Overview of Monitored Natural Attenuation (MNA)
- Physical, Chemical, and Biological Processes
- Advantages and Disadvantages
- EPA Policy on MNA
Geochemical Context for MNA
- Geochemical Processes
- Redox Zonation and Biodegradation Efficiency
Biodegradation of Petroleum Hydrocarbons and Fuel Oxygenates
- Determining Site Specific Assimilative Capacity (TEA Evaluation)
- Phase Considerations (LNAPL, dissolved, sorbed, and vapor)
- BTEX and Fuel Oxygenate Plume Behavior and Degradation Rates
- Daughter Products (toxicity and mobility)
- Geochemical Indicators
Biotransformation and Degradation of Chlorinated Hydrocarbons
- Determining Site Specific Assimilative Capacity
- Phase considerations (DNAPL, dissolved, sorbed, and vapor)
- Plume Behavior
- Daughter Products (toxicity and mobility)
- Geochemical Indicators
Site Hydrogeology and MNA Efficiency
- Groundwater Velocity Characterization
- Estimating Mechanical and Chemical Dispersion
- Assessing Sorptive Capacity of Aquifer Solids
- Microbiologic Testing - When is it necessary?
Natural Attenuation Feasibility Study
- Establishing Remediation Goals
- Evaluating Plume Characteristics
- Source Decay and Removal
- Predicting Plume Behavior
- Measuring and Estimating Degradation Rates
- Interpreting Geochemical Tracers
- Using Fate and Transport Models
- Developing the Conceptual Site Model
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Implementing MNA
- Groundwater Monitoring Plan Requirements
- Well Position and Number: How many wells are enough?
- Determining Trends in Contaminant Mass
- Tracking Geochemical Indicators
- Refining the Conceptual Site Model
- Selecting and Implementing Primary Source Control
- Evaluating Natural Attenuation and Plume Status
- Collecting Lines of Evidence for Natural Attenuation
- Using Institutional Controls
- Risk Management
Addressing Commingled Plumes
- Impact on Plume Geometry
- Geochemical Indicators
- Degradation Rates
Remediation by Enhanced Natural Attenuation
- Air Sparging
- ORC and HRC
- Enzyme Injection
- Fertilizer Application and Cometabolization
- Emerging Technologies
Criteria for Success and Site Closure
- Understanding the Persistence of Contaminant Mass
- Understanding Variations in Groundwater Velocity and Direction
- Correlating Groundwater Elevation with Contaminant Concentrations
- Cross Contamination Challenges and Forensics
- Rapid Site Assessment Technologies
- Adaptive Management
- Completing MNA and Demonstrating Site Restoration
MNA Case Studies and Interactive Exercises (throughout both
days)
Summary of MNA as a Remedial Action |