Improved Understanding of In Situ Chemical Oxidation Soil Reactivity
Abstract
The overall goal of Technical Objective 2: Soil Reactivity for this project was to assess how soil properties (e.g., soil mineralogy, natural carbon content) affect oxidant mobility and stability in the subsurface, and develop a standardized natural oxidant demand (NOD) measurement protocol. To fulfil this objective, materials from nine sites were obtained for use in this investigation and characterized with respect to physio-chemical properties and evaluated with respect to their total theoretical and experimental reductive capacity. These materials were then used in batch and column experiments with three oxidants, permanganate, Fenton s reagent and persulfate to evaluate the fundamental chemical properties affecting oxidant consumption, the maximum NOD of aquifer materials, kinetic behaviour of permanganate with various aquifer materials and oxidant transport. Theorectical Reductive Capacity (TRC) The TRC was evaluated as the sum of the reduced equivalencies of species associated with a given aquifer material that is required to convert them to their corresponding naturally occurring highest stable oxidation states using the analytical data. TRC was also evaluated experimentally using a dichromate chemical oxygen demand method. The results from a correlation analysis indicate that there is a strong linear relationship between the dichromate COD test results and TOC content. Further correlation analysis results showed that linear relationships do not exist between either TRC or Dichromate COD and any combinations of total Fe, total Mn, amorphous Fe, and amorphous Mn (r2 < 0.5). The impact of air-drying was also evaluated, and in general, the reduction capacity as measured by the various tests was higher for the nitrogen dried samples relative to the nitrogen dried/air exposed and air dried samples, but was not statistically significant for most sites likely due to reduction capacity heterogeneity within each aquifer material.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2007
- Accession Number
- ADA603998
Entities
People
- Kammy Sra
- Neil Thomson
- Xiuyuan Xu
Organizations
- University of Waterloo