1. LONG TERM MONITORING DATA
EVALUATION OF BIOAUGMENTATION
DURING ISCR-ENHANCED
BIOREMEDIATION OF TCE DNAPL
James G.D. Peale, RG
Erik I. Bakkom, PE
(Maul Foster & Alongi Inc.)
Jeff Roberts, Sandra Dworatzek
(SiREM Laboratories)
Josephine Molin
(FMC Environmental Solutions)
June 2013

2.  Site Overview
 Technology Summary
 Problem Statement
 Analysis
 Results
 Summary
 Implications
TOPICS

3.  Former MGP waste site redeveloped for
manufacturing in 1970s
 80+ acres adjacent to Portland Harbor NPL site
 TCE released from a recycling system (1980-1985)
 Impacts from release discovered in 2002
 TCE DNAPL Source Zone
 Impacts from about 5-34 m bgs
 TCE up to 592,000 ug/L (DNAPL levels)
 No TCE DNAPL observed
 Cis-1,2-DCE up to 90,800 ug/L
 Very little VC (< 100 ug/L)
Site Overview

4. Site Overview

5. Technology Summary
 EHC
 Powdered blend of zero-valent iron (ZVI) and hydrophilic
organic carbon
 Creates strongly reducing conditions in groundwater for in situ
chemical reduction (ISCR)
 ISCR results in abiotic dechlorination and supports anaerobic
bacteria
 KB-1
 Anaerobic consortium of dechlorinating bacteria
 Includes dehalococcoides sp.
 Requires ORP < -75 mV
 Both technologies demonstrated success for
dissolved CVOC plumes

6. Technology Summary
 EHC+KB-1 Full-Scale Implementation
 46 m x 21 m x 3 m PRB – Source area only
 Injected from ~12 – 34 m bgs
 Supplemental upgradient areas
 200+ injection points
 ~269,400 kg EHC
 1,831 L KB-1
 Direct-push drilling
 23 Performance Monitoring Wells

7. Injection Layout

8. Injection Layout

9. Source Area Geometry

10. Problem Statement
 Remedial action objective is 11,000 ug/L
 Threshold indicator for TCE DNAPL
 Achieved in less than 12 months
 Achieved mean TCE 3 ug/L
 Declining cDCE and VC, but still elevated in
some wells
 Dhc counts 107 – 108
 Question: how long can this continue?
 Will we see rebound?

11. Problem Statement
 How long will Dhc sp. flourish?
 Organic carbon needs
 (other)
 Continued reducing conditions?
 Field data
 Other functional requirements?
 Continued cVOCs?

12. Long-Term Data Sets
 Pilot Study Data
 2006-2008
 Shallow and deep wells, within and
downgradient of injection zone
 Full-scale Data
 2009-present
 19 wells + pilot study wells
 Monitoring program includes:
 VOCs, TOC, Dhcv, vCRA
 Field parameters

13. CVOC Data – kg estimated in
source area (EVS)
0
200
400
600
800
1,000
1,200
1,400
1,600
1,800
11/1/2008 5/20/2009 12/6/2009 6/24/2010 1/10/2011 7/29/2011 2/14/2012 9/1/2012 3/20/2013
TCE (kg) cDCE VC Ethene

14. CVOC Data – normalized (C/C0) to show
ethene generation (also VC…uh oh)
0.001
0.01
0.1
1
10
100
Nov-08 May-09 Dec-09 Jun-10 Jan-11 Jul-11 Feb-12 Sep-12 Mar-13
TCE cDCE VC Ethene CVOC

15. Not to worry - VC Data regression
y = -0.1601x + 6676.3
R² = 0.7136
-20
0
20
40
60
80
100
120
140
160
Dec-11 Apr-12 Jul-12 Oct-12 Jan-13 May-13 Aug-13 Nov-13 Mar-14 Jun-14
Estimated VC Mass (kg)
Estimated VC Mass (kg) Linear (Estimated VC Mass (kg))

16. TOC Data – Mean of Full Scale
Data Set (n=23)
194
0
500
1000
1500
2000
2500
3000
3500
Total Organic Carbon (Total and Dissolved)
Primary Well Group (mg/L)
TOC (Total) - Mean TOC (Total) - Geometric Mean TOC (Dissolved) - Mean TOC (Dissolved) - Geometric Mean
Background TOC ~ 10 mg/L

17. Dhc Data – Full Scale Data Set
(n=23)
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
1.E+10
7/1/2009 1/17/2010 8/5/2010 2/21/2011 9/9/2011 3/27/2012 10/13/2012 5/1/2013
DHC
Full Scale Well Group (Count)
1/2 of non-detect values used

18. vCRA Data – full scale data set
1.00E+04
1.00E+05
1.00E+06
1.00E+07
1.00E+08
1.00E+09
1.00E+10
6/1/2008 12/18/2008 7/6/2009 1/22/2010 8/10/2010 2/26/2011 9/14/2011 4/1/2012 10/18/2012 5/6/2013 11/22/2013
vcrA
Primary Well Group
(Count)
1/2 of non-detect values used

19. TOC and DHC Data – Long Term
(n=4)
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
0
500
1000
1500
2000
2500
3000
3500
4000
5/1/2006 9/13/2007 1/25/2009 6/9/2010 10/22/2011 3/5/2013
Dhc(count)
TOC(mg/L)
WS-19 WS-18-101 WS-18-71 DHC

20. ORP data
-200
-150
-100
-50
0
50
100
150
200
37922 38288 38653 39018 39383 39749 40114 40479 40844 41210
Redox potential
Mean of Primary Well Group (n varies) eH - Mean

21. Analysis
 All indicators look good!
 VOC mass decreasing
 Sustained elevated TOC levels
 Sustained negative ORP levels
 Continued ethene generation
 Regression predicts VC decrease by 2014
 Some indicators look iffy?
 Would like to see higher Dhc numbers?
 Others?

22. Results
 Success!
 Other considerations
 DNAPL/CVOC reduction
 Other
 Useful?

23. Summary (tbd)
 Literature range sets boundaries
 20 – 750 yrs (latter less useful)
 Developing data set
 Regression provides simple tool for prediction
 Dual rates observed and should be considered
 Early consumption followed by equilibrium
 Modeling is promising approach
 Estimates match lower range of regression
 Can provide conservative (short) predictions to
improve site planning/closure

24. Implications (tbd)
 Micro-scale ZVI is extremely durable
 Data fit well with other observations
 Similarity to presumed P&T timeframes (30 yrs)
 How do we manage long-term?
 Is monitoring required to demonstrate complete
exhaustion?
 How can we extend confidence of this long-term
remedy to support site closure?

25. Acknowledgements/Questions
 Thank you.
 SiREM Laboratories
 FMC Environmental Solutions
 Questions?