A sedimentation tank of height $100 \textit{ cm}$ is used in a conventional activated sludge process to separate a suspension of spherical shaped granular sludge biomass of $0.5 \textit{ mm}$ diameter. The viscosity of the liquid is $1 \textit{ cP}$. The difference in density between the suspended biomass and the liquid is $0.1 \textit{ g cm}^{-3}$. If the biomass reach their terminal velocity instantaneously, the biomass settling time in $\textit{min}$ (rounded off to two decimal places) is ___________