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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


Plume

Area = 2,325 ft2


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


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 Concentration range 7,790 and 31,300 ug/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



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 < 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)



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)



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)


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

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