Reactive Barriers for the Passive Remediation of Chlorinated Solvents in Sediments and Groundwater Discharge

Michelle M. Lorah USGS, Baltimore, Maryland

in cooperation with

DoD, Aberdeen Proving Ground USEPA, Region III NIEHS, Superfund Research Program

Conceptual model for chlorinated solvent contamination in wetland (modified from Lorah et al., 2005)

dissolved plumes

DNAPL

Aerobic micro-zones around roots

Fe2+ S2-

NH3

CH4

Stottmeister et al.(2003) Biotech.Advances

O2

Chlorinated VOCs at West Branch Canal Creek and

their anaerobic degradation pathways

Ethane

112TCA

12DCA

CA

1122- TeCA

TCE

12DCE

VC

Ethene

PCE

CT

CF

MeCl

Methane

CO2

HCA

PtCA

Ethane

112TCA

12DCA

CA

1122- TeCA

TCE

12DCE

VC

Ethene

PCE

CT

CF

MeCl

Methane

CO2

HCA

Parent VOCs in orange

Chlorinated ethanes: HCA= hexachloroethane PtCA= pentachloroethane

1122TeCA= 1,1,2,2-tetrachloroethane

Chlorinated ethenes: PCE= tetrachloroethene

TCE= trichloroethene

Chlorinated methanes: CT= carbon tetrachloride

CF= chloroform

Site Characterization Chloroform

Tetrachloroethene

West Branch Canal Creek, APG

TIR Image

PDB

Relative Abundances above 1%

100 liter

WBC-2 Dechlorinating Culture

Reactive Barrier Design and Monitoring

Single-hole multilevel diffusion samplers and multilevel wells

Hydraulic Gradient (Artesian)

Re-amendment System

Aquifer (~40 ft thick)

Geotextile

Wetland Sediment (10-15 ft thick)

Sand, Peat, Compost, ZVI (option for CT)

Sand, Peat, Compost, Chitin, WBC2

Pea Gravel

NOT TO SCALE

Seep Area

Below surface microwells

Passive diffusion bags

Microcosms: Wetland Sediment-Compost Mixtures

• Different composts tested for support of WBC-2 activity and VOC degradation

• Variable results with different composts for degradation of both parent and daughter compounds

Bioaugmented microcosms, TeCA

APG Reactive Barrier: Upward Flow Columns

Contaminant k

(day-1) t1/2

(hrs)

1122TeCA 3.4 4.8

Chloroform 2.3 7.2

Carbon tetrachloride 2.8 5.9

Tetrachloro-ethene 1.4 12

Trichloroethene 3.0 5.5

TeCA TCE

ethene ethane

VC

Salinity microcosms

0

20

40

60

80

100

120

0 10 20 30

Perc

ent T

eCA

rem

aini

ng

Days

TeCA Removal

0

10,000

20,000

30,000

40,000

50,000

0 10 20 30

Met

hane

(ug/

L)

Days

Methane

0

500

1,000

1,500

2,000

2,500

3,000

3,500

0 10 20 30

Sulfa

te, m

illig

ram

s pe

r lit

err

Days

Sulfate

Reactive Barrier- West Branch Canal Creek, APG

5 ft bls 1 ft bls

Standard Chlorine of Delaware,DNAPL Extent

CB, DCBs, TCBs DCBs, TCBs Not DNAPL

Aquifer

Wetland porewater

Containment wall

Chemical plant 1966-2002; EPA Superfund 2002 o 1981- 5,000 gal CB o 1986 storage tanks-

579,000 gal 14DCB and TCBs

Abuts Red Lion Creek, part of Delaware River watershed

Treatment in uplands, but not in wetlands

Half of water flow to Red Lion Creek is from Columbia Aquifer

Ethane

112TCA

12DCA

CA

1122- TeCA

TCE

12DCE

VC

Ethene

PCE

CT

CF

MeCl

Methane

CO2

M

135TCB,124TCB, 123TCB

Chlorobenzene*

14DCB, 13DCB, 12DCB

Benzene *

CO2, CH4

??

Biodegradation Pathways

Trichlorobenzenes*

Dichlorobenzenes* Aerobic CO2, HCl

* Parent contaminant

Anaerobic (reductive dechlorination)

• CB serves as terminal electron acceptor

• Separate e- donor required

• rate decreases with decreasing number Cl

Aerobic (oxidation) • O2 required as electron

acceptor • CBs utilized as C and e-

donor • rate increases with

decreasing number Cl • Short-lived

intermediates

5

100

75 (14DCB)

70 (124TCB)

Drinking Water MCL µg/L

Wetland Study Area, SCD

• Upward flow at all sites • Seepage

measured on wetland surface and creek bottom

Red Lion Creek 24-hr Seepage =

Conceptual model for contamination and dual-biofilm reactive barrier in wetland

dissolved plumes

DNAPL

Mixed anaerobic and aerobic conditions

Fe2+ S2-

NH3

CH4 DNAPL

O2

Sand+Inoculated GAC+Chitin sorbent and

biofilm attach GAC

Approach to evaluate natural and enhanced biodegradation

• In situ microcosms with Bio-Traps (Microbial Insights) – Stable isotope probing (13C-

labeled 14DCB, CB, B)

– Microbial species and functional genes for biodegradation

• Evaluate biodegradation processes in flow-through bioreactors – Upflow fixed film bioreactors

– Mimic growth in subsurface

– Allows changing conditions

Bioreactor polypropylene support matrix for biofilms

0.0

5.0

10.0

15.0

20.0

25.0

8 102 131 132 133 134 135 11 138 139 140 141 142 143 144

Conc

entr

atio

n, in

mill

igra

ms

per

liter

Site Number

Northwest PDBs, October 2011 Methane

Sulfide

Ferrous iron

Ammonia

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

106 107 108 109 110 6 112 113 114 14 116 117 118 119 120 122 123 15 125 126 127

Conc

entr

atio

n, in

mill

igra

ms

per

liter

Site Number

Northeast PDBs, October 2011 Methane

Sulfide

Ferrous iron

Ammonia

Bio-Traps: 13C-labeled Chloro-benzene -500

0

500

1,000

1,500

2,000

2,500

3,000

Background MNA Lactate/Chitin WBC-2

DIC

Del

(‰)

13C Utilized for CO2, 13C Chlorobenzene

PDB-01

PDB-04

PDB-07

PDB-10 (2009)

-40

-20

0

20

40

60

80

Background MNA Lactate/Chitin WBC-2

PLF

A D

el (‰

)

13C Utilized for Biomass, 13C Chlorobenzene PDB-01 PDB-04 PDB-07 PDB-10 (2009)

8 (NW) 104 (NW) 107 (NE) 6 (NE)

8 (NW) 104 (NW) 107 (NE) 6 (NE)

QuantArray Microbial Analysis- Anaerobic

Reductive dechlorination: DHC , Dehalococcoides spp. TCE, tceA reductase VCR, vinyl chloride reductase BV1 , vinyl chloride reductase DHBt, Dehalobacter spp. DHG, Dehalogenimonas spp.

J < <

1.0E+01

1.0E+02

1.0E+03

1.0E+04

1.0E+05

1.0E+06

1.0E+07

1.0E+08

DHC tceA vcr BVC DHBt DHG BCR bssA assA

Cells

/mL

MNA LAC WBC-2

BTEX, PAHs and alkanes: BCR, Benzoyl coenzyme A reductase bssA, benzylsuccinate synthase assA, alkylsuccinate synthase

-------Reductive dechlorination-------

QuantArray Microbial Analysis- Aerobic

pMMO, particulate methane monooxygenase sMMO, soluble methane monooxygenase TCBO, trichlorobenzene dioxygenase RDEG, toluene monooxygenase 2 RMO, toluene monooxygenase

< < < 1.0E+02

1.0E+03

1.0E+04

1.0E+05

1.0E+06

1.0E+07

1.0E+08

pMMO sMMO TCBO RDEG RMO PHE EDO PM1 ALKB

Cells

/mL

MNA LAC WBC-2

NA NA

PHE, phenol hydroxylase EDO, ethylbenzene/isopropyl- benzene dioxygenase PM1, Methylibium petroliphilum PM1 ALKB, alkane monooxygenase

0

500

1,000

1,500

2,000

2,500

3,000 3/

12

3/22

4/1

4/11

4/21

5/1

5/11

5/21

5/31

6/10

6/20

6/30

7/10

7/20

7/30

8/9

8/19

8/29

9/8

9/18

9/28

10/8

10/1

8

10/2

8

11/7

Tota

l CB

s +B

enze

ne ,

in µ

g/L

Native (C ) Bioreactor aerobic 6/20-8/25

added buffer + nutrients 7/27/12

aerobic 10/10-10/20

Inflow Tank

Waste

0

500

1,000

1,500

2,000

2,500

3,000

3/12

3/22

4/1

4/11

4/21

5/1

5/11

5/21

5/31

6/10

6/20

6/30

7/10

7/20

7/30

8/9

8/19

8/29

9/8

9/18

9/28

10/8

10/1

8

10/2

8

11/7

Tota

l CB

s +B

enze

ne ,

in µ

g/L

2012

WBC-2 (D) Bioreactor aerobic 10/10-10/20

Inflow Tank

Waste

SCD Bioreactors

Aerobic Native Culture (15B)

0

2,000

4,000

6,000

8,000

0 20 40 60

Conc

netr

atio

n (u

g/L)

Time (hrs)

15BN-B 124TCB

12DCB

Chlorobenzene

124TCB 12DCB CB

k (per hr) 0.051 0.071 0.15

half life (hrs) 13.6 9.8 4.6

r2 .972 .999 .968

Sand Grains

GAC – sorbent and biofilm support

Anaerobic Biofilm Predominant

Aerobic Biofilm Predominant

Chitin – Slowly dissolving C source

GW flow

O2 diffusion from surface and dispersed throughout from plant roots

H2O CO2

HCl

Anaerobic zone

Aerobic Zone

Reductive dechlorination

Aerobic degradation

Reactive Barrier Concept

GAC with WBC-2: Classes >1% Abundance

0

20

40

60

80

100

Rela

tive

Abu

ndan

ce (%

)

Bacilli

Actinobacteria

Mollicutes

Bacteroidia

Thermotogae

Gammaproteobacteria

Betaproteobacteria

Deltaproteobacteria

Synergistia

Clostridia

Dehalococcoidetes

Anaerolineae 1

2

Chloroflexi

GAC with 15B: Proteobacteria, Order

• Significant increase in the Betaproteobacteria group Burkholderiales on GAC.

0

10

20

30

40

50

60

15B.1 15B.2 +GAC.1 +GAC.2

Rela

tive

Abu

ndan

ce (%

)

Burkholderiales

Rhizobiales

Caulobacterales

Order

1

2

Microcosm Results: Anaerobic WBC-2 Biofilm on GAC

0

20

40

60

80

100

120

0 5 10 15

Perc

ent R

emai

ning

Days

Anaerobic WBC-2: 14DCB

W-DCB

GAC-DCB

W-GAC-DCB

DIW-DCB-TECA

Bacteria

GAC Biofilm-GAC

DIW Control

0

20

40

60

80

100

120

0 5 10 15

Perc

ent R

emai

ning

Days

Anaerobic WBC-2: 12DCB

W-DCB

GAC-DCB

W-GAC-DCB

DIW-DCB-TECA

Bacteria

GAC Biofilm-GAC

DIW Control

Slight decrease in CBs with culture in mineral media compared to DIW

Rapid sorption to GAC with and without anaerobic biofilm

Distinctly faster overall CB removal in biofilm-GAC

Microcosm Results: Aerobic 15B Seeded on GAC

0

20

40

60

80

100

120

0 5 10 15

Perc

ent R

emai

ning

Days

Aerobic: 14DCB

AB-DCB

A-GAC-DCB

AB-GAC-DCB

A-DIW-DCB

Bacteria

GAC Biofilm-GAC

DIW Control

0

20

40

60

80

100

120

0 5 10 15

Perc

ent R

emai

ning

Days

Aerobic: 12DCB

AB-DCB

A-GAC-DCB

AB-GAC-DCB

A-DIW-DCB

Bacteria

GAC Biofilm-GAC

DIW Control

Delay in sorption to GAC with aerobic biofilm

Slightly faster overall CB removal in biofilm-GAC

Column Testing Sand Columns: Medium Sand+ 5 % GAC + 3 % Chitin

Sediment Columns:

in progress- no data yet 5 % GAC + 3 % Chitin

Sand Columns: Medium Sand+ HRT= 0.45 day

A= WBC2-GAC B= WBC2+15B-GAC 0.000

0.050

0.100

0.150

0.200

0.250

0

5

10

15

20

25

0 5 10 15 20 25

Out

flow

(A2,

B2),

mg/

L

Inflo

w (A

1,B1

), m

g/L

A1 12DCB B1 12DCB A2: 12DCB B2 12DCB

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0

5

10

15

20

25

30

35

0 5 10 15 20 25

Out

flow

(A2,

B2),

mg/

L

Inflo

w (A

1,B1

), m

g/L

A1 CB B1 CB A2: CB B2 CB

28

Outflow VOC concentrations very low in both columns

Greater CB removal column with both the anaerobic and aerobic culture

Sand Columns: Sediment methanol extract analysis

A= WBC2-GAC B= WBC2+15B-GAC

0

50,000

100,000

150,000

0-2.5" 2.5-5.0" 5.0-7.5" 7.5-10" Co

ncen

trat

ion,

mg/

kg 12DCB, Sand Columns

A B

0

50,000

100,000

150,000

0-2.5" 2.5-5.0" 5.0-7.5" 7.5-10"

Conc

entr

atio

n, m

g/kg

CB, Sand Columns A B

Generally, less VOCs remaining in the columns that contained both the WBC-2 and 15B cultures

Depth from bottom of column

……lab testing ongoing but also started small-scale field pilot tests

GM: GAC-chitin-sand mixed into top 10” GAC seeded with WBC-2 and 15B aerobes Two plots- sites 135 and 8

GC: GAC-chitin-sand placed as 3” cap (remove top root mat) GAC seeded with WBC-2 and 15B aerobes One plot- site 8

C: sand placed as 3” control cap (remove top root mat) One plot- site 135

TOTAL Sand Chitin GAC pounds 783 30 43

Barrier Reactive Pilot Test Plots

31

GM

GC

C

10”

3”

3”

Site 135 test area with 3 plots and pre-installation sampling.

40 L of each culture

15B aerobes grown in lab in 5 days WBC-2 in anaerobic cylinder from Sirem Lab (20L mixed with DI-H20 for GAC seeding)

Buckets of pre-measured sand-chitin-seeded GAC dumped in plot and mixed into sediment to depth of 10 inches with small auger or “egg-beater” attachments on drill.

Johns Hopkins University Dr. Ed Bouwer Steven Chow, PhD student

Site characterization

Feasibility evaluation

Technology development

Pilot test remediation

USGS MD-DE-DC

Fate and Bioremediation Team Dr. Michelle Lorah

Jessica Teunis

Mastin Mount

Michael Brayton

Dr. Charles Walker

Roberto Cruz

Emily Majcher

Anna Baker

Luke Myers

NRP Collaborators:

Dr. Isabelle Cozzarelli

Dr. Denise Akob

Geosyntec Consultants Dr. Neal Durant Dr. Amar Wadhawan

Acknowledgements