Welcome to ITRC’s Internet Training

1. Welcome to ITRC’s Internet Training ITRC Technical and Regulatory Guidance Document: “Enhanced In Situ Bioremediation of Chlorinated Solvents in Ground Water” Sponsored by the ITRC, the EPA-TIO and the RTDF www.itrcweb.org

2. Natural Attenuation EISB (Enhanced In Situ Bioremediation) Permeable Reactive Barriers (basic and advanced) Diffusion Samplers Phytotechnologies ISCO (In Situ Chemical Oxidation) Constructed Treatment Wetlands Small Arms Firing Range Characterization and Remediation Systematic Approach to In Situ Bioremediation ITRC – Shaping the Future of Regulatory Acceptance ITRC Membership ITRC Internet Training Courses States ITRC Member State Federal Partners Sponsors Industry, Academia, Consultants, Citizen Stakeholders www.itrcweb.org

3. EISB Presentation Overview Regulatory Issues Chemical Terminology Microbial Processes / Degradation Pathways Questions & Answers Amendments & Delivery Field Pilots / Technical Requirements Benefits / Rules of Thumb Questions & Answers Links to additional resources Your feedback Logistical Reminders Phone Audience Keep phone on mute * 6 to mute your phone and again to un-mute Do NOT put call on hold Simulcast Audience Use at top of each slide to submit questions Enhanced In Situ Bioremediation of Solvents in Ground Water

4. Today’s Presenters • Ron Buchanan - Instructor • Principal Consultant, Dupont • ron.j.buchanan@usa.dupont.com • Guy Tomassoni – Instructor • Environmental Protection Specialist, EPA Office of Solid Waste / Corrective Actions • Tomassoni.guy@epa.gov • Mary Yelken - Moderator • Environmental Programs Advisor, WGA/ITRC • myelken@westgov.org

5. What is EISB? • Engineered technique for optimizing subsurface conditions (hydrogeological, geochemical, microbial) to biodegrade contaminants in situ • Includes injecting substrate and nutrients (i.e., amendments) • Creates in situ conditions conducive to microbes • May include extracting and recirculating amended groundwater • Establishes/accelerates contaminant biodegradation in situ

6. Regulatory Issues • EISB is a complex regulatory process • regulatory authorities • regulatory status of contaminated groundwater • regulation status of amendments

7. Regulatory Authorities • Regulatory Authority/Authorities • RCRA (Subtitle C) or CERCLA (Section 104 or 106) • Safe Drinking Water Act - 40 CFR Section 144 Underground Injection Control Program • State Cleanup programs

8. Regulatory Status of Contaminated Ground Water • Contaminated media, including ground water, may “contain” hazardous wastes and therefore be subject to regulation under RCRA subtitle C (contained-in policy) • If ground water contains HW we must understand application of; • Land Disposal Restrictions (LDRs) • Minimum Technological Standards (MTRs) • Permitting

9. Application of RCRA Subtitle C(continued) • Land Disposal Restrictions • RCRA Section 3020(b) clarification (EPA Guidance Memorandum “Applicability RCRA Section 3020 to In-Situ Treatment of Ground Water, Dec. 27, 2000”) • Treatment standards for waste waters • Site-specific treatment variance (if applicable) • Management that does not constitute “placement” • e.g., some NPDES permitting

10. Application of RCRA Subtitle C(Cont’d) • Minimum Technological Standards • different standards apply to different types of units • consider “temporary units” • Permitting • EPA, under CERCLA, and many states, under their own programs, exempt from administrative permitting requirements on-site cleanup provided substantive standards are achieved

11. Application of Underground Injection Control Programs • Class IV • waived under 40 CFR Part 144 .13 & must obtain waiver in each case • NJDEP intent to issue “General NJPDES Permit” where only amendments are added • Class V Wells • Federal Performance Standards • State Standards

12. Regulatory Status of Injection of Amendments • RCRA Subtitle C • Generally not regulated under Subtitle C • Exception is if amendment is a hazardous waste • Underground Injection Control Programs • Class IV wells • Class V Wells

13. Regulatory Issues Summary • Regulatory authorities • Regulatory status of contaminated ground water • Regulation of injection of amendments

14. Key Definitions PCE - Tetrachloroethylene C2Cl4 TCE - Trichloroethylene C2HCl3 DCE - Dichloroethylene C2H2Cl2 VC - Vinyl chloride C2H3Cl CT - Carbon tetrachloride CCl4 CF - Chloroform CHCl3 DCM - Dichloromethane CH2Cl2 TCA - 1,1,1 Trichloroethane C2H3Cl3

15. Preferred Electron Donors/Acceptors • Electron Donors: small, simple molecules like sugars, organic acids, alcohols, alkanes, aromatics; man-made organic compounds, and natural organic carbon can be used. • Electron Acceptors: Oxygen, nitrate, Mn(IV), Fe(III), chlorinated solvents, sulfate, and CO2

16. Electron Donor Biochemical Reactions • Lactate and hydrogen reactions 2CH3CH2OCOO- + 2H20 --> 4H2 + 2CH3COO- + 2CO2 TCE + H2 --> cDCE + Cl- + H+ cDCE + H2 -->VC + Cl- + H+ VC + H2 --> ETH + Cl- + H+ Overall: TCE + 3H2 --> ETH + 3Cl- + 3H+ • Theoretically requires approx. 1.3 moles of lactate to drive hydrogen mediated microbial reactions

17. Degradation Processes • Three Major Degradation Mechanisms • 1) Reductive Anaerobic Dechlorination • 2)Aerobic Cometabolism • 3) Oxidation - reactions may be used for the destruction of vinyl chloride, dichloromethane, 1,2 DCA, 1,2 DCE

18. Degradation Pathway 2H HCl 2H HCl 2H HCl 2H HCl H H Cl Cl Cl H H H H H C C C C C C C C C C H H Cl Cl Cl Cl Cl Cl Cl H PCE TCE DCEs VC ETH Relative Degradation Rates: PCE >TCE > VC > DCE

19. Degradation Processes “Reductive Anaerobic Dechlorination” 1) Reductive Anaerobic Dechlorination: • Process: • R-Cl + H2 + 2e- R-H + Cl- +H+ • dechlorination involves a series of reductions • reductions = gain of electrons • electron transfer may provide energy • organic substrate supplies H2 and electrons

20. Mass Balancing Dechlorination Reactions • Example: reductive dechlorination of TCE • TCE  DCE  VC  ETH • In gram moles: • C2HCl3 + 3 H2 C2H4 + 3 HCl • 131.5g TCE + 6g H2 28g Ethene + 109.5g HCl • TCE : H2 ratio is 21.9 : 1 • H2 solubility is 1.7 ppm, so you can degrade 37.2 ppm of TCE

21. Degradation Processes “Reductive Anaerobic Dechlorination” • Potential Problems: • Low hydraulic conductivity zones • biofouling • over abundance of electron acceptors

22. Degradation Processes “Aerobic Cometabolism” 2) Aerobic Cometabolism: • highly chlorinated compounds such as PCE and CCl4 do not appear to be susceptible to aerobic cometabolic degradation • non-specific oxygenase enzymes help metabolize substrate(s) • bacteria incidentally oxidize chlorinated compounds • process usually requires oxygen addition for aerobic bacteria • process usually requires a substrate such as methane, phenol, or toluene

23. Cometabolic Degradation • A fortuitous aerobic reaction carried out by enzymes designed to metabolize a different compound the bacteria normally grows on. • Bacteria are presumed to gain nothing from the reaction and in fact, may be harmed by intermediates that are formed

24. Cometabolic Biodegradation • Mechanism for ethenes is epoxidation: • /O\ • -C = C- => -C - C- => CO2 , other products Example: TCE /O\ Cl2-C=C-Cl => Cl2-C-C-Cl => CO2 , (small amounts of Cl2-C-COOH, dichloroacetic acid)

25. Cometabolic Degradation • Compounds documented in the literature supporting aerobic cometabolic reactions: • methane (Wilson and Wilson, 1985), other short-chained alkanes like ethane, propane (Wackett et. al., 1989), • simple aromatic ring compounds: toluene, phenol (Nelson et. al., 1986) • NH4+ (Arciero et. al., 1989)

26. Mass Balancing Cometabolic Reactions • Example: co-oxidation of TCE • 2 C2HCl3 + 21 O2 + 2 C7H8 --> 6 HCl + 18 CO2 + 6 H2O • In gram moles: • 263g TCE + 672g O2 + 184g C7H8 ----> 219g HCl + 792g CO2 + 108g H2O • TCE to O2 ratio is 0.39 : 1 • Water with 10 ppm dissolved oxygen can degrade a max of 3.9 ppm TCE

27. Degradation Processes “Aerobic Cometabolism (Cont’d)” • Potential Problems: • process does not work on highly chlorinated compounds • cost of maintaining aerobic conditions • intermediates may be toxic to bacteria (i.e.. epoxide) • substrate amendments maybe RCRA regulated compounds

28. Degradation Processes “Oxidation” 3) Oxidation: • used on dichloromethane (DCM), vinyl chloride,chloroethane, and chloromethane • Process: • oxidizing agent (amendment) / reducing agent (contaminant) • elemental oxygen and or hydroxyl radical replace chloride • oxidizing agent supplied directly or indirectly (i.e. O2, H2O2)

29. Direct Aerobic Biodegradation • Aerobic bacteria “grow” on the compound by using it as their carbon and energy source (electron donor). • Process is rapid, compound almost always degraded to CO2, degradation intermediates may be formed.

30. 1,2-DCA Degradation Pathways Aerobic Conditions Anaerobic Conditions 1,2-Dichloroethane (1,2-DCA) hydrolysis oxidation Vinyl Chloride (VC) Chloroethanol reductive dechlorination dihaloelimination Chloroethane (CA) Chloroacetate hydroloysis Ethene reductive dechlorination Ethanol CO2 Ethane CO2

31. Mass Balancing Oxidation Reactions • Example: oxidation of VC • 2 C2H3Cl + 5 O2 ---> 4 CO2 + 2 HCl +2 H2O • In gram moles: • 125g VC + 160g O2 ---> 176g CO2 + 73g HCl + 36g H2O • VC : O2 ratio is 0.78 : 1 • Water with 10 ppm dissolved oxygen can degrade a max of 7.8 ppm VC

32. Degradation Processes “Oxidation (cont’d)” • Potential Problems: • low hydraulic conductivity • Oxygen transport in ground water • high levels of naturally occurring organic carbon

33. Chlorinated Solvent Degradation 33

34. “Technical and Regulatory Requirementsfor Enhanced In Situ Bioremediation ofChlorinated Solvents in Ground Water” • Question & Answer

35. Amendment Delivery Systems • Effective EISB requires delivery of amendments to • the targeted portion of the plume • A) Dual Well or Trench Recirculation • extraction and reinjection of groundwater • effective mixing of amendments and water • forms a treatment zone • B) Injection Only Systems • gravity or forced injection • lack of hydraulic containment

36. Delivery Systems(Cont’d) • C) Gas Injection Systems • injection of vapor phase amendment(s) • D) Passive Systems • no forced injection or recirculation • amendments added within or in the path of a plume

37. Amendments for Microbial Growth • A) Substrate • growth source and electron donor • vary from site to site • example: Na lactate • B) Nutrients • ground water analysis for needed inorganics • monitoring of concentration levels • example: P, N

38. Amendments for Microbial Growth(cont’d) • C) Electron Acceptors • associated with aerobic cometabolism or direct oxidation • O2, H2O2 • D) Bioaugmentation • introduction of non-native bacteria • duration • short lived, outcompeted easily by indigenous microbes

39. When is EISB Appropriate? • To reduce chlorinated solvent levels below regulatory requirements • As a polishing step • When reduction-oxidation (redox) potential is low

40. EISB Flowchart Precursor Assessment Lab Optimization Study Hydrogeology Modeling Field Tracer Test Field Pilot Test Scale-up

41. Technical Requirements A) Site Assessment • review of previous site data • development of site characterization work plans • hydrogeologic and geochemical characterization

42. Technical Requirements (cont’d) A) Site Assessment (cont’d) • source area characterization • plume characterization • conceptual model and site evaluation

43. “Technical and Regulatory Requirementsfor Enhanced In Situ Bioremediation ofChlorinated Solvents in Ground Water” Not it Ethene Chlorine Hydrogen Vinyl Chloride Carbon Bond Cis-1,2-Dichloroethene 43 Trichloroethene

44. Technical Requirements (cont’d) B) Laboratory Treatability Test Phase • laboratory treatability studies • analysis • evaluating laboratory treatability results

45. Technical Requirements (cont’d) B) Laboratory Treatability Test Phase cont’d) • Anaerobic Laboratory Treatability Studies • Cookson, John T. - Bioremediation Engineering, Design • and Application, 1995, McGraw-Hill • Harkness (et al., 1998) - Stimulation of complete reductive • dechlorination of TCE in Strother Soil: Microcosm • and column studies. • ITRC In Situ Bioremediation Team (1998) - Technical and Regulatory Requirements for Enhanced In Situ Bioremediation of Chlorinated Solvents in Ground Water

46. Technical Requirements (cont’d) C) Field Pilot Test Phase • permitting and regulatory acceptance • preliminary site selection • focused hydrogeologic study

47. Pilot Location and Geology

48. Pilot Study Plume Configuration

49. Typical Lab Results: Microcosms

50. Hydrogeologic Modeling “EISB Recirculation System”