Practice Test: Question Set - 16
1. For laying a sewer line in a trench of 2 m width, an offset line is marked on the ground parallel to the given centre line at a distance of
- (A) 100 cm
- (B) 120 cm
- (C) 140
cm
- (D) 160 cm
2. The liquid wastes from kitchens, bath rooms and wash basins, is not called
- (A) Liquid waste
- (B) Sullage
- (C) Sewage
- (D) None
of these
3. The detention time (t) of a settling tank, may be defined as the time required for
- (A) A
particle to travel along its length
- (B) A particle
to travel from top surface to bottom sludge zone
- (C) The flow of
sewage to fill the tank
- (D) None of
these
4. The following is the physical characteristic of sewage
- (A) Turbidity
- (B) Color
- (C) Odour
- (D) All the
above
5. The effluent of a septic tank is
- (A) Fit for
discharge into any open drain
- (B) Foul and
contains dissolved and suspended solids
- (C) As good as
that from a complete treatment
- (D) None of
these
6. The design period of sewage treatment works in normally
- (A) 5 - 10 years
- (B) 15 - 20
years
- (C) 30 - 40
years
- (D) 40 - 50
years
7. In Chezy's formula V = C √rs for calculating the velocity of flow in circular sewer of diameter ‘D’ running full, the value of hydraulic mean radius is
- (A) D
- (B) D/2
- (C) D/3
- (D) D/4
8. It is customary to design a sewer for D.W.F. on the basis of
- (A) Average
demand
- (B) Twice the
average demand
- (C) Thrice the
average demand
- (D) Four times
the average demand
9. For sewer mains of 0.5 to 1 m diameter, the ratio of maximum daily sewage flow to the average daily sewage flow is assumed
- (A) 1.5
- (B) 2.0
- (C) 2.5
- (D) 3.0
10. Fresh sewage is generally
- (A) Alkaline
- (B) Acidic
- (C) Highly
decomposed
- (D) A source of
objectionable odour
11. The recommended detention period for grit chambers is
- (A) 1 minute
- (B) 2 minutes
- (C) 3 minutes
- (D) 5 minutes
12. For detecting the nitrites in the sewage, the matching color may be developed by adding
- (A) Potassium
permanganate
- (B) Sulphuric
acid and napthamine
- (C) Phenol-di-sulphuric
acid potassium hydroxide
- (D) None of
these
13. If ‘D’ is the diameter of upper circular portion, the overall depth of a standard egg shaped section, is
- (A) D
- (B) 1.25 D
- (C) 1.5 D
- (D) 1.75 D
14. The laying of sewers is done with
- (A) Magnetic
compass
- (B) Theodolite
- (C) Level
- (D) Clinometer
15. A rainfall may be classified as acidic if its pH value is less or equal to
- (A) 6
- (B) 7
- (C) 5
- (D) 6.5
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