A well oxidized sewage contains nitrogen mainly as___________________?
(A) Nitrates
(B) Nitrites
(C) Free ammonia
(D) None of these
If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is_________________?
(A) 100 mg/l
(B) 200 mg/l
(C) 300 mg/l
(D) 400 mg/l
Self-cleansing velocity is__________________?
(A) Velocity at dry weather flow
(B) Velocity of water at flushing
(C) Velocity at which no accumulation remains in the drains
(D) Velocity of water in a pressure filter
15 cumecs, the depth d and width are related by For drains up to___________________?
(A) d = 0.2 B
(B) d = 0.5 B
(C) B = 0.2 d
(D) B = 0.5 d
Cement concrete sewers are only suitable if non-scouring velocity is between_________________?
(A) 2.5 to 3.0 m/sec
(B) 3.0 to 4.0 m/sec
(C) 3.5 to 4.5 m/sec
(D) 4.5 to 5.5 m/sec
Primary treatment of sewage consists of removal of__________________?
(A) Large suspended organic solids
(B) Oil and grease
(C) Sand and girt
(D) Floating materials
The bottom of the sewage inlet chamber of septic tanks, is provided an outward slope_________________?
(A) 1 in 5
(B) 1 in 10
(C) 1 in 15
(D) 1 in 20
Which one of the following part of human body withstands minimum radiation ?
(A) Thyroid
(B) Kidneys
(C) Eyes
(D) Ovaries/testis
The intensity of rain is expressed in________________?
(A) cm/minute
(B) cm/hour
(C) cm/day
(D) None of these
Inter-distance between ventilation columns in a sewer line is kept__________________?
(A) 25 to 50 m
(B) 50 m to 100 m
(C) 100 m to 150 m
(D) 150 m to 300 m