Contaminant Mass Flux Changes With Induced Oxide Mineral Precipitation At The Up-Gradient Dnapl Source Zones

In this study, we investigated the feasibility of TCE source zone flow reduction using chemical oxidant of KMnO4. The flow reduction by the induced mineral formation at the source zone has been studied through numerical case studies so far. By considering actual flow and transport condition of fields, low concentration of permanganate is applied and pseudo-multidimensional setting of parallel column connection is utilized in the experiments. The combined effects of mass reduction and flow change are quantified based on lab experiments in which low concentration of potassium permanganate within limited time is introduced into the experiments. The observations indicate that partial source mass reduction due to chemical oxidation is effective for mass flux decrement even for lower concentration of permanganate. The water flux was decreased only for the period of KMnO4 flushing due to MnO2 precipitation but rebounded right after the finish of the flushing. It is suspected that 1) reduced aqueous TCE concentration during the flushing period accelerate TCE mass transfer and cause relative permeability increase; 2) initially small amount of MnO2 formed or Mn2+ ions formed under very low pH during KMnO4 flushing time.