W04 bioremediation of a chlorinated solvents site-turner

April 24, 2013
S. Shawn Turner, PG
Dean Carter, PE, CGC
Brendan V. Brown
APWA Florida – 2013 Annual Meeting & Trade Show
Groundwater Remediation Process
Case Study - Bioremediation of a Chlorinated
Solvents Site

Presentation Agenda
2
• Why Remediation is relevant at a Public Works Conference?
• Brief Description of the Groundwater Remediation Process
– Factors to consider for project success
– Overview of remediation technologies and selection criteria
• Case Study: Bioremediation of an Industrial Manufacturing Facility
– Conceptual Site Model / Remedial Alternatives Analysis
– Pilot Study
– Implementation of Selected Remedy
– System Optimization
Agenda

Why is Site Remediation Relevant?
• Contamination can be identified at any time
– Maintenance Shops / USTs
– Landfills / Solid Waste facilities
– Transportation Projects
– Land Redevelopment Projects
• Site Remediation is rarely planned for
• Rules/Regulations/Options are often not well understood
3
General Site Remediation Process

4

Generalized Site Remediation Process
5
• Site Assessment
• Conceptual Site Model Development
• Remediation Technology Screening
– Remedy Specific Sample Collection
• Bench-Scale / Pilot Testing (Proof of Remedy)
• Final Remedy Selection / Remediation Design
• Remediation Construction / Implementation
• Operation, Maintenance, and Monitoring
• Optimization
• Post-active Remediation Monitoring
• Site Closure
Design
Pilot Study
Remediation
Alternatives
Analysis
Construction /
Implementation
Operation,
Maintenance, &
Monitoring
Optimization
Site Closure
Site Assessment

Technologies & Selection
Criteria
6
• Ex-situ Treatment
• Air-Sparge / SVE
• Bioremediation
• In-situ Chemical Oxidation
• In-situ Chemical Reduction
• Barrier Technologies
• Thermal
• Solidification/Stabilization
Source: Federal Remediation Technology Roundtable – Remediation
Technology Screening Matrix and Reference Guide, Version 4.0

Chlorinated Solvent Groundwater Remediation
Technology Usage
Source: The Lebron Study, 2004
Thermal – 27 (22.9%)
Bioremediation – 25 (21.2%)
Chemical Oxidation –
25 (21.2%)
Dual Phase – 13 (11.0%)
Excavation – 11 (9.3%)
Other – 4 (3.4%)
ZVI/Nano-scale
Iron – 7 (5.9%)
Surfactant
Flushing – 6 (5.1%)

Project Success Depends on Multiple Factors…
8
Chemicals of
Concern
Site Geology
Land Use
CostSchedule
Rules /
Regulatory
Site Restrictions
OM&M /
Reliability
Successful
Remediation

• Former Industrial Manufacturing Facility
in Orlando, Florida
• Primary Contaminants:
(typically 100,000 - 700,000 ug/L)
– 1,1-DCE
– methylene chloride
• 3 Surficial Aquifer Zones:
– shallow (water table)
– intermediate (semi-confined)
– deep (confined)
• Contamination under existing facility
Selected Remedy: Bioremediation
Enhanced with Groundwater Circulation
Case Study: Bioremediation of a Chlorinated
Solvents Site
Site Description
9

• Contaminants of Concern
– Chlorinated Solvents
– High Concentrations (up to
700,000 ug/L)
• Site Geology
– 3 contaminated aquifer zones
– Clayey sands and clays
• Site Considerations
– Existing Manufacturing Building
– Existing Hydraulic Control System
• Land Use
– Planned for mixed use
redevelopment
Site Factors considered during the Remediation
Alternatives Analysis
Site Description
10
• Schedule
– No specific redevelopment
timeframe
– Low priority
• Cost
– Always a high priority
• Regulatory
– Initiated through consent order
– Client wants unconditional NFA
• Technology/Reliability
– innovative technologies
considered

Confirmed presence of
Dehalococcoides spp.
e- donor: potassium lactate
Groundwater recirculation used
to distribute lactate
north
EAB Pilot Test was conducted in the highest
concentration area of the site
VOCs
e- donor
microbes
Pilot Study
12

• 4 Extraction Wells
• 1 Injection Well
• Circulate 4 - 5 days/week
• Excess water –
ex-situ air-stripper
Bioremediation Pilot Study was conducted to
demonstrate Proof of Concept
Pilot Study
13

Illustration depicting biostimulation enhanced
with groundwater circulation
Dehalococcoides Electron Donor
Pilot Study
14

Baseline Month 4
Baseline Month 4
VCresults1,1-DCE Results: Concentrations reduced by up to
4 orders of magnitude in 4 months
DCEresults
Pilot Study
15

Ethene concentrations increased throughout
the pilot test cell
Baseline Month 4
Pilot Study
16
Ethene results

Implementation of Selected Remedy
17

Baseline TVOC results showed multiple wells
above 100,000 µg/L
18

Full-scale EAB: Horizontal extraction and vertical
injection wells used to distribute lactate
19
3 Horizontal Well
Segments
50 Injection Wells
Intermediate (30)
Deep (20)

The horizontal wells cut through all three surficial
aquifer zones
20

One-Pass Trencher and Installation of the
Horizontal Wells
21

One-Pass Trencher and Installation of the
Horizontal Wells
22

5
10
15
20
25
30
35
40
Feet(bls)
- Potassium Lactate
- Dehalococcoides spp.
- Monitor Wells
- Water Extraction
Graphical depiction of groundwater circulation
and pulsed lactate injection

HW-1
HW-2
24
Molar concentrations of chlorinated solvents
during EAB system cycling

TVOC Results – Intermediate
25
Startup Month 6
CurrentYear 2

pH Optimization
26
Optimization

Areas of slower degradation generally had low pH
27
pHTVOC
Optimization

Approach to pH Buffering
28
pH Optimization
pH buffer selection/calculation
• Bicarbonate
• pH modeling indicated need for ~6,000 lbs of bicarbonate
• Calculated solution ratios based on aquifer volume and field scale
testing
Chemical delivery/monitoring
• Limited access inside the building/future use of building
• Direct injection of horizontal well water to provide microbes
• Gravity feed of bicarbonate and lactate solutions
• Sub-slab vapor and indoor air monitoring

Injection wells were installed to address low
pH/high TVOC concentrations under the building
29
pH Optimization

pH under the building was lower than optimal
levels for reductive dechlorination
30
Baseline pH Levels
pH Optimization

Multiple injections of bicarbonate, lactate and
extracted groundwater were completed
31
HCO3
Lactate
HWs
(Direct pumping)
pH Optimization

Bicarbonate and lactate injections were
conducted by gravity feed
32
pH Optimization

Bicarbonate Injections and pH Results
33
0
1000
2000
3000
4000
5000
6000
7000
3.5
4.5
5.5
6.5
7.5
8.5
9.5
12/18/08 03/28/09 07/06/09 10/14/09 01/22/10 05/02/10 08/10/10 11/18/10 02/26/11 06/06/11
CumumaltiveBicarbonateInjected(lbs)
pH(SU)
Date
pH Under Building & Bicarbonate Injected
INJ29-4I
INJ29-5I
INJ29-6I
INJ29-7I
MW-29I
Bicarbonate
Purging at
MW-29I started
pH Optimization

MW-29I Purging
34
pH Optimization

Bicarbonate Buffer System Equilibrium Reactions
35
CO2(aq) + H2O H2CO3 H+ + HCO3
- 2H+ + CO3
2-
pH Optimization

Molar Concentrations: MW-29I
36
0
4
8
12
16
20
0
100
200
300
400
500
600
12/18/08 03/28/09 07/06/09 10/14/09 01/22/10 05/02/10 08/10/10 11/18/10 02/26/11 06/06/11
µmol/L(Ethene)
µmol/L(DCE/VC)
Date
ChlorinatedEthenes
1,1-DCE
Vinyl Chloride
Ethene
0
4
8
12
16
20
0
100
200
300
400
500
600
12/18/08 03/28/09 07/06/09 10/14/09 01/22/10 05/02/10 08/10/10 11/18/10 02/26/11 06/06/11
µmol/L(DCA/Ethane)
µmol/L(TCA)
Date
ChlorinatedEthanes
1,1,1-TCA
1,1-DCA
Ethane
Summary

pH Optimization Results
37
6,000 lbs
bicarbonate
Summary

Full-Scale EAB Results
38
TVOC mass = 2,800 lbs TVOC mass = 6 lbs
Summary

Alternate Technology Cost Comparison
From McCabe et al. (2005)
EnhancedEnhanced
BioremedBioremed..
n = 11n = 11
ChemicalChemical
OxidationOxidation
n = 13n = 13
CosolventCosolvent
SurfactantSurfactant
n = 6n = 6
ThermalThermal
n = 6n = 6
1
10
100
1000
10000
Enhanced Chemical Cosolvent Thermal
Bioremediation Oxidation Surfactant
n=11 n=13 n=6 n=6
CostperVolume($/cuyd)
1
10
100
1000
10000
n=11 n=13 n=6 n=6
MaxMax
75th %75th %
MedianMedian
25th %25th %
MinMin
KEYKEY
$2/yd$2/yd33
$27/yd$27/yd33
$29/yd$29/yd33
$225/yd$225/yd33
$152/yd$152/yd33
$20/yd$20/yd33
$47/yd$47/yd33
$125/yd$125/yd33
$194/yd$194/yd
33
$518/yd$518/yd33
$66/yd$66/yd33
$118/yd$118/yd33
$385/yd$385/yd33
$1322/yd$1322/yd33
$5500/yd$5500/yd33
$32/yd$32/yd33
$48/yd$48/yd33
$88/yd$88/yd33
$129/yd$129/yd33
$300/yd$300/yd33
EnhancedEnhanced
BioremedBioremed..
n = 11n = 11
ChemicalChemical
OxidationOxidation
n = 13n = 13
CosolventCosolvent
n = 6n = 6
ThermalThermal
n = 6n = 6
1
10
100
1000
10000
n=11 n=13 n=6 n=6
1
10
100
1000
10000
n=11 n=13 n=6 n=6
EnhancedEnhanced
BioremedBioremed..
n = 11n = 11
ChemicalChemical
OxidationOxidation
n = 13n = 13
CosolventCosolvent
n = 6n = 6
ThermalThermal
n = 6n = 6
EnhancedEnhanced
BioremedBioremed..
n = 11n = 11
ChemicalChemical
OxidationOxidation
n = 13n = 13
CosolventCosolvent
n = 6n = 6
ThermalThermal
n = 6n = 6
1
10
100
1000
10000
n=11 n=13 n=6 n=6
1
10
100
1000
10000
MaxMax
75th %75th %
MedianMedian
25th %25th %
MinMin
KEYKEY
MaxMax
75th %75th %
MedianMedian
25th %25th %
MinMin
KEYKEY
$2/yd3
$27/yd3
$29/yd3
$225/yd3
$152/yd3
$20/yd3
$47/yd3
$125/yd3
$518/yd3
$194/yd3
$66/yd3
$118/yd3
$385/yd3
$5500/yd3
$1322/yd3
$32/yd3
$48/yd3
$88/yd3
$300/yd3
$129/yd3
RITS Fall 2007: Bio—
State of the Practice
Enhanced
Bioremediation
n=11
Chemical
Oxidation
n=13
Cosolvent
Surfactant
n=6
Thermal
n=6

W04 bioremediation of a chlorinated solvents site-turner

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