A continuous flow stirred tank reactor (CSTR) operates under a steady-state condition with a flow rate of $300$ $\text{L}$ per hour. The influent concentration of a substrate entering the reactor is $150 \mathrm{mg} / \mathrm{L}$.
To give a treatment efficiency of $76 \%$ for the substrate that decays according to halforder kinetics with a rate constant of $0.05(\mathrm{mg} / \mathrm{L})^{1 / 2}$ per hour, the required volume of the reactor is $\_\_\_\_$ $\mathrm{m}^{3}$ (answer in integer).
