A wastewater having $250m\frac{g}{\text{I}}$COD is treated in a CSTR with recycle having substrate removal rate, $q=0\mathrm{.}4kg$ COD$/$kg VSS$.$day and hydraulic retention time of $8$ hours. Coefficients;

${}_{\text{m}\text{a}\text{x}}=7\mathrm{.}2da{y}^{-1},Ks=100m\frac{g}{\text{I}}$COD,$Y=0\mathrm{.}6gVS\frac{S}{g}$COD,$k_d=0\mathrm{.}05da{y}^{-1}$

$Q=1m\frac{3}{d}ayVS\frac{S}{S}S=0\mathrm{.}8$

a$)$ The sludge age

b$)$ Effluent COD

c$)$ Biomass concantration $($X$)$

d$)$ Sludge amont to be wasted $($ Px $)$

e$)$ Sludge waste flowrate for $xr=10000m\frac{g}{\text{I}}$