Hydrogen donors for reduction of RDX, 2,4-DNT, and nitrate in groundwater

摘要

The Pueblo Chemical Depot, located east of Pueblo, CO, is typical of a number of U.S. facilities that were involved in weapons manufacturing, training and testing, or demilitarization in which the soil and groundwater became highly contaminated with explosives residues and are needing remediation. In this study, soil amendments of Hydrogen Release Compound (R) (HRC (R)), sodium lactate and corn syrup were evaluated in bench-scale batch reactors, mimicking in situ treatment, to determine the effectiveness of hydrogen donors on the remediation of soil contaminated with primarily RDX, but also 2,4-DNT, and excessive nitrate. Bench-scale batch reactors made from 55-gallon drums were designed to simulate aquifer conditions with site soil and contaminated groundwater. HRC (R) and corn syrup achieved the groundwater cleanup levels of 0.25 mu g/L for RDX by day 25 of the study, 0.0885 mu g/L for 2,4-DNT by day 7, and 1.0 mg/L for nitrate by day 7, reducing their average concentrations from 10.48 +/- 0.48 mu g/L, 0.34 +/- 0.15 mu g/L, and 99.7 +/- 11.5 mg/L, respectively. The sodium lactate groups did not reach the groundwater cleanup goals for RDX, 2,4-DNT, or nitrate before returning to an oxidizing state. This indicates that HRC (R) and corn syrup are suitable electron donors for bioremediation, while sodium lactate may not be the best option for the remediation of RDX, 2,4-DNT, and nitrate.