CONCEPTUALIZING RDX-PERMANGANATE-BROMIDE MOVEMENT DURING AN IN SITU REMEDIAL TREATMENT OF CONTAMINATED GROUNDWATER

It is not uncommon for groundwater remedial programs to have an inadequate number of observations needed for spatial resolution of plume size or heterogeneity. Therefore, ad hoc methods relying on several monitoring wells, direct push methods, regional water table or hydraulic head information, and laboratory transport experiments are often the only available tools for designing remediation strategies. This situation is analogous to natural gradient tracer test where observed plume behavior deviates from projected trajectory or configuration. Our objective was to determine if sodium permanganate could remediate an RDX-contaminated aquifer in situ. This was accomplished by extracting groundwater from a center well, spiking it with permanganate and bromide and injecting it into two lateral wells in an effort to create a curtain of permanganate. A previous study at the same location had injected acetate in a similar manner but the monitoring well network was not sufficient to effectively track plume trajectory. Our results showed improved plume delineation by strategic placement of additional monitoring wells that allowed for improved aquifer characterization. We also used non-invasive geophysical techniques such as electrical resisitivity imaging to track permanganate within the treated area. These additional measurements allowed us to better conceptualize permanganate movement and quantify the efficacy of the remediation treatment.