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Remediation Management of Complex Sites

About this Website
Executive Summary
1 Introduction
1 Introduction Overview
1.1 What is a Complex Site?
1.2 Significance of Complex Sites
1.3 Site Objectives and Interim Objectives
1.4 Remediation and a Reasonable Remediation Time Frame
1.5 What is Adaptive Site Management?
1.6 Notable Previous Guidance for Complex Sites
2 Site Challenges
2 Site Challenges Overview
2.1 Technical Challenges
2.2 Nontechnical Challenges
2.3 Developing a CSM Based on Site Characteristics
3 Remediation Potential Assessment
3 Remediation Potential Assessment Overview
3.1 Whole Site versus Site Segment Analysis
3.2 Preremedy Implementation
3.3 Answering Preremedy Questions
3.4 Weighing the Evidence
3.5 Postremedy Implementation
4 Adaptive Site Management
4 Adaptive Site Management Overview
4.1 Steps in the Adaptive Site Management Process
4.2 Refine the Conceptual Site Model
4.3 Set or Revisit Site Objectives
4.4 Develop Interim Objectives and an Adaptive Remedial Strategy
4.5 Document Interim Objectives and the Remedial Approach
5 Long-Term Management
5 Long-Term Management Overview
5.1 Remedy Components
5.2 Basis for Predicting Performance and Decision Criteria
5.3 Periodic Evaluations
5.4 Decision Logic for Adaptive Site Management
5.5 Completion Strategy
5.6 Project Risks and Uncertainty
6 Case Studies (Part One)
6 Case Studies Overview
6.1 Koppers Oroville Wood Treatment Facility, California
6.2 Moffett-MEW Regional Plume, California
6.3 Rocky Flats Solar Ponds Plume, Colorado
6.4 Rocky Mountain Arsenal, Colorado
6.5 Naval Air Station Jacksonville OU 03, Florida
6.6 DOE Test Area North, INEEL, Idaho
6.7 Joliet Army Ammunition Plant, Illinois
6.8 Tri-State Mining District (Kansas, Oklahoma, Missouri)
6 Case Studies (Part Two)
6.9 Paducah Gaseous Diffusion Plant (PGDP) Groundwater, Kentucky
6.10 Velsicol Chemical, Michigan
6.11 Onondaga Lake, New York
6.12 Former UGI Columbia Manufactured Gas Plant, Columbia, Pennsylvania
6.13 Savannah River Site (SRS) F-Area Seepage Basins Groundwater, South Carolina
6.14 Former Naval Weapons Industrial Reserve Plant, McGregor, Texas
6.15 Hanford 200 Area ZP-1 OU, Washington
6.16 Industrial Site, Australia
7. Stakeholder Perspectives
Additional Information
Appendix A. Survey Results
Appendix B. Summary of Tools For Site Characterization
References
Acronyms
Glossary
Acknowledgments
Team Members and Contact Information
Document Feedback

 

Remediation Management of Complex Sites
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6. Case Studies

The case studies presented in this guidance represent regional differences in geology, climate, and regulatory programs. Many case studies include sites that were overseen by the USEPA through CERCLA regulations rather than state regulations. The survey of states (Appendix A) presents a guide to approaches accepted in the sites overseen by states. One international case study, located in Australia, is also included. Case studies for European sites were not available.

The cases highlighted in this guidance have long and intricate histories, consistent with an adaptive management approach. Stakeholders are often more engaged at these complex sites than at less complex sites. Stakeholder involvement, however, often is not as well documented as other technical or regulatory aspects of site histories. Several case studies include detailed descriptions of stakeholder involvement based on the experience of stakeholder representatives on the authoring team who were familiar with (or helped write) the case studies. A list of site attributes and remedial approaches for each case study site is presented in Table 14.

Table 14. Index of case studies

Site Name Location Complexities/Site Attributes Remedial Approach
1. Koppers Oroville Wood Treatment California Multiple contaminants
DNAPL
Impacts to drinking water aquifer
Surface water impacts
Recalcitrant contaminants
CSM revision
On-site landfill
TI waiver
Deed restrictions
Phased remedy (P&T system followed by bioremediation)
2. Moffett-MEW Regional Plume California

 

 

 

 

 

Multiple source areas
Multiple responsible parties
Comingled plumes
Large scale site (“regional plume”)
Multiple aquifers (8 zones)
Geologic heterogeneity
VI
High resolution sampling
Adaptive site management
Redevelopment
Excavation
SVE
Groundwater P&T system
Slurry walls
VI ventilation
VI barriers
Multiple remedial technologies
LUCs
ICs
Long-term management
3. Rocky Flats Solar
Ponds Plume
Colorado Contaminated structures (800)
Large scale site (421 SWMUs)
Comingled plumes
Elevated background concentrations
Long-term monitoring
Landfills
Groundwater treatment
Interim actions/removal actions
ICs
Remediation potential assessment
Remedy optimization
4. Rocky Mountain Arsenal Colorado Geologic heterogeneity
Fractured bedrock
Fluctuating groundwater levels
Arid climate/scarce water resources
Impacts to drinking water aquifer
Comingled plumes
LNAPL
DNAPL
Recalcitrant contaminants
Emerging contaminants
High contaminant concentrations
Multiple contaminants of concern (15 separate plumes)
High cumulative risk
Elevated background concentrations
Vapor issues (highly odorous)
Unexploded ordnance
Large-scale site (25 square miles, 10 square miles off-site)
Changing site objectives
Multiple PRPs
Litigation (ambiguity in state enforcement authority)
ICs
Redevelopment (wildlife refuge)
5. Naval Air Station Jacksonville OU 03 Florida Site includes over 100 buildings
Multiple source areas (8)
DNAPL
VI risk
Air sparging with soil vapor extraction (SVE)
MNA
High resolution site characterization
6. U.S. DOE Test Area North, Idaho National Engineering and Environmental Laboratory (INEEL) Idaho Deep contamination (200-300 feet)
Long plume (2 miles)
High contaminant concentrations (>20,000 µg/L TCE)
Fractured basalt geology
Pilot test of multiple technologies: metal-enhanced reductive dechlorination, monolithic confinement, in situ chemical oxidation, enhanced in situ bioremediation (ISB), MNA
Final remedy: ISB in high concentration areas and MNA in distal area
7. Joliet Army Ammunition Plant Illinois Extensive contamination (36 square miles)
Multiple contaminants and sources
Low-permeability heterogeneous glacial till overlying limestone dolomite bedrock
MNA
Groundwater management zones
ICs
Monitoring
Contingency phytoremediation
8. Tri-State Mining District Kansas
Oklahoma
Missouri
Large site (2,500 square miles)
Mining wastes
Impacts to drinking water aquifer
Geologic heterogeneity
Fractured bedrock
Karst-like conditions
Ecological impacts
Reuse and reprocessing
Backfilling and subaqueous disposal
Capping
Chemical stabilization
Excavation and disposal
Covers
Grading
Administrative controls
Alternate water supply
Residential buyout
Engineering controls
9. Paducah Gaseous Diffusion Plant (PGDP) Groundwater Kentucky Geologic heterogeneity
Low permeability zones
LNAPL or DNAPL
High contaminant concentrations
Multiple COCs
Long-lived contaminants
Large site
Depth of contamination
Comingled plumes
Source removal
Hydraulic control
Natural attenuation
Interim actions (source control)
Innovative technologies testing and implementation
10. Velsicol Chemical Michigan Multiple aquifers
Geologic heterogeneity
Impacts to drinking water aquifer
High contaminant concentrations
Highly toxic contaminants
Contaminated sediment
Ecological impacts
DNAPL
Fluctuating water levels
Deep groundwater contamination
Residential soil impacts
ICs
Slurry wall, clay cap
Leachate collection
Sediment removal
Excavation
Impoundment, capping
Sheet piling
TI waiver
In situ thermal treatment
In situ chemical oxidation
City wellfield replacement
DNAPL extraction and incineration
Groundwater extraction and treatment (planned)
11. Onondaga Lake New York Multiple sources including industrial discharges, stormwater runoff and wastewater treatment plant effluent
Sediment contamination
Artesian conditions (mudboils)
DNAPL removal from wells
Sewer retrofits
Metro treatment system upgrades
Lakeshore barrier wall and groundwater collection/ treatment system
Removal of contaminated sediments, dredging, disposal in an on-site containment facility
Isolation and thin-layer capping
Pilot and treatability testing Calcium nitrate addition to inhibit MeHg formation
Revegetation
Slurry wall, groundwater collection system, cap
Rehabilitate storm drain system
ICs
Landfill waste consolidation and capping
Excavation
Retention pond
Leachate collection system
Settling basins
Depressurization wells
Five-year reviews
12. UGI Columbia Manufactured Gas Plant (MGP) Pennsylvania DNAPL
Fractured bedrock
Contaminated sediment
On-site capping
ICs
Interim actions
TI waiver
13. Savannah River Site (SRS) F-Area Seepage Basins Groundwater South Carolina Impact to surface water system
Low pH plume
Multiple contaminants of concern (tritium, uranium (U), radioactive iodine (I) and technetium)
Diversity of contaminants (radiologic, cationic, anionic)
Cumulative risk associated with long lived radionuclides, primarily U, I, and strontium Sr
Large-scale site (extent of groundwater plume)
Funnel-and-gate for groundwater
In situ treatment of groundwater multiple remedial strategies
14. Former Naval Weapons Industrial Reserve Plant, McGregor Texas Comingled plumes (TCE/TCA plume with perchlorate plume)
Fractured limestone
Emerging contaminant (perchlorate)Porpoising effect created three separate plumes miles downstream
Bench-scale studies to evaluate remediation methods
Multiple pilot studies including active and passive anaerobic bioremediation systems (fluidized bed reactor [FBR], biowall)
Maintain groundwater elevation to prevent discharge to streams
Remedy expand passive anaerobic biowall with emulsified vegetable oil (EVO) and maintain FBR
Optimize system, transition fully to biowalls
15. Hanford 200 Area Washington Large scale site (12 square kilometer plume)
Multiple contaminants
Radionuclides
Comingled plumes
DNAPL
Deep groundwater
Source removal
Interim actions
MNA
Technology demonstrations
Multiple treatment trains
16. Industrial Site Australia Saline groundwater
Geologic heterogeneity
Fractured bedrock (basalt)
Multilayer aquifers
Low-permeability zones
DNAPL
Large source area
High dissolved phase concentration
Competing electron acceptors
Source area remediation
Air sparge and SVE
Enhanced in situ bioremediation (EISB)
Bioaugmentation
Adaptive management
Groundwater recirculation
Blast fracturing
Natural attenuation
Optimization and monitoring
PRBs
P&T system
Plume containment
Radiofrequency heating of groundwater
Multiple remedial technologies
Flux mass discharge (passive flux meters)
Cleaned up to the extent practicable

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