Technology Description

In this process, the readily biodegradable glycerol will stimulate anaerobic biodegradation of the target contaminants and will reduce naturally occurring Fe(III) oxides and hydroxides to Fe(II). This Fe(II) will provide a reservoir of reducing power to maintain anoxic conditions in the soil and will enhance abiotic degradation of RDX and other contaminants. The humic materials will also maintain reducing conditions by consuming oxygen, enhancing hydrophobic sorption, and enhancing covalent binding of TNT, and they may potentially serve as electron shuttles, enhancing abiotic degradation by Fe(II). The humic material is also expected to enhance sorption of any heavy metals that may be present. Irrigation and transport of the amendments at least 0.25 m into the soil profile will be important to reduce fire hazards, generate more strongly reducing conditions, and increase treatment longevity. The process builds heavily on prior work supported by SERDP (ER-1229) and ESTCP (ER-200434) that showed a combined peat-soybean oil treatment could be effective in reducing contaminant flux through the vadose zone.

This project will focus on developing a practical, easy to deploy technology that does not generate a fire hazard and does not interfere with training activities. A long-established, operational burn ground will be treated to reduce concentrations of perchlorate and other energetic compounds in the vadose zone. A phased approach will be used, consisting of (1) laboratory column studies to identify mixtures of glycerol or humic materials that are effective in treating contaminated soils in situ and preventing leaching of contaminants deposited in the future; (2) medium-scale field pilot tests to evaluate treatment performance under representative field conditions; and (3) a large-scale field demonstration of the technology on a heavily impacted burn area.