The velocity at which the soil particles will remain in suspension without settling in the bottom of a sewer is called:

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Detailed Solution:

Self cleansing velocity = V = {(8kgd(G-1)/f}½,

where k is constant depend upon type of solid in the sewage

f = friction factor

d= diameter of particle

g= acceleration due to gravity

G= specific gravity of solid

Note;-

v= 0.45m/sec for 1mm Inorganic particles and for 5mm organic particles

v should be greater than 0.8 -0.9m/sec  if sewer designed for design flow condition and velocity at design depth of flow