Description : The spacing of bars for perforations in coarse screens used for the treatment of sewage, is A. 20 mm B. 30 mm C. 40 mm D. 50 mm
Last Answer : ANS: D
Description : The spacing of bars of perforations of fine screens used for the treatment of sewage, is A. 2 to 3 mm B. 3 to 5 mm C. 5 to 8 mm D. 8 to 10 mm
Last Answer : ANS: A
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 : Disposal to sewage in large cities, is done in A. Irrigation B. Dilution C. Oxidation D. Purification
Last Answer : ANS: B
Description : The grit and silt of the grit chambers, may not be used for A. Raising low lying areas by dumping B. Concreting C. Both A. and B. D. Neither A. nor B.
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 : Facultative bacteria survive in A. The presence of oxygen B. The absence of oxygen C. Both cases A. and B. D. Neither A. nor B.
Last Answer : ANS: C
Description : In sewers designed with self cleansing velocity, A. The bottom is silted B. The bottom is scoured C. Both silting and scouring occur at the bottom D. Neither silting nor scouring occurs at the bottom
Description : Maximum permissible velocity 1.5 m/sec, is adopted in drains A. With beds of rocks and gravels B. Lined with stones C. Both A. and B. D. Neither A. nor B.
Description : In a trickling filter A. Filtration process is used B. Biological action is used C. Neither A. nor B. D. Both A. and B.
Description : For efficient working of a sewer, it must be ensured that A. Minimum velocity of 0.45 m/sec, is maintained at its minimum flow B. A maximum velocity of 0.90 m/sec, is maintained at its maximum flow C. Both A. and B. D. Neither A. nor B.
Description : The screens are fixed A. Perpendicular to the direction of flow B. Parallel to the direction of flow C. At an angle 30° to 60° to the direction of flow D. None of these
Description : Pick up the correct statement from the following: A. The materials separated by screens, is called screenings B. The screenings are disposed off either by burning or by burial or by dumping C. The process of burning the screenings, is known as compositing D. All the above
Description : Skimming tanks are A. Used to remove the grease and oil B. Those from which sludge is skimmed out C. Tanks provided with self- cleansing screens D. Improved version of grit chambers
Description : Fresh sewage may become stale in A. One hour B. Two to three hours C. Three to four hours D. Six hours
Description : For detecting the nitrites in the sewage, the matching colour may be developed by adding A. Potassium permanganate B. Sulphuric acid and napthamine C. Phenol-di -sulphuric acid potassium hydroxide D. None of these
Description : The detention time (t) of a settling tank, may be defined as the time required for A. A particle to travel along its length B. A particle to travel from top surface to bottom sludge zone C. The flow of sewage to fill the tank D. None of these
Description : For detecting the nitrates in sewage, the colour may be developed by adding A. Potassium permanganate B. Sulphuric acid and napthamine C. Phenol-di -sulphuric acid and potassium hydroxide 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 : Traps A. Are water seals which prevent the entry of foul gases B. Are used to trap the rats entering sewers C. Dissolve the foul gases D. Create symphonic action to increase the quick disposal of sewerage
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
Description : 1000 kg of sewage contains A. 0.112 kg in suspension B. 0.112 kg in solution C. 0.225 kg in solution D. Both A. and C. of above
Description : 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 A. 0.50 m/sec B. 0.60 m/sec C. 0.70 m/sec D. 0.75 m/sec
Description : In screen analysis, the notation +5 mm/-10 mm means particles passing through (A) 10 mm screen and retained on 5 mm screen (B) 5 mm screen and retained on 10 mm screen (C) Both 5 mm and 10 mm screens (D) Neither 5 mm nor 10 mm screen
Last Answer : (A) 10 mm screen and retained on 5 mm screen
Description : Before discharging the foul sewage into rivers, it is generally treated by A. Screening B. Sedimentation C. Oxidation D. All the above
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
Description : Aerobic activity is maximum A. In freshly produced sewage B. At sewer pipes C. In sewer treatment plants D. None of these
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 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 : 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 : 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 : 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 : 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 : Q No: 291 The coagulant widely used for sewage treatment, is A. Alum B. Ferric chloride C. Ferric sulphate D. Chlorinated copperas
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 : 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 : 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
Description : The sewage is pumped up A. From low lying areas B. From flat areas C. From basements D. All the above
Description : In sewage having fully oxidised organic matter, the nitrogen exists in the form of A. Nitrites B. Nitrates C. Free ammonia D. Aluminoid nitrogen
Description : Dry water flow in a combined sewer, is A. Industrial sewage B. Domestic sewage C. Storm water D. Inclusive of domestic and industrial sewage but excludes storm water
Description : The presence of free ammonia in sewage, is detected by A. Boiling B. Adding potassium permanganate C. Adding sulphuric acid D. Phenol-di-sulphuric acid
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 : 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 : The sewage treatment in septic tanks is due to A. Anaerobic decomposition B. Aerobic decomposition C. Parasitic decomposition D. None of these
Description : A rain sanitary sewer is constructed to carry A. Sanitary sewage B. Storm sewage C. Surface water D. Ground water
Description : Fresh sewage is generally A. Alkaline B. Acidic C. Highly decomposed D. A source of objectionable odour
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 : The design period of sewage treatment works in normally A. 5 – 10 years B. 15 – 20 years C. 30 – 40 years D. 40 – 50 years