Benzene Migration In Unsaturated Profile With Subsurface Drainage Concrete Pipe

The impact of benzene leakage on underlying unsaturated zone and nearby subsurface drainage concrete pipe is investigated. Work in the paper considers mass transfer into subsurface concrete pipe located in unsaturated profile. The 3D numerical simulations were implemented using the T2VOC code with the Petrasim2018 graphical user interface to analyze multiphase migration in the vadose zone and the impact on the concrete pipeline installed in a trench. The contaminant's gas, aqueous, and free product phases are assessed based on the model physical properties of soil and concrete materials. A case study is presented with data from a site located in the coastal plain physiographic region of North Carolina (NC). The site is a gas station located near the town of Jacksonville, NC. The analyses consider the effect of depth to groundwater table and volatilization into the atmosphere. The results illustrate the transport of the three phases in unsaturated soil domain and the potential of having the gas and aqueous phases breakthrough the subsurface concrete pipe.