A pipe conveying sewage from plumbing system of a single building to common sewer or point of immediate disposal is called________________?
(A) house sewer
(B) lateral sewer
(C) main sewer
(D) submain sewer
Scour valves are provided ______________?
(A) at street corners to control the flow of water
(B) at every depression and dead ends to drain out the waste water that may collect there
(C) at the foot of rising main along the slope to prevent back running of water
(D) at every summit of rising mains
Facultative bacteria are able to work in________________?
(A) presence of oxygen only
(B) absence of oxygen only
(C) presence as well as in absence of oxygen
(D) presence of water
The relative stability of a sewage sample, whose dissolved oxygen is same as the total oxygen required to satisfy BOD, is______________?
(A) 1
(B) 100
(C) infinite
(D) zero
In a BOD test, 1.0 ml of raw sewage was diluted to 100 ml and the dissolved oxygen concentration of diluted sample at the beginning was 6 ppm and it was 4 ppm at the end of 5 day incubation at 20°C. The BOD of raw sewage will be___________?
(A) 100 ppm
(B) 200 ppm
(C) 300 ppm
(D) 400 ppm
The rate of BOD exerted at any time is_____________?
(A) directly proportional to BOD satisfied
(B) directly proportional to BOD remain-ing
(C) inversely proportional to BO
(D) satisfied
Standard BOD is measured at________________?
(A) 20°C – 1day
(B) 25°C- 3day
(C) 20°C – 5day
(D) 30°C- 5day
Sewage treatment units are normally designed for______________?
(A) 5-10 years
(B) 15-20 years
(C) 30-40 years
(D) 40-50 years
The pathogens can be killed by_______________?
(A) nitrification
(B) chlorination
(C) oxidation
(D) none of the above
The type of sewer which is suitable for both combined and separate system is_____________?
(A) circular sewer
(B) egg shaped sewer
(C) horse-shoe type sewer
(D) semi-elliptical sewer