The maximum depth of sedimentation tanks, is kept A. 3 m B. 3.5 m C. 4 m D. 4.5 m

3 m
3.5 m
4 m
4.5 m

The maximum depth of sedimentation tanks is kept at 3.5 meters. This is because the settling velocity of particles in water decreases with increasing depth. Therefore, if the depth of the tank is too great, the particles will not have enough time to settle out before they reach the bottom of the tank. This can result in the particles being carried out of the tank with the effluent.

Option A is incorrect because it is too shallow. Option B is incorrect because it is too deep. Option C is incorrect because it is not a multiple of 0.5 meters. Option D is incorrect because it is too deep.