NGWA Event and Education Recordings Archive

The remediation of groundwater impacted by DNAPL is of public interest and remains a significant challenge facing many industrial sectors in Alberta and around the world. DNAPL constituents are hazardous compounds which have been shown to be toxic, mutagenic, and/or carcinogenic. An additional issue is the migration of the soluble plume off-site, yielding significant environmental and financial liabilities as well as public pressure on the site proponent. The primary objectives of this study are to ascertain (1) chemical/physical degradation of selected DNAPL constituents, (2) sorption characteristics of DNAPL constituents, (3) travel time modeling, (4) reactions of fluorescein tracer with ClO₂, (5) infiltration galleries for ClO₂ introduction into the groundwater. Sorption of DNAPL constituents on core samples retrieved from the site groundwater fabric could be best described mathematically by the Freundlich than Langmuir sorption model. Kd values derived at 6^oC ranged from 3.05 to 0.89 L/kg. Chemical degradation of DNAPL constituents could be best fitted to a first-order kinetic with a three-hour optimum reaction time. The results also indicate that UV radiation combined with ClO₂ can be an effective method for chemically degrading PAH, PCB-S, SVPHEN-S, F24FIDE-S, and BTEXHSAB-S contaminants. Treatment system of UV/ClO₂ at pH 3.5 was found to be the most effective degradation system. Dioxins or furans as by-products of chemical reactions were not detected. Practical implications for solutes DNAPL plume transport in the saturated zone were evaluated using a conservative approach to the contaminants. Calculated travel time for potential off-site migration ranged from 150 to 80,817 years. A testing program of infiltration gallery system was successfully evaluated in the laboratory.