Assume that Styrene is continuously discharged after aeration at a concentration of $100$ mg$/$L into the river flow, is not conservative $($no volatilization, no reaction, but can be adsorbed by the sediment$).$ You can model the system as $5,1$ km completely mixed reactors that are inline. The total sediment that interacts with the water is $5$ cm deep over the area of the sediment water interface $($dry bulk density of soil is $1\mathrm{.}5$ g$/$cm$3),$ and it is always at equilibrium with the water. The Kd for this soil$/$Styrene system is $98$ L$/$kg$.$ A$)$ what is the concentration of styrene in the sediment. B$)$ If we stop the discharge and only clean water flows into our system, when will the sediment concentration drop below the $10$ mg$/$kg in the all sediment. $($Model Advective Transport only, no diffusion$)$