$1.$ Industrial wastewater effluent is discharged into a $1\mathrm{.}0$ x $10^9$ m$3$ lake and contains $7\mathrm{.}0$ x $10^-6$M benzene

$($C$6$H$6).$ The industrial wastewater discharge stream has a flowrate of $8$ m$3/$s$.$ The stream feeding the lake

has a benzene concentration of $1\mathrm{.}0\backslash$mu g$/$L and a flowrate of $100$ m$3/$s$.$ Benzene has a decay rate of $0\mathrm{.}038$

day$-1.$

a$)$ What order is the reaction rate?

b$)$ What is the concentration of benzene in $\backslash$mu g$/$L in the lake after mixing?

c$)$ What is the maximum contaminant limit $($MCL$)$ for benzene $($check Table $6-1)?$ Does the concentration

you calculated in $($b$)$ meet the MCL set by the Safe Drinking Water Act?

Draw a diagram, write governing equations, and state all assumptions.