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Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 1
Enhanced Remediation of Chlorinated Enhanced Remediation of Chlorinated Solvents from Contaminated Solvents from Contaminated
Groundwater using a Bioreactor Groundwater using a Bioreactor SystemSystem
Charles Walker and Michelle Lorah
Chlorinated Organic SolventsChlorinated Organic Solvents
• Useful for degreasing oils, fats and resins
• Generally are harmful to human and environmental health
• Suspected carcinogens• Many different phases in
environment– Non Aqueous Phase Liquid (NAPL)– Dissolved– Vapor
• Most are heavier than water– Dense NAPL
• Volatile Organic Compound (VOC)
DNAPL
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 2
Aberdeen Proving GroundsAberdeen Proving Grounds• Chlorinated solvents were
used as decontaminating agents and degreasers
• Wastes were discharged directly into the creek, or through overland runoff
• Led to the contamination of the Canal Creek Aquifer
• 1990, APG was placed on National Priorities List, established under CERCLA (Superfund)
Phelan and others 2002
Site Site ContaminationContamination
Majcher and others, 2007; Weston Solutions, 2005
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 3
Common Chlorinated Solvents Common Chlorinated Solvents Found at APGFound at APG
Name Abbreviation Use
1,1,1,1‐Tetrachloromethane(carbon tetrachloride)
CT Agent manufacturing, fire extinguishers, refrigerant
Trichloromethane(chloroform)
CF Agent manufacturing,solvent
Trichloroethene TCE Anaesthetic
1,1,2,2‐Tetrachloroethane 1,1,2,2‐PCATeCA
Solvent, decontaminating agent
1,1,2,2‐TetrachloroethaneTrichloromethane Trichloroethene1,1,1,1‐Tetrachloromethane
Current Groundwater TreatmentCurrent Groundwater Treatment• Pump and Treat System
• Extracts groundwater from eight groundwater recovery wells
• 200 gallons per hour
• Removes chlorinated solvents using specialty resin
– Short lifespan
• Fouls easily with metals
– Metals removal
• 100 ug/L total VOC effluent limit
• TeCA is the main contaminant
• Expensive to run
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 4
Natural Degradation PathwaysNatural Degradation Pathways
• The majority of degradation is biologically mediated
• Replace chlorine atoms with hydrogen atoms
• Anaerobic conditions
• Requires electron donors– Carbon substrate
– Hydrogen gas
Abiotic
Time for some Time for some ‘‘CultureCulture’’• Characterization studies
in the wetland area around West Branch Canal Creek found natural degradation occurring.
• Sediments from this area were collected
• Culture was enriched
• Complete degradation
• Sediment free media
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 5
WBCWBC‐‐2 Microbial Composition2 Microbial Composition
• “West Branch Consortia”
• Contains at least 17 and 21 distinct Bacteriaphylotypes based on DGGE and clone library analysis, respectively
• Acetobacterium (40%), Dehalobacter (19%), and Acidaminococcacea (9%) most prominent; Dehalococcodies 5%
Acidaminococcaceae(putative)
No match
Dehalococcoides sp. CBDB1
No match
Dehalococcoidesethenogenes 195
Dehalococcoides sp. CBDB1
No matchSyntroph
usTrichlorob
acter
Deh
alob
acter
Spiroche
te
Deh
alococcoides
Desulfovibrio
WBC
‐2
WBCWBC‐‐2 Culture in Action2 Culture in Action
• Only known culture capable of degrading such a broad mixture of chlorinated alkanes, alkenes, and methanes
• The culture was successfully used to bioaugment a reactive mat at APG
• Can we create a pump and treat system with WBC‐2?
WBC‐2 Culture + TeCAMicrocosms
Reactive Mat
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 6
Project Goals and ObjectivesProject Goals and ObjectivesGoal: Conduct pre‐design testing necessary to evaluate the effectiveness of WBC‐2 for treating chlorinated VOCs in a bioreactor application.
Objectives:• Determine if a flow‐through bioreactor system can support
the WBC‐2 Culture and remove VOCs below the discharge limit.
• Determine operational parameters, such as pH, ORP, Temp, and HRT to aid in the design for a larger scale system.
• Determine the optimum electron donor.
Bioreactor Vessel
1Bioreactor Vessel
2Bioreactor Vessel
3
Argon
NutrientStock
Solution
BicarbonateStock
Solution
ORP Electrode
ClarifiedEffluent
Sludge Separation
PeristalticPump
GroundwaterEqualization
Tank
PeristalticPump
ElectronDonorSolution
Sampling Po
rts
Clarified Effluent
Settled Sludge
4.1
• equalization vessel to mix influent with nutrients and donor• 1-L pretreatment fixed film bioreactor• Two 1-L fixed film bioreactors for VOC removal• a 1-L separatory funnel for solids separation
Bench Scale Bioreactor DesignBench Scale Bioreactor Design
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 7
OperationsOperations• Two bioreactor systems, D (Design) and (E)
• Reactors contained a polyurethane foam and polypropylene support matrix, which was seeded with WBC‐2.
• Nutrients, electron donor, and TeCAwere added to the treatment plant influent in equalization tank
• Pumped to first vessel and then gravity fed
• Monitored for chlorinated solvents, pH, nutrients, oxidation reduction potential and flow rates.
MonitoringMonitoring• Samples removed from sampling ports– Analyzed for VOCs
• Immediately with GC‐MS
– ORP, pH, N, P, COD
• Continuous Monitoring– ORP, pH, flow, temperature
Bioreactor Vessel
1Bioreactor Vessel
2 Bioreactor Vessel
3
Sampling Po
rts
1
2
3
4
57
6
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 8
ResultsResultsGoal: Conduct pre‐design testing necessary to evaluate the effectiveness of WBC‐2 for treating chlorinated VOCs in a bioreactor application.
Objectives:•Determine if a flow‐through bioreactor system can support the WBC‐2 Culture and remove VOCs below the discharge limit.
•Determine operational parameters, such as pH, ORP, Temp, and HRT to aid in the design for a larger scale system.
•Determine the optimum electron donor.
6/7/2010 6/21/2010 7/5/2010 7/19/2010 8/2/2010 8/16/20108/30/2010
Tota
l VO
Cs
(µg
L-1 )
0
200
400
600
800
1000
1200
1400InfluentEffluent100 µg L-1 Discharge Limit
Total VOCs in D ReactorTotal VOCs in D Reactor
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 9
Total VOCs in E ReactorTotal VOCs in E Reactor
6/7/2010 6/21/2010 7/5/2010 7/19/2010 8/2/2010 8/16/20108/30/2010
Tota
l VO
Cs
(µg
L-1 )
0
200
400
600
800
1000
1200
1400
1600InfluentEffluent100 µg L-1 Discharge Limit
TeCA Removal in D ReactorTeCA Removal in D Reactor
D Reactor: Percent TeCA Remaining
D1 D2 D4 D6 D7
Per
cent
TeC
A R
emai
ning
0
20
40
60
80
100
12005/03/201005/24/201007/13/201007/20/201007/26/201008/11/201008/18/2010
Bioreactor Vessel
1Bioreactor Vessel
2 Bioreactor Vessel
3
Sampling Po
rts
1
2
3
4
57
6
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 10
TeCA Removal in E ReactorTeCA Removal in E Reactor
E Reactor: Percent TeCA Remaining
E1 E2 E4 E6 E7
Per
cent
TeC
A R
emai
ning
0
20
40
60
80
100
12005/03/201005/24/201007/13/201007/20/201007/26/201008/11/201008/18/2010
Bioreactor Vessel
1Bioreactor Vessel
2 Bioreactor Vessel
3
Sampling Po
rts
1
2
3
4
57
6
Formation of Daughter ProductsFormation of Daughter Products
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 11
Bioreactor Vessel
1Bioreactor Vessel
2 Bioreactor Vessel
3
Sampling Po
rts
1
2
3
4
57
6
D1 D2 D4 D6 D7
% T
rans
Pro
duce
d pe
r ini
tial T
eCA
con
cent
ratio
n
0
10
20
30
40
50
60
7005/03/201005/24/201007/13/201007/20/201007/26/201008/11/201008/18/2010
Percent Trans 1,2Percent Trans 1,2‐‐DCE Production: DCE Production: D ReactorD Reactor
Sampling Po
rts
Percent Trans 1,2Percent Trans 1,2‐‐DCE Production: DCE Production: E ReactorE Reactor
E1 E2 E4 E6 E7
% T
rans
Pro
duce
d pe
r ini
tial T
eCA
con
cent
ratio
n
0
20
40
60
80
100
120
14005/03/201005/24/201007/13/201007/20/201007/26/201008/11/201008/18/2010
Bioreactor Vessel
1Bioreactor Vessel
2 Bioreactor Vessel
3
Sampling Po
rts
1
2
3
4
57
6
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 12
ResultsResultsGoal: Conduct pre‐design testing necessary to evaluate the effectiveness of WBC‐2 for treating chlorinated VOCs in a bioreactor application.
Objectives:• Determine if a flow‐through bioreactor system can support
the WBC‐2 Culture and remove VOCs below the discharge limit.
• Determine operational parameters, such as pH, ORP, Temp, and HRT to aid in the design for a larger scale system.
• Determine the optimum electron donor.
Operational Parameters: Operational Parameters: pHpH
Apr May Jun Jul Aug Sep Oct
pH
4
5
6
7
8
9
10Supply TankFirst Reactor
Apr May Jun Jul Aug Sep Oct
pH
4
5
6
7
8
9
10Supply TankFirst Reactor
D Reactor pH E Reactor pH
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 13
Operational Parameters: Operational Parameters: ORPORP
D Reactor ORP E Reactor ORP
Apr May Jun Jul Aug Sep Oct O
RP
(mV)
-700
-600
-500
-400
-300
-200
-100
0Reactor 1Reactor 2Reactor 3
Apr May Jun Jul Aug Sep Oct
OR
P (m
V)
-700
-600
-500
-400
-300
-200
-100
0Reactor 1Reactor 2Reactor 3
Operational Parameters: Operational Parameters: TemperatureTemperature
Mar Apr May Jun Jul Aug Sep Oct
Tem
pera
ture
(C)
10
15
20
25
30
35Reactor DReactor E
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 14
Operational Parameters: Operational Parameters: HRTHRT
4/1/2010 5/1/2010 6/1/2010 7/1/2010 8/1/2010 9/1/2010
Ret
entio
n Ti
me
(Hou
rs)
10
15
20
25
30
35
40
45D ReactorE Reactor
ResultsResultsGoal: Conduct pre‐design testing necessary to evaluate the effectiveness of WBC‐2 for treating chlorinated VOCs in a bioreactor application.
Objectives:• Determine if a flow‐through bioreactor system can support
the WBC‐2 Culture and remove VOCs below the discharge limit.
• Determine operational parameters, such as pH, ORP, Temp, and HRT to aid in the design for a larger scale system.
• Determine the optimum electron donor.
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 15
DonorDonor Microcosms
• Tested different donors in microcosms first– Lactate
– Lactate/ethanol
– Corn Syrup
– Corn Starch Packing Peanuts
– Lactic Acid
– Lactic Acid Solids
Donors in BioreactorDonors in Bioreactor
LactateCorn Syrup
Packing Peanuts
Perc
ent T
otal
VO
C R
emov
al
0
20
40
60
80
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 16
Next Donor: Hydrogen GeneratorNext Donor: Hydrogen Generator
ConclusionsConclusions• WBC‐2 culture was
successfully established in a bioreactor system
• Effluent discharge limits are being met
• Despite varying operational parameters, effluent discharge concentrations were relatively stable
6/7/2010 6/21/2010 7/5/2010 7/19/2010 8/2/2010 8/16/20108/30/2010
Tota
l VO
Cs
(µg
L-1 )
0
200
400
600
800
1000
1200
1400InfluentEffluent100 µg L-1 Discharge Limit
6/7/2010 6/21/2010 7/5/2010 7/19/2010 8/2/2010 8/16/20108/30/2010
Tota
l VO
Cs
(µg
L-1 )
0
200
400
600
800
1000
1200
1400
1600InfluentEffluent100 µg L-1 Discharge Limit
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 17
ConclusionsConclusions
• The bioreactors operated efficiently with
a 15‐20 hour retention time
• pH was best controlled with Sodium Bicarbonate
• Corn syrup appears to be a good choice for donors
• Hydrogen generators may also be potential donors
ConclusionsConclusions• The WBC‐2 culture can adapt to different environments and degrade many different types of chlorinated organic compounds
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 18
Future Work: Pilot PlantFuture Work: Pilot Plant
Future Work: Pilot PlantFuture Work: Pilot Plant
3 mL/min to 3 gal/min
1 bottle per 3 months to 5 gal/1.5 weeks
Enhanced Remediation of Chlorinated Solvents from Contaminated Groundwater Using a Bioreactor System 19
Future Work: Future Work: Standard Chlorine of DelawareStandard Chlorine of Delaware
• Superfund Site
• Starting wetlands work
• WBC‐2 and Chlorobenzenes
AcknowledgmentsAcknowledgments• USGS MD‐DE‐DC Water Science Center
– Mastin Mount– Anna Baker– Jessica Teunis– Roberto Cruz– Luke Myers– Melody Finchblaugh– Bill Davies
• GeoSyntec– Duane Graves
• General Physics– Dennis Donovan
• ARMY– John Wrobel– Jeff Aichroth