Remediation of Explosives Contaminated Groundwater With Zero-Valent Iron
Abstract
A series of laboratory and field studies was performed to evaluate the in situ degradation of TNT and RDX using permeable reactive barriers (PRBs) made with zero-valent iron (ZVI). The disappearance of both TNT and RDX were shown to be rapid in the laboratory and ex situ field columns. Batch experiments performed with 14C-labelled TNT have showed that the products of reaction with iron metal are partly sequestered on the metal (oxide) particle surfaces. Most of the bound residue could not be solubilized using a range of extraction procedures. However, batch studies over a range of experimental conditions show considerable variability in the degradation products, while the primary TNT degradation product in column studies is TAT. Ex situ column experiments at the Umatilla Chemical Weapons Depot were used to examine the viability of the ZVI under field conditions. This site is challenging because the dissolved oxygen concentration is high. A series of column experiments were conducted at the site: including columns with 10%, 20%, 30%, and 100% iron by volume is silica sand. In all of these cases, oxygen is rapidly scrubbed from the water by the iron. For the low iron cases, oxygen and RDX breakthrough occurred after several thousand of pore volumes. The columns with higher iron content (30%, 100%) plugged after time. In at least some cases this was due to particulates coming from the column.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 2011
- Accession Number
- ADA553667
Entities
People
- Paul G Tratnyek
- Richard Johnson
Organizations
- Oregon Health & Science University