In Situ Groundwater Remediation Programs
November 2, 2011
Mike Mazzarese Program Manager Vironex, Inc Washington, D.C.
Eric Lindhult, P.E. Senior Project Manager
GZA GeoEnvironmental, Inc. Fort Washington, PA
Presentation Overview
• General Overview of In Situ Injection Programs
• Data Requirements for Proper Design and Conceptual Site Model Development
• Reagent Overview – In Situ Chemical Oxidation
– Bioremediation
• Techniques for Proper Distribution
• Case Studies
2
Common Sources of Contamination
• Petroleum Hydrocarbons
– Gas Stations Primarily
– Others: Home Heating Oil, Refineries, Manufacturing Facilities
• Chlorinated Solvents (Ethene focus)
– Dry Cleaners
– Manufacturing (e.g., Circuit Board Manufacturers, Degreasing Operations)
3
The Challenges - Complex Plume Geometries and Proper Reagent Distribution
• Contact
• Monitoring wells can rarely be used to adequately develop a Site Conceptual Model and Injection Strategy
• Mass vs. Lithology
• Define Remediation Strategy or Strategies – Source Reduction
– Plume Treatment
– Permeable Reactive Barrier (PRB)
4
VA Drycleaner Example
5
VA Drycleaner Example
6
Well Screen Zone
MD Drycleaner Site
7
Source Mass
Bound in Fine
Grained Soil
Source Mass
Bound in Course
Grained Soil
Data Requirements
• Define Areal & Vertical Extent and Lithology Using Multiple Lines of Evidence
– Traditional Data (Soil/GW/Vapor)
– Advanced Characterization Techniques (MIP/HPT)
– Real Time Screening Tools (Color-Tec, UVF)
– 3D Imaging
• Injection Parameters
– Injection Flow Rate, Pressure
– Radius of Influence 8
Injection Strategies Overview
• Direct Push (Geoprobe) vs. Injection Wells
• Spacing or Radius of Influence
– Site/Reagent/Goal Specific
• Injection Patterns
– Grid: Source or Plume Area
– Barrier: Plume or PRB
9
What’s in the Toolbox?
• Membrane Interface Probe (MIP) for real time VOC delineation
10
MIP Detectors
Contaminants MIP System Detection
Ranges
ECD
Halogenated Compounds
(TCE, PCE)
0.25 – 10 ppm
Qualitative
XSD Halogenated Compounds
(VC, DCE, TCE, PCE)
0.25 – 500 ppm
Qualitative
PID
Double-Bonded Compounds
(gasoline, BTEX, High level PCE
& TCE)
1 - 20,000 ppm
Qualitative
FID
Combustible Hydrocarbons
(gasoline, BTEX methane,
butane, landfill gases)
1 - 100,000 ppm
Qualitative
What’s in the Toolbox?
• Hydraulic Profiling Tool (HPT) helps evaluate hydraulic properties (EC, pressure and flow) in real time
12
Hydraulic
Pressure > 75 psi
Technology Overview
• Targeted Mass Removal (e.g., excavation, mixing)
• ISCO for Source Treatment (e.g., RegenOx, K or Na Pmag, Activated Sodium Persulfate, DrillOx)
• ISCR (e.g., ZVI, EHC)
• Aerobic Bioremediation (e.g., ORC)
• Anaerobic Bioremediation (e.g., EVO, HRC, Lactate, Whey, Bioaugmentation)
13
Additive Injection Overview
• In-Situ Chemical Oxidation (ISCO)
• Works on many COCs, most commonly TPH and cVOCs
• Destroys COCs through oxidation
• Bioremediation
• Generally aerobic (oxygen-rich) environment to remediate TPH
• Generally anaerobic (minimal oxygen) to remediate cVOCs
In-Situ Chemical Oxidation (ISCO)
• Introduce strong oxidizers to destroy or transform COCs
• Reaction for most COCs is rapid
• Reduces COC mass and concentrations, and the remediation time of the site
• Source/mass reduction only
Common ISCO Additives
• Persulfate
• Permanganate
• Ozone
• Hydrogen Peroxide
• Fenton’s Reagent – combination of H2O2 and Fe+2 to form hydroxide radicals
Enhanced Bioremediation
• Bioremediation is occurring at most sites, but may be limited due to poor biogeochemical conditions – e.g., too much/little oxygen, nutrients
• Introduction of additives (or air/oxygen) to enhance and expedite the native bacteria to destroy the COCs
• Changes the biogeochemical conditions in the groundwater to stimulate biological activity
• Can introduce specialized bacteria (bioaugmentation)
Organic
Carbon
Oxygen Water
Nitrate NH , N
Iron (III)
Mn (IV) Iron (II), Mn (III)
Sulfate Hydrogen Sulfide
CO Methane
cVOC Ethene / Ethane
2
2 +
Electron Ladder Theory
Nitrate Respiration
Methanogenesis
Oxygen e- consumption complete
Manganese/Iron Respiration
CO2 Respiration
Sulfate Respiration
Enhanced Reductive
Dechlorination (ERD)
Theory for Beginners
Terminal Electron
Acceptor (TEA)
Ladder
cVOC Remediation
• Generally performed under anaerobic conditions – some exceptions
• Typically through enhanced reductive dechlorination (ERD)
• Common additives
• Emulsified vegetable oil (EVO)
• Zero valent iron (ZVI)
• Hydrogen Release Compound (HRC®)
• ERDENHANCED®
Review of Enhanced Reductive Dechlorination (ERD)
• RD = Substitution of H for Cl
• Environmental Conditions – Anaerobic (<0.5 mg/L DO)
– Chemically Reducing (<50 mV)
– Hydrogen (Dechlorination “Fuel”)
• Mechanisms – Metabolic (Dehalorespiration)
– Abiotic reactions with FeS
– Co-metabolic
Dehalococcoides
Enhanced Reductive Dechlorination (ERD) of cVOCs
• Electron Donor Drive ERD – Scavenge TEAs from Groundwater
– Provides Fermentable Substrate to Yield H+
– Replaces Cl- from cVOCs with H+
TPH Remediation
• Generally performed under aerobic conditions
• Achieved mechanically
• Air sparging – injecting air
• DO-IT, iSOC – oxygen recirculation
• Chemical additives • Peroxides
• ORC®/EHC-O®
• EAS™
• TPHENHANCED®
} Aerobic Pathway
Anaerobic Pathways }
TPH Remediation
Microorganisms capable of degrading TPH generally ubiquitous
Aliphatic hydrocarbons: branched-chains (isoprenoids) more recalcitrant than straight chains
Aromatic hydrocarbons (BTEX) most mobile but degradable
Primary end products CO2, H2O, and microbial biomass
Surgical Injection Plan
• Treatment Design Based on Project Goals, Advanced Characterization Data and Technology Selection
• Assumptions Made Regarding Distribution (ROI) – Must take into consideration injection volume,
reagent longevity and seepage velocity
• Determine if Bench/Lab Testing is Necessary (SOD, DHC, etc)
25
Pilot Testing
• Verify Injection Methodology
– Injection Tooling (Top-Down, Bottom-Up, Jetting)
– Pump Selection (Moyno, Diaphragm, Hydracell)
– Low or High Pressure (Fracturing Necessary?)
• Verify Design Assumptions
– Radius of Influence
• Dyes, changes in geochemistry or EC can be used
– Injection Rate, Pressure and Volume
26
Delivery Systems
27
Pilot Test - ROI Confirmation
28
ROI Verification using EC
29
0
500
1000
1500
2000
2500 0
2.5 5
7.5
10
12
.5
15
17.5
20
22
.5
25
27.5
30
32
.5
35
37.5
40
42
.5
45
47.5
50
52
.5
55
57.5
60
62
.5
65
67.5
70
72
.5
75
77.5
80
82
.5
85
EC (
mS/
m)
Depth (ft bgs)
Avg Baseline
Injection Method A
Injection Method B
Shal
low
Inje
ctio
n
Zon
e
Dee
p In
ject
ion
Zo
ne
Full Scale Equipment
30
Full-Scale Equipment
31
Case Studies
32
1,300 ppb
200 ppb
150 ppb
Source Projection
Area = 1300 ft2
Injection Zone = 18-22 ft
300 ppb
300 ppb = [PCE]
Source Area
Area = 1350 ft2
Injection Zone = 7-22 ft
Plume
Area = 2,325 ft2
Injection Zone = 18-22 ft
Case Studies
• NJ Gas Station
33
Bio-Barrier C (75’)
Bio-Barrier B (150’)
Bio-Barrier A (150’)
ISCO Area B (5,425 ft^2)
ISCO Area A (2,000 ft^2)
Case Studies
34
Manufacturing Facility Lebanon, NH
• Conceptual Site Model: – Up to ~35 feet Silty Clay, w/Two Sand & Silt Units (18-25
feet bgs; 30-33 feet bgs): • Laterally Continuous
• Hydraulically Conductive
– Baseline Contaminant Signature: • Total Parents: ~100 ppm; TCE, PCE
• Total Daughters: ~0.25 ppm; 1,1-DCE, DCEs, VC
• Molar Parent Ratio: >99%
– Plume Migrating Off-Site > NHDES Standards
– Goal: <1 mg/L TCE, >99% Reduction
GROUNDWATER FLOW
SOURCE AREA RESULTS
• cVOC Trends: – 99.99% Reduction [TCE]
– > two orders of magnitude increase [c-1,2-DCE] for first 5 years, then 99% Reduction
– Minimal detection of Vinyl Chloride
• Indicator Parameter Trends: – One order of magnitude increase [Chloride]
– Two orders of magnitude increase [Ethene]
• Confirms RD of vinyl chloride and presence of dehalococcoides
– 90% Reduction [Sulfate]
– One order of magnitude increase [CH4]
– Four orders of magnitude increase [COD]
MW-104D TCE Concentrations (µg/L)
1
10
100
1000
10000
100000
09/03/01 11/27/02 02/20/04 05/15/05 08/08/06 11/01/07 01/24/09 04/19/10
TCE decreases >83 % in first 6 months.
Injection Program 9/01
MW-104D TCE Concentrations (µg/L)
1
10
100
1000
10000
100000
09/03/01 11/27/02 02/20/04 05/15/05 08/08/06 11/01/07 01/24/09 04/19/10
Injection Program 9/01
TCE Concentration range 7,790 and 31,300 ug/L
MW-104D TCE Concentrations (µg/L)
1
10
100
1000
10000
100000
09/03/01 11/27/02 02/20/04 05/15/05 08/08/06 11/01/07 01/24/09 04/19/10
Injection Program 9/01
MW-104D TCE Concentrations (µg/L)
1
10
100
1000
10000
100000
09/03/01 11/27/02 02/20/04 05/15/05 08/08/06 11/01/07 01/24/09 04/19/10
Injection Program 9/01
TCE < 10 ug/L
May 25, 2010
MW-104D Concentrations (µg/L)
1
10
100
1000
10000
100000
09/03/01 11/27/02 02/20/04 05/15/05 08/08/06 11/01/07 01/24/09 04/19/10
TCE (ug/L)
Injection Program 9/01
MW-104D Concentrations (µg/L)
1
10
100
1000
10000
100000
09/03/01 11/27/02 02/20/04 05/15/05 08/08/06 11/01/07 01/24/09 04/19/10
TCE (ug/L) cis-1,2-DCE (ug/L)
Injection Program 9/01
MW-104D Concentrations (µg/L)
1
10
100
1000
10000
100000
09/03/01 11/27/02 02/20/04 05/15/05 08/08/06 11/01/07 01/24/09 04/19/10
TCE (ug/L) cis-1,2-DCE (ug/L) Ethene (ug/L)
Injection Program 9/01
Notable Conclusions
• One of Earliest ERD Projects for DNAPL
• 99.99%Reduction [TCE] & Achieved Performance Goal in 5 Years MNA
• Minimal [VC] & Significant [Ethene] Production
• 2009 [COD] ~2,000 mg/L = ~8 yrs Additive Residence Time
• Total Remedial Cost <$100K
• Food-Grade Waste Material as Additive = Green Remediation
• No Observed Rebound in [cVOC]s
• ERD = Passive-Aggressive Source Control Strategy