New Directions for Electrokinetic Remediation Research

Transcription

1 New Directions for Electrokinetic Remediation Research Krishna R. Reddy, PhD, PE, DGE, FASCE Professor of Civil & Environmental Engineering Director, Geotechnical & Geoenvironmental Laboratory University of Illinois, Chicago, USA 13 th Symposium on Electrokinetic Remediation (EREM2014) Malaga, Spain, September 8, 2014

2 Presentation Outline 1. Status on Electrokinetic Remediation 2. Current Research Trends 3. Practical Issues/Considerations 4. Final Remarks

3 The Problem Estimated Number of Contaminated Sites in the U.S. (Cleanup horizon: ) Just started to realize the problem in developing countries such as India, China,...

4 Remediation Technologies Soil Remediation Soil Vapor Extraction Soil Washing/Flushing Chemical Oxidation/Reduction Stabilization/Solidification Electrokinetic Remediation Thermal Desorption Vitrification Bioremediation Phytoremediation Groundwater Remediation Pump and Treat In-Situ Flushing Permeable Reactive Barriers Air Sparging Monitored Natural Attenuation Bioremediation Still striving to develop efficient, rapid and costeffective in-situ technologies?

5 Electrokinetic Remediation (EKR) Fundamentals: Electrolysis Electromigration Electroosmosis Electrophoresis Geochemical Reactions Adsorption/Desorption Precipitation/Dissolution Oxidation/Reduction Complexation Rxns Dynamic geochemistry Spatial and temporal changes in solution chemistry and solid surface properties

6 Unique Advantages Applicable to Different Soil Conditions Low Permeability/Heterogeneous Soils Unsaturated and Saturated Soils Applicable to Variety of Contaminants Metals, Radionuclides, or Organic Compounds Mixed Contaminants Easy to integrate with other remediation technologies

7 Electrokinetic Remediation: Overview Electrochemical Remediation Technologies for Polluted Soils, Sediments and Groundwater Krishna R. Reddy, Claudio Cameselle (Editors) ISBN: Hardcover. 760 pages. September

8 Removal of Heavy Metals Cationic Metals Migrate towards the cathode Migration retarded by high ph and the presence of multiple contaminants Anionic Metals Migrate towards the anode Migration retarded by low ph and the presence of multiple contaminants Enhancement Strategies Increase treatment duration? Increase electric potential gradient/vary mode of application? Polarity reversal? Use cation/anion exchange membranes in the electrodes? Circulating electrolytes? Use enhancement (electrode conditioning) solutions Chelates (e.g., EDTA, DTPA) Organic Acids (e.g., Acetic Acid, Citric Acid)

9 Removal of Organic Contaminants Hydrophobic organic contaminants must be desorbed/solubilized using: Surfactants Cosolvents Cyclodextrins Removal depends upon electroosmosis (EO), but EO decreases due to: reduced electrical conductivity, reduced soil ph (<PZC), and the type of flushing solution used Sustain/increase EO by: ph control (>PZC throughout the soil) Magnitude/Mode of electric potential application (e.g., pulsed- on/off cycles)

10 Integrated/Coupled Technologies Integrated (or Coupled) Technologies such as Electrokinetic Chemical Oxidation/Reduction Electrokinetic Bioremediation Electrokinetic Phytoremediation Electrokinetic Permeable Reactive Barriers Electrokinetic Stabilization Advantages Overcome the deficiencies of common technologies Detoxify organics within the soil/groundwater (no effluent to treat) Remove/recover heavy metals (no long-term issues/value) Achieve both of the above (ideal for mixed contaminants) Practical? Cost-effective?

11 EKR Current Status Electrokinetic remdiation by itself or with enhancements may be costly and impractical. Integrated electrokinetic remediation technologies have great potential to be effective and practical. Ideally suited for: Remediation of low permeability/heterogeneous subsurface Source zone remediation Difficult contaminants Mixed contaminants Provides greater flexibility to adapt at any time during the remediation process to changing or different contaminant conditions, without the need for major changes in the field setup

12 Current Research Trends EKR continues to be a very active research topic worldwide!!! Topic=(electrokinetic remediation) Results: 885 Source: Web of Science (As of August 15, 2014)

13 EKR Publications Topic=(electrokinetic remediation) Results: 885 Source: Web of Science (As of August 15, 2014)

14 EKR Publications Topic=(electrokinetic remediation) Results: 2957 Source: Google Scholar (As of August 15, 2014)

15 EKR Publications Topic=(electrokinetic remediation) Results: 2957 Source: Google Scholar (As of August 15, 2014)

16 Basic Vs Applied Research

17 Practical Issues/Considerations 1. Reliability of the technology 2. Costs of application 3. Practicality of implementation 4. Application of and ability to meet risk-based remediation goals 5. Anticipated remediation time 6. Acceptability to project stakeholders 7. Necessity of special permits 8. Implications on end-use of the site 9. Sustainability considerations, including triple bottom line parameters 10.Remediation versus management paradigm for complex sites

18 Practical Issues/Considerations 1. Reliability of the technology 2. Costs of application 3. Practicality of implementation 4. Application of and ability to meet risk-based remediation goals 5. Anticipated remediation time 6. Acceptability to project stakeholders 7. Necessity of special permits 8. Implications on end-use of the site 9. Sustainability considerations, including triple bottom line parameters 10.Remediation versus management paradigm for complex sites

19 Removal of Heavy Metals Ni (II) Kaolin Ni (II) Glacial Till mass fraction INITIAL MASS ph mass fraction INITIAL MASS ph 0.00 anode section 1 section 2 section 3 section 4 section 5 cathode anode section 1 section 2 section 3 section 4 section 5 cathode 0.0 Cr (VI) Kaolin Cr (VI) Glacial Till mass fraction INITIAL MASS ph mass fraction INITIAL MASS ph 0.00 anode section 1 section 2 section 3 section 4 section 5 cathode anode section 1 section 2 section 3 section 4 section 5 cathode 0.0

20 Enhanced Heavy Metal Removal Overall Removal Efficiency Kaolin Water EDTA Acetic Acid SQEEK % Removal Chromium Nickel Cadmium

21 Enhanced Heavy Metal Removal Overall Removal Efficiency Glacial Till Water EDTA Acetic Acid Citric Acid Sulfuric Acid % Removal SQEEK Chromium Nickel Cadmium

22 Removal of Organic Contaminants Cumulative Flow Volume (ml) Periodic Continuous Elapsed Time (days) Normalized Concentration C/Co Periodic Continuous Normalized Distance from Anode Kaolin; Phenanthrene=500 mg/kg Anode: 0.01M NaOH/Surfactant; VG=2 VDC/cm

23 Removal of Mixed Contaminants Concentration (C/Co) EK-NP-1: 5% Igepal Nickel Phenanthrene Normalized distance from Anode (Conc. 500 mg/kg each; 2 VDC/cm-periodic)

24 Integrated EK-Fenton Phenanthrene Concentration (mg/kg) H 2 O 2 Conc. Initial 0% 5% 10% 20% 30% Normalized Distance from Anode Kaolin Soil with Phenanthrene and Nickel (each at 500 mg/kg); VG=1 VDC/cm

25 Co-Existing Ni Removal Nickel Concentration (mg/kg) H 2 O 2 Conc. Initial 0% 5% 10% 20% 30% Normalized Distance from Anode Kaolin Soil with Phen and Nickel (each at 500 mg/kg)

26 Field Contaminated Soils PROPERTY Field A* Soil B** Soil D* Soil E* % gravel = 0 % gravel = 0 % gravel = % gravel = 0.1 Grain size distribution % sand = 84.0 % sand = 5.2 % sand = % sand = 8.4 % fines = 16.0 % fines = 94.8 % fines = % fines = 91.5 LL = 50.0 LL = 45.0 Atterberg limits Non-Plastic PL = 24.0 Non-Plastic PL = 31.7 PI = 26.0 PI = 13.7 USCS classification SP-SM CH - fat clay SM CL Water content N/A 6.36% 7.55% 78.60% Organic content 11.10% 2.63% 2.69% % 19.20% Specific gravity Max. dry density N/A N/A 2.03 g/cm g/cm3 Optimum moisture content N/A N/A 10.40% 24.00% ph Redox porential mv mv mv mv Electrical conductivity 2.68 m-s/cm m-s/cm 1435 m-s/cm 0.37 m-s/cm All the soil properties were determined by ASTM standards *Contaminated with both heavy metals and PAHs ** Contaminated with heavy metals only

27 Testing Program Test Testing Voltage Pore Number Designation Gradient Flushing Solution Volumes (VDC/cm) 1 EK-A-1 0 Deionized Water Deionized Water M EDTA 6 2 EK-A M EDTA % Igepal CA % Igepal CA EK-A-1a 0 0.2M EDTA % Igepal CA EK-A-3 0 5% Igepal CA M EDTA EK-A-4 0 5% Igepal CA M EDTA EK-A-5 1 5% Igepal CA M EDTA EK-A % HP-β - CD EK-A % HP-β - CD EK-B M EDTA EK-B M KI EK-B M DTPA EK-B % HP-β - CD EK-B M KI - 14 EK-B M EDTA - 15 EK-B M KI - 16 EK-B M EDTA - 17 EK-D-1 2 5% Igepal CA EK-D % HP-β - CD EK-D % n-butylamine EK-D-4 2 3% Tween EK-E-1 2 5% Igepal CA EK-E % HP-β - CD EK-E % n-butylamine EK-E-4 2 3% Tween

28 Iron Thallium Vanadium Zinc Selenium Silver Sodium Nickel Potassium Lead Magnesium Manganese Mercury Cobalt Copper Chromium Field Soil A EK-A-1 EK-A-1a EK-A-2 EK-A-3 EK-A-4 EK-A % Removal Aluminum Antimony Arsenic Barium Beryllium Cadmium Calcium

29 Pyrene Fluoranthene Fluorene Indeno(1,2,3-cd)pyrene Naphthalene Phenanthrene Chrysene Dibenz(a,h)anthracene Benzo(g,h,i)perylene Benzo(k)fluoranthene Field Soil A EK-A-1 EK-A-1a EK-A-2 EK-A-3 EK-A-4 EK-A-5 % Removal Acenaphthene Acenaphthylene Anthracene Benz(a)anthracene Benzo(a)pyrene Benzo(b)fluoranthene

30 Field Soil B 0.2M EDTA, 2VDC/cm 0.2M KI, 2VDC/cm EK-B-1 Toxic Contaminant Distribution EK-B-2 Toxic Contaminant Distribution Contaminant concentration (mg/kg) Lead S-1 (Near Anode) S-2 (Middle) S-3 (Near Cathode) Mercury Contaminant Concentration (mg/kg) Lead S-1 (Near Anode) S-2 (Middle) S-3 (Near Cathode) Mercury EK-B-3 and EK-B-4 were not effective in contaminant removal

31 Field Soil D 5% Igepal, 2VDC/cm 3% Tween, 2VDC/cm EK-D-1, % Remaining in Each Soil Section EK-D-4, % Remaining in Each Soil Section S-1 (Near Anode) S-2 (Middle) S-3 (Near Cathode) S-1 (Near Anode) S-2 (Middle) S-3 (Near Cathode) Percent Remaining (%) Acenaphthene Acenaphthylene Anthracene Benz(a)anthracene Benzo(a)pyrene Benzo(b)fluoranthene Benzo(g,h,i)perylene Benzo(k)fluoranthene Chrysene Dibenz(a,h)anthracene Fluoranthene Fluorene Indeno(1,2,3-cd)pyrene Naphthalene Phenanthrene Pyrene Acenaphthene Acenaphthylene Anthracene Benz(a)anthracene Benzo(a)pyrene Benzo(b)fluoranthene Benzo(g,h,i)perylene Benzo(k)fluoranthene Chrysene Dibenz(a,h)anthracene Fluoranthene Fluorene Indeno(1,2,3-cd)pyrene Naphthalene Phenanthrene Pyrene EK-D-2, EK-D-3 were not effective in contaminant removal

32 Field Soil E Acenaphthene Acenaphthylene Anthracene 0 EK-E-1 EK-E-2 EK-E-3 EK-E-4 Pyrene % Removal Benz(a)anthracene Benzo(a)pyrene Benzo(b)fluoranthene Benzo(g,h,i)perylene Benzo(k)fluoranthene Chrysene Dibenz(a,h)anthracene Fluoranthene Fluorene Indeno(1,2,3-cd)pyrene Naphthalene Phenanthrene No heavy metals were removed

33 So, how reliable is this technology?

34 Practical Issues/Considerations 1. Reliability of the technology 2. Costs of application 3. Practicality of implementation 4. Application of and ability to meet risk-based remediation goals 5. Anticipated remediation time 6. Acceptability to project stakeholders 7. Necessity of special permits 8. Implications on end-use of the site 9. Sustainability considerations, including triple bottom line parameters 10.Remediation versus management paradigm for complex sites

35 Costs of Application Costs depend on: Zone of contamination (area and depth), type of contaminants, and type of soils Initial and target contaminant concentrations Electrode wells & electrodes and their installation Electrode conditioning solutions Electricity consumption Effluent treatment Operation and monitoring Site preparation and permits Actual costs unknown, estimated to be: $20 to $225/yd 3, but generally more than $60/yd 3 Very deep sources (>40 ft) and very small sites (<0.1 acres) usually cost more whereas larger, shallower sites cost less. Bottom line is that the costs have to be lowered.

36 Costs of Application Large scale EK systems should be simple to be competitive. Extensive electrode fluid management: expensive high operating costs greater chance of failure. Manage the cathode and anode fluids as passively as possible.

37 So, what is the cost of using this technology?

38 Practical Considerations 1. Reliability of the technology 2. Costs of application 3. Practicality of implementation 4. Application of and ability to meet risk-based remediation goals 5. Anticipated remediation time 6. Acceptability to project stakeholders 7. Necessity of special permits 8. Implications on end-use of the site 9. Sustainability considerations, including triple bottom line parameters 10.Remediation versus management paradigm for complex sites.

39 Electro-reclamation at Loppersum Year 1989 Volume 250 m³ Type of contamination As in heavy clay Concentration at start Max. 500 mg/kg Average 115 mg/kg Concentration at end Max. 29 mg/kg Average 10 mg/kg Energy 150 kw/ton Duration 80 days of 18 hours Product removed 38 kg As by ER 14 kg As by excavation (Lageman, 2003)

40 Electro-reclamation at Stadskanaal Year Volume 2500 m³ Type of contamination Cd in fine clayey sand Concentration at start Cd >2000 mg/kg Average 250 mg/kg Concentration at end Cd 5-40 mg/kg Average 11 mg/kg Energy 200 kw/ton Duration 2 ½ years (Lageman, 2003)

41 Electro-reclamation at Woensdrecht Year Volume 3500 m³ Energy 150 kw/ton Duration 2 years C o n c e n tr a ti o n (m g / k g ) Cr Zn Ni Cu Pb Cd D e c r e a s e (% ) Start (mg/kg) End (mg/kg) Decrease % (Lageman, 2003)

42 EK: Lasagna TM Process (Athmer, 2004) Lasagna TM is the patented and trademarked name for the integration of DC electricity and in-situ treatment and was developed by a consortium of scientists from DuPont, General Electric and Monsanto along with the USEPA and US DOE.

43 Installation of Electrodes Lasagna system installation was extremely successful in reducing TCE contamination at sites in the USA

44 EK: Lasagna TM Process DOE Facility, Paducah, KY TCE stored in a lined pit and used for testing of uranium storage steel cylinders TCE leaked and contaminated subsoil Clayey soil, K=1x10-6 cm/s Contaminated zone:90 x70 x40 (Athmer, 2004) Max TCE conc mg/kg

45 EK: Lasagna TM Process Electrodes and treatment zones installed with hollow mandrel systems Steel plate electrodes at 45 spacing Treatment zones (1-inch thick) at 5 spacing (iron filings) Powered volts, depending on temperature increase (50 to 90 0 C) EO flow at 0.5 cm/day, recycled, 1.6 pore volumes (Athmer, 2004)

46 EK: Lasagna TM Process Average TCE conc. of 0.38 mg/kg with max. conc. 4.5 mg/kg Only one sample had detectable levels of cis,1-2- dichloroethylene (Athmer, 2004)

47 e-barrier (Sale et al., 2005)

48 Bench-scale Study TCE as a function of position (20 V). Position 0 is the center of the electrode pack. (Sale et al., 2005)

49 Composite Panel Detail (Sale et al., 2005)

50 Construction Initial topsoil removal Excavation prior to trench box installation Electrode panel components (Sale et al., 2005) Lifting of nine linked e-barrier modules (panels) prior to placement in trench

51 Construction Placement of eight linked e-barrier modules into the trench linking with in-place ebarrier modules Backfilling of trench with imported soil. Note risers containing electrical connections, gas vests, washout tubing and multilevel sampling bundles Top of risers prior to surface completion (Sale et al., 2005) Surface completion

52 Lessons Learned Sustained TCE flux reduction up to 95% No adverse reaction intermediates Cost comparable to other technologies (e.g. ZVI PRB) Limitations: Deep installation Scale formation in high TDS waters Flux reduction may be insufficient to meet the regulatory groundwater concentration requirement

53 Practicality of Implementation Useful for small, source zones Very limited full-scale applications in the USA! Lasagna TM process is well documented! Incomplete technology developers information on pilot or full-scale field applications Lack of well documented case studies (detailed design, performance data and cost) No guidance on designing full-scale systems

54 Practicality of Implementation Well based electrodes may not be efficient significant reduction in electrical current passage and voltage drop due to open area. Larger planar electrodes are easier to install than well based electrode no waste soil to manage EK systems should be coupled with in-situ destruction techniques ZVI barrier walls placed in the flow path works well (Lasagna TM ) Enhanced bio shows promise Electrolytic barrier

55 So, how practical is to implement this technology?

56 Practical Issues/Considerations 1. Reliability of the technology 2. Costs of application 3. Practicality of implementation 4. Application of and ability to meet risk-based remediation goals 5. Anticipated remediation time 6. Acceptability to project stakeholders 7. Necessity of special permits 8. Implications on end-use of the site 9. Sustainability considerations, including triple bottom line parameters 10.Remediation versus management paradigm for complex sites

57 Pre-Risk Era (Early 80s) Remediation goals often set to pristine condition/restoration Proved to be cost and time prohibitive

58 Emergence of Risk Era National Research Council/National Academy of Sciences (NRC/NAS) RED BOOK (1983) Risk Assessment in the Federal Government: Managing the Process Addressed health risk assessments across all Federal Agencies Defined four-step risk assessment process Steps used in several EPA statutes but with different methods (e.g., RCRA, CERCLA, FIFRA, TSCA)

59 Risk Assessment & Management

60 Risk Characterization Likelihood of injury, disease, or death resulting from exposure to a potential environmental hazard Cancer Risk Equation Cancer Risk = ADD x CSF Risk = incremental probability of an individual developing cancer from exposure ADD = chronic lifetime daily dose averaged over 70 years CSF = cancer slope (or potency) factor Noncancer Risk Equation Hazard Quotient = ADD/RfD ADD = average daily dose (or intake) RfD = reference dose HI > 1 potentially of health concern Address uncertainty and variability Assumes risk additive over all chemicals in mixture

61 Risk-based Screening & Corrective Levels Calculate allowable concentrations in media based on allowable risk - inverse of USEPA approach Risk-based Corrective Action (RBCA) for Petroleum Release Sites ASTM E1739 Tiered Approach States - examples Illinois: Tiered Approach to Corrective Action Objectives (TACO)- IAC 620 California:» Department of Toxic Substances Control (DTSC) California Human Health Screening Levels (CHHSLs)» San Francisco Bay Regional Water Quality Control Board (RWQCB) Environmental Screening Levels (ESLs)

62 TACO Tier 1 SRO Contaminant Type Residential Properties - Concentration (mg/kg) Ingestion Inhalation Soil component of ground water ingestion Industrial/Commercial Properties - Concentration (mg/kg) Ingestion Inhalation Soil component of ground water ingestion Class I Class II Class I Class II Arsenic Barium Cadmium Chromium Lead Anthracene Benzo(a)pyrene Benzo(k)fluoran thene Fluoranthene Naphthalene Pyrene (Sharma and Reddy, 2004)

63 How are treatment target concentrations decided?

64 Practical Issues/Considerations 1. Reliability of the technology 2. Costs of application 3. Practicality of implementation 4. Application of and ability to meet risk-based remediation goals 5. Anticipated remediation time 6. Acceptability to project stakeholders 7. Necessity of special permits 8. Implications on end-use of the site 9. Sustainability considerations, including triple bottom line parameters 10.Remediation versus management paradigm for complex sites.

65 Anticipated Remediation Time No reliable way to estimate remediation time Limited modeling studies Depends on the site area/depth, contamination, and EK system design/operation Case studies Lageman ( ) Heavy Metal Site 1: 80 days Heavy Metal Site 2: 2.5 years Heavy Metal Site 3: 2 years Athmer (2004) TCE Site 1: 2 years TCE Site 2: 2.5 years Sale et al. (2005) TCE Site: 1.5 years

66 How can we estimate cleanup time?

67 Practical Considerations 1. Reliability of the technology 2. Costs of application 3. Practicality of implementation 4. Application of and ability to meet risk-based remediation goals 5. Anticipated remediation time 6. Acceptability to project stakeholders 7. Necessity of special permits 8. Implications on end-use of the site 9. Sustainability considerations, including triple bottom line parameters 10.Remediation versus management paradigm for complex sites

68 Stakeholder Acceptability Stakeholders Owner, consultant, regulators/government, community/public Effects on underground utilities and liabilities

69 Practical Considerations 1. Reliability of the technology 2. Costs of application 3. Practicality of implementation 4. Application of and ability to meet risk-based remediation goals 5. Anticipated remediation time 6. Acceptability to project stakeholders 7. Necessity of special permits 8. Implications on end-use of the site 9. Sustainability considerations, including triple bottom line parameters 10.Remediation versus management paradigm for complex sites

70 Special Permits Injection of electrode conditioning solutions Toxicity data Fate of residual in subsurface Compatibility of electrodes with subsurface Effluent management and treatment Treatment Discharge permits (e.g., NPDES)

71 Practical Considerations 1. Reliability of the technology 2. Costs of application 3. Practicality of implementation 4. Application of and ability to meet risk-based remediation goals 5. Anticipated remediation time 6. Acceptability to project stakeholders 7. Necessity of special permits 8. Implications on end-use of the site 9. Sustainability considerations, including triple bottom line parameters 10.Remediation versus management paradigm for complex sites

72 End-use of the Site What will be the end-use of the site? Residential Commercial Agricultural Nature preserve End-use affects the remediation goals (based on human and ecological risks) Physical, mineralogical, chemical and biological changes in subsurface due to EK Extreme final ph, depletion of nutrients, Will the treated soil suitable as: Construction material/support (strength, compressibility, hydraulic conductivity, ) Agricultural land (nutrients, crop growth, ) Habitat

73 Practical Considerations 1. Reliability of the technology 2. Costs of application 3. Practicality of implementation 4. Application of and ability to meet risk-based remediation goals 5. Anticipated remediation time 6. Acceptability to project stakeholders 7. Necessity of special permits 8. Implications on end-use of the site 9. Sustainability considerations, including triple bottom line parameters 10.Remediation versus management paradigm for complex sites

74 Sustainability Presidents Executive Orders Greening the Government through Efficient Energy Management (6/1999) Federal Leadership in Environmental, Energy, and Economic Performance (10/2009) 2011 NRC Green Book Recommends EPA to formally adopt sustainability approach Framework for EPA Sustainability Decisions Theme Cleanup based on holistic approach (triple bottom line)

75 Green and Sustainable Remediation Definition the site-specific use of products, processes, technologies, and procedures that mitigate contaminant risk to receptors while balancing community goals, economic impacts, and net environmental effects (ITRC, ASTM)

76 Core Elements of Green Remediation Minimize, Reuse, and Recycle Reduction, Efficiency, and Renewables Conserve, Protect, and Restore Protect Air Quality; Reduce Greenhouse Gases Improve Quality; Decrease Quantity of Use (USEPA)

77 Triple Bottom Line/Sustainable Design

78 Sustainability/LCA-based Design Electrode Choice Electrode Conditioning Solutions Choice Energy Source/Consumption Water Consumption Waste/Effluent Generated Direct and Indirect Economic Benefits Community Acceptance/Benefits Net broader impacts?

79 Electrodes: LCA Results 500 Impacts, mpt Carcinogens Resp. organics Resp. inorganics Climate change Radiation Ozone layer Ecotoxicity Acidification/ Eutrophication Land use Minerals Fossil fuels Titanium Iron Graphite Carbon Electrode Types

80 Electrode Solutions: LCA Results Impacts, mpt Carcinogens Resp. organics Resp. inorganics Climate change Radiation Ozone layer Ecotoxicity Acidification/ Eutrophication Land use Minerals Fossil fuels Solvent EDTA DTPA Citric Acid Acetic Acid Electrode Solutions

81 Practical Considerations 1. Reliability of the technology 2. Costs of application 3. Practicality of implementation 4. Application of and ability to meet risk-based remediation goals 5. Anticipated remediation time 6. Acceptability to project stakeholders 7. Necessity of special permits 8. Implications on end-use of the site 9. Sustainability considerations, including triple bottom line parameters 10.Remediation versus management paradigm for complex sites

82 Management vs Remediation Paradigm for Complex Sites NRC report published in 2013 Complex Sites Fractured media Very large plumes Radioactive contaminants Very deep contamination Fine-grained units

83 Complex Sites Passive Long-term Management Option MNA, NA, permeable reactive barrier, or physical containment Active Long-term Management Option Community outreach program Contaminant monitoring plan Institutional and engineering controls

84 Final Remarks 1 Electrokinetic remediation by itself or with enhancements may be ineffective and/or costly 2 Integrated electrokinetic/electrochemical remediation technologies have great potential to be effective and practical Potential to design green and sustainable systems (use DC solar power supply, in-situ degradation, metal recovery & reuse) 3 Ideally suited for: Remediation of low permeability/heterogeneous subsurface Source zone remediation Difficult contaminants, including the contaminant mixtures

85 Final Remarks 4 Provides greater flexibility to adapt at any time during the remediation process to changing or different contaminant conditions, without the need for major changes in the field setup 5 Many studies investigated the fundamental aspects of electrokinetic remediation, but very limited studies address the practical issues to successfully implement the technology at actual contaminated sites -Need more use-inspired basic research/applied research

86 Take Away Message As we do our research, let s keep the following practical considerations in mind: 1. Reliability of the technology 2. Costs of application 3. Practicality of implementation 4. Application of and ability to meet risk-based remediation goals 5. Anticipated remediation time 6. Acceptability to project stakeholders 7. Necessity of special permits 8. Implications on end-use of the site 9. Sustainability considerations, including triple bottom line parameters 10. Remediation versus management paradigm for complex sites

87 Acknowledgements Funding Graduate Students R. Saichek S. Chinthamreddy K. Maturi A. Al-Hamdan K. Darko-Kagya Related Publications

88 Thanks! Questions & Answers