The settling velocity of a particle in a sedimentation tank depends on__________________?
(A) depth of tank
(B) surface area of tank
(C) both depth and surface area of tank
(D) none of the above
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
The detention period in coagulation tanks is usually kept as_______________?
(A) 1 to 2 minutes
(B) 30 to 45 minutes
(C) 2 to 6 hours
(D) 2 to 6 days
The chemical most commonly used to increase speed of sedimentation of sewage is_______________?
(A) sulphuric acid
(B) copper sulphate
(C) lime
(D) sodium permanganate
The rate of filtration in slow sand filters in million litres per day per hectare is about_____________?
(A) 50 to 60
(B) 100 to 150
(C) 500 to 600
(D) 1400 to 1500
Air binding phenomena in rapid sand filters occur due to_________________?
(A) excessive negative head
(B) mud ball formation
(C) higher turbidity in the effluent
(D) low temperature
The phenolic compounds in public water supply should not be more than_______________?
(A) 0.1 ppm
(B) 0.01 ppm
(C) 0.001 ppm
(D) 0.0001 ppm
The maximum discharge of a tube-well is about_________________?
(A) 5 litres/sec
(B) 50 litres/sec
(C) 500 litres/sec
(D) 1000 litres/see
Ground water is usually free from________________?
(A) suspended impurities
(B) dissolved impurities
(C) both suspended and dissolved impuri¬ties
(D) none of the above
Standard EDTA (ethylene diamine tetra acetic aciD. solution is used to determine the_______________?
(A) hardness in water
(B) turbidity in water
(C) dissolved oxygen in water
(D) residual chlorine in water