Formatted Title:

Air Bubble Curtain Pilot Study

Background/Objectives:

The air bubble curtain (ABC) bench-scale study evaluated the use of ABC technology as a supplemental environmental control during implementation of sediment remediation activities. Bench-scale study objectives included:

Assessing the effectiveness of ABC technology as an in-water physical barrier to control suspended sediment (i.e., turbidity), non-aqueous phase liquid (NAPL), surface sheens, and dissolved phase contaminants in stationary and flowing water conditions.
Obtaining data from bench-scale testing to develop and validate a three-dimensional (3-D) computational fluid dynamics (CFD) model to predict ABC flow patterns and effectiveness at field scale.
Evaluating monitoring techniques to assess effectiveness of ABCs at bench and field scales.

Approach/Activities:

Bench-scale testing was conducted in two phases of increasing scale and complexity.

Phase 1 included testing in stationary water conditions in an 800-gallon portable tank.
- Optimal ABC configurations were evaluated using different bubble tube configurations, spacing, air flow rates, bubble sizes, and rising velocities.
Phase 2 included testing in flowing water conditions (i.e., current) in a 7,000-gallon temporary flume tank.
- Based on Phase 1 testing, the Phase 2 tank size, current conditions, and CFD modeling, the ABC configuration was further evaluated and revised in Phase 2 using three straight ABCs placed perpendicular to current flow and spaced at 3 meters apart with the air flow rates, bubble size, and rising velocity determined in Phase 1.
Each testing phase evaluated the performance of the ABC system and modified the ABC system configuration for optimal performance.
Monitoring techniques included use of turbidity sensors; visual assessments using video recording, color reactive fabrics, polyethylene samplers, and other observations; and dissolved phase sampling.

Results/Lessons Learned:

The ABC bench-scale testing and CFD modeling results and lessons learned will include discussion of:

ABC effectiveness to control suspended solids (i.e., turbidity), sheens, NAPL, and dissolved phase contaminants in both stationary and flowing water conditions.
The effectiveness of various monitoring techniques.
CFD modeling results.

Field videos and modeling simulations will be used to support the presentation.

Prem Thodi

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(Group 2, Poster Board #22) Air Bubble Curtain Pilot Study