(ITRC, 2005) Status Report on Innovative In Situ Remediation Technologies Available to Treat Perchlorate-Contaminated Groundwater August 2006 Prepared By Jennifer Raye Hoponick National Network for Environmental Management Studies Fellow for U.S. Environmental Protection Agency Office of Superfund Remediation & Technology Innovation Technology Innovation & Field Services Division Washington, D.C. www.epa.gov www.clu-in.org Status Report on In Situ Treatment Technologies to Remediate Perchlorate-Contaminated Groundwater NOTICE This document was prepared by a National Network of Environmental Management studies grantee under a fellowship from the U.S. Environmental Protection Agency. This report was not subject to EPA peer review or technical review. The EPA makes no warranties, expressed or implied, including without limitation, warranty for completeness, accuracy, or usefulness of the information, warranties as to the merchantability, or fitness for a particular purpose. Moreover, the listing of any technology, corporation, company, person, or facility in this report does not constitute endorsement, approval, or recommendation by the EPA. The report contains information attained from a wide variety of currently available sources, including project documents, reports, periodicals, Internet websites, and personal communication with both academically and commercially employed sources. No attempts were made to independently confirm the resources used. It has been reproduced to help provide federal agencies, states, consulting engineering firms, private industries, and technology developers with information on the current status of this project. About the National Network for Environmental Management Studies The National Network for Environmental Management Studies (NNEMS) is a comprehensive fellowship program managed by the Environmental Education Division of EPA. The purpose of the NNEMS Program is to provide students with practical research opportunities and experiences. Each participating headquarters or regional office develops and sponsors projects for student research. The projects are narrow in scope to allow the student to complete the research by working full-time during the summer or part-time during the school year. Research fellowships are available in Environmental Policy, Regulations and Law; Environmental Management and Administration; Environmental Science; Public Relations and Communications; and Computer Programming and Development. NNEMS fellows receive a stipend determined by the student’s level of education and the duration of the research project. Fellowships are offered to undergraduate and graduate students. Students must meet certain eligibility criteria. ii Status Report on In Situ Treatment Technologies to Remediate Perchlorate-Contaminated Groundwater ABSTRACT Advancing low-cost, effective in situ treatment technologies is a proactive way to address perchlorate contamination in our nation’s groundwater. EPA’s Technology Innovation and Field Services Division provided a grant through the National Network for Environmental Management Studies (NNEMS) for an environmental science student to research and write a status report on innovative in situ treatment technologies available to remediate perchlorate- contaminated groundwater. This report was prepared during the summer of 2006 by Jennifer Hoponick, a 3rd year graduate student at Indiana University earning a joint degree in Environmental Science and Policy. It has been reproduced to help provide federal agencies, states, consulting engineering firms, private industries, and technology developers with information on the current status of in situ treatment technologies for perchlorate. ACKNOWLEDGMENTS I would like to thank the individuals and organizations who contributed information, data, and insight during the preparation of this report. In particular, I would like to acknowledge the Technology Innovation and Field Services Division of the United States Environmental Protection Agency for their support throughout this process. iii Status Report on In Situ Treatment Technologies to Remediate Perchlorate-Contaminated Groundwater TABLE OF CONTENTS PURPOSE....................................................................................................................................... 1 1. INTRODUCTION ...................................................................................................................... 1 2. OCCURRENCE IN THE ENVIRONMENT ............................................................................. 2 3. CHEMICAL AND PHYSICAL PROPERTIES......................................................................... 4 4. TOXICITY OF PERCHLORATE.............................................................................................. 5 4.1 Disposition .................................................................................................................... 5 4.2 Mechanism of Action.................................................................................................... 6 5. REGULATORY STATUS ......................................................................................................... 8 6. TREATMENT TECHNOLOGIES............................................................................................. 8 6.1 Ex Situ Treatment Technologies................................................................................... 8 6.2 In Situ Treatment Technologies.................................................................................... 9 6.2.1 Advantages & Disadvantages ........................................................................ 9 6.2.2 Types of In Situ Treatment .......................................................................... 10 7. ENHANCED ANAEROBIC IN SITU BIOREMEDIATION (ISB)........................................ 11 8. ISB DESIGN CONSIDERATIONS......................................................................................... 12 8.1 Microbiology of Perchlorate-Reducing Bacteria........................................................ 13 8.1.1 Perchlorate Reduction Pathway ................................................................... 13 8.1.2 Types of DPRB............................................................................................ 14 8.1.3 Identification of DPRB ................................................................................ 15 8.1.4 Utilization of Electron Acceptors ................................................................ 16 8.1.5 Biofouling .................................................................................................... 17 8.1.6 Bioaugmentation.......................................................................................... 18 8.2 Recirculation............................................................................................................... 18 8.3 Mobile or Immobile Design........................................................................................ 21 8.4 Substrate Types........................................................................................................... 23 8.4.1 Soluble Substrate ......................................................................................... 25 8.4.2 Slow-Release Liquid Substrate.................................................................... 25 8.4.3 Slow-Release Solid Substrate ...................................................................... 26 8.4.4 Combinations of Substrate Types ................................................................ 27 8.4.5 Experimental Substrates............................................................................... 28 8.4.6 Minimizing Substrate Costs......................................................................... 29 8.5 Environmental Factors Affecting ISB Effectiveness.................................................. 29 8.5.1 pH................................................................................................................. 30 8.5.2 Microbial Nutrients...................................................................................... 31 8.5.3 Salinity ......................................................................................................... 31 8.5.4 Hydrogeology .............................................................................................. 31 8.5.5 Geochemistry ............................................................................................... 32 8.6 Legal Concerns ............................................................................................... 32 9. ISB CASE STUDY 1: NAVAL SURFACE WARFARE CENTER, INDIAN HEAD, MD.. 35 9.1 Site Characterization................................................................................................... 35 9.1.1 Source of Contamination ............................................................................. 35 9.1.2 Site Hydrogeology ....................................................................................... 36 9.2 Laboratory Study Findings ......................................................................................... 36 9.3 Pilot Study Design ...................................................................................................... 37 iv Status Report on In Situ Treatment Technologies to Remediate Perchlorate-Contaminated Groundwater 9.3.1 Substrate Addition ....................................................................................... 38 9.3.2 Buffer Addition...........................................................................................