Questions

A two$-$stage cascade aerator is used for the aeration of groundwater with a concentration of $1\mathrm{.}3g\frac{O_2}{m^3}.$ The $O_2$ concentration of the aerated water is $6\mathrm{.}5g\frac{O_2}{m^3}$ and the temperature is $10C.$ Since this oxygen concentration was not considered sufficient, the construction of a third stage was planned. What will be the dissolved oxygen content after the third stage? If the groundwater were anaerobic, what would be the dissolved oxygen concentration after the third stage?

Hir$*$

$C_e=6\mathrm{.}5\frac{g}{m^3},10C$

$C_s=11\mathrm{.}3$

$C_{}=1\mathrm{.}3\frac{g}{m^3}$

$\frac{C_e-C_0}{C_s-C_0}=K$