WESTERN AREA COUNSEL OFFICE ENVIRONMENTAL LAW TRAINING SYMPOSIUM 13-14 April 2017 Pacific Views Event Center, Camp Pendleton, CA REGISTRATION FORM Name Luis Ledesma Occupation: Head Head, Installation Restoration Employer Title or Command: Environmental Security Address: Bldg 22165 Camp Pendleton E-Mail Address: luis.ledesma@usmc.mil Phone: 725-9744 Fax: If offered, would you participate in an on-premises social hour following the Thursday class day? Please mark x to indicate your preference: Yes [ ] No[ X ] This form may also be faxed (DSN 365-5132/(760) 725-5132), or e-mailed to andrea.givens@usmc.mil. If you have any questions, please call Andrea Givens at (760) 725-5196, or Donald Bal at (760) 763-0045. Thank you.
MCB CAMP PENDLETON SITE 1115 CONCEPTUAL SITE MODEL & RI/FS UPDATE 5 January 2017 120 th FFA Meeting
SITE 1115 CSM AND RI/FS UPDATE Location Site Status Site Background/Site History Previous Investigations/Removal Actions (Prior to RI/FS) RI/FS Update and Conceptual Model Remedial Alternatives 2
SITE 1115 CSM AND RI/FS UPDATE Site Location Located in Mainside Base Area Approximately 14.5 acres Relatively steep topography (topography sloping to north) N Site 6/7 Site 1 Site 5/8/9/17 3
Overview SITE 1115 CSM AND RI/FS UPDATE RIFS Complete Three pilot studies recently completed (to be discussed in a following presentation) Pilot study reporting is on-going Plans underway to update Conceptual Site Model based on pilot study performance Use pilot study results to optimize remedial approach Preparation of ROD and Proposed Plan pending 4
SITE 1115 CSM AND RI/FS UPDATE History/Background Site 1115 was formerly known as the 13 Area, Force Service Support Group (FSSG) Lot Historical Site use for vehicle staging, service, fueling Originally 17 separate UST sites were identified on the property, one of which (Site 17) was a pipeline (connecting Sites 5 and 8) The 17 UST sites were later combined into groups based on proximity: Former UST Site 1, 5/8/9/17, and 6/7. One site (17), was a pipeline connecting Sites 5 and 8 All USTs have been removed or closed in-place and remaining contamination is being addressed as Site 1115 5
SITE 1115 CSM AND RI/FS UPDATE Historical Aerial Photos 6
SITE 1115 CSM AND RI/FS UPDATE History/Background (Continued) Multiple investigations of UST sites under Base UST Program since 1986 Transferred to IR (under CERCLA) in 2002 due to the presence of VOCs in groundwater the site. Current site use - vehicle staging area (no fueling or servicing) 7
SITE 1115 CSM AND RI/FS UPDATE Recent Aerial Photo with Identified Source Areas N Site 1 Site 6/7 Site 5/8/9/17 8 ~200 feet
SITE 1115 CSM AND RI/FS UPDATE Previous Investigations and Interim Actions at Site 1115 (Under IR Program) Previous investigations under IR Program leading up to RI/FS: Final Soil Investigation Report for the OU 5 sites (FWENC, 2002) Action Memorandum For Non-Time Critical Removal Action, Operable Unit 5, Site 1115, 13 Area (2003). Draft Final OU 5 RI prepared for Sites 1A-1, 6A, 21, 1111, and 12 (Appendix M) (2004) Previous interim actions leading up to RI/FS: Pilot scale testing of SVE conducted at Former UST Site 1 in 2000 Soil removal action at Former UST Site 1 in 2002 Pilot scale testing of in situ bioremediation at Site 5/8/19/17 in 2009/2010 9
SITE 1115 CSM AND RI/FS UPDATE Conceptual Model and RI/FS Update Shallow and deep groundwater zones exist at the site. Dissolved-phase groundwater COPCs generally limited to the shallow zone except benzene which is present above RGs in both zones at Site 1. Fourteen groundwater VOCs exceed their MCLs, and two VOCs exceed their California Response Levels (RLs). Twelve additional COCs were identified in soil and soil gas. Primary dissolved-phase chlorinated VOCs in groundwater are TCE, cis-1,2- DCE, and 1,2-DCA. LNAPL historically present in portions of the shallow groundwater, and one deep well. Residual COCs also present in the vadose zone soils. Potentially significant levels of VOCs in soil gas roughly correspond to the footprint of the groundwater plumes exceeding MCLs. 10
SITE 1115 CSM AND RI/FS UPDATE Conceptual Model and RI/FS Update (continued) Santiago Formation occurs as shallow depths - low-permeability siltstone/sandstone. Groundwater contamination has spread several hundred feet beyond the three initial source areas, however there s no evidence of off-site migration. Historically, surface water has collected and infiltrated north of the unpaved crescent-shaped area, resulting in a groundwater mound. Surface water flow in ephemeral creek north of site. Surface runoff from Site 1115 joins San Luis River, reaching the Pacific Ocean approximately 11 miles downstream. Surface flow within tributaries to the San Luis Rey river is ephemeral. No municipal wells are known to exist within 7 miles downstream of the site. 11
SITE 1115 CSM AND RI/FS UPDATE Conceptual Model and RI/FS Update (continued) Groundwater flow in the shallow aquifer is multi-directional due to a mound near former Building 13162. Groundwater flows: 1) south and southwest beneath the western and southern portions of the site; 2) west beneath the east-central portion of the site; and 3) north and northeast in the northern portion of the site. Deep groundwater at Site 1115 generally flows to the west-southwest at a gradient of ~0.005 feet/foot. The in-situ thermal remediation pilot study implemented within the shallow groundwater zone, is believed to have affected the occurrence of groundwater in the vicinity of Former UST Site 9 (i.e. formerly saturated soils remain unsaturated). 12
SITE 1115 CSM AND RI/FS UPDATE 2012 Shallow Groundwater Elevations from RI/FS 13
SITE 1115 CSM AND RI/FS UPDATE 2012 Deep Groundwater Elevations from RI/FS 14
SITE 1115 CSM AND RI/FS UPDATE Nature and Extent Based on limited groundwater sampling performed during the 2016 pilot studies, the contour maps presented in the RI/FS (2014) were recently updated. The data included on contour maps in the RI/FS (2014) were a minimum i of 4 years old (data from 2012 and older). The recent data (2016) is limited to the western and southwestern portion of the site. These updates are presented on the following slides, and generally represent only minor changes; any exceptions will be discussed d below. 15
SITE 1115 CSM AND RI/FS UPDATE TCE in Shallow Groundwater Zone 16 2012 data set with 2016 updates
SITE 1115 CSM AND RI/FS UPDATE Cis-1,2-DCE in Shallow Groundwater Zone 17 2012 data set with 2016 updates
SITE 1115 CSM AND RI/FS UPDATE Benzene in Shallow Groundwater Zone 18 2012 data set with 2016 updates
SITE 1115 CSM AND RI/FS UPDATE Benzene in Deep Groundwater Zone 19 2012 data set with 2016 updates
SITE 1115 CSM AND RI/FS UPDATE 1,2-DCA in Shallow Groundwater Zone 20 2012 data set with 2016 updates
SITE 1115 CSM AND RI/FS UPDATE 1,2-DCA in Deep Groundwater Zone 21 2012 data set with 2016 updates
SITE 1115 CSM AND RI/FS UPDATE Nature and Extent (Continued) Approximately 4 acres (30% of the site) is underlain by groundwater having COCs exceeding MCLs or RLs. Primarily fuel-related compounds at former UST Site 1. A mixture of fuel-related compounds and solvents are at former UST Sites 6/7 and 5/8/9/17. COC concentrations in shallow groundwater zone are approximately 1 order of magnitude greater than in the deep groundwater. 22
SITE 1115 CSM AND RI/FS UPDATE Nature and Extent (Continued) As of the 2012-2013 timeframe (RI/FS), LNAPL was present in five wells (four at Former UST Sites 5/8/9/17, one at Former UST Site 1). LNAPL has historically been present at 13 wells. Thickest LNAPL is in vicinity of Sites 5/8/9/17; product recovery reduced LNAPL thickness substantially. Residual soil contamination, VOCs and TPH, at each source area. VOCs in soil did not exceed residential RSLs, except for two samples deeper than 10 feet bgs at Sites 5/8/9/17. VOCs in soil gas are at potentially significant concentrations over groundwater plume area. 23
SITE 1115 CSM AND RI/FS UPDATE Former UST Site 1 LNAPL (through Jan 2013) 24
SITE 1115 CSM AND RI/FS UPDATE Former Sites 5/8/9/17 and 6/7 LNAPL (through Jan 2013) 25
SITE 1115 CSM AND RI/FS UPDATE Fate and Transport Based on RI/FS data plumes are generally not expanding beyond their current extent. LNAPL is a continuing source of COCs to the underlying groundwater, and is a much more significant source of contaminant than leaching of residual COPCs from soils. Geochemical conditions within the source areas are generally anaerobic. Geochemical conditions at the outer edges of the plume are predominantly aerobic. Concentration trends of key VOCs (TCE, benzene, and cis- 1,2-DCE) decreasing or stable at leading edge of shallow groundwater plume. 26
SITE 1115 CSM AND RI/FS UPDATE Risk Assessment 2012 FS No current complete exposure pathways for human receptors were identified in the RI/FS; groundwater is not used, no buildings, and no plans for development or construction. ti Risk from the hypothetical potable use of groundwater > than 1 x 10-4 and the hazard index is > 1.0. Aquifer has low yield and TDS, but groundwater at the site is classified as having beneficial uses for municipal, agricultural, and industrial supply. VOCs in groundwater and soil gas could pose a significant VI risk (i.e., > 1x10-6 and up to a max of 2 x 10-3 for a hypothetical resident over S1-MW25). Soils not considered to pose a threat to human health via direct contact (i.e., incidental ingestion and dermal contact) based on the soil data to date. The threat to ecological receptors from COPCs at Site 1115 is negligible. 27
SITE 1115 CSM AND RI/FS UPDATE Target Treatment t Zones Contaminated areas of Site 1115 are presented in the FS as Target Treatment Zones (TTZs). The designation of the TTZs is based upon 1) distinctive mixtures of contaminants present; 2) the relative concentrations of contaminants present; and, 3) distinct aquifer zones. TTZs were designated in the FS to facilitate t the identification of appropriate technologies, processes, and remedial alternatives in select portions of the larger Site 1115. 28
SITE 1115 CSM AND RI/FS UPDATE Target Treatment t Zones (continued) TTZ-1S: Defined as shallow aquifer groundwater in the vicinity of the former UST Site 1 gas station. TTZ-1SP: Shallow, dilute groundwater contaminant plume adjacent to TTZ-1S, and excluding areas adjacent to the east with non-fuel related contamination (TCE, 1,2-DCE) exceeding respective MCLs. TTZ-1D: Deep aquifer groundwater near former UST Site 1. TTZ- 1D is addressed as a near-source area with the highest benzene and 1,2-DCA, and a relatively small downgradient dilute plume area. TTZ-2L: Groundwater near former UST Site 9 impacted by LNAPL; Also includes additional smaller areas of historical LNAPL identified near UST Sites 5/8/17 and 6/7. 29
SITE 1115 CSM AND RI/FS UPDATE Target Treatment t Zones (continued) TTZ-2S: Shallow groundwater underlying LNAPL areas defined by TTZ-2L. The CSM assumes LNAPL is a source of dissolved phase contaminants, including benzene and TCE, among other COCs; therefore, in close proximity to LNAPL is considered a source area. TTZ-2SP: Shallow aquifer groundwater downgradient/crossgradient from TTZ-2L and TTZ-2S, extending to the edges of the dilute groundwater plume with contaminant concentrations above MCLs. TTZ-2D: Represents deep aquifer groundwater, excluding TTZ- 1D. Historical sampling in TTZ-2D shows exceedances of MCLs; but sampling during the RI//FS did not show continued impacts above MCLs in TTZ-2D. As such, potential remedial technologies, processes and alternatives for TTZ-2D were not developed. 30
SITE 1115 CSM AND RI/FS UPDATE Shallow Groundwater Target Treatment Zones 31
SITE 1115 CSM AND RI/FS UPDATE Deep Groundwater Target Treatment Zones 32
SITE 1115 CSM AND RI/FS UPDATE Target Treatment Zones on Cross Section A-A 33
SITE 1115 CSM AND RI/FS UPDATE Remedial Alternatives Applied to TTZs Alternative 1: No Action Alternative 2: Land Use Controls and Long-Term Monitoring, with Monitored Natural Attenuation Remedial alternatives for the various TTZs include one or more combinations of the following technologies (note that all alternatives listed below [or combinations of alternatives] also include Alternative 2) Excavation and extraction of groundwater and/or LNAPL In situ chemical oxidation (ISCO) Biosparge Biosparge Barrier Dual phase extraction (DPE) Automated LNAPL recovery Enhanced in situ bioremediation and air sparging/soil vapor extraction (AS/SVE) (sequentially) 34
SITE 1115 CSM AND RI/FS UPDATE Remedial Alternatives Applied to TTZs 35
SITE 1115 CSM AND RI/FS UPDATE TTZ-1S Shallow Groundwater, Former UST Site 1 Area Alternatives 36
SITE 1115 CSM AND RI/FS UPDATE TTZ-1D Deep Groundwater, Former UST Site 1 Area Alternatives 37
SITE 1115 CSM AND RI/FS UPDATE TTZ-2L LNAPL Source Zone Alternatives 38
MCB CAMP PENDLETON SITE 1115 PILOT STUDIES UPDATE 5 January 2017 120 th FFA Meeting
Overview Site 1115 Pilot Study Update Site 1115 pilot studies overview and preliminary results In Situ Thermal Remediation (ISTR) at Former UST Site 9 ISCO Applied into open excavation and by Injection at Former UST Site 1 Hydraulic Fracturing at Former UST Site 1 Path Forward 2
Site 1115 Pilot Study Update Pilot Studies conducted in two of the sources areas: Near Former UST Site 9 and Former UST Site 1 In Situ Thermal Remediation (ISTR) Pilot Study at Former UST Site 9 (TTZ-2L and TTZ-2S), which is part of Site 5/8/9/17. Excavation to address shallow impacts at Former UST Site 1 (TTZ-1S), followed by introduction of chemical oxidant in excavation. The excavation was implemented as a Removal Action. ISCO injection into the deep aquifer at Former UST Site 1 (TTZ-1D). Fracking Pilot Study at Former UST Site 1 (TTZ-1D) Permeability Enhancement Technology using hydraulic fracturing technique). 3
Site 1115 Pilot Study Update 4
Site 1115 Pilot Study Update ISTR Pilot Study Area 80 ft x 80 ft area near Former UST Site 9 5
Site 1115 Pilot Study Update In Situ Thermal Remediation Pilot Study Assess the effectiveness of thermal conductive heating (TCH) at mobilizing and removing LNAPL and reducing shallow groundwater COCs to below MCLs. Obtain sufficient data to evaluate and optimize the design for full scale implementation of TCH technology to other source/treatment areas. The TCH system consisted of natural gas powered heaters installed in steel TCH wells. The heaters transferred heat to the TCH well casing and then into surrounding soils. NAPL and COCs were mobilized through steam stripping and volatilization and captured through multiphase extraction (MPE) wells. System consisted of: 80 TCH wells 32 MPE Wells Horizontal extraction wells on top of the ground surface (beneath insulating layer) to contain any escaping vapors. 4 temperature monitoring points. 6
Site 1115 Pilot Study Update ISTR Pilot Study Area System Layout. 7
Site 1115 Pilot Study Update ISTR - Pilot Study Final Temperatures @ 111 Days Day 111 3 BGS Day 111 10 BGS Day 111 20 BGS Day 111 35 BGS 8
Site 1115 Pilot Study Update In Situ Thermal Remediation Pilot Study Pre-Treatment Max Soil Concentrations: TPH Diesel 18,000 mg/kg TPH Motor Oil 1,300 mg/kg TPH Gasoline 3,700 mg/kg 1,2,4-TMB 25,000 µg/kg Naphthalene 29,000 µg/kg TCE 820 µg/kg BTEX Not detectable Post-Treatment Max Soil Concentrations TPH Diesel 2,600 mg/kg TPH Motor Oil 720 mg/kg TPH Gasoline < PSLs (6.5 mg/kg) All VOCs/BTEX < PSLs Pre-Treatment LNAPL Max Thickness Pre-treatment Max LNAPL thickness = 11.2 feet in MPE-11 Post-Treatment LNAPL Max Thickness Unknown (groundwater and/or LNAPL has not recovered/rebounded following thermal treatment) 9
Site 1115 Pilot Study Update In Situ Thermal Remediation Pilot Study Pre-Treatment Max Groundwater Concentrations 1,2,3-Trichloropropane (0.64 J μg/l),2-dibromoethane (0.52 J μg/l) 1,2-Dichloroethane (38 μg/l) Benzene (120 μg/l) cis-1,2-dce (26 μg/l) Methylene Chloride (10 μg/l) Naphthalene (78 μg/l) Tetrachloroethene (0.47 (J) μg/l) TCE (18 μg/l) TPH-d (6,200 μg/l) TPH-g (1,600 μg/l) TPH-mo (590 μg/l) Post-Treatment Max Groundwater Concentrations Groundwater was absent within the treatment area so no post treatment sampling performed 10
Site 1115 Pilot Study Update ISTR Pilot Study Treatment System, Former UST Sites 5/8/17 11
Site 1115 Pilot Study Update ISTR Pilot Study Treatment System, Former UST Sites 5/8/17 12
Excavation with ISCO, Former UST Site 1 Site 1115 Pilot Study Update Excavation occurred between August and November 2014 to remove vadose zone impacts and deliver chemical oxidants to shallow groundwater. Excavation was 106 feet by 89 feet by 26 feet deep. Excavation extended the 2002 excavation limits by 7 feet towards the east, south, and west, and by 9 feet to the north, and was 6 feet deeper (20 ft bgs in 2002, and 26 ft bgs in 2016). No groundwater or LNAPL encountered during excavation. Wet soils were located from 20 to 26 feet (native soils) and in some areas within the sidewalls outside the previous investigation (most notable at approximately 14 ft bgs). 41 confirmation samples collected, with maximum concentrations found in soil sample 1115-SW-06014 (14 ft bgs): 10,000 mg/kg benzene 61,000 mg/kg ethylbenzene 2,800 J mg/kg TPH gasoline 1,600 J mg/kg TPH diesel 13
Site 1115 Pilot Study Update Excavation with ISCO, Former UST Site 1 14
Site 1115 Pilot Study Update Excavation with ISCO, at Former UST Site 1 11,380 tons of soil excavated. 7,275 tons of vadose zone overburden used as backfill following analytical testing, 4,105 tons were disposed of as contaminated soil. 4,628 lbs of ORC was applied to excavation floor (at ~26 feet bgs) prior to backfill. The entire footprint of excavation from zero to 8 feet bgs was backfilled with imported, clean fill material. 15
Site 1115 Pilot Study Update Deep ISCO Injection, Former UST Site 1 ISCO Pilot Study occurred between December 2014 and March 2016. Well abandonment activities (S1-MW25 and S1-MW26 located within excavation footprint). Eleven groundwater monitoring wells were installed (1115 -MW-25R, 1115-MW-26R, 1115-MW-29 through 1115-MW-31, and 1115-MW-33 through 1115-MW-38). Nineteen injection wells were installed (1115 -IW-01 through 1115- IW-18, and 1115-IW-32 (formerly 1115-MW-32). Two injection events (sodium persulfate and sodium hydroxide), performed in April and September 2015. 16
Site 1115 Pilot Study Update Deep ISCO Injection, Former UST Site 1 First Injection Event - 7,920 pounds of sodium persulfate and 11,186 gallons of sodium hydroxide. Second Injection Event - 3,080 pounds of sodium persulfate and 1,645 gallons of sodium hydroxide. Sodium persulfate solution was mixed at a ratio of 24, 55 lb bags per 400 gallons of water. A total of 3,330 gallons of sodium persulfate solution was injected over both events. Four performance monitoring events performed (December 2015, March 2016, and June 2016, September 2016). Groundwater results in key monitoring wells (MW-30, MW-31, MW- 33, and MW-34) show a decrease in benzene concentrations ranging from 88% to 99% and 1,2-DCA ranging from 19% to 98%. Reporting on ISCO Pilot Studies at Site 1 on-going. 17
Site 1115 Pilot Study Update Hydraulic Fracturing, Former UST Site 1 Technique can deliver a uniform and effective distribution of treatment amendments in low permeability and fractured media. Goal of pilot study is to demonstrate the effectiveness of the technology using the hydraulic approach in delivering remediation amendments into low permeability zones. In this case, a high-viscosity fluid (guar) was injected into one borehole at multiple depth intervals to overcome in situ confining stress, resulting in soil fracturing. Sand was injected simultaneously to keep the fractures from collapsing. Fracturing was performed in one borehole at multiple depth intervals, followed by conversion of the borehole into an injection well for injection of an NaOH-activated persulfate amendment. Three performance monitoring wells were installed within the 25 foot injection ROI. 18
Site 1115 Pilot Study Update Hydraulic Fracturing Results, Permeability Enhancement Unit 19
Site 1115 Pilot Study Update Well Layout Used for Hydraulic Fracturing with 25 ft ROI ROI = 25 1115-HMW#3 Enhancement point 1115-HMW#1 1115-HMW#2 20
Site 1115 Pilot Study Update Preliminary Monitoring Data One month following the hydraulic fracturing and subsequent persulfate injection, significant decreases in BTEX compounds were observed at all three new monitoring wells (1115-HWM-01, -02, and -03). 21
Site 1115 Pilot Study Update Hydraulic Fracturing Results Successfully created high-k sand lenses and allowed for distribution of a treatment amendment. 1-month post-fracturing results show significant contaminant reduction at monitoring wells located within the anticipated ROI of the fracturing. Decreases in contaminant concentrations were also seen at existing monitoring wells located cross-gradient and downgradient of the demo area and such decreases are expected to continue as groundwater travels downgradient from demonstration area. 22
Site 1115 Pilot Study Update Proposed Path Forward Pilot studies are being completed with final data rounds to be collected and results reports to be prepared in 2017. Parsons to prepare a technical memorandum to summarize / consolidate pilot study findings and present an updated site conceptual model. Based on final pilot study results remedial alternatives will be selected in consultation with the FFA team and presented in the proposed plan. 23
5 January 2017 120 th FFA Meeting
Site Locations Sites 1116 and 14112 2
Sites 1116 and 14112 3
Sites 1116 and 14112 Status Site 1116 encompasses both former Subsites 1491 and 140008. The 1491 and 140008 subsite designations are no longer needed. Subsite 14112 is still referred to separately since it is geographically separated (1,600 feet northwest). Site 1116 originally consisted of nine former UST sites. Further action recommended at 14112, 1491, and 140008 in 2011; No further action determined for remaining sites in 2013. 4
Sites 1116 and 14112 Three Recent Documents Final Site 1116 Non-Time Critical Removal Action Completion Report (ECM, March 2015). Objective of RA was to address VOCs and fuels in soil and groundwater to reduce potential risks to human health and the environment. The NTCRA included soil excavations, DPE system, and an EISB pilot test. Draft Site 1116 Investigation Summary Report (TetraTech, November 2015). Objective of investigation was to delineate extent of VOCs in groundwater and develop TCE concentration trends. Draft Post NTCRA Performance Groundwater Monitoring Report (ECM, December 2015). Includes groundwater monitoring between January 2014 (Baseline) and March 2015 (5 events total). 5
Sites 1116 and 14112 Site Setting/Hydrogeology Mission Hydrologic Subarea of the Lower San Luis Hydrologic Area, within the San Luis Rey Hydrologic Unit. Groundwater has designated beneficial uses including domestic supply, but nearest supply wells are ~1 mile from the site. Groundwater is within alluvium, Santiago Formation or weathered granodiorite. Groundwater depth is 5 to 15 ft bgs. Groundwater flow at the site is northeast/east. Up to 7.5 ft of fill or alluvium is overlying sedimentary Santiago Formation or granodiorite it bedrock (Site 1116). 6
Sites 1116 and 14112 Groundwater Flow, Former Subsite 140008 7
Sites 1116 and 14112 Groundwater Flow, Former Subsite 1491 8
Sites 1116 and 14112 Groundwater Flow, Site 14112 9
Sites 1116 and 14112 Site 1116 Plume Extent (Tri-Eco, 2014) 10
Site 1116 Status Sites 1116 and 14112 Former UST Subsites 1491 and 140008 are now referred to as Site 1116 (subsite designations are no longer needed). Site 1116 COCs are VOCs and fuel-related compounds, specifically: Benzene, cis-1 1,2-DCE, TCE, and TPH-d (1491), 1,1,2-TCA, TCE, and TPH-d (140008), and 1,2-DCA, benzene, naphthalene, TCE, and TPH-d (14112) Cleanup goals for VOCs were established during previous investigations as MCLs; for TPH-d the cleanup goal was established as 100 µg/l (SF Board ESL). 11
Former Subsite 1491 Sites 1116 and 14112 Former administrative offices and parking. Two 1,000 gallon USTs removed in 1996. 700 cubic yards removed in 2006. Building 1491 demolished in 2012. Two phases of investigation completed in 2012 (17 CPTs, 9 hydropunches, and sampling 8 new wells in addition to 9 existing wells). 2nd Phase of NTCRA in 2013 - excavation of 665 cubic yards (45 x25 x18 ) and excavation dewatering. Followed by EISB pilot study injection in July - August 2014 reduced d TCE in MW-21 from 140 µg/l to 10 µg/l, but limited area of influence (<80 feet downgradient). 12
Sites 1116 and 14112 Site 1116 Pilot Study Area (red oval) 13
Sites 1116 and 14112 Site 1116, Former Subsite 140008 Former 12,000 gal diesel tank was removed in 1995. Removal action in 2013 230 cubic yards were excavated south of building and excavation was dewatered. Sewer line connection near 140008-MW09 (15th and E St) may be a contributing factor for the multi-site plume. Potential source near 140008-MW07A/B (in the vicinity of Bldg 140008) may have contributed to the Building 140008 portion of the plume, which is unbounded to the north and east. Movement of combined plume is likely controlled by geologic factors; i.e., contact between Santiago Formation and granodiorite. 14
Site 1116, Subsite 14112 Sites 1116 and 14112 Two diesel USTs removed in 1997. Several investigations between 1999 and 2012. NTCRAs Source area excavation (270 yards) and dewatering in 2013, DPE system installed in 2014 to address PSH, and System operated in Feb 2015 and was discontinued after generating large amounts of water requiring treatment to concentrations below system capabilities. 15
Sites 1116 and 14112 Site 14112 - Jan 2014 Groundwater Results 16
Sites 1116 and 14112 Subsite 14112 - March 2015 Groundwater Results 17
Sites 1116 and 14112 Plans Going Forward per Final Tech Memo (2016) Site 1116 (Former Subsites 1491 and 140008) Sampling to refine extent of plume, including addressing data gaps near upgradient source areas and downgradient edge. Determine best EISB locations and configuration based on geology and updated CSM. Collect soil gas data and perform risk assessment. Site 14112 Further define extent of plume extending off site, including TCE and TPH in groundwater. Remove LNAPL via periodic placement of absorbent socks, track thickness and removal rates. Determine optimized remedial strategy based on additional groundwater monitoring data. 18
Sites 1116 and 14112 Proposed Well and Soil Gas Locations at Site 1116 19
Sites 1116 and 14112 Proposed Well and Soil Gas Locations at Site 1116 1116-MW07 relocated 100 feet southwest due to an on-going construction project that prevented access. 1116-MW07 relocated approximately 15 feet to the west due to encountering non-water bearing granite at shallow depths in original location. 20
Sites 1116 and 14112 Proposed Well Locations at Subsite 14112 21
Sites 1116 and 14112 Proposed Well Locations at Site 14112 (continued) Due to CPEN safety concerns about installing MW-16 in the baseball field, it was moved ~190 east-northeast to a location behind the outfield fence. This well will confirm groundwater hydraulics and extent of contamination northeast of Site 14112. Drainage swale (view to east), between the swimming pool and the baseball field, along with irrigation of the ball field may be influencing groundwater flow northeast of Site 14112. 22
Completed Field ldactivities iti Sites 1116 and 14112 Field reconnaissance of all drilling locations for accessibility and logistical constraints. Utility Clearance work by Base FMD, USA, and Geophysical Survey completed at Site 1116 and Site 14112. Drilling began on Dec 12th, 2016 at Site 1116. All nine groundwater monitoring wells and six soil gas points installed at Site 1116 as of Dec 20th. Installation of 4 wells to be completed at Site 14112 by Dec 23rd, 2016. As of Dec 20th, only MW-17 installed. Indications are that all wells will produce groundwater. 23
Sites 1116 and 14112 Schedule Going Forward Dec 2016 Groundwater Well Development at Sites 1116 and 14112. Jan 3 through Jan 20, 2017 Groundwater sampling at Sites 1116 and 14112, and soil gas sampling at Site 1116. Jan 23, 2017 Replace/install ll absorbent b socks at Site 14112. March 2017 IDW removal. April 2017 Validated Analytical Results Available. June 2017 Reporting of results from field investigation. Tetratech is under contract to prepare p the PP and ROD and are currently preparing the remedial design to include EISB, MNA, and LUCs. PP currently under Navy review. 24
MCB CAMP PENDLETON SITE 1119 PILOT STUDY DESIGN MEMORANDUM PROJECT UPDATE 5 January 2017 120 th FFA Meeting
Presentation Overview Document Submittals Site Conceptual Model SITE 1119 Selected Remedy from ROD Source Area EAB Pilot and EAB Permeable Reactive Barrier Implementation Path Forward 2
SITE 1119 Document Submittals (needs to be updated) Final RI/FS - May 15, 2014 Final Proposed Plan January 2015 Final Record of Decision Being Circulated for Signatures Final Design Study Work Plan for Enhanced In-Situ Bioremediation January 2016 Final Design Study Technical Memorandum (for EISB) December 14 2016 3
4
Site Discovery SITE 1119 Originally defined as groundwater in the vicinity of Base supply wells 26016 and 26018. In well 26016, TCE was previously detected at 11 µg/l during a pumping test by the FMD in 2008. In well 26018, TCE was detected on multiple occasions, including a maximum detection of 2.6 µg/l collected by the FMD in 2009. The TCE contamination in this area was designed as IR Site 1119 and a Remedial Investigation/Feasibility Study was initiated in 2011. 5
SITE 1119 RI/FS Results - 2011 and 2013 TCE Detections 6
SITE 1119 Conceptual Site Model from RI/FS Upper Ysidora Subbasin (UYS) is an alluvium-filled valley. Groundwater flow is toward the southwest. Depth to bedrock in the UYS up to 150. Depth to bedrock in potential source area is 80-90 feet bgs. Bedrock consists of Santiago Formation and granite, depending on location. 7
SITE 1119 CSM Updated with Results of EISB Design Study 8
SITE 1119 CSM Updated d with Results of ESIB Design Study 9
SITE 1119 Summary of Nature and Extent TCE is the only contaminant that exceeds MCLs with a max concentration is 440 µg/l detected in well 1119-MW-20 located 450 feet downgradient of Building 2611. Verbal accounts of site operations during the 1960s-1970s indicate that drums of solvent may have been emptied in the low area near well 1119-MW-20. The current treatment area measures approximately 420 feet long by 160 wide. Source area is identified with the 200 µg/l TCE contour line, which is defined by detections > 200 µg/l in wells 1119-MW-18, 1119-MW-20, and 1119-MW-9. 10
SITE 1119 Selected Remedial Alternatives ti from ROD Land Use Controls and Long Term Monitoring (FS Alternative 2) Source Area Treatment via In Situ Enhanced Bioremediation (EISB) (FS Alternative 5) Reactive Barrier Installed via Injection Wells Downgradient of the Source Area (Alternative 8) A Design Study was included in Alternative 5 to provide additional source area characterization prior to the implementation of EISB 11
SITE 1119 Alternative 5 from RI/FS - Source Area Treatment via EISB Installation of EISB system to destroy contaminant mass in groundwater at the source area. Mixture of organic substrate(s) and ph buffer to induce geochemical and microbial conditions that will support biodegradation. Multiple injection events needed to achieve required mass reduction in the source area within 10 years. Need to drive the aquifer from moderately aerobic to anaerobic conditions. This alternative included a design study to provide additional source area characterization prior to the implementation of EISB. The results of this design study are incorporated into the slides below. 12
SITE 1119 TTZ-1 Proposed Injection Well Locations 13
SITE 1119 TTZ-2 Proposed Injection Well Locations 14
SITE 1119 Alternative 8 Details: Reactive Barrier (PRB) Installed via Injection Wells Downgradient of the Source Area Installation of an EISB system in a linear configuration perpendicular to groundwater flow and downgradient of the source area (i.e., Permeable reactive barrier). Injection to occur at multiple well locations (spaced ~25 feet apart). The Draft RD increased the number of injection locations from the nine (stated in the ROD) to 12 to enhance system performance. Designed to destroy TCE mass in groundwater as it passes through the reactive zone. Requires injection of a mixture of organic substrates and ph buffer to induce conditions conducive to biodegradation. Would need to be maintained indefinitely due to the expected persistence of the TCE source area. FS includes eight reinjection events over 30 years. 15
SITE 1119 Updated PRB Layout Reflecting Design Study Results 16
SITE 1119 Installation of Permeable Reactive Barrier (PBR) Pre-field activities to include coordination with Base and NAVFAC, permitting and notifications, utility clearance, mobilization and staging of equipment. 12 PRB well injection locations with four injection wells at each location and screened intervals configured to maximize the coverage of the targeted strata to a maximum depth of 80 feet. Wells will be installed in separate boreholes. The deepest well at each location will be drilled and logged first using rotosonic methods. Six of the 12 deepest wells will be installed as 4-inch diameter wells to allow extraction of make up water. The three shallower wells at each the 12 injection locations will be installed to a maximum depth of 58 feet using Direct Push. Lithology obtained from soil boring logs during the rotosonic drilling will be used to optimize locations of well screen intervals. 17
SITE 1119 PRB Well Installation Diagram 18
SITE 1119 Installation of Permeable Reactive Barrier (PBR) Baseline groundwater sampling will be conducted before injection to define pre-treatment t t water conditions. Performance monitoring program design currently under consideration. Approximately 106,000 gallons of water will be extracted from the six 4-inch diameter PRB wells prior to injection for use as makeup water. Injectants to include 8,890 gals (10,252 lbs) of 60% sodium lactate solution 8,977 gallons of EVO 750 lbs of soda ash 204 liters of the microbial culture (SDC-9 TM ) 19
Path Forward SITE 1119 Source Area EISB Pilot Preliminary field activities: January 2017 Well installation: February March 2017 Baseline groundwater sampling: Late March 2017 Substrate injection: March April 2017 Performance monitoring: July 2017 July 2018 EAB Permeable Reactive Barrier Draft Remedial Design Revision: February 2017 Regulatory comments receipt: April 2017 Final Revised Remedial Design: May June 2017 MCBCP field kickoff: k June 2017 Mobilization to the field: July 2017 Well installation / injection: July September 2017 20