobic sludge digesters
(f) Bacteria-algae symbiosis

KnowledgeIsFun.com has some good information on this topic for your reference:

• Water resource engineering
• Waste-water
• Waste water treatment