Hydraulics Analysis for Groundwater Flow Through Permeable Reactive Barriers

Groundwater flow modelling is an important tool in simulating and predicting hydraulic behaviour of groundwater transporting in the domain consisted of groundwater flow zone (aquifer) and permeable reactive barriers (PRBs). The aquifer regime is modelled using the Darcy equation, whereas PRBs are simulated by the Brinkman equation. By combining the above equations, the present paper is devoted to analyse the effect of permeability of aquifer (K (aq) ) and reactive media (K (p) ), groundwater flow velocity, and barrier size as well as assembled style of barriers on key barrier design parameter, such as the hydraulic capture zone width. The simulations indicate that the capture zone width generally decreases with a decrease in K (p) at a given K (aq) ; however, there is relatively little decrease in capture zone width when the K (p) of freshly installed reactive media is roughly 10 times higher than the K (aq) . For a given barrier system, the absolute capture zone width increases with an increase in barrier size, whereas the increment of relative capture zone width decreases dramatically. Although the capture zone width remains relatively unchanged as groundwater flow velocity increases, it results in a shorter residence time in the reactive media that may require greater barrier thickness so that contaminant levels can be reduced to regulatory limits. In addition, the effect of parallel barriers interaction on the capture zone width should be incorporated into the design. The present paper is based on the continuous reactive barrier and homogeneous barrier system. Similar methods can be used to analyse the hydrodynamics of funnel-and-gate system and heterogeneous settings by the appropriate modification.