Permeable Reactive Barrier $($PRB$)$ Design $(+15)$

Some of the contamination under the tank farm area at the Centre County Kepone Superfund Site has

moved into the saturated soils and is migrating slowly downgradient through a clay lens. Design an in situ

permeable reactive barrier wall to treat $725m\frac{g}{L}1,1,2,2-$TCA in groundwater. Characteristics of the local

aquifer indicate that the thickness of the clay lens is approximately $5$ feet, the porosity is $0\mathrm{.}45,$ and the

average linear groundwater velocity is $0\mathrm{.}8ft/$day$.$ You may assume that the plume of contamination extends

throughout the depth of the clay lens $(5$ feet$)$ and that it is $160$ feet wide $($which is the width of the tank farm

area$).$ Design an in situ permeable reactive treatment wall of zero valent iron $(Fe)$ to treat the

contamination.

a$.$ Calculate the minimum amount of $Fe$ in metric tons needed to degrade the plume down to $1u\frac{g}{L}.$

Answer: $M=2\mathrm{.}5$ metric tons