Welcome Environmental Advisory Board Meeting Robins Air Force Base February 4, 2016 1
Welcome and Program Introduction Mr. Lex Stokes EAB Installation Co-chair 2
Acronyms and Abbreviations AS/SVE Air Sparge/Soil Vapor Extraction CAP Corrective Action Plan CERCLA Comprehensive Environmental Response, Compensation, and Liability Act COC Contaminant of Concern cvoc Chlorinated Volatile Organic Compound EAB Environmental Advisory Board ERD Enhanced Reductive Dechlorination FYR Five-Year Review GA EPD Georgia Environmental Protection Division 3c
Acronyms and Abbreviations ISCO In Situ Chemical Oxidation isoc In Situ Oxygen Curtain LF004 Landfill No. 4 LUCs Land Use Controls MCLs Maximum Contaminant Levels MNA Monitored Natural Attenuation NPL National Priorities List OES Optimized Exit Strategy OU Operable Unit PCE Tetrachloroethene 4
Acronyms and Abbreviations ppb parts per billion RAOs Remedial Action Objectives RCRA Resource Conservation and Recovery Act RL Remedial Level ROD Record of Decision TCE Trichloroethene WP14 Waste Pit 14 µg/l micrograms per liter US EPA United States Environmental Protection Agency VOCs Volatile Organic Compound 5
Environmental Advisory Board SWMU 36 (DC034) Update on Progress Mike Perlmutter, P.E. Technical Lead CH2M February 4, 2016 6
Overview Background Site Layout Contract Performance Objective Air Sparging/Soil Vapor Extraction (AS/SVE) System Remedial Action Progress Path Forward 7
Background Horse Pasture Trench Disposal Site Used for disposal of wastes in pits and trenches from mid 1950s to mid 1970s Nearly 64,000 tons of impacted soil excavated and disposed offsite Completed in November 2004 In situ chemical oxidation (ISCO) used to remediate chlorinated ethenes, chlorobenzene, and dichlorobenzene in groundwater from January 2005 to November 2006 8
Background Revised Corrective Action Plan (CAP) prepared in 2013 to address remaining groundwater impacts Implementation of three technologies Corrective Action Objective: Reduce contaminants of concern (COCs) in groundwater to below the remediation levels (RLs) Limit further off-site migration of groundwater COCs 9
Background Remedy Construction Dates Start-up Dates Enhanced reductive dechlorination (ERD) Aerobic bioremediation using in situ submerged oxygen curtain (isoc) Aug. to Sept. 2013 Sept. to Oct. 2013 (injection) Oct. 2013 and Jan. 2014 Feb. 2014 AS/SVE cut-off barrier Oct. 2013 to Jan. 2014 Feb. 2014 10
Site Layout Note: PPB = parts per billion 11
Contract Performance Objective To be achieved by September 2020 Implement an Optimized Exit Strategy (OES) Three contractual performance metrics Reduction of trichloroethene concentrations in seven (7) ERD performance monitoring wells Reduction of chlorobenzene concentrations in three (3) isoc performance monitoring wells Reduction of total volatile organic compounds (VOC) in three (3) AS/SVE performance monitoring wells CAP goals to reduce offsite VOC concentrations within a specific timeframe or implement a supplemental remedy 12
AS/SVE System Remediation equipment compound AS and SVE lines Perimeter road after construction 13
AS/SVE System Cross section of AS/SVE cut-off barrier Schematic of AS/SVE System Site Layout = Contract performance monitoring wells = Effectiveness monitoring wells 14
Remedial Action Progress Note: µg/l = micrograms per liter 15
Remedial Action Progress By Well 16
Remedial Action Progress By Well 17
Remedial Action Progress By Well Combined total VOC reduction for the five wells 90 percent from December 2013 to October 2015 18
Path Forward (added to monitoring program in October 2015) Proposed Monitoring Wells Continue to sample Year 1 and Year 2 monitoring wells Year 2 wells are farther from the AS/SVE barrier Install proposed monitoring wells to verify plume delineation Continue operation of all three remediation systems 19
Environmental Advisory Board Results of the Five-Year Review for the National Priorities List (NPL) Site Maria Pijnenburg, P.G. AECOM February 4, 2016 20
Overview Background Purpose of Five-Year Review (FYR) FYR Schedule FYR Process FYR Results FYR Summary 21
Background 22
Background 1987 Landfill No. 4 (LF004) and Waste Pit 14 (WP14) added to NPL Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) site Operable Unit 1 (OU1) Source Areas LF004 45-acre landfill Operated 1965 to 1978 General refuse and industrial waste WP14 1.5-acre sludge lagoon Operated 1962 to 1978 Industrial waste treatment plant sludge OU2 Wetlands Wetlands remediated under Resource Conservation and Recovery Act (RCRA) regulations, August 2003, no longer associated with LF004 OU3 Groundwater Groundwater impacted by OU1 source areas VOCs and metals 23
Background OU1 LF004 and WP14 remedies WP14 treatment In-situ volatilization, excavation, and solidification (1996) LF004 engineering and institutional controls Cover system with geocomposite liner (1998) Passive landfill gas venting system (1998) Stormwater management controls (1998) Land Use Controls (LUCs) Quarterly inspections Annual operations and maintenance (O&M) reporting LF004 Passive Gas Vent LF004 LUC (Fence and Locked Gate) 24
Background OU3 Groundwater remedies Groundwater recovery and treatment system installed (1997) Groundwater recovery ceased (2007) Monitored Natural Attenuation (MNA) study initiated (2007) Final approval to transition to MNA (2010) Annual groundwater sampling (commenced 1991) Annual performance evaluation and reporting Groundwater Treatment Plant 25
Purpose of FYR Evaluate performance of the remedy Example Graph Determine if remedy is protective of human health and the environment 26
FYR Schedule First FYR March 2001 Final Record of Decision (ROD) September 2004 Second FYR June 2006 Third FYR June 2011 Fourth FYR Final Report to be completed in June 2016 27
FYR Process Develop review team Notify regulators and community of initiation of FYR process Conduct a site inspection Complete a technical assessment and associated reporting Notify regulators and community of results 28
FYR Process FYR Team Robins AFB United States Environmental Protection Agency (US EPA) Georgia Environmental Protection Division (GA EPD) AECOM 29
FYR Process Notification of Initiation Notification of initiation at November 2015 Environmental Advisory Board (EAB) Meeting 30
FYR Process Site inspection Quarterly O&M site inspections and reporting by Robins AFB FYR site visit occurred 28 October 2015 US EPA visit Technical assessment and reporting for FYR Draft FYR submitted to Robins AFB November 2015 Draft FYR submitted to regulators in February 2016 Final FYR to be completed in June 2016 Notification of Results February 2016 EAB 31
FYR Results OU1 LF004 and WP14 Remedial Action Objectives (RAOs) Containment Exposure control RAOs are being met Cover system Surface water control Passive landfill gas collection Site access control Continued inspection and maintenance 32
FYR Results OU3 Groundwater RAOs Containment and exposure controls Prevent impact to wetlands Restore groundwater to Maximum Contaminant Levels (MCLs) First two are being met; continued significant progress toward groundwater restoration 33
FYR Results Protectiveness statement OU1 and OU3 Remedy is protective of human health and the environment Potential exposure pathways are controlled by the landfill cover system and implementation of LUCs 34
FYR Results Groundwater Remediation Progress TCE 1997 2014 > 5 µg/l > 10 µg/l > 5 µg/l > 50 µg/l > 100 µg/l > 1,000 µg/l LF004 Boundary TCE Concentrations TCE Concentrations LF004 Boundary LF4WP8 2,800 µg/l and LF4-23 2,200 µg/l LF4WP8 8.5 µg/l and LF4-23 3.7 µg/l Approximately 80% reduction in aerial extent Approximately 95% reduction in TCE concentrations 35
FYR Results Groundwater Remediation Progress All plumes 2008 2014 Legend Green Benzene Yellow Carbon Tetrachloride Blue Chlorobenzene Pink Tetrachloroethene (PCE) Brown TCE Red Vinyl chloride Reduction in plumes overall aerial extent 36
FYR Results Monitoring Well Location MCL for Chlorobenzene MCL for TCE and Benzene 37
FYR Results MCL for Chlorobenzene Monitoring Well Location MCL for TCE and Benzene 38
FYR Results MCL for Chlorobenzene Monitoring Well Location MCL for TCE and Benzene 39
FYR Results TCE concentrations continue to decrease under MNA Overall aerial extent of LF004 plumes continues to decrease Time to achieve RAOs with MNA continues to be reasonable Protectiveness statement Remedy is protective of human health and the environment Potential exposure pathways are controlled through the landfill cover system and implementation of LUCs 40
FYR Summary Remedial actions at LF004 are protective of human health and the environment Final fourth-fyr report to be completed in June 2016; report will be placed in Administrative Record, which is available to the public Next FYR scheduled for June 2021 41
Questions/Comments Contact Information: Maria Pijnenburg, P.G. Maria.Pijnenburg@aecom.com (478) 542-4633 42
Environmental Advisory Board Administrative Record Overview Laurel Cordell Environmental Engineer AFCEC/CZO-E February 4, 2016 43
Overview CERCLA Requirement Previous Location Nola Brantley Current Online Location http://afcec.publicadmin-record.us.af.mil/ Website Overview 44
New Business and Program Closing Mr. Lex Stokes EAB Installation Co-chair 45
Next EAB Meeting Thursday, 5 May 2016 46
Please Complete the meeting evaluation and feedback form and leave at your seat Leave your name tag at the sign-in table for the next meeting Thank you! 47