Q. Sewer pipes are designed for maximum discharge with 25% to 33% vacant cross-sectional area for

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Q. 5 days-biochemical oxygen demand (BOD₅) is taken at a temperature of

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Q. Water content of sewage is about

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Q. Imhoff cone is used to measure

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Q. For a grit chamber, if the recommended velocity of flow is 0.2 m/sec and detention period is 2 minutes, the length of the tank, is

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Q. If the peak discharge of a storm water drain (S.W. Drain) is e.xpected to exceed 150 cumecs, the free board to be provided, is

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Q. PH value of sludge during alkaline regression stage, is

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Q. Depletion of ozone layer in the outer atmosphere may cause

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Q. The spacing of bars of perforations of fine screens used for the treatment of sewage, is

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Q. The self-cleansing velocity of water flowing through pipe lines, is

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Q. The pH value of fresh sewage is usually

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Q. The moisture content of a sludge is reduced from 90% to 80% in a sludge digestion tank. The percentage decrease in the volume of sludge, is

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Q. Inter-distance between ventilation columns in a sewer line is kept

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Q. The factor responsible for purification of sewage in river is

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Q. 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 day-incubation at 20°C, the DO. concentration was 5 mg/l. The BOD of raw sewerage is

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Q. The arrangement made for passing the sewer line below an obstruction below the hydraulic gradient lines called

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Q. The angle subtended by the surface of sewer water with partial flow, at sewer centre is 120°, the depth of sewerage is

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Q. Imhoff cone is used to determine

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Q. 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

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Q. If the grit in grit chambers is 4.5 million litres per day, its cleaning is done

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