DNAPL source depletion: linking architecture and flux response

Area of Science:

• Environmental Science
• Geochemistry
• Hydrogeology

Background:

• Dense non-aqueous phase liquids (DNAPLs) are persistent groundwater contaminants.
• Understanding DNAPL mass reduction and contaminant flux is crucial for effective remediation.
• The influence of source zone architecture on contaminant release is not fully understood.

Purpose of the Study:

• To experimentally investigate the relationship between DNAPL mass reduction and contaminant mass flux.
• To analyze the impact of NAPL architecture on contaminant dissolution dynamics.
• To evaluate simplified models for simulating DNAPL dissolution.

Main Methods:

• Experiments were conducted in four model source zones using a segmented extraction well.
• Spatially resolved flux information was collected and coupled with NAPL distribution image analysis.
• NAPL architecture was defined by streamtube analysis and effective NAPL content.

Main Results:

• The relationship between DNAPL mass reduction and contaminant mass flux is primarily controlled by NAPL architecture.
• The distribution of NAPL content among streamtubes dictates dissolution dynamics.
• Two models, a streamtube model and an effective Damkohler number model, were assessed for simulation capabilities.

Conclusions:

• DNAPL architecture is a critical factor governing contaminant mass flux and reduction.
• Effective remediation strategies must consider the spatial distribution of DNAPL.
• Further research into modeling DNAPL dissolution dynamics based on architecture is warranted.