Example problem

$3$:

An environmental engineer mapping contaminant fate and

transport observes that groundwater flow though a specific

aquifer removes a colour causing contaminant from the

water. The engineer is confident that the colour$-$causing

contaminant is removed via adsorption. If the rate constant

for adsorption is $0\mathrm{.}35/$day$,$ how long will it take to remove

$90\%$ of the colour causing contaminant?$$

Set$-$up a mass balance analysis$($ the mass balance equation etc$)$ based scheme for solving

this problem, ending with you providing a solved equation

that can be used in resolving this problem. DO NOT SOLVE

THE PROBLEM! Draw a sketch of the problem$($It is an environmental engineering question$)$