A. Flourish in the presence of free oxygen
B. Consume organic matter as their food
C. Oxidise organic matter in sewage
D. All the above
Related Mcqs:
- The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known_________________?
A. Bio-Chemical Oxygen Demand (B.O.D.)
B. Dissolved Oxygen (D.O.)
C. Chemical Oxygen Demand (C.O.D.)
D. None of these - Aerobic activity is maximum_______________?
A. In freshly produced sewage
B. At sewer pipes
C. In sewer treatment plants
D. None of these - To maintain aerobic biological activity, the moisture content of the compost mass should be about_________________?
A. 45 %
B. 50 %
C. 55 %
D. 60 % - Pick up the correct statement from the following?
A. The water supply pipes carry pure water free from solid particles
B. The water supply pipes get clogged if flow velocity is less than self cleansing velocity
C. The sewers may be carried up and down the hills and valleys
D. The sewer pipes are generally laid along level hills - 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 - 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 - If 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 - Discrete or granular particles change their_________________ ?
A. Size
B. Shape
C. Weight
D. None of these - The sewage treatment in septic tanks is due to__________________?
A. Anaerobic decomposition
B. Aerobic decomposition
C. Parasitic decomposition
D. None of these - In a city the ratio of the drainage to sewage is 20, the percentage discharge passing through non-monsoon periods, is_____________________?
A. 5
B. 10
C. 15
D. 20
