Description : running partially full with central angle , For a circular sewer of diameter A. d/D = ½ (1 – – B. a/A C. r/R = [1 – D. All the above
Last Answer : ANS: D
Description : You are asked to design sewer pipes of diameters 0.4 m to 0.9 m at maximum flow, you will assume the sewer flow running at A. Full depth B. Half full C. Two third full D. Three fourth full
Last Answer : ANS: B
Description : If the discharge of a sewer running half is 628 1.p.s., i = 0.001, and n = 0.010, the diameter of the sewer, is A. 1.39 m B. 1.49 m C. 1.59 m D. 1.69 m
Description : Pick up the correct statement from the following: A. The sewer pipes of sizes less than 0.4 m diameter are designed as running full at maximum discharge B. The sewer pipes of sizes greater than 0.4 m ... discharge C. The minimum design velocity of sewer pipes is taken as 0.8 m/sec D. All the above
Description : Assertion A.: A free board of 0.3 m is provided above the top sewage line in septic tanks. Reason (R): It helps to accommodate the scum in the septic tank. A. Both A and R is true and R is the correct ... is not a correct explanation of A C. A is true but R is false D. A is false but R is true
Last Answer : ANS: A
Description : The reduced levels of the string at the consecutive sight rails A and B are 203.575 m, 203.475 m respectively. If the difference of their R.D.s is 10 m, the gradient of the sewer line is A. 1 in 100 upward B. 1 in 500 upward C. 1 in 100 downward D. 1 in 503 upward
Last Answer : ANS: C
Description : In Chezy’s formula V = C rs for calculating the velocity of flow in circular sewer of diameter running full, the value of hydraulic mean radius is A. D B. D /2 C. D/3 D. D/4
Description : A sewer running partially full and hurried with back filled, fails in compression due to A. Weight of the pipe B. Weight of the back fill C. Superimposed traffic loads D. All the above
Description : The pressure exerted by A. The sewage when running full from inside, is called internal pressure B. The internal pressure if any, causes tensile stress in the pipe material C. Pressure sewers are designed to be safe in tension D. All the above
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
Description : The standard B.O.D. of water is taken for A. 1 day B. 2 days C. 3 days D. 5 days
Description : 3.0 ml of raw sewage is diluted to 300 ml. The D.O. concentration of the diluted sample at the beginning of the test was 8 mg/l. After 5 dayincubation at 20°C, the D.O. concentration was 5 mg/l. The BOD of raw sewerage is A. 100 mg/l B. 200 mg/l C. 300 mg/l D. 400 mg/l
Description : If D.O. concentration falls down to zero in any natural drainage, it indicates the zone of A. Degradation B. Active decomposition C. Recovery D. Cleaner water
Description : 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 A. 50 mg/l B. 100 mg/l C. 150 mg/l D. 250 mg/l
Description : A five day B.O.D. at 15°C of the sewage of a town is 100 kg/day. If the 5 day B.O.D. per head at 15°C for standard sewage is 0.1 kg/day, the population equivalent is A. 100 B. 1000 C. 5000 D. 10000
Description : If the depletion of oxygen is found to be 5 ppm after incubating a 2.5% solution of sewage sample for 5 days at 21°C, B.O.D. of the sewage is A. 50 ppm B. 100 ppm C. 150 ppm D. 200 ppm
Description : If 2% solution of a sewage sample is incubated for 5 days at 20°C and depletion of oxygen was found to be 5 ppm, B.O.D. of the sewage is A. 200 ppm B. 225 ppm C. 250 ppm D. None of these
Description : In trickling filter, B.O.D. is reduced to A. 30 to 40% B. 40 to 60% C. 60 to 80% D. 80 to 90%
Description : Dried sewage after treatment is used as A. Fertilizer B. Building material C. Chemical for lowering B.O.D. D. Base material for paints
Description : 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
Description : Pick up the correct statement from the following: A. Hydrogen sulphide gas in excess, may cause corrosion of concrete sewers B. 4 ppm of Dissolved Oxygen (D.O.) is ensured before discharging the treated ... river C. Solubility of oxygen in sewage is 95% of that of distilled water D. All the above
Description : Pick up the correct statement from the following: A. In treated sewage, 4 ppm of D.O. is essential B. Only very fresh sewage contains some dissolved oxygen C. The solubility of oxygen in sewage is 95% that is in distilled water D. All the above
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 : House connections to the laterals is generally made by A. R.C.C. B. P.C.C. C. Cast iron D. Glazed stonewares
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 : 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 : Assertion A.: The minimum self cleansing velocity in the sewer, at least once a day, must be generated. Reason (R): If certain deposition takes place and is not removed, it obstructs free flow and causes further ... correct explanation of A C. A is true but R is false D. A is false but R is true
Description : Assertion A. : Discharging the effluents from the oxidation ponds just up stream of lakes or reservoirs is undesirable. Reason (R) : The discharged algae get settled in the reservoirs and cause anaerobic decomposition and other ... of A C. A is true but R is false D. A is false but R is true
Description : weight of water, the hydraulic mean depth of the sewer and the bed slope w is the unit of the sewer, then the tractive force exerted by flowing water, is A. w r S S B. w r1/2 C. w r S D. w r2/3
Description : The sewer which resists sulphide corrosion, is A. Brick sewer B. Cast iron sewer C. R.C.C. sewer D. Lead sewer
Description : Assertion A.: The determination of pH value of sewerage is important. Reason (R): The efficiency of certain treatment methods depends upon the availability of pH value. A. Both A and R are true and R is the ... correct explanation of A C. A is true but R is false D. A is false but R is true
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 : 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 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 : If is the rugosity coefficient, is the bed slope of sewer, the velocity of flow in m/sec may be obtained by the formula V = (1/n) r2/3 s1/2 evolved by A. Chezy B. Manning C. Bazin D. Kutter
Description : The dimensions of a rectangular settling tank are: length 24 m, width 6 m and depth 3 m. If 2 hour detention period for tanks is recommended, the rate of flow of sewage per hour, is A. 204 cu.m B. 208 cu.m C. 212 cu.m D. 216 cu.m
Description : For a peak discharge of 0.0157 cumec, with a velocity of 0.9 m/sec, the diameter of the sewer main, is A. 10 cm B. 12 cm C. 15 cm D. 18 cm
Description : For sewer mains of 0.5 to 1 m diameter, the ratio of maximum daily sewage flow to the average daily sewage flow is assumed A. 1.5 B. 2.0 C. 2.5 D. 3.0
Description : For laying a sewer line in a trench of 2 m width, an offset line is marked on the ground parallel to the given centre line at a distance of A. 100 cm B. 120 cm C. 140 cm D. 160 cm
Description : The ratio of maximum sewage flow to average sewage flow for trunk mains having diameters more than 1.25 m, is A. 1.5 B. 2.0 C. 3.0 D. 4.0
Description : Pick up the correct statement from the following: A. The boning rod is used for checking the levels of the sewer inverts B. Manhole covers are made circular for the convenience of the cleaning staff C. A manhole is classified as shallow manhole if its depth is less than 0.9 m D. All the above
Description : 221 For non-scouring velocity 5 m/sec, the type of sewers generally preferred to, is A. Cast iron sewers B. Cement concrete sewers C. Glazed bricks sewers D. Stone ware sewers
Description : The width of a settling tank with 2 hour detention period for treating sewage 378 cu m per hour, is A. 5 m B. 5.5 m C. 6.5 m D. 7 m
Description : A sewer pipe contains 1 mm sand particles of specific gravity 2.65 and 5 mm organic particles of specific gravity 1.2, the minimum velocity required for removing the sewerage, is A. 0.30 m/sec B. 0.35 m/sec C. 0.40 m/sec D. 0.45 m/sec
Description : For trunk sewers more than 1.25 m in diameter, the ratio of the maximum daily sewage flow to the average daily sewage flow is assumed A. 1.5 B. 2.0 C. 2.5 D. 3.0
Description : If the over land flow from the critical point to the drain is 8 km and the difference in level is 12.4 m, the inlet time is A. 2 hours B. 3 hours C. 4 hours D. 5 hours
Description : Ventilating shafts are provided to a sewer line at every A. 100 m B. 150 m C. 200 m D. 300 m
Description : The maximum spacing of manholes specified by Indian standard in sewers upto 0.3 m diameter is A. 20 m B. 30 m C. 45 m D. 75 m
Description : The maximum diameter of sewers adopted in the designs is A. 1.0 m B. 2.0 m C. 3.0 m D. 4.0 m
Description : A manhole is classified as shallow if its depth is between A. 0.4 to 0.5 m B. 0.5 to 0.7 m C. 0.7 to 0.9 m D. 0.9 to 1.20 m