MCQ
23981. The effluents from the septic tank are discharged into--
soak pit
drainage
oxidation pond
sewer
23982. The minimum diameter of a manhole cover should be-
25cm
50cm
75cm
100cm
23983. Slow sand filter is more efficient for the removal of-
bacteria
turbidity
odour
all of these
23984. By lime soda process, hardness can be reduced to less than
50 ppm
75 ppm
150 ppm
100 ppm
23985. The minimum size of a fire hydrant is--
5cm
10cm
15cm
20cm
23986. Cleaning period for a rapid sand filter is taken as-
2 to 3 hours
2 to 3 days
2 to 3 weeks
2 to 3 months
23987. The equipment used for cleaning the sewers easily is called-
gauge
claw
scoop
scraper
23988. The human excreta is a ---waste.
dry
liquid
semi-liquid
solid
23989. The percentage of chlorine in fresh bleaching powder is-
20 to 25%
25 to 30%
30 to 35%
35 to 40%
23990. The amount of chlorine used for plain b chlorination of water is about-
0.2 ppm
0.3 ppm
0.4 ppm
0.5 ppm
23991. The water from kitchens, bathrooms, wash basins is called-
sewage
raw sewage
sullage
none of this
23992. The time of contact for chlorination should be at least-
5 minutes
20 minutes
1 hour
2 hours
23993. The coefficient of uniformity for slow sand filters is-
1.35
1.75
1.55
2.05
23994. The aeration of water is done to remove--
colour
taste
odour
all of these
23995. Rapid sand filter can remove turbidity from water upto an extent of-
15 to 25 ppm
25 to 35 ppm
35 to 40 ppm
40 to 50 ppm
23996. The secondary treatment of sewage is carried out by the use of-
screens
grit chambers
trickling filters
chlorinators
23997. The cross-section recommended for separate system of sewerage is--
circular
rectangular
egg-shaped
none of these
23998. The process of killing pathogenic bacterias from water is called-
sedimentation
coagulation
filteration
disinfection
23999. The internal diameter of the sewer should not be less than-
15cm
25cm
50cm
75cm
24000. Rapid sand filter can remove bacteria upto an extent of-
60 to 70%
70 to 80%
80 to 90%
90 to 99%