Presentation Description
Long-term Geochemical Effects of Permanganate ISCO: A Review of Data from 30 Field Sites
A review was conducted of data from 30 sites where permanganate in situ chemical oxidation (ISCO) was implemented.  The goal was to determine statistically if there were long-term geochemical impacts from permanganate ISCO and if impacts correspond with specific site or design conditions.  To be included in the study sites must have had (1) at least one full year of post-implementation data; (2) well-documented pre- and post-oxidation site and geochemistry data; (3) well-documented ISCO system design information (i.e., delivery methods, concentration of oxidant used, and mass of oxidant delivered); and (4) full reports (including adequate QA/QC sections) from state and federal agencies or other peer-reviewed sources.  Evaluations focused on post-ISCO pH, ORP, Mn, and Cr values.  Results indicate that there are limited long-term impacts to site groundwater geochemistry (i.e., water quality indicators approach pre-oxidation levels within 2 years of implementation); and  that site and design conditions do dictate short-term geochemical effects (i.e., especially site media type, mass of oxidant injected, and initial ORP.  For example, manganese concentrations and its persistent were greater for
sites with higher initial ORP, permeable and homogeneous media, and a higher total mass of injected permanganate (but not higher concentration).