Bioavailability and Remediation of Complex DNAPLs

Background
The ability to conduct accurate risk assessments of the potential human-health-related impacts of contaminated sites relies on understanding site characteristics and factors influencing contaminant bioavailability in the subsurface. An enhanced understanding of contaminant transport and fate processes in subsurface systems is needed to ensure accurate risk assessment.

Schematic of vertical circulation well system used in combination with enhanced sloubiliation agent for removal of immiscible organic liquids from the subsurface.

Goal
To enhance our understanding of the dissolution, bioavailability, and remediation of complex, multiple-component, dense nonaqueous-phase, immiscible organic liquids (DNAPLs) in subsurface systems.

Objectives
1. Investigate the effect of DNAPL composition and mass-transfer constraints on the dissolution of complex (multiple-component) DNAPL.

2. Investigate the bioavailability and biodegradation of complex DNAPLs.

3. Investigate the effect of solubilization agents on the dissolution and bioavailability of complex DNAPLs.

4. Develop and evaluate advanced mathematical models capable of simulating the dissolution, biodegradation, and transport of DNAPL constituents in heterogeneous porous media.

Significant Findings
1. Completed studies to investigate the impact of NAPL composition and mass transfer constraints on NAPL dissolution and evaporation. The results of this research have provided greater understanding of the evaporative mass-transfer behavior of complex immiscible liquids.

2. Developed a novel approach to allow simultaneous in-situ characterization of solute concentration and microbial activity (biodegradation) under transport conditions.

3. Conducted pilot-scale (demonstration) tests to evaluate the performance of two innovative source-zone remediation technologies—enhanced solubilization using cyclodextrin and in-situ chemical oxidation using potassium permanganate. As a result of the potassium permanganate demonstration tests, full-scale remediation of the source zone at the Air Force Plant 44 site is being implemented.

Publications

Contact
Mark Brusseau
brusseau@ag.arizona.edu
520-621-3244