A continuous flow completely mixed reactor $($CFCMR$)$ with solids recycle has

a biomass concentration of $4000$ mg MLSS$/$L is used to reduce the

concentration of the organic matter from $300$ to $30$mgBO$\frac{D_5}{L}($soluble$).$

What is the sludge and hydraulic detention times needed to achieve this goal?

The following data is given:

${}_m=1\mathrm{.}2d^{-1},Y=0\mathrm{.}65\frac{mgMLSS}{mgBO{D}_5},K_s=250$mgBO$\frac{D_5}{L},K_d=0\mathrm{.}06d^{-1}$