Underlying Mechanisms in Groundwater Remediation via In Situ Chemical Oxidation

Remediation of groundwater contaminated by organic compounds in porous and fractured media is a persistent and not well understood challenge. In situ chemical oxidation (ISCO) is a remediation technology that delivers oxidants to the subsurface to transform contaminants into benign products. The reactions take place in the aqueous phase where the oxidant comes in contact with the dissolved phase of the contaminant. In this work, we report on the impact of by-product formation on the effectiveness of ISCO. We conducted a series of batch experiments to identify by-products and increase our understanding for time scales required for complete mineralization of petroleum hydrocarbons. This was coupled with micro-CT imaging of column experiments and imaging in a glass fractured rock replica to track the formation of gaseous and solid by-products and determine their effect on flow, transport, and mass transfer. The final aim of this study is to propose novel strategies for improved remediation efficiency.