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Chemical Engineering :: Environmental Engineering

  1. Water filtration rate in a slow sand filter ranges from __________ litres/m2/hr.

  2. A.
    10 to 20
    B.
    100 to 200
    C.
    1500 to 2500
    D.
    4000 to 5000

  3. Lagoons used for purification of polluted water

  4. A.
    are large shallow artificial lakes also known as clarification lakes, maturation ponds or oxidation ponds.
    B.
    use micro-organisms/bacteria in presence of dissolved oxygen.
    C.
    gives an excellent final effluent (with 3 to 4 lagoons arranged in series) having suspended solid < 1 mg/litre and BOD = 3.8 mg/litre.
    D.
    all (a), (b) & (c).

  5. The principal gas evolved from sludge digestion tank is

  6. A.
    CO
    B.
    CO2
    C.
    CH4
    D.
    N2

  7. There are thirteen metals which are treated as pollutants. Which of the following metals is not a pollutant ?

  8. A.
    Mercury
    B.
    Arsenic
    C.
    Aluminium
    D.
    Lead

  9. The function of skimming tank in sewage treatment is to remove __________ substances.

  10. A.
    dissolved solid
    B.
    suspended solid
    C.
    oil & fatty
    D.
    gritty & inorganic

  11. The weakest sound that can be heard by a person in a quiet environment is equivalent to __________ decibel.

  12. A.
    1
    B.
    5
    C.
    10
    D.
    20

  13. Inorganic impurities causing water pollution is

  14. A.
    fats
    B.
    carbohydrates
    C.
    salts of metals
    D.
    protein

  15. The main type of sludge gas evolved during sewage treatment in Imhoff tank is

  16. A.
    CO2
    B.
    CH4
    C.
    CO
    D.
    H2

  17. From pollution control point of view, the maximum permissible concentration of sulphur dioxide in atmospheric air is about __________ ppm.

  18. A.
    1
    B.
    5
    C.
    50
    D.
    500

  19. The pH value of oxidised sewage is about

  20. A.
    1.8
    B.
    6.2
    C.
    7.3
    D.
    13.4