Question

As per IS 10313:1982, which of the following factors does NOT influence the sedimentation process in a sedimentation tank ?
1. Surface overflow
2. Size. shape and weight of particle
3. Inlet and outlet arrangement
4. pH value of water

Answer 1

Correct Answer - Option 4 : pH value of water

Concepts:

As per IS 10313: 1982, the factors that influence sedimentation are:

1. Size, shape and weight of particle;
2. Viscosity and temperature of water;
3. Surface overflow;
4. Surface area;
5. Velocity of flow;
6. Inlet and outlet arrangement;
7. Detention periods; and
8. Effective depth of basins.

 

Additional Information:

Sedimentation usually finds application in two principal ways in water treatment, that is, plain sedimentation and sedimentation following coagulation, flocculation or softening.

 1. Plain sedimentation is used to remove settleable solids that occur naturally in surface waters. These solids settle without any previous treatment. Plain sedimentation is usually used as a preliminary process to reduce heavy sediments prior to subsequent treatment process such as coagulation.

2. Sedimentation following chemical coagulation and flocculation is used to remove suspended solids that have been rendered settleable by chemical treatment.