M.Sc. (Semester II) (CBCS) Examination Mar/Apr-2018
Environmental Science
WATER AND WASTEWATER ENGINEERING
Time 2½ Hours
Max. Marks: 70
Instructions: Answer any Five Question. All Questions carry equal marks. Question No. 1 is Compulsory. Attempt any two from Q.No.2, 3 and 4. Attempt any two from Q.No.5, 6 and 7.
Q.1
Select the answer among the following.
14
In a sludge tank, the gas mainly produced, is
Oxygen
Nitrogen
Hydrogen
Carbon dioxide
For evaporation and measurement of settable solids, the apparatus used, is
A jar
A breaker
A test tube
An Imhoff cone
The grit chambers of sewage treatment plants, are generally cleaned after
2 days
7 days
12 days
14 days
Kjeldahl nitrogen is a mixture of
Ammonia and nitrogen
Nitrogen and organic nitrogen
Organic nitrogen and ammonia
All the above
In normal conditions, the period for sludge digestion, is
10 days
20 days
30 days
60 days
Pick up the correct statement from the following:
Indore method of composting involves decomposition under aerobic conditions
Bangalore method of composting involves under anaerobic conditions
Fully stabilized refuse by the Bangalore method of compositing is a powdery mass called humus
All of these
No treatment of the sewage is given if dilution factor is
Less than 150
Between 150 to 200
Between 200 to 300
More than 500
A measure of oxidisable impurities present in the sewage is
COD
BOD
Atmospheric oxygen
Ozone
Page 2 of 2
SLR-UI-364
Conversion of Fe to Fe2+ is,
Oxidation
Reduction
Corrosion
None of above
10) Corrosion is a process reverse of of metal.
Destruction
Extraction
Rusting
Galvanizing
11) A1is than Zn.
Less anodic
More anodic
Less Cathodic
More Cathodic
12) If the depletion of oxygen is found to be 5 ppm after incubating a 2.5% solution of sewage sample for 5 days at 210C, B.O.D. of the sewage is
50 ppm
100 ppm
150 ppm
200 ppm
13) Primary treatment of sewage consists of removal of
Large suspended organic solids
Oil and grease
Sand and girt
Floating materials
14) Acid regression stage of sludge digestion at a temperature extends over a period of
15 days
30 days
60 days
90 days
Q.2
Briefly explain the various methods of principle and design aspect of sedimentation tank.
14
Q.3
Explain in brief, the various methods of sludge thickening and alkaline stabilization?
14
Q.4
Explain the process and design aspect of continuous stirring tank reactor (CSTR) with neat labeled diagram.
14
Q.5
Write a short notes on following:
14
Reverse osmosis
Sludge dewatering
Q.6
Write in with suitable illustration of the following:
14
Principles, applications and designing aspects of skimming tank.
Explain the various methods water and waste water disinfection.
Q.7
Write an account on the following:
14
Population forecasting and its application.
Merits and demerits of land filling techniques in sludge disposal.