A sewer running partially full and hurried with back filled, fails in compression due to
1.weight of the pipe
2.weight of the back fill
3.superimposed traffic loads
4. all the above.
Posted Date:-2021-05-21 10:56:34
In a city the ratio of the drainage to sewage is 20, the percentage discharge passing through non-monsoon periods, is
1.5
2.10
3.15
4.20
Posted Date:-2021-05-21 10:56:34
In case of Imhoff tanks,
1.the shape is rectangular
2.detention period is 2 hours
3. the velocity of flow is restricted to 0.30 m/minute
4.All the above.
Posted Date:-2021-05-21 10:56:34
Nitrogen cycle of sewage, is
1. Liberation of ammonia-formation of nitrites-formation of nitrates-liberation of nitrogen
2.Liberation of nitrogen-liberation of ammonia-formation of nitrites- formation of nitrates
3.Liberation of nitrogen-formation of nitrates-formation of nitrites-liberation of ammonia
4.Formation of nitrates-formation of nitrites-liberation of nitrates-liberation of nitrates
Posted Date:-2021-05-21 10:56:34
Pick up the correct statement from the following :
1.Turbidity is more in strong sewage
2.The black colour indicates septic sewage
3.The fresh sewage is practically odourless
4.All the above.
Posted Date:-2021-05-21 10:56:34
Pick up the correct statement from the following :
1.The larger the sewer in size, more will be velocity
2.The smaller the sewer in size, less will be velocity
3.The larger the sewer in size, no deposition will take place
4.The larger the sewer in size, deposition will take place.
Posted Date:-2021-05-21 10:56:34
The detention period for plain sedimentation water tanks, is usually
1.4 to 8 hours
2.8 to 16 hours
3.16 to 24 hours
4.24 to 36 hours.
Posted Date:-2021-05-21 10:56:34
A manhole is classified as shallow if its depth is between
1. 0.4 to 0.5 m
2.0.5 to 0.7 m
3.0.7 to 0.9 m
4.0.9 to 1.20 m
Posted Date:-2021-05-21 10:56:34
Dry water flow in a combined sewer, is
1.industrial sewage
2.domestic sewage
3.storm water
4.excludes storm water.
Posted Date:-2021-05-21 10:56:34
In septic tanks,
1. free board of 0.3 m may be provided
2.the baffles or tees are extended up to top level of scum
3. the clear space between the baffle top and covering slab is about 7.5 cm
4.all the above.
Posted Date:-2021-05-21 10:56:34
It is customary to design a sewer for D.W.F. on the basis of
1.average demand
2.twice the average demand
3. thrice the average demand
4.four times the average demand.
Posted Date:-2021-05-21 10:56:34
Pick up the correct statement from the following :
1.The maximum rate of storm run off is called peak drainage discharge
2. Rational method of estimating peak run off, may be used precisely for areas less than 50 hectares
3.The period after which the entire area starts contributing to the run off, is called the time of concentration
4.The time required by water to reach the outlet of a catchment from the most remote point, is called time of concentration
Posted Date:-2021-05-21 10:56:34
Rate of flow of sewage is generally assumed
1.more than the rate of water supply
2.equal to the rate of water supply
3. less than the rate of water supply
4.at 150 litres per capita.
Posted Date:-2021-05-21 10:56:34
The liquid wastes from kitchens, bath rooms and wash basins, is not called
1.liquid waste
2.sullage
3.sewage
4.none of these.
Posted Date:-2021-05-21 10:56:34
The recommended detention period for grit chambers is
1.1 minute
2.2 minutes
3.3 minutes
4.5 minutes
Posted Date:-2021-05-21 10:56:34
A drop manhole is provided if
1.a sewer drops from a height
2.a branch sewer joins the main sewer at higher level
3.a lamp is inserted to check obstruction
4.none of these.
Posted Date:-2021-05-21 10:56:34
During preliminary treatment of a sewage
1.Oil and grease are removed from skimming tanks
2. Floating materials are removed by screening
3.Girt and sand are removed by girt chambers
4.All the above.
Posted Date:-2021-05-21 10:56:34
For design purposes, the normal rate of infiltration of ground water into the sewer, is
1.500 litres/km/cm
2.1000 litres/km/cm
3.1500 litres/km/cm
4.2000 litres/km/cm
Posted Date:-2021-05-21 10:56:34
For providing an Indian type W.C., the R.C.C. slabs in the toilet portion
1.should be sunk by 20 cm
2.should be kept 20 cm above the adjacent portion
3.should be sunk by 50 cm
4.need not be sunk.
Posted Date:-2021-05-21 10:56:34
For trunk and out-fall, the type of sewers generally used, is
1.standard egg shaped
2.circular shaped
3.horse shoe shaped
4.parabolic shaped
Posted Date:-2021-05-21 10:56:34
Fresh sewage may become stale in
1.six hours.
2. two to three hours
3.three to four hours
4.ten hours.
Posted Date:-2021-05-21 10:56:34
he amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known
1.Bio-Chemical Oxygen Demand (B.O.D.)
2. Dissolved Oxygen (D.O.)
3.Chemical Oxygen Demand (C.O.D.)
4.None of these.
Posted Date:-2021-05-21 10:56:34
he presence of free ammonia in sewage, is detected by
1.boiling
2. adding pottassium permanganate
3.adding sulphuric acid
4.phenol-di-sulphuric acid.
Posted Date:-2021-05-21 10:56:34
Hydraulic mean radius is
1.mean radius of sewer
2.difference in heads between two points in circular pipes
3.mean of radii in a pipe line of varying cross-sections
4.cross-sectional area/wetted perimeter.
Posted Date:-2021-05-21 10:56:34
If the depletion of oxygen is found to be 2.5 mg/litre after incubating 2.5 ml of sewage diluted to 250 ml for 5 days at 20°C, B.O.D. of the sewage is
1.50 mg/l
2.100 mg/l
3.150 mg/l
4.200 mg/l
Posted Date:-2021-05-21 10:56:34
In sewage having fully oxidised organic matter, the nitrogen exists in the form of
1.nitrites
2.nitrates
3.free ammonia
4.aluminoid nitrogen
Posted Date:-2021-05-21 10:56:34
In sewers the highest non-scouring velocity is achieved in
1.glazed bricks sewers
2.cast iron sewers
3.cement concrete sewers
4.stone ware sewers.
Posted Date:-2021-05-21 10:56:34
The most dangerous pollutant in vehicular emissions is
1.CO
2.SO2
3.CO2
4.O3.
Posted Date:-2021-05-21 10:56:34
Maximum permissible velocity 1.5 m/sec, is adopted in drains
1.with beds of rocks and gravels
2. lined with stones
3.both (a) and (b)
4.neither (a) nor (b).
Posted Date:-2021-05-21 10:56:34
Pick up the correct statement from the following :
1. Indore method of composting involves decomposition under aerobic conditions
2.Bangalore method of composting involves decomposing under anaerobic conditions
3.Fully stabilised refuse by the Bangalore method of compositing is a powdery mass called humus
4.all of these.
Posted Date:-2021-05-21 10:56:34
Pick up the correct statement from the following :
1.The materials separated by screens, is called screenings
2.The screenings are disposed off either by burning or by burial or by dumping
3.The process of burning the screenings, is called incineration
4.All the above.
Posted Date:-2021-05-21 10:56:34
Pick up the incorrect statement from the following
1.Septic tanks are horizontal continuous flow type of sedimentation tanks
2. Septic tanks are generally provided a detention period of 12 to 36 hours
3.Septic tanks are completely covered and high vent shafts are provided for the escape of foul gases
4.None of these.
Posted Date:-2021-05-21 10:56:34
Sewer ventilating columns are generally placed at
1.distances 150 m to 300 m
2. upper ends of branch sewers
3.every change in the size of sewers
4.all the above.
Posted Date:-2021-05-21 10:56:34
The algae dies out in the zone of
1.degradation
2.active decomposition
3.recovery
4.cleaner water.
Posted Date:-2021-05-21 10:56:34
The clarigesters are
1.circular septic tanks
2. rectangular septic tanks
3.circular Imhoff double tanks with bottom hoppers
4. circular Imhoff double storey tanks without bottom hoppers.
Posted Date:-2021-05-21 10:56:34
The digested sludge from septic tanks, is removed after a maximum period of
1.3 years
2.3.5 years
3.4 years
4.5 years
Posted Date:-2021-05-21 10:56:34
The drop man holes are generally provided in sewers for
1.industrial areas
2. large town ships
3. hilly town ships
4.cities in plains.
Posted Date:-2021-05-21 10:56:34
The effluent of a septic tank is
1.fit for discharge into any open drain
2.foul and contains dissolved and suspended solids
3. as good as that from a complete treatment
4.none of these.
Posted Date:-2021-05-21 10:56:34
The gradient of sewers depends upon
1.velocity of flow
2.diameter of the sewer
3.discharge
4.all the above.
Posted Date:-2021-05-21 10:56:34
The ratio of the diameter of a circular section and the side of a square section hydraulically equivalent, is
1.1.095
2.1.085
3.1.075
4.1.065
Posted Date:-2021-05-21 10:56:34
The settling velocity of the particles larger than 0.06 mm in a settling tank of depth 2.4 is 0.33 m per sec. The detention period recommended for the tank, is
1.30 minutes
2. 1 hour
3.1 hour and 30 minutes
4.2 hour
Posted Date:-2021-05-21 10:56:34
The sewer pipe which carries sewage from a building for immediate disposal is
1.house sewer
2. lateral sewer
3. intercepting sewer
4.main sewer.
Posted Date:-2021-05-21 10:56:34
The small sewers are cleaned by
1.flushing
2.cane rodding
3.wooden pills
4.none of these.
Posted Date:-2021-05-21 10:56:34
The standard B.O.D. of water is taken for
1.1 day
2.2 days
3.3 days
4.4 days
Posted Date:-2021-05-21 10:56:34
To prevent settling down of sewage both at the bottom and on the sides of a large sewer, self-cleaning velocity recommended for Indian conditions, is
1.0.50 m/sec
2.0.60 m/sec
3.0.70 m/sec
4. 0.75 m/sec
Posted Date:-2021-05-21 10:56:34
To prevent settling down of sewage both at the bottom and on the sides of a large sewer, self-cleaning velocity recommended for Indian conditions, is
1.0.50 m/sec
2.0.60 m/sec
3. 0.70 m/sec
4. 0.75 m/sec
Posted Date:-2021-05-21 10:56:34
Which one of the following tests is used for testing sewer pipes :
1.water test
2.ball test
3.mirror test
4. all of these.
Posted Date:-2021-05-21 10:56:34