Optimizing In-Situ Chemical Oxidation
Performance Monitoring and Project Management
   Using Compound Specific Isotope Ana...
CSIA
 – A powerful tool to document in-situ degradation
 – Validated academic sector and regulatory agencies
 – Newly avai...
CSIA can guide remediation decisions by:
  – Identifying cost reduction opportunities
  – Assessing the effectiveness of e...
Applications of CSIA

• In-Situ Remediation
  • Chemical Oxidation and Reduction
  • Biological Oxidation and Reduction

•...
Stable Isotopes in In-Situ Degradation

• Focus on carbon and hydrogen isotopes

• Can be determined in continuous flow mo...
Stable Isotopes in In-Situ Degradation

• Compounds with Light isotopes in the reactive
  position degraded more rapidly t...
Stable Isotopes in In-Situ Degradation

Any process which breaks a bond…..


     biological oxidation or reduction
     c...
Stable Isotopes in In-Situ Degradation

 Significant Fractionation Occurs in:
 • Biological Oxidation
 • Biological Reduct...
Stable Isotopes in In-Situ Degradation

 Little or No Fractionation Occurs in:
 • Dilution
 • Volatilization
 • Sorption
Stable Isotopes in In-Situ Degradation

• Light isotopes degraded more rapidly than heavy isotopes
• Product remaining bec...
The Stable Isotope Ratio

Ratio = R = ([heavy] / [light])

         R = ([13C] / [12C])

         R = ([2H] / [1H])
The Stable Isotope Parameter δ

We define a parameter “del” ≡ δ
and for a compound X
δx = {(Rx – Rstd) / Rstd } x 1000


T...
CSIA and Degradation
  Degradation
“chews” away at
                      heavier
the lightest stuff,
leaving behind the
he...
Anaerobic Degradation of Toluene
           under Sulfate Reducing Conditions
                               Meckenstock, ...
CSIA and In-Situ Degradation
• WSP has used CSIA at approximately 30 sites
  world wide to make better decisions that have...
CSIA & ISCO
• The use of CSIA to track ISCO remedial progress is an
  emerging application of the CSIA technology
• WSP ha...
Pre-ISCO Application
• Contaminant mass can be present dissolved in
  groundwater, sorbed to aquifer sediment, and as a
  ...
Post-ISCO Application
Immediately following oxidant application, dissolved
contaminant concentrations decrease
Post-ISCO Application
      ISCO effect on carbon isotopic ratios:

Baseline            13C
                        (aq) :...
Post-ISCO Application
  Site data show significant fractionation immediately
  following ISCO application

New Jersey Site...
Rebound
With the depletion of the oxidant, a flux of “untreated”
contaminant enters the treated groundwater. Desorption is...
Rebound
    Rebound effect on carbon isotopic ratios:

Baseline
Isotopic Conditions C(aq) : C(aq) = C(s) : C(s)
          ...
Rebound
Isotopic evidence interpreted as desorption rebound


Switzerland Site                             MW-4
          ...
Rebound
 Isotopic effects of a chem/bio application
                      Baseline/Pre-ISCO
 Florida Site         sample n...
Rebound
 Inefficient oxidant delivery can also cause “rebound”
      •Preferential flow paths limit treatment to a fractio...
Rebound
 Delivery rebound effect on carbon isotopic ratios:

Baseline Isotopic Conditions
                     13C
       ...
Rebound
Site data show isotopic evidence of delivery rebound

New Jersey Site                               MW-1
         ...
CSIA and ISCO Summary
• The presented information shows the potential for CSIA
  to aid in:
   – Confirmation of contamina...
Case Study – New Jersey Site
                          Injections       Injection   Injection       Pneumatic Fracturing
 ...
THE END
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CSIA ISCO Webinar

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Optimizing In-Situ Chemical Oxidation
Performance Monitoring and Project Management
Using Compound Specific Isotope Analysis

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CSIA ISCO Webinar

  1. 1. Optimizing In-Situ Chemical Oxidation Performance Monitoring and Project Management Using Compound Specific Isotope Analysis Matt Burns1, Robert Pirkle2, Patrick McLoughlin2 1 WSP Environment & Energy, Woburn, Massachusetts (matt.burns@wspgroup.com) 2 Microseeps, Inc, Pittsburgh, Pennsylvania (rpirkle@microseeps.com; pmcl@microseeps.com)
  2. 2. CSIA – A powerful tool to document in-situ degradation – Validated academic sector and regulatory agencies – Newly available services widening the use of CSIA – provides new information completely independent of concentration. – Isotopic composition measures the type of molecules that make up a VOC – Concentration measures the number of those molecules.
  3. 3. CSIA can guide remediation decisions by: – Identifying cost reduction opportunities – Assessing the effectiveness of existing remediation strategies – Providing a new kind of data that helps avoid un-necessary or redundant controls CSIA provides valuable insights about: – degradation mechanisms. – degradation versus dilution. – extent of degradation.
  4. 4. Applications of CSIA • In-Situ Remediation • Chemical Oxidation and Reduction • Biological Oxidation and Reduction • Remedial Forensic Investigations • Source Forensic Investigations
  5. 5. Stable Isotopes in In-Situ Degradation • Focus on carbon and hydrogen isotopes • Can be determined in continuous flow mode • Applicable to environmentally interesting concentrations
  6. 6. Stable Isotopes in In-Situ Degradation • Compounds with Light isotopes in the reactive position degraded more rapidly than compounds with Heavy isotopes in the reactive position • Product remaining becomes isotopically heavier • Process of isotopic change is called fractionation
  7. 7. Stable Isotopes in In-Situ Degradation Any process which breaks a bond….. biological oxidation or reduction chemical oxidation or reduction ……causes isotopic fractionation
  8. 8. Stable Isotopes in In-Situ Degradation Significant Fractionation Occurs in: • Biological Oxidation • Biological Reduction • Abiotic Degradation • In-Situ Chemical Oxidation • In-Situ Chemical Reduction
  9. 9. Stable Isotopes in In-Situ Degradation Little or No Fractionation Occurs in: • Dilution • Volatilization • Sorption
  10. 10. Stable Isotopes in In-Situ Degradation • Light isotopes degraded more rapidly than heavy isotopes • Product remaining becomes isotopically heavier • Process of isotopic change is called fractionation • Fractionation is unequivocal proof of in-situ degradation • Related to the mechanism of degradation • Related to the fraction of component degraded • Related to the rate of degradation • Used in groundwater modeling
  11. 11. The Stable Isotope Ratio Ratio = R = ([heavy] / [light]) R = ([13C] / [12C]) R = ([2H] / [1H])
  12. 12. The Stable Isotope Parameter δ We define a parameter “del” ≡ δ and for a compound X δx = {(Rx – Rstd) / Rstd } x 1000 The units of δx are ppt or “per mil”….. often denoted by the symbol “ ‰”
  13. 13. CSIA and Degradation Degradation “chews” away at heavier the lightest stuff, leaving behind the heavy stuff. This is called “fractionation.” For parent molecules (i.e. what was originally released, typically PCE or TCE) fractionation is unequivocal proof lighter of degradation.
  14. 14. Anaerobic Degradation of Toluene under Sulfate Reducing Conditions Meckenstock, et al., 1999. 350 Toluene (µM) Sulfide δ13C -22 2.0 300 -24 1.5 Toluene [nM] 250 Sulfide [mM] δ13C [0/ 00]0 200 -26 1.0 150 100 -28 0.5 50 0 -30 0.0 1 4 8 9 10 11 Time [days]
  15. 15. CSIA and In-Situ Degradation • WSP has used CSIA at approximately 30 sites world wide to make better decisions that have expedited site closure and minimized costs. Applications include: – Monitored Natural Attenuation (MNA) – Enhanced In-Situ Remediation – In Situ Microcosm Studies – In-Situ Chemical Oxidation (ISCO)
  16. 16. CSIA & ISCO • The use of CSIA to track ISCO remedial progress is an emerging application of the CSIA technology • WSP has used CSIA to monitor remedial progress and optimize performance at 4 ISCO sites – Remediation is ongoing at all 4 sites – Tests were paid for by clients. Results were expected to provide actionable data and achieve closure as rapidly and cost effectively as possible • CSIA has been found to be beneficial to: – Confirm contaminant destruction where contaminant concentration data is inconclusive – Identify delivery limitations – Better target/time supplemental ISCO applications
  17. 17. Pre-ISCO Application • Contaminant mass can be present dissolved in groundwater, sorbed to aquifer sediment, and as a separate non-aqueous phase • Partitioning between these phases is equilibrium-based and dependent on characteristics of: •Aquifer sediments (e.g., organic content) •Contaminant (e.g., solubility) •Groundwater (e.g., pH)
  18. 18. Post-ISCO Application Immediately following oxidant application, dissolved contaminant concentrations decrease
  19. 19. Post-ISCO Application ISCO effect on carbon isotopic ratios: Baseline 13C (aq) : 12C (aq) = 13C : 12C Isotopic Conditions (s) (s) Ox + 12C(aq) oxidized 12C(aq, g) + reduced Ox (inorganic 12C(aq, g) removed from system) Post-ISCO 13C (aq) : 12C (aq) >> 13C : 12C Isotopic Conditions (s) (s)
  20. 20. Post-ISCO Application Site data show significant fractionation immediately following ISCO application New Jersey Site MW-1 MW-2 Pre-ISCO Post-ISCO Pre-ISCO Post-ISCO TCE: CSIA, δ13C (‰) -29.6 -3.7 -34.4 -25.7 TCE Concentration (μg/l) 3,000 80 400 500 Very large isotopic Significant isotopic fractionation fractionation with (enrichment of 13C/ 12C increase in TCE within the dissolved concentration carbon pool comprising TCE) with very large decrease in TCE concentration
  21. 21. Rebound With the depletion of the oxidant, a flux of “untreated” contaminant enters the treated groundwater. Desorption is typically the primary mechanism of “rebound”: • Contaminant oxidation reactions are believed to be more efficient in the aqueous phase • Sorbed contaminant not as efficiently treated • Contaminants desorb and partition into the aqueous phase
  22. 22. Rebound Rebound effect on carbon isotopic ratios: Baseline Isotopic Conditions C(aq) : C(aq) = C(s) : C(s) 13 12 13 12 Ox + 12C(aq) oxidized 12C(aq, g) + reduced Ox Post-ISCO 13C (aq) : 12C (aq) >> 13C : 12C Isotopic Conditions (s) (s) desorption Isotopic Fractionation Shifts dissolution During Rebound 13C (aq) : 12C (aq) > 13C (s) : 12C (s)
  23. 23. Rebound Isotopic evidence interpreted as desorption rebound Switzerland Site MW-4 Pre-ISCO Post-ISCO T-1 Post-ISCO T-2 PCE: CSIA, δ13C (‰) -25.8 -23.7 -24.5 PCE Concentration (μg/l) 6,100 480 1,700 Increase of δ13C Decrease of δ13C and lower PCE and increased PCE concentration concentration with following ISCO time following ISCO application application
  24. 24. Rebound Isotopic effects of a chem/bio application Baseline/Pre-ISCO Florida Site sample not collected MW-5 Post-ISCO T-1 Post-ISCO T-2 Post-ISCO T-3 Benzene: CSIA, δ13C (‰) -24.6 -26.4 -25.5 Benzene Concentration (μg/l) 200 800 151 MTBE: CSIA, δ13C (‰) -24.6 -26.3 -25.6 MTBE Concentration (μg/l) 70 40 10 Assume Decrease of A contaminant enrichment of δ13C within the degradation rate 13C or increase dissolved greater than the of δ13C contaminant rate of contaminant Typical δ 13C of benzene and MTBE plume desorption/dissolution in gasoline: leads to increase in • Benzene: -23.5 ‰ to -31.5 ‰ δ 13C. • MTBE: -27.5 ‰ to -33.0 ‰
  25. 25. Rebound Inefficient oxidant delivery can also cause “rebound” •Preferential flow paths limit treatment to a fraction of the affected volume •Desorption rebound occurs from area where oxidant was delivered •Delivery rebound occurs when untreated water moves into treated zones. In-situ longevity of oxidant limits transport into less permeable areas Contaminants move from less permeable Preferential areas to more Flow Path permeable treated areas
  26. 26. Rebound Delivery rebound effect on carbon isotopic ratios: Baseline Isotopic Conditions 13C (aq) : 12C (aq) = 13C (s) : 12C (s) flux ater ed g ro undw Ox + 12C(aq) oxidized 12C(aq, g) + reduced Ox un treat Post-ISCO Isotopic Conditions 13C (aq) : 12C (aq) >> 13C (s) : 12C (s) desorption Isotopic Fractionation dissolution Shifts During Rebound 13C (aq) : 12C (aq) ≥ 13C : 12C (s) (s)
  27. 27. Rebound Site data show isotopic evidence of delivery rebound New Jersey Site MW-1 Pre-ISCO Post-ISCO T-1 Post-ISCO T-2 PCE: CSIA, δ13C (‰) -27.3 -16.8 -33.1 PCE Concentration (μg/l) 6,000 80 600 large isotopic large isotopic fractionation rebound
  28. 28. CSIA and ISCO Summary • The presented information shows the potential for CSIA to aid in: – Confirmation of contaminant destruction where contaminant concentration data are inconclusive – Identify delivery limitations – Better target/time supplemental ISCO applications
  29. 29. Case Study – New Jersey Site Injections Injection Injection Pneumatic Fracturing Feb & May ’08 Aug ‘08 Dec ‘08 & Injection Apr ‘09 MW-1 Nov-07 Jul-08 Dec-08 Mar-09 Jun-09 • PCE rebounded/ δ13C decrease CSIA, δ13C (‰) greater than baseline conditions can PCE -27.27 -16.84 -33.1 -34.69 -23.55 not be explained by bond-breaking TCE -29.55 -3.74 -27.03 -25.04 -26.99 reactions. Likely mobilized non- cis-DCE -29.84 -7.42 -30.45 -26.25 -26.2 degraded PCE VCl -38.37 NR -35.76 -33.22 -37.65 Large isotopic shift and concentration • Conclude that although the Concentration (μg/l) decrease followed by large rebound concentrations are decreasing the PCE 6,000 80 600 300 3,000 remediation is not progressing TCE 3,000 80 1,000 1,000 <500 adequately. Isotopic data suggests cis-DCE 20,000 2,000 30,000 30,000 10,000 water is being pushed around VCl 600 <5 900 40 800 • Enhance delivery by pneumatically fracturing the saturated soils Baseline isotopic conditions • Post enhanced delivery results show effected by biodegradation large contaminant concentration increases accompanied by significant fractionation (i.e., the MW-3 larger contaminant mass is being Nov-07 Jul-08 Dec-08 Mar-09 Jun-09 treated) CSIA, δ13C (‰) PCE -28.50 -27.69 -28.71 NS -25.75 • Conclusions: TCE -32.31 -30.51 -31.04 NS -31.03 •CSIA data identified delivery cis-DCE -31.31 -29.38 -31.34 NS -37.21 inefficiencies where concentration VCl -33.83 -34.18 -36.94 NS NR data alone were inconclusive Limited isotopic shift given the large •Enhancing delivery has increased Concentration (μg/l) concentration decrease contaminant destruction efficiency PCE 30,000 20,000 9,000 NS 60,000 and will reduce oxidant and TCE 7,000 1,000 5,000 NS 5,000 application costs significantly cis-DCE 7,000 20,000 10,000 NS 700 (20% estimated) over the duration VCl 500 500 <500 NS 30 of the project
  30. 30. THE END
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