The gas from sludge digestion tank is mainly composed of __________________?

Related Mcqs:

1. For satisfactory working of a sludge digestion unit, the pH range of digested sludge should be maintained as___________________?

   A. 4.5 to 6.0
   B. 6.5 to 8.0
   C. 8.5 to 10.0
   D. 10.5 to 12.0

2. For normal sludge, the value of sludge index for Indian conditions is________________?

   A. 0 to 50
   B. 50 to 150
   C. 150 to 350
   D. 350 to 500

3. For the same solid content, if the quantity of sludge with moisture content of 98% is X, then the quantity of sludge with moisture content of 96% will be__________________?

   A. X/4
   B. X/2
   C. X
   D. 2X

4. Sludge volume index is defined as the ratio of_______________?

   A. percentage of sludge by volume to percentage of suspended solids by weight
   B. percentage of sludge by volume to percentage of total solids by weight
   C. percentage of suspended solids by weight to percentage of sludge by volume
   D. percentage of total solids by weight to percentage of sludge by volume

5. The length of rectangular sedimentation tank should not be more than_______________?

   A. B
   B. 2B
   C. 4B
   D. 8B

   where B is the width of the tank

6. The settling velocity of a particle in a sedimentation tank increases if______________?

   A. particle size is decreased
   B. the surface area of tank is increased
   C. the depth of tank is decreased
   D. none of the above

7. Septic tank is a______________?

   1) settling tank
   2) digestion tank
   3) aeration tank
   The correct answer is?

   A. only (1)
   B. (1) and (2)
   C. (1) and (3)
   D. only (3)

8. For a given discharge, the efficiency of sedimentation tank can be increased by______________?

   A. increasing the depth of tank
   B. decreasing the depth of tank
   C. increasing the surface area of tank
   D. decreasing the surface area of tank

9. The settling velocity of a particle in a sedimentation tank increases if_________________?

   A. particle size is decreased
   B. the surface area of tank is increased
   C. the depth of tank is decreased
   D. none of the above

10. The velocity of flow of water in a sedimentation tank is about__________________?

    A. 5 to 10 cm/sec.
    B. 15 to 30 cm/sec.
    C. 15 to 30 cm/minute
    D. 15 to 30 cm/hour