QUESTION $9$

A one meter diameter packed tower aerator is used to remove chloroform from treated and disinfected surface water to meet the Disinfection By$-$products Rule. The influent chloroform concentration is $120m\frac{g}{L}$ and the desired effluent concentration is $25m\frac{g}{L}.$ The design water temperature is $10C$ and the average flow rate is $2,270\frac{m^3}{d}.$ The Henry's law constant for chloroform is $3\mathrm{.}67$atm$*\frac{m^3}{k}$mol, and the transfer rate constant is $0\mathrm{.}008s^{-1}.$ When the airflow rate is $30$ times the water flow rate, the aerator height is most nearly:

a$)8\mathrm{.}4$ m

b$)12\mathrm{.}6$ m

c$)6\mathrm{.}2$ m

d$)10\mathrm{.}7$ m