Practice Test: Question Set - 11
1. The pH value of fresh sewage is usually
- (A) Equal to 7
- (B) More than 7
- (C) Less than 7
- (D) Equal to
zero
2. The maximum depth of sedimentation tanks, is kept
- (A) 3 m
- (B) 3.5 m
- (C) 4 m
- (D) 4.5 m
3. If the depletion of oxygen is found to be 5 ppm after incubating a 2.5% solution of sewage sample for 5 days at 21°C, B.O.D. of the sewage is
- (A) 50
ppm
- (B) 100
ppm
- (C) 150
ppm
- (D) 200
ppm
4. Pick up the correct statement from the following:
- (A) Indore
method of composting involves decomposition under aerobic conditions
- (B) Bangalore
method of composting involves decomposing under anaerobic conditions
- (C) Fully
stabilized refuse by the Bangalore method of compositing is a powdery mass
called humus
- (D) All of these
5. Lead caulked joints are used for laying
- (A) Stone ware
pipes
- (B) Earthenware
pipes
- (C) C.I. pipes
- (D) G.I. pipes
6. If D is the diameter of a circular sewer and D' is the top horizontal diameter of an equivalent egg shaped section, the relationship which holds good, is
- (A) D' =
0.64 D
- (B) D' =
0.74 D
- (C) D' =
0.84 D
- (D) D' =
0.94 D
7. The spacing of man holes along a straight portion of a sewer is 300 m, the diameter of the sewer may be
- (A) 0.9 cm
- (B) 1.2 m
- (C) 1.5 m
- (D) > 1.5 m
8. A sewer running partially full and hurried with back filled, fails in compression due to
- (A) Weight
of the pipe
- (B) Weight of
the back fill
- (C) Superimposed
traffic loads
- (D) All the
above
9. A five day B.O.D. at 15°C of the sewage of a town is 100 kg/day. If the 5 day B.O.D. per head at 15°C for standard sewage is 0.1 kg/day, the population equivalent is
- (A) 100
- (B) 1000
- (C) 5000
- (D) 10000
10. Kjeldahl nitrogen is a mixture of
- (A) Ammonia and
nitrogen
- (B) Nitrogen and
organic nitrogen
- (C) Organic
nitrogen and ammonia
- (D) All
the above
11. The quantity of liquid waste which flows in sewers during the period of rainfall, is known
- (A) Sanitary
sewage
- (B) Industrial
waste
- (C) Storm sewage
- (D) None of
these
12. Nitrogen cycle of sewage, is
- (A) Liberation
of ammonia-formation of nitrites-formation of nitrates-liberation of nitrogen
- (B) Liberation
of nitrogen-liberation of ammonia-formation of nitrites- formation of nitrates
- (C) Liberation
of nitrogen-formation of nitrates-formation of nitrites-liberation of ammonia
- (D) Formation of
nitrates-formation of nitrites-liberation of nitrates-liberation of nitrates
13. Depletion of ozone layer in the outer atmosphere may cause
- (A) Lung cancer
- (B) Skin
cancer
- (C) Bronchitis
- (D) Heart
disorder
14. The minimum diameter of a sewer is kept
- (A) 10 cm
- (B) 15 cm
- (C) 20 cm
- (D) 25 cm
15. A cylindrical ejector having its height 2 m fills after every 10 minutes with a peak sewage discharge of 0.0157 cumec. The diameter of the ejector chamber, is
- (A) 2.30 m
- (B) 2.40 m
- (C) 2.45 m
- (D) 2.50 m
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