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2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
FULL - SCALE IMPLEMENTATION OF A PULSED
AIR SPARGE AND SVE SYSTEM FOR
TREATMENT OF VOCS, SVOCS, AND ARSENIC
Presented By:
Nadira Najib, Omer Uppal, Matthew
Ambrusch, Annie Lee, Jessica Friscia,
Kawalpreet Kaur, Stewart Abrams, P.E.,
Steve Ciambruschini, LEP
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
Presentation Outline • Intro to Air Sparging
• Former Lagoon Area [FLA], Montville NJ
• Background
• Why Air Sparging?
• Pilot Testing Activities
• Modeling Results/Considerations
• Final Design
• System Implementation
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
Zone of Air Distribution Air Channeling
What is Air Sparging? An in-situ remedial technology that reduces concentrations of
VOCs dissolved in groundwater or adsorbed to soils through
volatilization and bioremediation by the injection of air.
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
What is Air Sparging?
http://www.clu-in.org/download/techfocus/air-sparging/ABR09-4-AS.pdf
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
How Air Sparging Works?
• In-situ air stripping of dissolved VOCs in groundwater:
• Henry’s Law Constant
• Vapor Pressure
• Volatilization of trapped and adsorbed VOCs in soils:
• Soil Organic Carbon-Water Partitioning Coefficient
• Precipitation of metals in groundwater:
• Oxidizing environment
• Biosparging versus Air Sparging
• Aerobic biodegradation
eeg.geoscienceworld.org
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
Design Considerations
• Radius of Influence
• Target Interval
• Subsurface Conditions
• Intrinsic Permeability
• Confining Layers
• Fracture Pressure
• Contaminants of Concern
• Air flow rate and pressure at wellhead
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
Importance of Pilot Testing/Modeling Pilot Testing : An opportunity to test, measure, and collect site specific subsurface characteristics, including permeability and pressure/vacuum flow relationships, etc.
0
0.5
1
1.5
2
2.5
3
0 50 100
30 SCFM
40 SCFM
50 SCFM
Design Flow
Distance from Vapor
Vac
uu
m (
inH
2O
)
Modeling : Evaluate and engineer the most effective remedial design, taking
into consideration ROI, air flow rate, and pressure/vacuum.
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
Former Lagoon Area [FLA]
Montville, New Jersey
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
Site Background
• Former manufacturing facility with active
lagoon operations through 1954 and
backfilled between 1967 and 1970
• Benzene, VOCs, SVOCs, and heavy metals
(i.e., Arsenic) in soil and groundwater
• Former biosparge system operation from
2002 through 2012 - Model predicted
cleanup time frames >> 50 years
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
Site Layout
GW Flow Direction DIAGNOSTIC TESTING
FOCUSED AREAS
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
FLA – Background • Former textile mills/pharmaceuticals manufacturing plant
• Primary COCs :
• Benzene up to 20,900 ug/L
• Phenol up to 12,800 ug/L
• Arsenic up to 31.2 ug/L
• Geology
• Fill layer
• Alluvium layer
• Glacial Till layer
• Hydrogeology • Groundwater table ranges approximately 1.5 to 6.5 feet bgs
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
FLA – Why Air Sparging? • Past Remediation Efforts:
• Biosparge
• Excavation
• Primary COC
• Size of Potential Treatment Area
• Source/Concentrations
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
FLA-Pilot Testing Activities
• Testing Methods
• SVE/Point Permeability
• Air Sparge/Helium Tracer
• Biorespiration
• Parameters of Interest
• Air flow rate
• Pressure
• Vacuum
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
FLA – Pilot Testing Activities
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
FLA – Pneumatic Modeling Results/Considerations MDFIT – Computer Pneumatic Modeling Program
5.5 scfm
8.5 scfm
13 scfm
0
20
40
60
80
100
120
140
160
180
0 2 4 6 8 10 12 14 16
Vac
uu
m (
in H
2O
)
Distance from Test Well (feet)
Permeability Calibration for Engineered Fill Material
5 SCFM
7.5 SCFM
10 SCFM
12.5 SCFM
MeasuredVacuum
Calibrated Permeability Kr = Kz = 3.50E-08 Kc = 1.83E-06
5.4 scfm
6.75 scfm 8.9 scfm
11 scfm
0
50
100
150
200
250
300
0 5 10 15 20
Vac
uu
m (
in H
2O
)
Distance from Test Well (feet)
Permeability Calibration for Native Soils
5 SCFM
7.5 SCFM
10 SCFM
12.5 SCFM
MeasuredVacuum
Calibrated Permeability Kr = Kz = 3.70E-08 Kc = 7.79E-08
• Leaky Confining Layer
• Low Permeable Vadose Zone
• Shallow Water Table
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
MDFIT
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
FLA – Air Sparge Modeling Results/Considerations
0.1
1
10
100
1000
10000
100000
0 5 10 15 20 25Benz
ene
Con
cent
ratio
n (u
g/L)
Air Sparging Flow Rate (SCFM)
Test Area 1 - Air Sparging Design
Lagoon FillUpper GlacialDeep Glacial
0%
20%
40%
60%
80%
100%
0 5 10 15 20 25Be
nzen
e Pe
rcen
t Red
uctio
n Air Sparging Flow Rate (SCFM)
Lagoon Fill
Upper Glacial
Deep Glacial
Test Area 1 - Design Percentage Reduction
• Mass removal rate for each COC
• Target Interval
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
Air Stripping Modeling
Modeling resulted in a more cost-effective
optimization strategy.
Sparging Trench Dimensions
5 to 10 ft
Where:
C L,e = COC concentration in reactor/trench effluent (ug/L), 20 ft
C L,i = COC concentration in reactor/trench influent (ug/L),
Qg = Gas or air flow rate (ft3/day),
QL = Liquid or groundwater flow rate per unit length (ft3/day),
Hc = Henry’s law constant (unitless), and Groundwater Flow
φ = Saturation parameter
Where:
K(La)COC = Mass transfer coefficient for COCs (1/day), and
V = Volume of reactor per unit length/porosity (ft3).
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
Remedial Strategy
EXCAVATION
• Removal and off-site disposal of approximately 2,200 tons of NAPL impacted soil - October 2012
PULSED AIR SPARGE SYSTEM
• VOCs /BTEX
• Volatilization/Stripping
• Aerobic biodegradation
• PHARMACEUTICALS (Phenol) and ALCOHOLS (Ethanol)
• Aerobic biodegradation
• METALS (Arsenic)
• Co-precipitation with dissolved minerals (i.e., iron and calcium)
• Sorption on metal/iron oxy-hydroxides SEM images of Fe-Al-Si oxy-hydroxide
precipitate formed in groundwater
(EDS analytical spectra)
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
FLA – Final Design • High Water Table
• Artificial Cap
• Horizontal Vapor Collection
• Leaky Confining Layer
• Impermeable Membrane
• ROI
• 10-15 feet 53 air sparge wells
• 15 feet 41 vapor collection wells
• Prevent Over Pressurization
• Pulsing Strategy
• Chimney Wells
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
System Design
DESIGN COMPONENTS
53 multi-level air sparge wells
41 horizontal vapor collection wells
17 vapor vent wells
11 chimney wells
2 dry wells
3-ft Clean Fill Cap
Pulsing Strategy
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
Engineering Design
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
Remedy Implementation
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
Strategy Benefits • System Construction Ongoing
• Startup planned for January 2015
• Anticipated Cleanup Timeframe - 3 to 5 years
• Reduced Cleanup Timeframe
• Cost Savings
• More innovative, cost effective, and sustainable in-situ remediation technology than
excavation
2014 – Contaminated Site Management (CSM-2014) Sustainable Remediation & Management of Soil, Sediment and Water
Questions?