Description : Before discharging the foul sewage into rivers, it is generally treated by A. Screening B. Sedimentation C. Oxidation D. All the above
Last Answer : ANS: D
Description : Sewer manholes are generally provided at A. The change of gradient B. The change of direction C. The junctions of sewers D. All of these
Description : In 1000 kg of sewage, the total solids approximate A. 0.5 to 1.0 kg B. 1 kg to 2.0 kg C. 5 kg to 7.5 kg D. 7.5 kg to 10 kg
Last Answer : ANS: A
Description : Aerobic activity is maximum A. In freshly produced sewage B. At sewer pipes C. In sewer treatment plants D. None of these
Description : If the diameter of a sewer is 100 mm, the gradient required for generating self cleansing velocity is A. 1 in 60 B. 1 in 100 C. 1 in 120 D. None of these
Description : hydraulically equivalent, the relationship which holds good, is A. D8/3 = 4 b8/3 B. D3/8 = 4 b3/8 C. D2/3 = 4 b2/3 D. D3/2 = 4 b3/2
Description : To test chemical oxygen demand (C.O.D.) of sewage, organic matter is oxidised by potassium dichromate in the presence of A. Hydrochloric acid B. Sulphuric acid C. Nitric acid D. Citric acid
Last Answer : ANS: B
Description : Sewer pipes need be checked for A. Minimum flow B. Maximum flow C. Both A. and B. D. None of these
Last Answer : ANS: C
Description : The sewer which transports the sewage to the point of treatment, is called A. House sewer B. Out-fall sewer C. Branch sewer D. Main sewer
Description : In septic tanks, decomposition of organic bacteria, is done by A. Anaerobic bacteria B. Aerobic bacteria C. Both types of bacterias D. None of these
Description : If a paper moistened with lead acetate for five minutes when placed in manhole turns black. The sewer certainly contains A. Hydrogen sulphide B. Carbon dioxide C. Methane D. Oxygen
Description : The sewerage system originates from A. House sewers B. Lateral sewers C. Branch sewers D. Main sewers
Description : The gas evolved in sewers is A. Carbondioxide B. Hydrogen sulphide C. Methane D. All of these
Description : During purification process of sewage the gas given off, is A. Carbon dioxide B. Hydrogen C. Ammonia D. All the above
Description : In sewage, the solids in mg per litre is A. 100 to 500 B. 500 to 1000 C. 1000 to 1500 D. 1500 to 2000
Description : Drop manholes at the junctions of sewer lines, are provided if A. Invert level of a branch sewer is more than 60 cm that of the main sewer B. Sewer line runs along a main road C. Ordinary manhole cannot be built D. Two sewer lines intersect
Description : If is the diameter of upper circular portion, the area of cross-section of a standard egg shaped sewer, is A. D² B. D² C. D² D. D²
Description : The sewage discharge in a detritus tank of a treatment plant is 576 litres/sec with flow velocity of 0.2 m/sec. If the ratio of width to depth is 2, the depth is A. 100 cm B. 110 cm C. 120 cm D. 150 cm
Description : The small sewers are cleaned by A. Flushing B. Cane rodding C. Wooden pills D. None of these
Description : Fresh sewage may become stale in A. One hour B. Two to three hours C. Three to four hours D. Six hours
Description : In sewers the gas generally found, is A. Hydrogen sulphide (H2S) B. Carbon dioxide (CO2) C. Methane (CH4) D. All the above
Description : The standard B.O.D. of water is taken for A. 1 day B. 2 days C. 3 days D. 5 days
Description : If the depth of partial flow in a sewer of diameter 2 m, is 50 cm, its wetted perimeter is A. B. /2 C. /3 D. 2 /3
Description : The gradient of sewers depends upon A. Velocity of flow B. Diameter of the sewer C. Discharge D. All the above
Description : Rate of flow of sewage is generally assumed A. More than the rate of water supply B. Equal to the rate of water supply C. Less than the rate of water supply D. At 150 litres per capita
Description : Removal of oil and grease from sewage, is known A. Screening B. Skimming C. Filtration D. None of these
Description : In R.C. sewer pipes, the percentage longitudinal reinforcement to the cross-sectional area of concrete is kept A. 10.0 B. 5.0 C. 2.0 D. 0.25
Description : The ratio of minimum hourly flow to the average flow of sewage is A. 1/4 B. 1/3 C. 1/2 D. 3/4
Description : House connections to the laterals is generally made by A. R.C.C. B. P.C.C. C. Cast iron D. Glazed stonewares
Description : Q No: 291 The coagulant widely used for sewage treatment, is A. Alum B. Ferric chloride C. Ferric sulphate D. Chlorinated copperas
Description : In primary sedimentation, the 0.2 mm inorganic solids get separated if specific gravity is A. 2.25 B. 2.50 C. 2.55 D. 2.65
Description : For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed A. 3 ppm B. 4 ppm C. 5 ppm D. 10 ppm
Description : In olden days the type of section adopted in trunk and out fall sewers was A. Parabolic shaped B. Horse shoe shaped C. Egg shaped D. Circular shaped
Description : The width of a rectangular sewer is twice its depth while discharging 1.5 m/sec. The width of the sewer is A. 0.68 m B. 0.88 m C. 1.36 m D. 1.76 m
Description : Which one of the following resists hydrogen sulphide corrosion? A. R.C.C. B. Glazed stone wares C. Asbestos cement D. Glazed ware
Description : In SI units the power of sound is represented in A. Kgs B. Joules C. Newtons D. Watts
Description : The ratio of design discharge to the surface area of a sedimentation tank is called A. Surface loading B. Overflow rate C. Overflow velocity D. All of these
Description : The sewer pipe which carries sewage from a building for immediate disposal is A. House sewer B. Lateral sewer C. Intercepting sewer D. Main sewer
Description : Discrete or granular particles change their A. Size B. Shape C. Weight D. None of these
Description : For providing an Indian type W.C., the R.C.C. slabs in the toilet portion A. Should be sunk by 20 cm B. Should be kept 20 cm above the adjacent portion C. Should be sunk by 50 cm D. Need not be sunk
Description : Imhoff cone is used to determine A. Settleable solids B. Suspended solids C. Dissolved solids D. None of these
Description : Flocculated particles do not change their A. Size B. Shape C. Weight D. None of these
Description : As compared to fresh river water, sea water contains oxygen A. 10% less B. 20% less C. 10% more D. 20% more
Description : When drainage to sewage ratio is 20, the peak dry weather flow is A. 20% of the design discharge B. Slightly less than 5% of the design discharge C. Slightly more than 5% of the design discharge D. None of these
Description : With self cleansing velocity in sewers A. Silting occurs at bottom B. Scouring occurs at bottom C. Both silting and scouring occur at bottom D. Neither silting nor scouring occurs at bottom
Description : The non-clog pump which permits solid matter to pass out with the liquid sewage, is A. Centrifugal pump B. Reciprocating pump C. Pneumatic ejector D. None of these
Description : The ratio of depths at partial flo A. 1 – B. 1 – C. ½ (1 – D. ½ (1 –
Description : Which one of the following tests is used for testing sewer pipes? A. Water test B. Ball test C. Mirror test D. All of these
Description : If the grit in grit chambers is 4.5 million litres per day, its cleaning is done A. Manually B. Mechanically C. Hydraulically D. Electrically
Description : Q No: 271 Pick up the correct statement from the following: A. Turbidity is more in strong sewage B. The black colour indicates septic sewage C. The sewage omits offensive odours after four hours D. All the above