MCQ
20981. Grit chambers of a sewage plant are usually changed after-
1 day
2 weeks
1 week
4 weeks
20982. The secondary treatment of sewage is carried out by the use of-
screens
grit chambers
trickling filters
chlorinators
20983. In high rate activated sludge treatment, bacteria are removed from-
20 to 40%
40 to 60%
60 to 80%
80 to 95%
20984. Biological action is used in-
screens
trickling filters
sedimentation tank
all of these
20985. The sewage is treated by aerobic bacteria action in-
settling tank
trickling filter
oxidation pond
all of these
20986. In primary settling tank, suspended solids are reduced from-
10 to 20%
20 to 40%
40 to 70%
70 to 90%
20987. The minimum size of a fire hydrant is--
5cm
10cm
15cm
20cm
20988. Aerobic bacteria takes place in the of ---light.
Presence
absence
20989. The human excreta is a ---waste.
dry
liquid
semi-liquid
solid
20990. The water from kitchens, bathrooms, wash basins is called-
sewage
raw sewage
sullage
none of this
20991. The minimum diameter of a manhole cover should be-
25cm
50cm
75cm
100cm
20992. The sewage is treated by aerobic bacteria action in -
settling tank
oxidation pond
trickling filter
all of these
20993. Air vent pipe is not essentially required in a septic tank-
true
false
20994. By lime soda process, hardness can be reduced to less than
50 ppm
75 ppm
150 ppm
100 ppm
20995. The effluents from the septic tank are discharged into--
soak pit
drainage
oxidation pond
sewer
20996. The aeration of water is done to remove--
colour
taste
odour
all of these
20997. The cross-section recommended for separate system of sewerage is--
circular
rectangular
egg-shaped
none of these
20998. The internal diameter of the sewer should not be less than-
15cm
25cm
50cm
75cm
20999. The equipment used for cleaning the sewers easily is called-
gauge
claw
scoop
scraper
21000. The biochemical treatment of sewage effluent is a process of-
oxidation
self-purification
deoxidation
sedimentation