SEQUENTIAL ELECTROLYTIC DEGRADATION OF ENERGETIC COMPOUNDS IN GROUNDWATER

Recent research at Colorado State University (CSU) has demonstrated the potential utility of electrolytic degradation of organic compounds in a permeable reactive barrier format (e-barriers). Investigations to date have demonstrated that e-barriers can degrade aqueous chlorinated solvents in a laboratory setting through sequential oxidation and reduction. In principle, an electrolytic approach to degrade cyclic organic compounds such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) or trinitrotoluene (TNT) can overcome limitations of management strategies that involve solely oxidation or reduction, through sequential oxidation-reduction or reduction-oxidation. The objective of this project was to evaluate degradation of aqueous RDX and TNT in flow-through electrolytic reactors. A total of six identical column reactors packed with quartz feldspar sand were used in the experiment. Three columns tested TNT degradation and three tested RDX degradation. Electrode sequence was varied between columns and one column for each contaminant acted as a no-voltage control. Over 97% of TNT and 93% of RDX was removed in the reactors under sequential oxidation-reduction. Significant accumulation of known degradation intermediates was not observed under sequential oxidation-reduction. Removal of approximately 90% of TNT and 40% of RDX was observed under sequential reduction-oxidation. 4-Amino-DNT accumulation was observed in the TNT reactors under sequential reduction-oxidation. Power requirements on the order of 3 watt/m² were measured during the experiment, suggesting that an electrical approach may be feasible for management of groundwater contaminated with explosive compounds.