Abstract

Conventional pump-and-treat (P&T) is an applicable component of many remedial systems. However, such a system will not be appropriate to achieve restoration in portions of many sites due to hydrogeologic and contaminant-related limitations. This includes the presence of significant accumulation of DNAPLs (denser-than-water nonaqueous phase liquids) trapped below the water table. Here chemical enhancements to P&T shows some promise by mobilizing or dissolving the contaminants. However, this will make a portion of the injected chemicals and the contaminant to cross the boundary of the targeted site that causes the loss of chemicals and results in pollution migration to uncontaminated areas. To confine the flow of the injected chemical to the target site, traditionally one sets up physical barriers around the boundaries of the site. In the present study, simple hydrodynamic principles related to image wells are used to provide hydrodynamic barriers around the site. Simple mathematical model and laboratory experiments were developed to assess the effectiveness of hydrodynamic barriers. The study shows that the degree of leakage of the chemicals injected into the target site can be controlled by the proper choice of the system of image wells set outside the target area. For more realistic systems, further study is needed to define its applicability