Pick up the incorrect statement from the following ?
(A) Septic tanks are horizontal continuous flow type of sedimentation tanks
(B) Septic tanks are generally provided a detention period of 12 to 36 hours
(C) Septic tanks are completely covered and high vent shafts are provided for the escape of foul gases
(D) None of these
For sewers, inverted siphon is provided for___________________?
(A) One pipe
(B) Two pipes
(C) Three pipes
(D) Four pipes
Which one of the following gases is most significant as air pollutant ?
(A) Carbondioxide
(B) Oxygen
(C) Nitrogen
(D) Sulphur-dioxide
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
Depletion of ozone layer in the outer atmosphere may cause___________________ ?
(A) Lung cancer
(B) Skin cancer
(C) Bronchitis
(D) Heart disorder
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
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
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
Design period of 40 to 50 years is adopted for_________________?
(A) Branch sewers
(B) Main sewers
(C) Trunk sewers
(D) All the above
The disintegrating pump in which solid matter is broken up before passing out, is__________________?
(A) Centrifugal pump
(B) Reciprocating pump
(C) Pneumatic ejector
(D) None of these