Brief Overview of: Lowry Landfill Superfund Site Denver, Colorado… · 2019. 6. 5. · 3 The...
Transcript of Brief Overview of: Lowry Landfill Superfund Site Denver, Colorado… · 2019. 6. 5. · 3 The...
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Brief Overview of: Lowry Landfill Superfund Site
Denver, Colorado, USAFrank LewisFrank LewisFrank LewisFrank Lewis
International Seminar on Solid Waste Management in Metropolitan RegionsInternational Seminar on Solid Waste Management in Metropolitan RegionsInternational Seminar on Solid Waste Management in Metropolitan RegionsInternational Seminar on Solid Waste Management in Metropolitan RegionsSSSSããããoooo Paulo, Paulo, Paulo, Paulo, BrasilBrasilBrasilBrasil
29 September 2005 29 September 2005 29 September 2005 29 September 2005
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LowryLandfill
Site
LowryLandfill
SiteAsbestos
Disposal Pit
G un
Club
Roa
d
East Quincy Avenue
East Hampden Avenue
Unn
eam
e d C
re k
Tire Shreds Monofill
Limit of Refuse
WMCMaintenanceFacility
Section 6
Section 3
Not to Scale
Former Tire PileArea
Landfill Mass
North BoundaryBarrier Wall
UnnamedCreek
Section 31Landfill Site
Former WastePits
Command Post
Water TreatmentPlant
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The Problem
✦ “Codisposal” of 138 million gallons of liquid industrial waste andsolid municipal waste dumped into 75 unlined trenches or wastepits with refuse, tires, and soils to absorb the liquids– Asbestos, sewage sludges, metal plating wastes, radioactive and
non-radioactive medical wastes, petroleum derived products,pesticides, industrial solvents, sewage sludge, paints, tires, animalcarcasses
– 8 million tires stockpiled✦ Contaminated liquids seeped out of waste pits and mixed with
surrounding soils, surface, water, and groundwater
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Early History
✦ 1940-62 Air Force Lowry
Bombing Range✦ 1966 -1980 Co-disposal of liquid,
solid and industrialwaste
✦ After 1980 Only municipal waste
disposal
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Pre-Remedial Investigation Activities
✦ 1982 - Preliminary Assessment and Site Inspectionconducted
✦ 1984 - Site placed on the National Priorities List✦ 1985 - North Boundary Barrier Wall and Water
Treatment Plant constructed (Interim RemedialMeasures)
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Phase I Remedial Investigation✦ 1985 to 1986 - Phase I Remedial Investigation (RI)
– Borings– Geophysics– Soil vapors and air monitoring– Sampled ground and surface-water– Soils– Sediments– Landfill solids– Landfill gas– Waste pit locations, etc…
✦ Phase I Report issued September 1986
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Remedial Investigation Activities
✦ 1985 -1989– Fund-lead investigations– Potential Responsible Party searches– Initial waste-in list developed
✦ 1987– Determination of public health threat due to:
• Groundwater contamination• Volatile organic compounds (VOCs) released from the soil
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Phase II Remedial Investigation
✦ 1987-1989 - EPA conducted Phase II RI including:– Borings– Well points– Deep and shallow ground-water wells– Soil and landfill solids sampling– Water and liquid level monitoring– Refuse leachate wells– Waste pit liquids– Limited air monitoring– Preliminary Endangerment Assessment, identification of
alternatives, operable units, overall work plan,database
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Interim Removal Measures
✦ Groundwater barrier wall and water treatment facilityoperating since 1985 to address the northwardmigration of groundwater
✦ Surface Water Removal Action built within unnamedcreek to separate contaminated groundwater fromsurface water drainage
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Key Milestones
✦ 1989-1992 - City of Denver tire shredding operation– Shredded 8 million stockpiled tires– Stored in a monofill onsite
✦ 1989 - Drum Removal Action Phase I:– Removed and stabilized liquids from damaged drums on site– Constructed temporary lined storage pads to manage liquids
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Key Milestones
✦ 1990 - Drum Removal Action Phase II: EPA and the Cityof Denver– Bulked and treated less contaminated waste at the WTP– Repackaged old drums– Decontaminated and disposed of empty drums– Decommissioned the temporary drum storage pad
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✦ 1988 - 1993 - Operable Units Studies– Site divided into six Operable Units due to the size and
complexity of the site– Objectives developed for all Operable Units– Remedy priorities set for the most critical areas– Administrative Orders on Consent negotiated with groups of
PRPs to perform studies and remedies on the Operable Unitswith EPA and State of Colorado oversight
Key Milestones (cont.)Key Milestones (cont.)
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Operable Unit Studies – ActionsPerformed by EPA and State
✦ Perform risk assessment✦ Develop/maintain community involvement program✦ Development of Remedial Action Objectives✦ Formulation of Record of Decision
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Operable Unit Studies – ActionsPerformed by PRPs
✦ Separate activities conducted for each Operable Unit– Initial evaluation of existing field data– Perform additional site characterization studies– Develop reports nature and extent of contamination– Perform treatability studies– Evaluate Applicable or Relevant and Appropriate
Requirements (ARARs)– Develop feasibility studies/remedial costs
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Baseline Risk Assessments✦ 1992-1993 Risk assessments preformed
– Provide analysis of conditions– Basis for action– Determine levels of contamination– Provide basis for comparison of potential health impacts
Data Collection &Evaluation
Data Collection &Evaluation
ExposureAssessmentExposure
AssessmentToxicity
AssessmentToxicity
Assessment
RiskCharacterization
RiskCharacterization
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Record of Decision
✦ 1994 - Record of Decision– The selected sitewide remedy was an integrated remedy
incorporating interim remedial measures and remedies forthe Operable Units and all contaminated media.• Groundwater and landfill gas are addressed by containment,
collection, and treatment• Landfill solids and soils and addressed by containment• Contaminated seepage and surface water addressed through
drainage and underground collection• Former tire pile area waste pits and principal threat wastes
addressed through excavation and treatment
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Sitewide Remedy
✦ North Boundary Barrier Wall System✦ Landfill Gas Collection and Treatment System✦ Wetlands Mitigation✦ East/South/West Ground-water Bentonite Slurry
Wall✦ North Toe Groundwater Extraction System✦ On-site Water Treatment Plant
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Sitewide Remedy
✦ Institutional Controls including site restrictions,fences, signs, deed restrictions, zoning controls
✦ Performance and Compliance Monitoring✦ Five-Year Review✦ Continuation of the Interim Measures
LowryLandfillSitewideRemedy
LowryLandfillSitewideRemedy
ClosedLandfill Area
North BoundaryGround-Water
Barrier WallOld Ground-WaterTreatment Plant and
Landfill Gas Flare
North ToeGround-Water
ExtractionSystem
E/S/WBentoniteSlurryWall
E/S/WBentoniteSlurryWall
E/S/W BentoniteSlurry Wall
WetlandsMitigation
Area
Surface WaterRemoval Action
CollectionSystem
Former TirePile Area
Waste Pits
North FaceLandfill Cover
Lowry LandfillSitewide Remedy
Gas Extraction Wells
Legend:Green = CompleteRed = Incomplete
Ground-WaterFlow Direction
WMCMaintenanceFacility
E A S T Q U I N C Y A V E N U E
EAS TH AM P D EN
AV EN U E
Gate
Not to Scale
CommandPost
N
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Technical Challenges
✦ Hidden complexities of hydrogeology– Sand channels/heterogeneities– Complex subsurface conditions difficult to identify and monitor
migration pathways– Evolving site understanding
✦ North Boundary Barrier Wall– Because of residual contamination at time of construction, difficult
to evaluate its effectiveness✦ Chemical complexity and complex mixtures of wastes
– Treatability issues
Remedial ActionConceptual Site Model
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Technical Challenges✦ Multiple types of waste disposal in northern portion
– Tank bottoms, sludge disposal✦ Subsidence of landfill
– Challenge to maintain cover✦ Unlined Landfill
– Highly dependant on groundwater monitoring✦ Physical constraints
– East - two high pressure gas lines– West - high tension power lines– South – other utilities– All around - limited space between the barrier wall and adjacent
facilities
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Community Concerns of Area Residents
✦ Containment Concerns✦ Contaminant migration/ drinking well concerns✦ Potential for vertical contamination✦ Reliability of the Onsite Water Treatment Plant✦ Maintenance of the Landfill Cover✦ Development/Land Use Concerns✦ Secrecy of the Lowry Trust✦ Political concerns
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Next Steps
✦ Top portion of closed landfill to be re-opened for C&Dwaste.– Settlement created depression on top of landfill– Increase final slope from 1% to 5%– Provide revenue to partially offset costs of remediation.– Private company operating at a profit.
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Total Approximate Costs
✦ $40 Million total spent to 1994.✦ $134 Million since 1994 and projected into the future.
– Treatment plant operation– Groundwater monitoring (> 6 km perimeter, multiple depths)– Data base management– Landfill cap maintenance– Erosion control– Fence repair– Reporting