ANALYTICAL SOLUTIONS FOR TRANSFORMATION OF TCE THROUGH ARGILLACEOUS MEMBRANES WITH OR WITHOUT A BIOFILM

Compacted argillaceous membranes with biomass immobilized on the outside surface or within the membrane matrix may be a viable biostimulated remediation alternative to treating chlorinated hydrocarbons. The majority of these toxic substances and their metabolites are the most frequently observed groundwater contaminants in the United States. Hyperfiltration (reverse osmosis) has been adopted in attenuation and/or remediation of chlorinated hydrocarbons with most membranes employing aerobic conditions to treat recalcitrant compounds. The benefits of biostimulated montmorillonite reverse osmosis systems in mitigation of chlorinated organics under anaerobic conditions have largely been ignored. Specifically, the following questions for prototype systems need to address the following: (1) what kinetic adsorption rates would be observed between organic contaminant and membrane and/or immobilized biofilm/membrane matrix? (2) What biofilm growth and loss rates would be observed? (3) What influent concentrations can be accurately modeled? (4) What final contaminant concentration is attainable? (5) How long will transformation processes take place for the reaction chain TCE→c-DCE→VC (vinyl chloride) and possibly VC→CH₂CH₂→CH₃CH₃?, and (6) Will predicted levels of the very toxic compound VC be above the maximum permissible concentration levels? Some specific objectives that also need to be addressed would include developing 1) a numerical model with empirically derived parameters for chlorinated-organics transport and fate through compacted montmorillonite slurry that can be applied to pilot systems, 2) a rapid method to quantify the amount and compaction pressures of montmorillonite needed for effective hyperfiltration of known influent concentrations, 3) a chemical speciation algorithm that would determine ideal conditions for the stability of daughter products, and/or 4) a spectral absorbance library of mineralogical changes and basal spacing changes of the montmorillonite membrane post-filtration.