In a continuous flow settling tank, $3\mathrm{.}5$ m deep and $65$ m long, if the flow velocity of water observed is $1\mathrm{.}22$ cm$/$s$,$ what size of the particles of specific gravity $2\mathrm{.}65$ may be effectively removed? Assume temperature $25\backslash$deg C and kinematic viscosity of water as $0\mathrm{.}01$ cm$^3/$s