Waste Water Engineering Questions

• For design of sewers, percentage of sewage discharge is assumed
• For a peak discharge of 0.0157 cumec, with a velocity of 0.9 m/sec, the diameter of the sewer main, is
• A circular sewer section is preferred to because
• The sewer which transports the sewage to the point of treatment, is called
• The porosity of sediments in sewer pipes, is usually taken as
• 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
• Pick up the correct statement from the following :
• Imhoff cone is used to determine
• In septic tanks, decomposition of organic bacteria, is done by
• Pick up the incorrect statement from the following :
• A nuisance is experienced in diluting water if dilution factor is less than
• Drop manholes at the junctions of sewer lines, are provided if
• In sewage, the solids in mg per litre is
• In case of sewer lines
• 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 deposition leading to complete blocking of the sewer.
• 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
• The arrangement made for passing the sewer line below an obstruction below the hydraulic gradient lines called
• If a paper moistened with lead acetate for five minutes when placed in manhole turns black. The sewer certainly contains
• A safety lamp when inserted in the upper portion of a manhole causes flames. It indicates the presence of
• To test chemical oxygen demand (C.O.D.) of sewage, organic matter is oxidised by pottassium dichromate in the presence of