Activity Completion Report No. 2

ENVIRONMENTAL REMEDIATION AT DANANG AIRPORT

CONSTRUCTION MANAGEMENT AND OVERSIGHT

Activity Completion Report No. 2

March 9, 2016 This document was produced for review by the United States Agency for International Development. It was prepared by CDM International, Inc. (CDM Smith).

Environmental Remediation at Danang Airport Construction Management and Oversight

Activity Completion Report No. 2 Prepared by: Beau Sanders, Chief of Party (COP)

Organization: CDM International, Inc. (CDM Smith)

Submitted to: Maura Patterson United States Agency for International Development (USAID) Contracting Officer's Representative (COR)

USAID Contract No.: AID-EDH-1-00-08-00023

USAID Order No.: AID-486-TO-12-00001 Report Date: March 9, 2016

TABLE OF CONTENTS 1 Introduction .......................................................................................... 1

1.1 Site Description .............................................................................................................................. 2 1.2 Project Objective ........................................................................................................................... 4 1.3 IPTD Contractor Budget Summary ........................................................................................... 4

1.3.1 Vouchers ................................................................................................................................... 4 1.3.2 Cost Projections and Overruns ........................................................................................... 5

1.4 Original Scheduling......................................................................................................................... 5 1.4.1 Delayed Pile Turnover ............................................................................................................ 6 1.4.2 Rainwater Influx During Filling and Constructing the Surface Cover .......................... 8 1.4.3 Thermal Treatment System Controlled Shutdown .......................................................... 8 1.4.4 Heater and Heater Cable Failures ........................................................................................ 9

1.4.4.1 Water Infiltration-Induced Failures ............................................................................. 9 1.4.4.2 Heat Saturation-Induced Delays .................................................................................. 9

1.4.5 Rainwater Influx through Surface Cover During Operations....................................... 10 1.4.6 Confirmation Soil Sampling ................................................................................................. 11

1.5 Current Implementation Schedule ........................................................................................... 12

2 Roles and Responsibilities................................................................... 12 2.1 USAID ............................................................................................................................................. 13 2.2 Construction Management Contractor ................................................................................... 13 2.3 ECC ................................................................................................................................................. 14 2.4 IPTD Contractor .......................................................................................................................... 14

2.4.1 Pre-construction .................................................................................................................... 14 2.4.2 During Construction ............................................................................................................. 15 2.4.3 Post Construction ................................................................................................................. 15

3 IPTD® Design ..................................................................................... 15

4 Health and Safety ............................................................................... 16 4.1 Safety Training & Performance .................................................................................................. 17 4.2 Medical Monitoring ...................................................................................................................... 18 4.3 Blood Dioxin Monitoring Results ............................................................................................. 18 4.4 Personal Protective Equipment ................................................................................................. 20 4.5 Activity Hazard Analyses ............................................................................................................ 20 4.6 Dioxin in Ambient Air ................................................................................................................. 20 4.7 Compliance with Vietnamese Environmental Law ................................................................ 21

5 Phase I Construction .......................................................................... 21 5.1 Kick-off Meeting Conference Call ............................................................................................ 21 5.2 Pre-work Conference Danang .................................................................................................. 22 5.3 Preconstruction ............................................................................................................................ 22

5.3.1 Annual Implementation Plan ................................................................................................ 22 5.3.2 Staffing ...................................................................................................................................... 23

5.3.3 Tax and Value Added Tax Recovery ................................................................................. 23 5.3.4 Connections to Water and Power Services .................................................................... 24 5.3.5 Procurement ........................................................................................................................... 24 5.3.6 International Logistics/Customs Clearance ...................................................................... 24 5.3.7 Mobilization............................................................................................................................. 25 5.3.8 Equipment Laydown Area .................................................................................................... 25 5.3.9 Site Access and Security ....................................................................................................... 25

5.4 General Construction Activities ............................................................................................... 25 5.5 Wellfield Installation .................................................................................................................... 26 5.6 LVTP Construction ...................................................................................................................... 27 5.7 Commissioning and Readiness Review ..................................................................................... 28 5.8 Operations and Maintenance Manual ....................................................................................... 29 5.9 Electrical Distribution System .................................................................................................... 29 5.10 As-Builts ......................................................................................................................................... 30

6 Phase 1 Thermal Treatment Operations ......................................... 30

6.1 IPTD® Pile O&M ......................................................................................................................... 30 6.1.1 Startup ...................................................................................................................................... 30 6.1.2 Steam Phase ............................................................................................................................ 30

6.1.3 Heat up to 335oC ................................................................................................................. 30 6.1.4 Thermal Treatment System Controlled Shutdown ........................................................ 31 6.1.5 Thermal Treatment System Re-start ................................................................................. 31 6.1.6 Rainwater Infiltration ............................................................................................................ 31 6.1.7 Corrective Action .................................................................................................................. 33

6.1.7.1 Supplemental Surface Cover ...................................................................................... 33 6.1.7.2 Raising Heaters .............................................................................................................. 33 6.1.7.3 Shortened Heaters and Increasing Thermal Set Point ......................................... 33

6.1.8 335oC Average Temperature ............................................................................................. 34

6.1.9 Cooling to 100oC Average (Quenching) .......................................................................... 34 6.2 In-pile Temperature ..................................................................................................................... 34 6.3 Pile Manifold Vacuum .................................................................................................................. 35 6.4 LVTP O&M and Monitoring ....................................................................................................... 35

6.4.1 LVTP Monitoring and Compliance Overview .................................................................. 35 6.4.1.1 Monitoring and Compliance Criteria ......................................................................... 36 6.4.1.2 Monitoring and Sampling Frequency ........................................................................ 37

6.4.2 Liquid Treatment ................................................................................................................... 37 6.4.2.1 MPPE ................................................................................................................................ 38 6.4.2.2 LGAC ................................................................................................................................. 38 6.4.2.3 GFH and Arsenic............................................................................................................ 38 6.4.2.4 2,3,7,8-TCDD................................................................................................................. 38 6.4.2.5 COD .................................................................................................................................. 42

6.4.3 Vapor Treatment ................................................................................................................... 42 6.4.3.1 Dioxin ............................................................................................................................... 42 6.4.3.2 Benzene ........................................................................................................................... 43

6.4.4 Ambient Air ............................................................................................................................ 43 6.4.5 Other Analysis Related To Phase I IPTD Operations .................................................... 47

6.4.5.1 Water Running out of the CMU Blocks ................................................................... 47 6.4.5.2 Soil Samples around the IPTD Structure ................................................................. 47 6.4.5.3 Pre-treatment IPTD Soil Samples ............................................................................... 48 6.4.5.4 Arsenic in IPTD water ................................................................................................... 48

6.5 Stakeholder Coordination .......................................................................................................... 55

7 Confirmation Soil Sample Results .................................................... 56 7.1 Interim Soil Samples ..................................................................................................................... 56 7.2 Improvements to Sampling Method after Interim Sampling ............................................... 57 7.3 Final Soil Sample Results ............................................................................................................. 58

7.3.1 Dioxin Results ........................................................................................................................ 59 7.3.2 Arsenic Results ....................................................................................................................... 59 7.3.3 Decontamination Procedures and Equipment Rinsate Results .................................... 65

7.3.3.1 Overview .......................................................................................................................... 65 7.3.3.2 Work Zones .................................................................................................................... 66 7.3.3.3 Quality Control ............................................................................................................... 66

7.3.4 Investigation-Derived Waste ............................................................................................... 66 7.4 Dioxin Mass Balance Estimate for Phase 1 ............................................................................. 69 7.5 In Pile Destruction ....................................................................................................................... 73 7.6 Destruction and Removal Efficiency (DRE) ............................................................................ 75

8 IPTD® Pile Decommissioning .......................................................... 76

9 Lessons Learned ................................................................................. 76 9.1 Lessons Learned Process ............................................................................................................ 76 9.2 Action Items .................................................................................................................................. 77

9.2.1 IPTD Contractor Action Items ......................................................................................... 77 9.2.2 CMC Action Items ............................................................................................................... 79 9.2.3 ECC Action Items ................................................................................................................. 80

10 Assessment – Measurement and Evaluation of Project Indicators ............................................................................................................. 80

List of Tables

Table 1 - Monitored parameters during Phase I treatment Table 2 - Exceedances at Sen Lake Outfall During Phase I Operation Table 3 - Dioxin (TEQ pg/m3) and Dust (µg/m3) Data Collected During Excavation Activities Table 4 - Results of IPTD Pile Water Sampling Table 5 - Interim soil results Table 6 - IPTD Confirmation Sampling Results – Dioxin Table 7 - IPTD Confirmation Sampling Results – Arsenic Table 8 - IPTD Confirmation Sampling Results – IVBA and RBA Table 9 - Geotechnical Results – representative material from IPTD structure Table 10 - Equipment Rinsate Results

List of Figures

Figure 1 - Project Areas and Site Layout Figure 2 - Concentrations of 2,3,7,8-TCDD measured at the LVTP, Outfall Ditch and Sen Lake Outlet

during Phase I operations Figure 3 - IPTD Sampling Areas Figure 4 - Decontamination Station Layout on the IPTD structure

Appendices

Appendix A Ambient Air Sample Results

ACRONYMS AND ABBREVIATIONS

2,4-D 2,4-dichlorophenol 2,4,5-T 2,4,5-trichlorophenol µg/L micrograms per liter µg/m3 micrograms per cubic meter ACR Activity Completion Report ADAFC Air Defense Air Force Command AHA activity hazard analysis AIP air injection point Airport Danang Airport BTV baseline threshold value °C degrees Celsius CBR California Bearing Ratio CC Chemical Command CDM Smith CDM International, Inc. cm centimeter CMC Construction Management Contractor CMU concrete masonry unit CO Contracting Officer COD chemical oxygen demand COP Chief of Party COR Contracting Officer Representative CRZ contamination reduction zone DCR Design Change Record DD Drainage Ditch DONRE Department of Natural Resources and Environment DS decontamination station DU decision unit DXL Dioxin Laboratory EA Eastern Area ECC Excavation and Construction Contractor EH Eastern Hotspot EMMP Environmental Mitigation and Monitoring Plan EW Eastern Wetland FTIR Fourier transform infrared spectroscopy FY fiscal year GAC granular activated carbon GFH granular ferric hydroxide GVN Government of Vietnam ha hectare HASP Health and Safety Plan Hatfield Hatfield Consultants Partnership HAZMAT hazardous materials HCl hydrochloric acid

HDPE high density polyethylene HI hazard index HPWDS high-pressure wash-down station hr hour H&S health and safety ID identification IDW investigation-derived waste in inch IPTD In-Pile Thermal Desorption IVBA in vitro bio-accessibility kg kilogram kg/L kilograms per liter kg/m2 kilograms per square meter kg/m3 kilograms per cubic meter kN/m2 kilonewton per square meter L liter LGAC liquid granular activated carbon LVTP liquid vapor treatment plant LWIC lightweight insulating concrete m meter m3 cubic meter M&E monitoring and evaluation mg/kg milligrams per kilogram mg/L milligrams per liter mg/m3 milligrams per cubic meter min minute MIS Multi Increment Sampling mL milliliter MLA former Mixing and Loading Area mm millimeter MND Vietnamese Ministry of National Defense MPPE macro-porous polymer extraction m/sec meters per second NA not applicable NAPL non-aqueous phase liquid ND non-detect ng/L nanograms per liter ng/m3 nanograms per cubic meter ng TEQ/kg nanograms TEQ per kilogram NM not measured No. number NTP Nam Thuan Phat NTU nephelometric turbidity unit O&M operations and maintenance ODA Official Development Assistance

OSHA Occupational Safety and Health Administration OWS oil water separator PGAC pressure granular activated carbon pg TEQ/g picograms TEQ per gram pg/L picograms per liter pg/m3 picograms per cubic meter PISA former Pacer Ivy Storage Area PMU Project Management Unit PPE personal protective equipment ppq parts per quadrillion ppt parts per trillion PUF polyurethane foam QC quality control RBA relative bioavailability ROP Regional Office of Procurement RSL Regional Screening Level SA former Storage Area SAP Sampling and Analysis Plan SAP/QAPP Sampling and Analysis Plan/Quality Assurance Project Plan SEW Southeastern Wetland SL Sen Lake SPLP Synthetic Precipitation Leaching Procedure SSO Site Safety Officer STEL short-term exposure limit TCDD tetrachlorodibenzo‐p‐dioxin TCDF tetrachlorodibenzofuran TEF toxic equivalency factor TEQ toxicity equivalence TMP temperature monitoring point TSSA Temporary Soil Stockpile Area TerraTherm TerraTherm, Inc. Tetra Tech Tetra Tech, Inc. UCL upper confidence limit U.S. United States USAID United States Agency for International Development USEPA United States Environmental Protection Agency USG United States Government UXO unexploded ordnance VAT value added tax VGAC vapor granular activated carbon VOA volatile organic analyte VOC volatile organic compound VRTC Vietnam Russia Tropical Center WA Western Area WHO World Health Organization


1 Introduction On June 18, 2012, the United States Agency for International Development (USAID) awarded a contract to CDM International, Inc. (CDM Smith) to carry out the project, "Construction Management and Oversight of the Environmental Remediation at Danang Airport." As the Construction Management Contractor (CMC), CDM Smith is responsible for the construction management and oversight of the Excavation and Construction Contractor (ECC) and In-Pile Thermal Desorption (IPTD) Contractor. The ECC contract was awarded to Tetra Tech, Inc. (Tetra Tech) on 06/28/12. The IPTD contract was awarded to TerraTherm, Inc. (TerraTherm) on 02/18/13.

Activity Completion Reports (ACRs) are to be prepared by the CMC to provide third party observations, analyses of work performed, and summary information for USAID to verify and document that significant project activities have been completed by the ECC and IPTD Contractor. The CMC’s contract includes the following ACRs:

• ACR Number (No.) 1: Completion of the IPTD Pile Structure and Phase 1 Soil Excavation and Delivery to IPTD Pile Structure. ACR No. 1 was submitted to USAID on 01/02/14.

• ACR No. 2: Completion of Phase 1 Thermal Installation and Treatment (inclusive of quench and dismantle).

• ACR No. 3: Completion of Removal/Placement of Treated Phase 1 Soils, Phase II Soil Excavation and Delivery to IPTD Structure.

• ACR No. 4; Completion of Phase II Thermal Installation and Treatment (inclusive of quench and dismantle).

• ACR No. 5: Completion of Removal/Placement of Treated and Untreated Phase II Soils.

• ACR No. 6: Completion of Site Restoration and Demobilization.

This document is ACR No. 2, and it presents a summary of activities performed by the contractors, the results of sampling by the CMC, and conclusions and/or recommendations to USAID by the CMC based on observations and data review. The format of ACR No. 2 mirrors the format of the IPTD Contractor’s IPTD® Final Report – Phase I dated 10/20/15 to allow USAID to easily compare the two documents; the report sections are listed in the following bullets.

• Section 1: Introduction, site description, project objectives, IPTD Contractor budget summary, original scheduling, and the current implementation schedule.

• Section 2: Roles and Responsibilities for USAID, CMC, ECC, and IPTD Contractor, including IPTD Contractor submittals.

• Section 3: IPTD® Design.

• Section 4: Health and Safety (H&S), CMC’s responsibilities, safety training and performance, medical monitoring, blood dioxin monitoring results, personal protective equipment (PPE), activity hazard analyses (AHAs), and dioxin in ambient air.

• Section 5: Phase I Construction, activities from the kick-off meeting and pre-work conference, pre-construction work, general construction activities, wellfield installation, liquid vapor treatment plant (LVTP) construction, commissioning and readiness review, operations and maintenance (O&M) manual, electrical distribution system, and as-builts.

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• Section 6: Phase I Thermal Operations, including O&M from startup through shutdown, discussion of the in-pile temperature, the pile manifold vacuum, O&M and monitoring of the LVTP, and stakeholder coordination throughout operations.

• Section 7: Confirmation Soil Sample Results, including interim sampling of the pile, improvements made to the confirmation sampling methods, and the final confirmation sampling results.

• Section 8: IPTD® Pile Decommissioning.

• Section 9: Lessons Learned, including summary of the two Lessons Learned workshops held by USAID.

• Section 10: Assessment based on measurement and evaluation (M&E) of the project indicators.

For the convenience of the Project team members, links to the CMC’s eRoom are provided throughout this report to access supporting, referenced documents.

1.1 Site Description Some areas within the Danang Airport (Airport) property have been referred to as dioxin "hotspots" due to investigations revealing high dioxin concentrations remaining decades after large volumes of Agent Orange and other defoliants were handled at these sites. The Government of Vietnam (GVN) has requested assistance from the United States Government (USG) to remediate dioxin-contaminated soil and sediment at the Airport.

Figure 1 provides an overview of the project area and site layout. During Phase I, 43,348 cubic meters (m3) of contaminated soil and sediment were treated. The Phase 1 contaminated soil and sediment was excavated from the southern part of the site, mainly from the former Mixing and Loading Area (MLA), former Storage Area (SA), southern end of the Drainage Ditch (DD), southern end of the Eastern Wetland (EW), and the former Pacer Ivy Storage Area (PISA).

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Figure 1: Project Areas and Site Layout

EASTERN AREA

WESTERN AREA

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1.2 Project Objective Dioxin is a toxic chemical associated with a range of health effects. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is the most toxic form of dioxin, and was the main congener present in the Agent Orange mixture. In the main hotspot areas of the Airport, TCDD comprises greater than 90 percent of the toxicity equivalent (TEQ), indicating Agent Orange as the source of contamination.

In 2009, the GVN established a national standard for dioxin of 1,000 parts per trillion (ppt) TEQ in soil and 150 ppt TEQ in sediment per Vietnam National Standard TCVN 8183:2009 (National Standard 8183: Dioxins threshold in the soil and sediment). The primary project objective is to reduce human health and environmental exposure to dioxin arising from contamination at the Danang Airport. To achieve this objective, the project is excavating all soil and sediment to the above standards and treating all material above the 1,000 ppt standard via thermal desorption.

The primary project objective, once completed, will drastically improve site conditions and result in a safer environment. However, the potential interim environmental impact of the project during implementation is substantial as it requires the excavation, transport, and disposition of large volumes of dioxin-contaminated soil and sediment. While the remediation activities are underway, there are potential environmental impacts to air quality, surface water quality, and/or groundwater quality. These impacts could result in potential adverse effects to terrestrial ecosystems, aquatic ecosystems, workers and/or surrounding residents. As a result, a key component of the project objective is to ensure potential environmental impacts during implementation are minimized, avoided, or rectified through the implementation of the site-wide Project Environmental Mitigation and Monitoring Plan (EMMP). The latest approved update to the Project EMMP (fiscal year [FY] 2014/FY 2015 update) dated 10/29/14 is available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport- Remediation/0_30544. The Draft FY 2016 Project EMMP was submitted to USAID for review on 09/30/15 and is currently being finalized by the CMC.

1.3 IPTD Contractor Budget Summary This section provides a summary of the CMC’s activities related to review/analysis of the IPTD Contractor’s cost projections, budget overruns, and vouchers.

1.3.1 Vouchers During Phase I thermal treatment, the CMC received a copy of each voucher submitted by the IPTD Contractor to USAID. At the beginning of the project the vouchers included the expenditures in a format that was difficult to verify. Working with USAID and the IPTD Contractor, the CMC assisted in developing a process for reviewing the vouchers that enabled clear verification before recommending payment. It was agreed with USAID that the CMC would only review the voucher and not the detailed backup that was largely in Danish or Vietnamese.

For each voucher, the CMC reviewed the voucher and provided a list of comments for the IPTD Contractor and USAID to consider. Typically, the IPTD Contractor provided responses to the CMC’s comments. Due to USAID deadlines for voucher approval (5 working days), USAID would often authorize payment before the CMC comments were received; however USAID reviewed all CMC comments and assessed whether they impacted the invoiced costs in the vouchers. Moving forward, USAID has requested the CMC prioritize voucher reviews and provide comments no later than 3 working days

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https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-%20Remediation/0_30544



after receipt; this process will be followed for Phase II to ensure USAID can review and assess the CMC’s comments before authorizing payment.

1.3.2 Cost Projections and Overruns When the IPTD Contractor began work (early 2013), the CMC requested they provide expenditure projections with each voucher in order to compare projections to the budget and identify any cost savings or overruns. The CMC facilitated several meetings with the IPTD Contractor and USAID to develop a spreadsheet and format for the expenditure projections. This spreadsheet was then submitted regularly by the IPTD Contractor starting with their first voucher.

The majority of CMC comments on the IPTD Contractor’s vouchers were related to expenditure projections. For example, substantial cost savings were associated with the original buyout and fabrication of equipment and the CMC requested the IPTD Contractor break out these cost savings in the vouchers and provide a line item for contingency that could be tracked separately.

The original IPTD Contractor budget for Phase I was $17,662,437. The CMC identified and reported to USAID during onsite meetings in January 2015 that this budget would likely be exceeded. The IPTD Contractor has identified that the Phase 1 budget was exceeded by $2,106,441 and has provided a list of additional scope items and unanticipated additional expenses that contributed to the Phase 1 cost overrun (see IPTD Contractor’s Final Report-Phase 1 dated 10/20/15). The CMC finds the list to be an accurate description of the additional work items conducted as requested/approved by USAID and the unanticipated additional expenses. However, the IPTD Contractor’s additional operating expenses associated with extended operations as well as the overrun in engineering costs were not accounted for in the IPTD Contractor’s backup for the cost overrun. The CMC estimates these additional factors in the cost overrun could potentially be on the order of $700,000 and in order to evaluate these factors further, the CMC will need to be able to see the cost projections and work with USAID and the IPTD Contractor to manage any overruns.

In Apri l 2015, the IPTD Contractor stopped submitting the cost projections with monthly vouchers, they were instead submitted separately in letters to USAID’s Contracting Officer (CO). The CMC was not provided with these letters, and therefore, was unable to review and evaluate the IPTD Contractor’s projected engineering cost overrun amount for Phase I. The CMC recommended that USAID ask the IPTD Contractor to provide an explanation or justification for the overrun. The CMC also requested the IPTD Contractor to provide an explanation of how they intended to manage the engineering costs during Phase I; this information was not received from the IPTD Contractor.

1.4 Original Scheduling The IPTD Contractor provided a baseline project schedule on 12/10/12. During the course of implementing Phase I, they provided intermittent updates to the project schedule that are documented in the CMC’s Monthly and Quarterly Reports. The CMC reviewed and commented on the schedules provided, focusing on correct logic and sequencing and evaluating the conservatism of the schedule. After evaluating the schedule, the CMC combined the IPTD Contractor’s schedule into the overall project schedule.

The IPTD Contractor’s Phase I contract milestones defined in Section F.5.1 of their contract include:

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• “Start installation of the IPTD system for Phase I as soon as possible, but no later than July 1, 2013. Phase 1 installation should be completed in approximately 8 months.”

• “Notify USAID and the CMC that they can begin their Phase I confirmation sampling approximately 4 months after start of heating.”

• “After receiving the notification that the cleanup goals have been achieved for Phase I, begin quenching operations within 3 days and complete quenching and dismantling M&E installations in or on the pile structure in approximately 3.5 months. This signifies completion of Phase I.”

Additional milestones are included for Phase II and will be addressed in ACR No. 4.

Due to various delays, the contract schedule milestones were not met. The following sections describe the CMC’s evaluation of the sources of schedule delay. The modeled heating duration was 120 days and that the actual heating duration was 312 days, based on a start date of 05/30/14 once all heaters were set to an automatic set point of 50 degrees Celsius (°C). Therefore, the total delay related to the extended heating time was 192 days. Factors contributing to the extended heating duration included the thermal treatment system controlled shutdown (see Section 1.4.3 below), heater and heater cable failures (see Section 1.4.4 below), and rainwater influx (see Section 1.4.5 below). It is difficult to calculate the exact delay associated with each of these separate issues, but the major contributor to the extended heating duration was rainwater influx (see Section 1.4.5 below).

1.4.1 Delayed Pile Turnover The pile turnover from the ECC to the IPTD Contractor did not occur on 07/01/13 per the IPTD Contractor’s contract milestone. In the months leading up to the turnover of the IPTD, the CMC had daily field meetings with the IPTD Contractor and the ECC to closely coordinate the turnover; this section provides the CMC’s evaluation of this delay.

The ECC built the IPTD structure 20% larger than the primary design (this 20% expansion of the structure was provided as an option in the design specifications). They opted to do this in order to avoid having to expand the structure in the event that there was an overrun on volume requiring treatment. The ECC was behind schedule due to performing additional over-excavation, but could have easily added shifts to meet the 07/01/13 turnover date in the IPTD Contractor’s contract. However, based on discussions held on site with the CMC, ECC and IPTD Contractor, it was evident that the IPTD Contractor was not ready to receive the IPTD structure and begin work until 08/01/13. The bulleted timeline below (based on IPTD Contractor’s daily and weekly reports) provides specifics regarding the activities conducted up to 08/01/13 when the IPTD Contractor began work on the IPTD structure. This timeline demonstrates that the ECC’s excavation schedule was not a limiting factor in starting installation of the IPTD system by the contract deadline of 07/01/13. In addition, a meeting was held on site between the CMC, IPTD Contractor, and ECC and it was agreed that it would be acceptable to turn over half of the IPTD structure so the IPTD Contractor could begin work.

• 06/26/13 – The IPTD Contractor airfreighted required safety supplies (expected arrival date was 07/02/13 later extended to the week of 07/08/13 due to customs issues).

• 06/27/13 – The IPTD Contractor received the first shipment of heater cans. As of 07/07/13, the IPTD contractor had 180 heater cans on site.

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• 07/01/13 to 07/02/13 – The IPTD Contractor conducted the initial off pile test of the excavator-mounted can driving equipment.

• 07/05/13 – First blood sampling was conducted for IPTD Contractor staff.

• 07/11/13 – The IPTD Contractor and the CMC met with the Airport to discuss vertical height restrictions.

• 07/17/13 – The ECC turned over 55% of the IPTD structure to the IPTD Contractor.

• 07/22/13 – The IPTD Contractor set up and had physicals done for their crew to perform vertical pipe installation.

• 07/26/13 – The IPTD Contractor reviewed workers’ physicals to choose a crew to begin work.

• 07/29/13 – The IPTD Contractor explained that vertical pipe installation will begin after resolution/completion of workers’ physicals, H&S paperwork, and vertical pipe placement survey.

• 07/30/13 – The IPTD Contractor submitted the AHA for vertical pipe installation.

• 07/31/13 – The IPTD Contractor performed respirator fit tests on the initial 10 man crew and realized that the equipment operator did not have his physical.

• 08/01/13 – The IPTD Contractor started work on the IPTD pile and identified a possible problem with the gravel placed on top of the IPTD structure by the ECC after they started staging material to drive cans. The gravel included too much fine material that could prevent the plenum layer from functioning as designed. It was very difficult to visually observe whether the material met specifications; however, prior to placement of the gravel, the CMC reviewed the sieve analysis results (provided by the supplier) and confirmed that the results met the design specifications. It was not until after placement, that settling of fine material towards the bottom of the layer was visually evident. To ensure delivery of gravel that meets the design specifications in Phase II, the CMC recommends the ECC perform sieve analysis on site after the gravel is delivered to the site. No less than four sieve analyses should be conducted during installation of the gravel layer to ensure consistency in the material specifications.

• 08/01/13 to 08/08/13 – The ECC removed and replaced the gravel layer.

• 08/06/13 –The IPTD Contractor inspected the plenum layer gravel removal and accepted the area as ready for new gravel.

• 08/08/13 – The IPTD Contractor began surveying the gravel layer and installed heater can location markers from the northeast corner out following the gravel placement crew.

• 08/09/13 –- The IPTD Contractor accepted the 55% plenum layer placed and graded.

• 08/10/13 – The IPTD Contractor started heater can installation.

• 08/20/13 – The IPTD Contractor placed the last heater can in available turned over area and began preparing for installation in the remaining area to be turned over.

• 08/27/13 – The IPTD Contractor trained their crew on how to install pipe in the plenum layer.

• 09/03/13 – The IPTD Contractor started installation of quench piping in the plenum layer.

Replacing the gravel plenum layer on the IPTD

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• 09/12/13 – The ECC turned over 100% of the IPTD structure, the IPTD Contractor accepted and started surveying and laying out heater can locations in the remaining area.

• 10/05/13 – The IPTD Contractor started form work for light weight insulating concrete (LWIC).

• 11/06/13 – The IPTD Contractor finished the first layer of LWIC.

1.4.2 Rainwater Influx During Filling and Constructing the Surface Cover While the IPTD structure was being filled and the cap was being installed in 2013, there were several rain events that allowed water to infiltrate the soil in the IPTD structure. One intense rain event during the installation of the LWIC cap required the IPTD Contractor to stop work for 2.5 days due to H&S concerns. In addition, heavy rain during installation would have compromised the concrete finish and created a substandard product that would not have passed the quality control (QC) requirements.

In 2014, attempts were made to measure the standing water inside the IPTD structure and estimate the volume of water in the IPTD structure prior to commissioning the IPTD system. A cost benefit analysis was conducted to compare the cost of draining/treating the leachate versus boiling off the leachate. Based on this analysis, before IPTD operations began and during the startup and shakedown phase, the leachate collection pipe valves were opened to drain off as much leachate water as possible. This appeared to be a practical solution as it would cost more and likely take longer to leave the water in the pile and convert the water to steam. However, all the water could not be freely drained from the IPTD structure, and treating the leachate caused fouling in the LVTP due to high iron content. The high iron and organic content of the leachate water plugged up the bag filters, requiring them to be changed every few hours. The CMC believes this contributed to the fouling of the macro-porous polymer extraction (MPPE) media as well. Overall, treating the leachate water (2 weeks) and converting the water that would not drain to steam added approximately 1 month to the schedule.

For Phase II, the CMC recommends not draining and treating leachate in Phase II due to the issues discussed above. During the Phase II filling and cap construction it is recommended to install a rolling tarp system to prevent water from infiltrating the IPTD structure and eliminating the need for treating the leachate. If leachate were to enter the IPTD during Phase II filling and cap construction, then the water would be removed from two newly installed sumps on the north end of the IPTD and the water would be treated outside of the existing LVTP.

1.4.3 Thermal Treatment System Controlled Shutdown On 07/22/14, the CMC recommended to USAID that thermal treatment be suspended due to consecutive dioxin exceedances in the liquid effluent of the LVTP (see Section 6.4.2.4 for additional information related to these exceedances). Operations were immediately suspended on 07/22/14. Then USAID, the CMC and the IPTD Contractor coordinated to develop a plan to identify the reason for the exceedance and restart the system. The delay from the controlled shutdown was 17 days.

There was never a final conclusion on why the exceedances occurred; however, it is suspected that negatively charged colloidal particles were facilitating transport of dioxin through the treatment system. Particle size analysis did indicate significant dioxin mass associated with particles with small diameters (e.g., 1 micron). The source of these particles is not known conclusively, but it is expected that they could have originated as pile leachate, recirculated solids, small pieces or “dust” from the granular

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activated carbon (GAC) media, or biologically-generated solids from within the LVTP. Therefore, the CMC recommends not treating leachate and not recirculating water through the LVTP during Phase II.

1.4.4 Heater and Heater Cable Failures This section describes the CMC’s evaluation of various problems with the heaters and heater cables that occurred during Phase 1. The cables overheated in the conduit which caused the insulation to burn or crack and eventually led to the wires burning (see IPTD Contractor’s Final Report-Phase 1 dated 10/20/15). This caused failures of entire heater zones, and during the most significant failure event nearly 50% of the heaters were offline. The IPTD Contractor exposed all the cables and made the necessary repairs, including running the cables in cable trays above ground, with separation to prevent cross currents (increases in amperage or variances in voltage) and heat buildup. The cables supplying power to different portions of the IPTD overheated at different times, and were repaired as problems arose. The IPTD wellfield was never completely de-energized as a result of cable failures. Therefore, it is difficult to calculate the exact delay associated with this issue; however, the cable failures are not considered to be a significant contributor to the overall delay in heating.

1.4.4.1 Water Infiltration-Induced Failures

During Phase I, the heaters failed due to rainwater infiltrating the cap, which caused a difference in the current that ran through the circuits causing an automatic shutdown. Typically, in an outdoor wiring configuration, it’s normal to install circuit transformers to read variations in amperage. If the variation in amperage becomes too great between phases, then the breaker shut down the circuit. The IPTD Contractor’s design used a different type of wire protection that would read resistance in ground rather than variations in amperage. This system is much more sensitive and maybe better for indoor use where water won’t contact the wires. This was a problem until the IPTD Contractor raised the set points and disabled this system. As described in Section 1.4.4.1, when a shutdown occurs, it shocks the system, causing scaling and spalling of the heater cans and liners that fall against the heater element and the liner or heater causing the heater element to short out or melt, which in turn shuts down the whole circuit of 8 to12 heaters. The CMC and the IPTD Contractor kept very detailed records of the heater change outs and repairs; these can be found in the CMC’s Monthly Reports and the IPTD Contractor’s Daily Reports. There were several days that a large percentage of the heaters were not in operation; however, it is difficult to estimate the exact overall delay associated with this issue because not all of the heaters were off at one time. Regardless, it is the CMC’s opinion that this was a significant contributor to overall delay, and has therefore been taken into consideration for Phase II within the effort to redesign the cap.

1.4.4.2 Heat Saturation-Induced Delays

During Phase I, the heaters cycled off more frequently than anticipated due to heat saturation. Because of unexpected cooling at the top of the pile, and stagnation of heating at the bottom, those portions of the IPTD structure were not heating quickly, while the temperatures in the center of the IPTD structure

Changing heater elements that were damaged from water infiltration

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exceeded expectations. Because the middle was too hot, and operation of the heaters at those elevated temperatures would risk additional heater failure, the heaters could not turn on completely and would idle at 10% power. The IPTD Contractor first raised and then shortened approximately half of the heaters in an effort to get more heat into the soil near the top of the pile. The heaters had a boosted section at the bottom, but shortening them to half-length still left the boosted section in the heat saturated middle zone. Changing the heater design is addressed under Section 8, Lessons Learned where a new heater design is proposed that will improve the heater performance.

1.4.5 Rainwater Influx through Surface Cover During Operations IPTD operations began on 05/30/14 and by October 2014 the average pile temperature as reported by the IPTD Contractor was 260°C; Phase I treatment operations were expected to be completed in November 2014. However, in mid-October 2014, several heavy rain storms in October 2014 resulted in water infiltrating the IPTD structure through cracks in the surface cover. The subsequent cooling of soil being treated in the IPTD structure was likely the most significant issue in extending the Phase I thermal treatment schedule. It took approximately 2 months to regain the same average pile temperature prior to the persistent rain event in October 2014. Additionally, after achieving the prior average pile temperature, the rate of temperature increase over the next 3 months was slower than before the persistent rain event. This may have been a result of residual moisture and cooling, and could also have been a result of other issues described in this section (e.g., heater shutdown, cable failures, etc.). The temperature curves and the effects of the cooling can be referenced in the IPTD Contractor’s Weekly Operational Reports.

Section C.4.3.1 of the IPTD Contractor’s contract states: “there is a general expectation that the rainy season should not significantly impact the IPTD Contractor and that the IPTD Contractor must perform most activities in the rainy season” and that “The IPTD Contractor should be able to notify USAID well in advance of any activities that would fall during the rainy season period and be potentially not advisable to implement during rainy days. It is the IPTD Contractor’s responsibility to request down period time in advance and receive USAID approval.” The IPTD Contractor did not submit any notifications to USAID or the CMC stating that thermal operations should not be performed during the rainy season (August through December).

Heater cans and liners degraded from excessive heat

Cracking in the LWIC

Steam rising from the top of the IPTD during rain storm

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While the IPTD Contractor expected cracking of the cap and had a contingency plan in place to repair the cracks, the cap cracked faster and to a greater extent than anticipated. The CMC observed that the spray-on liner visually appeared to be performing as intended before the cracking began.

During the early stages of design, the IPTD Contractor considered both a spray-on-liner and a high density polyethylene (HDPE) liner. For the 30% design submittal, the IPTD Contractor presented the pros and cons of both options, and appeared to be leaning towards use of an HDPE liner. However, for the 90% design submittal, the IPTD Contractor selected the spray-on-liner option based on the following reasoning:

“It is critical for the success of the thermal remediation process to prevent water from entering the treatment pile. The yearly average rainfall is ~2000 millimeters (mm) (79 inches [in]) in the Danang area. To manage this amount of rainwater and keep it out of the pile, it would be beneficial to use a waterproof liner as the top of the surface cover. In addition, such a liner will help ensure that a tight vapor seal is maintained to prevent fugitive emissions should cracks occur in the surface cover. Earlier in the design a HDPE liner installed on top of the pile was suggested. This approach could accommodate moderate to severe cracking of the cover with minor disruptions since it would not be glued to the concrete. However, an HDPE liner installed on top of the surface cover would require many penetrations to be manually sealed and maintained throughout operations. The liner would also be exposed to wind suction forces when storms occur in the area and would have to be secured to avoid lifting. Based on the dimensions 105 x 70 meters (m) at 7.5 m elevation, a coastal area terrain category with a velocity pressure of 2.25 kilonewtons per square meter (kN/m2), and a pressure coefficient of -0.7, the lifting force would be in the magnitude of 1.6 kN/m2 with a wind speed 37 meters per second (m/sec) (grade 12 storm). To compensate for this lifting force and secure the liner, additional weight would have to be placed on the surface cover (e.g., sandbags or an extra concrete layer approximately 250 kilograms per square meter [kg/m2]). Due to the impracticability of this approach, a spray-on liner was chosen to seal the concrete surface cover. The spray-on liner will be applied up and around all well sleeves and all other pipes penetrating the surface cover. If cracks occur during heating, they will be repaired using a thin concrete mixture and/or applying extra rubber liner material. Details on spray-on liner are found in Appendix I 101-00 Surface Cover.”

The IPTD Contractor procured the spray-on liner product; however, there was an issue procuring the spray-on liner applicator equipment. The IPTD Contractor conducted a trial, reviewed manufacturer’s recommendations, and decided that applying the spray-on liner using a roll on application technique would perform the same or better as the spray-on technique. The IPTD Contractor temporarily ceased application of the spray-on liner during a few rain events. The CMC observed that the liner was applied correctly.

The CMC recommends redesigning the cap for Phase II to better protect the IPTD structure from rainwater infiltration. The CMC recommends the redesign include an HDPE liner that extends over the sides of the IPTD structure in order to convey the water away from the LWIC and structure itself.

1.4.6 Confirmation Soil Sampling The CMC was responsible for conducting the Phase I confirmation sampling. Three significant changes to the original Phase I confirmation sampling strategy were made in consultation with USAID prior to sampling. The first change was to sample the 0-1 m layer decision unit (DU) in its entirety in order to have the earliest possible indication on whether treatment was successful in this layer, which was the most heavily impacted by rainwater infiltration. The second change was to collect sub-DU samples from only the 0-1 m layer DU instead of from all DUs; this decision was made after sub-DU sample results from the 0-1 m layer DU were received and indicated that dioxin concentrations in all sub-DU samples were below the project action levels.

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The third change was to collect the triplicate sample in the 2-3 m layer DU rather than the 0-1 m layer DU. Collecting triplicates in the 0-1 m layer might have introduced additional variability (e.g., significant temperature changes would have occurred in the layer between collection of the first sample and collection of the third sample for the triplicate), which would artificially and adversely affect the 95% upper confidence limit (UCL) for this sampling event. Note that heating continued throughout sample collection and was turned off more than 2 weeks after the 0-1 m layer was sampled.

The following factors contributed to the extended schedule for confirmation sampling, from an original estimate of 10 days to a final schedule of more than 2 months:

• Encountering refusal during drilling activities due to compaction and solidification of soils after extended thermal treatment at high temperatures. This was the primary cause of the extended sampling schedule.

• Developing new sampling techniques. As described in Section 7, traditional drilling methods could not be used for the confirmation sampling. The innovative equipment and procedures for confirmation sampling included substantially more decontamination than anticipated, which led to delays in the schedule.

• Sampling the 0-1 m layer DU in its entirety first. Original plans included drilling one boring at a time and collecting samples from all six DUs sequentially (0-1 m, 1-2 m, 2-3 m, 3-4 m, 4-5 m, and 5-6 m). This change required drilling 30 additional borings after drilling the 30 borings to collect the 0-1m DU sample, which led to a schedule extension of approximately one week.

• Collecting triplicate samples from a depth of 2-3 m. The plan changed from triplicates in the top 0-1 m layer DU, to triplicates in the 2-3 m DU. This change required drilling the 60 additional borings to 2-3 m as opposed to 0-1 m across the entire pile. Although 30 of these borings were shared with the 0-1 m sample mentioned in the bullet above, drill rigs and crews had to be mobilized back to the 0-1 m locations after that DU had been collected in its entirety.

The above-listed factors resulted in a lot of additional moving and decontamination of drill rigs, both of which extended the schedule. The CMC has conducted an internal Lessons Learned process and is working to improve the efficiency of confirmation sampling for Phase II.

1.5 Current Implementation Schedule The current Implementation Schedule is still under review and is not finalized at this time.

2 Roles and Responsibilities USAID has separated the implementation of the remediation project at the Danang Airport among three primary parties: the CMC, the ECC, and the IPTD Contractor. This ACR focuses on the activities that have been completed by each contractor during Phase 1 thermal installation and treatment (inclusive of quench and dismantle). Presented below is a summary of USAID’s responsibilities and each contractor’s scope of work, or responsibilities, for the Phase I thermal installation and treatment.

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2.1 USAID USAID is the implementing agency for the Airport remediation and procured the ECC (Tetra Tech) and the IPTD Contractor (TerraTherm) to conduct the remediation activities. USAID also procured the CMC (CDM Smith) to oversee and manage the construction activities to ensure the remediation is implemented in accordance with the final design and applicable GVN rules and regulations.

2.2 Construction Management Contractor The CMC is responsible for the construction management and oversight of the ECC and IPTD Contractor. For the Phase I thermal installation and treatment, the CMC’s responsibilities included:

• Coordinate as necessary the performance of construction, sampling and remediation work with USAID, GVN and other government agencies including the Vietnam Russian Tropical Center (VRTC) and Chemical Command (CC), and contractors of other projects that might impact the Airport remediation project.

• Hold weekly meetings with the Department of Natural Resources and Environment (DONRE) and other public officials, as required.

• Work with the Danang Airport Authority and Vietnamese Ministry of National Defense (MND) officials to provide for site security.

• Review preconstruction submittals and support USAID to ensure critical preconstruction activities are completed on schedule, meet project requirements, are of high quality, and ensure safe mobilization into construction.

• Facilitate an Operational Readiness Review meeting before the thermal treatment begins.

• Provide technical memoranda and comments as necessary to support USAID with recommendations.

• Manage and oversee day-to-day construction activities for all tasks being performed by the ECC and IPTD Contractor.

• Conduct inspections to ensure the IPTD system installation is conducted in accordance with plans/specifications, including verifying location, dimensions, and orientation of structures and documenting activities with photos.

• Implement the Site-Wide Sampling and Analysis Plan (SAP) and SAP Addendum which includes procedures for air and dust monitoring, soil/sediment post-excavation confirmation sampling, soil/sediment post-treatment confirmation sampling, and project-affected water sampling. The CMC’s subcontractor, Hatfield Consultants Partnership (Hatfield) assists with this responsibility. The Site-Wide SAP and SAP Addendum are available on the CMC eRoom: (https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_3ef35).

• Provide a Project EMMP, update the Project EMMP on an annual basis, and ensure all implementing contractors conduct the required monitoring and inspections in the Project EMMP. Hatfield assists with this responsibility. The latest approved update to the Project EMMP (FY 2014/FY 2015 update) dated 10/29/14 is available on the CMC eRoom: (https://team.cdm.com/eRoom/ca2/USAIDDanangAirport- Remediation/0_30544). The Draft FY 2016 Project EMMP was submitted to USAID for review on 09/30/15 and is currently being finalized by the CMC.

• Pay for power and water required for Phase I and II thermal treatment.

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• H&S – see Section 4 for detailed information of the CMC’s H&S responsibilities.

• Conduct weather monitoring to ensure work is conducted in favorable weather conditions and the project area is secured during unfavorable weather conditions (e.g., high winds, storms, etc.).

2.3 ECC The ECC is responsible for constructing the IPTD structure, excavating and transporting soil and sediment to the IPTD structure (i.e., Dig & Haul), and backfilling resulting excavations. As a result, the ECC did not perform activities related to Phase I thermal treatment during the thermal installation and treatment portion of the project.

2.4 IPTD Contractor The IPTD Contractor is responsible for the installation and operation of the IPTD treatment system. The IPTD Contractor’s responsibilities include:

• Submit the IPTD 100% design, schedule for thermal installation and treatment, Sampling and Analysis Plan/Quality Assurance Project Plan (SAP/QAPP), Mobilization Plan, task-specific Health and Safety Plan (HASP), O&M Manual and Implementation Plan for thermal installation and treatment.

• Furnish, install, and construct facilities and mobilize all required equipment, materials, supplies, and incidentals needed for performance of the work.

• Coordinate equipment placement and utility needs with the Contracting Officer’s Representative (COR) and the CMC.

• Provide the qualified, trained, and professional personnel required prior to the start of on-site activities and provide for all other preparatory work required to start work.

• Provide the necessary transformer and distribution panel and make all connections to the provided water and power services, and bear the costs associated with these utility connections.

• Maintain all temporary facilities in a clean, safe, and sanitary condition at all times during on-site activities.

• Complete all work according to all applicable requirements, design, project plans, and procedures.

• Conduct operational monitoring to ensure compliance with applicable regulations and assess system performance.

• Provide a task-specific HASP and provide oversight of subcontractors to ensure they are in compliance with the plan and any Vietnamese laws or regulations.

The IPTD Contractor’s contract-required submittals are listed below. The IPTD Contractor submitted all the required submittals. The specific details for the submittals are discussed in other sections of this report as noted in the list below.

2.4.1 Pre-construction • Mobilization Plan – see Section 5.3.7.

• Implementation Plan – see Section 5.3.1.

• HASP – see Section 4.

• SAP/QAPP – see Section 6.4.1.

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• O&M Manual – see Section 5.8.

• Project Schedule – See Section 1.4. 2.4.2 During Construction

• Project schedule updates – see Section 1.4.1.

• Design Change Records (DCRs). The IPTD Contractor’s DCRs can be made available by the IPTD Contractor in hard copy and are also available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_2097a.

• Notification of changes – the IPTD Contractor submitted notifications of changes for the additional scope items and unanticipated additional expenses described in Section 1.9 (Budget Summary) of the IPTD Contractor’s IPTD® Final Report - Phase I. The IPTD Contractor also provided budget projections for in scope overruns and cost savings as described in Section 1.3.

• Daily Reports – The IPTD Contractor provided Daily Reports that provided record of the daily activities during the implementation of Phase I. These reports can be made available by the IPTD Contractor in hard copy and are also available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_1f05c.

• Weekly Operation Reports during Thermal Operations – The IPTD Contractor provided Weekly Operation Reports that provided record of the weekly activities during the implementation of Phase I. These reports can be made available by the IPTD Contractor in hard copy and are also available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_2c349.

• Monthly Reports – The IPTD Contractor provided Monthly Reports that provided record of the monthly activities during the implementation of Phase I. These reports can be made available by the IPTD Contractor in hard copy and are also available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_1f290.

• Vouchers – The IPTD Contractor provided vouchers throughout the implementation of Phase I as described in Section 1.3.

2.4.3 Post Construction • As-Builts or Record Drawings – Record Drawings can be made available by the IPTD Contractor in

hard copy and are also available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_2c1ea.

• End of Treatment Report for each phase of treatment – the IPTD Contractor submitted their IPTD® Final Report – Phase I on 10/20/15.

• Demobilization and equipment disposition plan.

3 IPTD® Design Section 3 of the IPTD Contractor’s IPTD® Final Report – Phase I report discusses the IPTD® Design. All details regarding the design can be found in the IPTD Contractor’s 100% Design Report that was developed and delivered under another contract and is not addressed further in this report. The IPTD Contractor’s 100% Design Report is available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_1d8e1

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At the end of Phase I operations, several areas for improvements in the Phase II design were identified. Details on Lessons Learned and Phase II design changes are presented in the Section 9.

4 Health and Safety The documents that describe all components of the Project’s H&S program are the Site Wide HASP, the CMC’s task-specific HASP, the IPTD Contractor’s task-specific HASP and the ECC’s task-specific HASP. These documents are updated as needed to keep a safe work environment as conditions change.

The CMCs responsibilities for H&S are:

• Provide a Site Wide HASP for all implementing contractors and revise the Site Wide HASP as needed to meet H&S requirements on a dynamic job site. The latest revision to the Site Wide HASP (FY 2016 update) was sent to USAID, the IPTD Contractor and the ECC on 11/05/15. The Site Wide HASP is available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_3ec6e

• Provide oversight and reporting on GVN’s unexploded ordnance (UXO) clearance. The CMC reviewed all documents pertaining to UXO clearance needs, set up UXO clearance with MND, and subcontracted with a UXO oversight contractor to oversee all MND’s UXO clearance operations. The CMC also reviewed all documents provided by MND and the UXO contractor and made recommendations to USAID after review of the documentation provided by the UXO contractor.

• Provide H&S oversight of the IPTD Contractor’s implementation of the Site Wide HASP. To meet this responsibility, the CMC conducted the following:

o Performed inspections of the daily operations of all contractors and prepared daily formal written safety inspections. The daily safety inspections are available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_30212.

o Met with the IPTD Contractor’s safety representatives on a regular basis to discuss operational, daily and H&S activities. Communication is integral to a safe work site.

o Hosted monthly manager’s safety meetings to review concerns and to be kept informed of upcoming activities. The CMC distributed notes to all participants after each meeting.

• Stop work if the work would endanger the health, welfare or safety of the public or any project workers. The CMC takes the protection of the workers on site and the public at large very seriously. After the work stoppage, the issue is discussed and appropriate measures are taken to ensure a high level of safety is maintained. When all agree to the plan of action, personnel are informed of the new plan and work resumes. For example, the CMC stopped crane lifts from taking place after inspecting the rigging and finding it out of compliance. In each case, proper rigging was obtained and then the lift took place.

• Review implementing contractor’s task-specific HASPs, revisions to plans, and AHAs. The CMC reviewed and commented on changes to the IPTD Contractor’s HASP and AHAs. Revisions often addressed changes in PPE requirements for new tasks, PPE down-grades/up-grades or procedural changes.

• Ensure the IPTD Contractor’s (and their subcontractors’) compliance with the Site Wide HASP. The following activities were conducted to meet this responsibility:

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o Health monitoring is a requirement of all contractors. Pre-employment physicals and annual/semi-annual physicals after work commences are the requirement. The IPTD Contractor’s health professionals make a determination of fitness for work. If the employee does not pass the physical, then they are not allowed to work on-site. All employees working in zones wearing PPE must pass a respirator fit test. Fit tests are given semi-annually after the initial fit test. The CMC reviewed all fit tests and posted results on the CMC’s eRoom. The CMC is informed of and reviews the decisions made by the IPTD Contractor’s H&S/Medical professionals.

o Blood monitoring has always been part of the H&S program. During Phase I operations, a more stringent blood monitoring program and a pre-work lifestyle questionnaire were developed for all employees in response to elevated levels of 2,3,7,8 TCDD found in some workers’ blood samples. The CMC reviewed the blood dioxin sample results for the implementing contractors and compared baseline results and follow up results (when available). The comparison was done to determine if a significant change (greater than the laboratory uncertainty of 20%) had occurred between baseline and follow up results. All results were also compared to the 30 picograms per liter (pg/L) project action level. This information was used to determine if the training, level of PPE, and inspections performed may need to be changed or improved. If workers had any signs of elevated levels of dioxin, the CMC reviewed the level of PPE, the training the employee received, and if they had any problems wearing their PPE during safety inspections. This information, along with the results of similar monitoring of co-workers, was used to determine if any changes in the level of PPE or other controls were necessary. Section 6.4.4 contains related, pertinent air monitoring information.

o Training in construction and hazardous materials (HAZMAT) is done by all contractors.

o During Phase I, the CMC helped with training and reviewed the material for training. The CMC provided guidance to the other contractors on when certain types of training may be useful or needed. The training documents were reviewed by the CMC and posted to the CMC eRoom. A log of the yearly training is maintained by the CMC for all contractors.

o Regular general safety inspections were performed by the CMC and documented for review on the CMC eRoom. The CMC also utilizes a near miss/good catch program to help correct safety problems before injuries occur.

o All chemicals brought on site by the IPTD Contractor must include material safety data sheets, that must be compiled in their O&M Manual and be accessible at all times to workers at the site.

4.1 Safety Training & Performance The CMC developed a site-specific 16-hour training course that all contractors use as the basis for their training of employees on the project. In November 2012, the CMC trained several Vietnamese H&S personnel to give the course so they could implement training in Vietnamese language. The training had previously been given in English and simultaneously translated to Vietnamese, but it is now provided in Vietnamese only unless the need arises for an English version.

The CMC oversees and reports on the IPTD Contractor’s H&S program, including training. The CMC, the IPTD Contractor and the ECC have worked together to develop a culture of safety that did not

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previously exist in Danang, Vietnam. The training does not stop at the door of the class room; it continues on site each and every day starting with the morning safety meetings, review of safe work practices throughout the day and safety inspections directed at correcting bad habits, thus keeping employees constantly vigilant where safety is concerned. The program has been successful, as reflected in the fact that no contractor has had the equivalent of a lost time or Occupational Safety and Health Administration (OSHA) reportable incident with over 650,000 site work hours since the project began.

During Phase I, the IPTD Contractor trained their employees for the dynamic nature of the job site. The IPTD Contractor had 266,360 hours worked during Phase I with no injury or incidents. Going from construction to operations with many of the same workers meant a lot of cross training had to be done. It is not a simple task to develop a culture of safety in a country where none existed previously, and to do so while working on a hazardous waste site without having any equivalent OSHA time lost or reportable incidences is a significant undertaking.

4.2 Medical Monitoring The medical surveillance program is described in the Site Wide HASP that sets forth minimum guidelines for contractors’ H&S/medical professionals to use in the development of their own medical surveillance programs. The medical surveillance program is meant to cover all employees working with hazardous substances, and not just 2,3,7,8-TCDD. It is very important for a monitoring program to be developed based on the criteria and hazards specific to each contractor’s work.

All workers on site are subject to the medical surveillance program requirements. The required monitoring includes annual or biennial physicals depending on job description and risk, blood monitoring, baseline and exit for dioxin of all field workers. The FY 2016 Site Wide HASP includes an appendix specific to blood monitoring that explains the requirement for monitoring employees blood dioxin levels for 2,3,7,8,-TCDD. Implementing contractors must meet the requirements of the Site Wide HASP, and must develop their own task-specific H&S programs based on the level of hazard that exists in their specific job tasks.

As noted above, all implementing contractors must comply with the minimum guidelines set forth in the Site Wide HASP requirements which address 2,3,7,8-TCDD specifically. In addition, implementing contractors must develop their own task-specific H&S programs based on the level of hazard that exists in their specific job tasks. The intent is for the implementing contractors’ H&S/Medical professionals to develop a comprehensive program that is tailored to the needs and unique situations their employees will face. While developing their program, implementing contractors are responsible for assessing the H&S risks of their activities and determining whether the minimum requirements set forth in the Site Wide HASP are sufficient for their activities.

4.3 Blood Dioxin Monitoring Results During Phase 1 operations, an expanded health monitoring program was developed to address recommendations for further action regarding blood dioxin monitoring. Appendix A of the FY 2016 Site Wide HASP (originally submitted to implementing contractors on 08/05/15) gives greater detail to the health monitoring program that was developed during Phase I operations based on USAID and CMC recommendations, and specifies the steps to be taken after receiving blood dioxin results. If an individual’s blood dioxin results are above the site action level of 30 ppt, the new plan explains that the results

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should be reviewed with the employee, the employee should be removed from hazardous waste work zones, and the employee should be re-trained on proper use of PPE including a new respirator fit test and the care and storage of their respirator. The expanded health monitoring program also includes the collection of additional blood dioxin level samples from workers and review of the results with medical professionals as there may be additional action needed. While the document was being prepared and finalized, the CMC worked closely with the IPTD Contractor’s on-site personnel to help them understand what the new requirements would be and how to implement them for employees with elevated results over the action level prior to the plan being formally finalized and distributed.

The CMC also monitors the blood dioxin levels of their own employees. A total of 18 CMC personnel have been sampled during Phase I.

The IPTD Contractor’s site H&S manager and site supervisor have been proactive in gathering blood dioxin data. While the new requirements were being finalized by the CMC and USAID (i.e., prior to receiving the 08/05/15 information mentioned above), the IPTD Contractor developed a sampling plan that met the new requirements and fulfilled what they believed they needed to do for worker safety while the new plan was being finalized. When the requirements were finalized and distributed to the implementing contractors on 08/05/15, the IPTD Contractor was substantially complete with their sample regimen and were awaiting results. The IPTD Contractor’s medical monitoring plan was approved on 01/29/16.

The IPTD Contractor met the requirements of overseeing their blood monitoring program by the end of Phase I. The IPTD Contractor was however out of compliance with the original Health Monitoring Plan during Phase I operations, including during electrical issue repairs on the IPTD and the change out of spent carbon. The amount of time required to receive data is the only aspect of the program that could be improved at this time, but all contractors are in a similar situation with the dioxin samples and data.

Based on air monitoring data, the IPTD Contractor determined that vapor granular activated carbon (VGAC) change outs are a source of dioxin exposure and that many of the workers with elevated levels of dioxin were involved with VGAC change outs. The CMC concurs that evidence points to VGAC change outs as one of the sources for dioxin exposure; however, the CMC also suspects the OWS and/or MPPE units are also potential sources and Level B respiratory protection should be used in the LVTP while the system is in operation. A blood dioxin summary sheet can be found on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport- Remediation/0_343a0. The blood monitoring results indicate that the highest potential for exposure is associated with working in the LVTP. The IPTD Contractor believes that workers may have exposures to dioxin outside the work place, giving the example of incinerating trash in a backyard setting. However, the lifestyle questionnaire that is part of the blood monitoring program is not mentioned. Rather than speculate on potential exposure pathways for workers, it would be more appropriate to use actual data gathered from the lifestyle questionnaires. In addition, backyard incineration is unlikely to contribute significantly to increased levels of 2,3,7,8-TCDD in blood.

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4.4 Personal Protective Equipment The CMC reviewed and discussed task specific PPE requirements with the IPTD Contractor regularly as situations and work conditions changed. The IPTD Contractor and the CMC conducted visual inspections of personnel to ensure they were wearing the required PPE in accordance with their site specific HASP. When air monitoring data indicated elevated dioxin concentrations in ambient air on the IPTD and in the LVTP, the IPTD Contractor increased vacuum on the IPTD structure, secured all hatches, tightened all fittings attached to vessels, watered the area around the LVTP heavily and cleaned all surfaces in the LVTP.

The CMC recommends PPE requirements for Phase II be modified to include Level B at all times when personnel are working in or around the LVTP. As a lesson learned from Phase I, it has been determined that the implementing contractors cannot rely solely on air monitoring data to make adjustments to the levels of PPE worn.

4.5 Activity Hazard Analyses The CMC developed AHAs for each definable feature of CMC work according to the CMC’s task- specific HASP. The CMC also reviewed and commented on the IPTD Contractor’s AHAs for construction and operations of the thermal system and the LVTP. During Phase I, the CMC observed and determined that the IPTD Contractor met the requirements for developing and implementing AHAs according to their approved task-specific HASP for hazardous or potentially hazardous site activities.

4.6 Dioxin in Ambient Air As described in Section 6.4.4, the CMC took regular ambient air samples at the perimeter of excavation areas in accordance with the Project EMMP during Phase I operations. VRTC collected ambient air samples around the IPTD structure and LVTP and found higher dioxin levels than expected. The CMC and IPTD Contractor started taking regular samples around these areas as well. The results showed higher than expected concentrations of dioxin on top of the IPTD structure and in the LVTP confirming VRTC’s results. Stricter PPE requirements and a more robust monitoring effort were put in place due to these sample results. Significant effort was put forth by the IPTD Contractor and the CMC to determine the source of the dioxin emissions. Conclusive evidence was not found, but there are several suspected sources such as carbon change outs, especially the VGAC, the OWS, the MPPE unit, and sumps in the LVTP. The CMC’s Monthly Reports document the level of PPE worn for Phase I activities in response to ambient air monitoring results. CMC Monthly Reports can be found on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_301e5.

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The IPTD Contractor’s IPTD® Final Report – Phase I states that the source of dioxin in ambient air on top of the IPTD pile was steam or vapors emitting from the cracks in the IPTD surface cover. The CMC agrees that cracks in the surface of the IPTD pile cover did have steam coming out of them; however, steam also came out of many other penetrations in the surface of the IPTD structure. As a corrective action (see Section 6.1.7.1 for additional information), the surface of the IPTD structure was covered with HDPE, and then another layer of insulating concrete was applied over the HDPE. Samples collected after implementing these measures indicate that they reduced the concentration of dioxin in ambient air samples collected from the top of the IPTD structure. Cracks in the new top layer of insulating concrete also emitted steam, and steam could be seen coming up from around heater cans, thermocouple pipes, sleeves, and from the inside of these same objects. Most of the steam that was produced did not come from within the pile but from rain water reaching hot surfaces near the top of the pile. Other water entered the pile via a combination of pipe penetrations and cracks, and then exited the pile as steam.

The IPTD Contractor believes that the dioxin concentrations in the LVTP ambient air were suspected to be influenced by general O&M activities, surrounding excavation and hauling activities, and a lack of sufficient airflow through the LVTP. As discussed in Section 6.4.4, based on excavation monitoring results, the levels of dioxin observed around the excavation areas were lower than those observed in the LVTP and the levels of dust were also low. Therefore, it is unlikely that dust from other site activities caused significantly increased levels of dioxin in ambient air within the LVTP.

4.7 Compliance with Vietnamese Environmental Law The implementing contractors have clauses in their contracts that require them to comply with Vietnamese law. The project is an environmental project that requires the implementing contractors performing environmental work to have proper Vietnamese licenses. The CMC reminded both the ECC and IPTD Contractor that they must comply with the Vietnamese law and ensure their subcontractors have the appropriate licensing.

5 Phase I Construction This section describes activities conducted during installation of the thermal system from the Kick-Off meeting through the development of as-builts at the end of construction.

5.1 Kick-off Meeting Conference Call The contract required a Kick-Off meeting to be held via conference call when designated by the COR. This meeting was held on 03/08/13 and the meeting agenda can be found on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_3ef38. The meeting covered the following topics:

• Project Team Organization / Communications

• Scope of Work

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• Branding and Marking

• Submittals

• Equipment and Material

• Mobilization, Setup, and Site Access Requirements

• Construction/Implementation Schedule

• H&S

• Other/Miscellaneous

5.2 Pre-work Conference Danang The contract required a Pre-Work Conference to be held in Danang, Vietnam when designated by the COR. This meeting was held on 04/16/13 to 04/19/13 and the meeting agenda can be found on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_3ef3c. The meeting covered the following topics:

• Contracting/Financial

• Project Team Organization/Communications

• Mobilization, Site Setup, and Site Access

• Overview of Outstanding Design Issues

• Equipment and Material

• Construction/Operation Deliverables, Reporting, and Meetings

• Preliminary Schedule Discussion

• Regional Office of Procurement (ROP) (Karittha Jenchiewchan) meetings with Implementing Contractors

• Stakeholders Meeting

• In-Depth Schedule Discussion

• Construction/Operation

• Contract Administration, Payment Procedures, Change Management

• H&S and Environmental Requirements

• Compliance Sampling

• Quality Control

5.3 Preconstruction This section describes the preconstruction activities including development of plans, staffing, mobilization and procurement.

5.3.1 Annual Implementation Plan The IPTD Contractor’s FY 2013 Implementation Plan was submitted to USAID on 04/02/2013; the CMC provided comments to USAID on 04/10/2013 and USAID forwarded the comments to the IPTD Contractor. The IPTD Contractor provided responses on 05/07/13, and the CMC provided additional comments to USAID on 05/13/13. On 11/22/13, USAID provided the IPTD Contractor with comments to be incorporated into the FY 2014 Implementation Plan, and stated that the plan did not need to be

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resubmitted, and requested the IPTD Contractor combine their FY 15 and FY 16 Implementation Plans and submit by 11/30/15. The available Implementation Plans are available on the CMC eRoom here: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_30d99.

5.3.2 Staffing The IPTD Contractor’s on-site construction manager, Glenn Anderson, arrived in Danang on 03/25/13. He began establishing the IPTD Contractor presence immediately following his arrival. Mr. Anderson was joined by Dzung Tran, a Vietnamese native, with prior United States (U.S.) environmental work experience. The IPTD Contractor hired Paul Wells for the Site Safety Officer (SSO) position. Mr. Wells mobilized to Danang in May 2013 when the actual construction work began.

The IPTD Contractor’s original plan was to have Mr. Anderson on a rotation schedule of approximately 4 months in Danang, followed by 2 months home (U.S.). During Mr. Anderson’s periodic rotations, Bill Condon would replace Mr. Anderson as the on-site construction manager. During Phase I, the IPTD Contractor’s plan changed, and Mr. Anderson only travelled home twice. Mr. Condon replaced Mr. Anderson the first time, and Stan Walker replaced Mr. Anderson the second time.

During Phase I, the CMC recommended to USAID that Tim Burdett mobilize to Danang to assist Mr. Anderson with administrative duties. Mr. Burdett was mobilized on 09/23/13, stayed through the completion of Phase I operations and demobilized on 08/07/15. After the thermal system began operating, Mr. Burdett’s main responsibility was to implement the IPTD Contractor’s sampling plan.

During Phase I, the IPTD Contractor was supported by their project manager (Jim Galligan), their technical director (Ralph Baker), their engineer (Mr. Walker), various supporting engineers (including Steve McInerney), and other engineering or construction experts as required. The IPTD Contractor home office support periodically traveled to Vietnam to oversee certain critical construction, start-up or operation activities.

The IPTD Contractor’s subcontractor’s (which is a joint venture between Kru ger and Veolia Vietnam) staff that were scheduled for full time assignment in Danang are identified in the IPTD Contractor’s Mobilization Plan (Table 2.2). The Kru ger site manager, Keld Myren, mobilized for construction in April 2013 and was replaced by Pawel Gierszewski half way through the implementation of Phase I. The Mobilization plan is available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_30de9.

5.3.3 Tax and Value Added Tax Recovery The IPTD Contractor is responsible for seeking reimbursement of value added tax (VAT) charged on local purchases in Vietnam. The IPTD Contractor is required to submit these charges to the local tax authority for reimbursement. However, during Phase I, the IPTD Contractor was not able to recover any VAT due to difficulties with the Danang Tax Department. The IPTD Contractor, the CMC and USAID escalated this issue within the Vietnamese government and requested support from the Project Management Unit (PMU). USAID worked with Air Defense Air Force Command (ADAFC) to request assistance from the General Tax Department in Hanoi. The General Tax Department issued direction to the Danang Tax Department that all implementing contractors are eligible for VAT reimbursement and need to work with the Danang Tax Department to file and receive the VAT refunds. Regarding corporate tax, ADAFC provided direction and authorization for the Department of Planning and

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Investment to work with the implementing contractors to get a signed copy of the Bilateral Agreement between the GVN and the U.S. in order to complete their exemption. The matter of personal income tax was resolved with the help of ADAFC and USAID giving clear direction to the Danang Tax Department that all expat employees working on a nonrefundable Official Development Project are exempt from paying income taxes in Vietnam.

5.3.4 Connections to Water and Power Services Section C.4.1.2. of the IPTD Contractors’ contract states: “The IPTD Contractor will not be responsible for payment of water and power service associated with the operation of the IPTD system and quenching. The IPTD Contractor will be responsible for the payment of all other utility services, including but not limited to water, power, and sewer for temporary facilities, field trailers, etc.”

During Phase I, the CMC recommended that the IPTD Contractor manage the installation of the water line. The CMC worked with the Danang Water Department to develop a design and a price for construction and connection. The water line installation plan is available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_3054a. MND used their counterpart funds to construct the power line and the substations to provide power for thermal treatment. USAID requested the IPTD Contractor provide maintenance and service of the substation as additional work under their contract.

MND, USAID and the CMC worked together with Thanh Khe Power to get preferential rates for power. After the rates were negotiated, it was agreed in a Memorandum of Understanding between USAID and MND that MND would sign the contract with Thanh Khe Power and USAID would pay the bill directly to Thanh Khe Power through the CMC.

USAID issued a modification to the CMC in June 2014 to pay for the water and power for Phase I and Phase II thermal treatment.

5.3.5 Procurement The IPTD Contractor’s Procurement Quality Assurance Plan describes how they planned to procure goods and services required to accomplish the project. The purpose of the plan was to identify the critical procurements necessary for construction, define the key roles and responsibilities of key individuals involved in the IPTD Contractor’s procurements, and formulate detailed advance plans/strategies to minimize technical, cost and schedule risk to the project. The CMC did not oversee the procurement that was done outside of Vietnam. However, upon observation of received materials in Vietnam, the CMC concurs that the IPTD Contractor followed their Procurement Quality Assurance Plan and realized a substantial buy-out savings that went to fund other portions of the project.

5.3.6 International Logistics/Customs Clearance In advance of the IPTD Contractor’s mobilization, the CMC and USAID met with the Vietnam Department of Customs to understand the procedures for importing equipment to construct the thermal system. USAID worked with MND to get the tax exemptions allowed under an Official Development Assistance (ODA) project. The IPTD Contractor provided a preliminary list of material and equipment to be imported to Vietnam for USAID to submit to MND.

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The CMC observed that the import of equipment was well planned and well executed by all parties. The import of all the major equipment went very smoothly and without incident.

5.3.7 Mobilization The IPTD Contractor was required to submit a Mobilization Plan as defined in Section F.5.2 of their contract prior to mobilizing to the site. This plan was submitted on 03/08/13. With assistance from the CMC, USAID provided comments on the Mobilization Plan to the IPTD Contractor on 03/15/13. On 03/22/13, the IPTD Contractor provided responses. On 03/28/13, USAID provided additional comments, and the IPTD Contractor submitted the final Mobilization Plan on 05/29/13. The Mobilization Plan defined how the IPTD Contractor would furnish, install, and construct facilities and mobilize all required equipment, materials, supplies, and incidentals needed for performance of the work. The Mobilization Plan also defined how the IPTD Contractor would use the IPTD Laydown Area for staging materials and for operation of the treatment system and other remediation components. An additional storage and staging area to the south of the IPTD Laydown Area was constructed by and leased from Army Division 372. The IPTD Contractor implemented Phase I activities in accordance with this Mobilization Plan. The Mobilization Plan is available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_30de9.

5.3.8 Equipment Laydown Area The general equipment layout plan is shown on drawing 01-207 of the IPTD Contractor’s Implementation Plan. The IPTD structure was designed to have access ramps on both the west and east sides. The east side ramp was not constructed in order to give more storage room to the IPTD Contractor. The IPTD Contractor used that space for storing parts for the heater wells during Phase I construction. After having overheating issues with the electrical cables going from the power control units to the IPTD structure, much of the space was used for above ground electrical and associated crossings.

5.3.9 Site Access and Security The CMC and USAID jointly managed site access and work with Army Division 372. USAID requested the CMC to sign a contract with Army Division 372 to provide security services. With the proper approvals and subcontract waiver in place, the CMC continues to work with Army Division 372 to provide security services.

USAID manages site access requests through the PMU, ADAFC, in Hanoi, as well as the Ministry of Foreign Affairs (for international media outlets). All persons visiting the site must provide the proper credentials in advance of visiting the site.

During Phase I, the IPTD Contractor coordinated with the CMC and USAID to ensure all their equipment and personnel had proper access. They also made formal requests on occasion, when necessary, to extend regular working hours to accomplish certain critical tasks.

5.4 General Construction Activities During construction of the thermal system, the IPTD Contractor was required to complete all work according to all applicable requirements, design, project plans, and procedures. The IPTD Contractor’s contract states that they “must use trained, qualified, and professional craftsmen to perform all construction

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work and their disciplines must be related to the task performed. For example, work on electrical systems must be conducted by professional electricians that have experience with the type of electrical systems on which work is being done. Equipment and services must be of professional quality so as to minimize downtime during remediation. Any down time due to inadequate parts will not be an excusable delay and the IPTD Contractor will be fully responsible lost/down time”.

The IPTD Contractor’s contract states under section F.5.1.A, “that the contractor shall start installation of the IPTD system for Phase I as soon as possible but no later than July 1, 2013. Phase I installation should be completed in approximately 8 months.” The IPTD Contractor satisfied this contractor requirement and installed the Phase I treatment system in approximately 8 months.

Each piece of equipment used to perform the construction (not the equipment being installed) was inspected by the CMC for obvious defects and for OSHA regulation compliance. The CMC reported results of the equipment inspection to the COR. For any equipment that did not meet OSHA requirements, the COR instructed the IPTD Contractor to tag it out of service and repair or remove it from the site. All systems and equipment had provisions for OSHA lock out/tag out. Because the work was performed at an active civilian and military airport, there were height restrictions identified on the IPTD design drawings. Any planned changes that may have caused exceedances of the height limits were coordinated with the USAID COR and the CMC in writing.

During construction of the IPTD system and the LVTP, the CMC received the IPTD Contractor’s weekly quality control reports. These reports were reviewed by the CMC and checked for accuracy. Comments were given to the IPTD Contractor and any corrections or deviations were corrected.

5.5 Wellfield Installation Fabrication of the heaters began in the IPTD Contractor’s home office on 02/11/13 and they were shipped to the site in batches and were received without incident. Heater can installation began on 08/10/13 on the north half of the IPTD. Before installation began, the IPTD Contractor coordinated with the CMC to perform the necessary calculations and coordination with the Airport to ensure that there would be no exceedance of the height restrictions. A total of 1,254 heater cans, 106 temperature monitoring points (TMPs), 202 air injection points (AIPs), 8 pressure monitoring points and 1,254 stainless steel sleeves were installed. This work was completed on 09/27/13. The installation was successful and was completed much faster than originally anticipated. The original schedule had 44 working days to complete installation, and the task was completed in 22 working days.

The IPTD Contractor’s subcontractor Nam Thuan Phat (NTP) began assembly of the horizontal vapor collection system in the IPTD gravel plenum layer on 08/29/13. NTP also worked on the quench manifold during this time. NTP completed installation on 10/07/13. Typhoon Nari damaged the horizontal vapor collection pipe. An assessment was conducted and repairs were completed on 10/18/13.

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The IPTD Contractor’s subcontractor Vinausen began LWIC placement on 10/07/13 under the supervision of a Kruger representative. Preparations for pouring the concrete included forming up alternating sections then laying out geotextile fabric so the concrete would not flow down into the plenum layer of gravel. Grease was then applied to all the vertical pipes to allow for unimpeded thermal expansion. The concrete was poured in two layers and 98 horizontal sections. The first layer was 45 centimeters (cm) thick and was finished on 11/06/13. When sections were cured, stainless steel sleeves were placed around the vertical well penetrations, the top 15 cm of concrete was then placed in sections. After curing for 7-14 days, a water-proofing membrane was applied. The water proofing spray-on liner application began on 11/26/13. The LWIC, including the surface cover, was completed on 12/03/13. The spray-on liner was applied correctly using a roll-on technique and it seemed reasonable at the time that it would serve its function to repel water from the surface of the LWIC cap. The IPTD Contractor’s subcontractor Lilama continued to install the vapor manifold lines and supports on the IPTD structure in December 2013.

On 11/01/13, the IPTD Contractor’s subcontractor ELA started installing cable ladder supports for running cable up onto the IPTD structure. The IPTD Contractor trained ELA on how to install heater boxes and cables on 11/08/13 in preparation for starting installation. Due to several delays, ELA did not start installing heater boxes on the IPTD structure until 11/21/13. Heater boxes were finished on 01/16/14. On 12/07/13, ELA started to install heater elements in the heater cans. Installation of the heater elements was completed on 01/17/14. On 01/27/14, the fiber optic cable from the power units to the control trailer was run.

On 11/12/13, Lilama started to survey in the positions for the vapor manifold system on the IPTD. Installation of the pipe stands began on 11/23/13. Lilama finished the vapor manifold on 02/13/14 with the installation of the flex couplings for expansion. Pressure testing of the well field vapor manifold began on 03/24/14 and was completed successfully on 03/28/14.

In April 2014, the IPTD structure piping and electrical was substantially complete, and on 05/20/14, the leachate valve to the LVTP was opened. After removing leachate water for more than a week, the IPTD Contractor informed USAID and the CMC that they intended to energize the IPTD heaters. On 05/29/14, the IPTD Contractor idled the heaters at 20% to remove condensate from the heater casings, then the system was ramped up to 100ºC on 06/01/14.

5.6 LVTP Construction On 09/09/13, the IPTD Contractor’s subcontractor Locus began work on the treatment system foundation. Foundation piers were dug, formed up and poured. Footings and containment walls followed, and on 10/21/13, the treatment system pad was completed. Also on 10/21/13, Locus completed the containment wall and slab for the quench/scrubber tower. The quench/scrubber tower

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was installed on a separate slab. Construction on the cooling tower started on 01/13/14 and was substantially complete on 02/18/14 with only a small amount of packing material left to install. The last of the packing material was installed on 03/24/14. During construction of the treatment system foundation, Locus fabricated the steel for the roof structure to cover the treatment system in their shop. On 12/05/13, Locus finished installing the columns and rafters for the LVTP. On 12/06/13, Locus started installing the purlins and bracing on the LVTP structure. Locus started to install the roofing on the LVTP on 12/19/13, and finishing the roof and gutters on 01/06/14. Locus left a section of the roof off to facilitate the installation of the MPPE units.

On 11/01/13, the IPTD Contractor’s subcontractor Lilama began surveying equipment placement positions on the treatment pad. On 11/05/13, Lilama placed the stands for the shell in tube heat exchangers on the equipment pad; they finished setting the heat exchangers on 11/10/13. Six pressure liquid granular activated carbon (LGAC) vessels, one buffer tank, three low pressure LGAC vessels, one back flush buffer tank and one OWS were set on the treatment pad on 11/20/13. From January to March 2014, Lilama continued to set and plumb in equipment on the LVTP pad. On 03/27/14, Lilama started to pressure test the vapor manifold in the LVTP.

The IPTD Contractor’s subcontractor NTP started fabrication of the liquid treatment piping at the LVTP on 02/12/14 NTP made a great deal of progress in March 2014 with much of their scope of work completed. The liquid treatment pipe was substantially complete on 04/17/14.

The IPTD Contractor’s subcontractor Novas started installing instrumentation and control lines on 02/25/14. Novas’ work in the LVTP was substantially complete in March 2014.

The IPTD Contractor’s subcontractor CEMC fabricated and coated the LVTP LGAC and VGAC vessels. After shipping them to the site some repairs and re-coating needed to be done. This work was completed on 03/04/14.

The IPTD Contractor did much of their commissioning work in April and early May 2014 and started treating leachate water from the IPTD pile on 05/20/14.

5.7 Commissioning and Readiness Review Section C.4.1.9 of the IPTD Contractor’s contract states: “At the completion of construction activities and prior to the start of operations, the IPTD Contractor must conduct a checkout of the system. The system checkout test must be completed no sooner than 15 days before the start of operations. The system checkout must test and evaluate construction of the system against the approved design and as-built drawings, initial operation of the system, pressure tests on piping, operation of equipment, and

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operational procedures. At the completion of the system checkout, the COR, the CMC and the IPTD Contractor will hold a readiness review for operations to determine and document whether the system is ready for operations”.

On 05/19/14, the CMC and the IPTD Contractor conducted a readiness review meeting to determine if the shakedown of the systems components had been successfully completed and if the IPTD and LVTP system was ready for start-up. The CMC agreed that the system’s individual parts had passed the proper function tests and could be put in to operation mode for full system shakedown.

5.8 Operations and Maintenance Manual Section C.4.1.8 of the IPTD Contractor’s contract states: “An O&M Manual must be completed by the IPTD Contractor for each treatment phase, submitted to the COR and the CMC, and accepted by the COR. The O&M Manual must be completed prior to the readiness review for operations. The O&M Manual must describe activities and procedures to be performed during operations. The O&M Manual must list the phases of the operation, strategy for each phase, decision points, criteria for proceeding to the next phase, and guidelines for the remediation. Procedures from the IPTD Contractor and their Subcontractors must be included in the same O&M Manual.”

The IPTD Contractor submitted the O&M manual for review on 02/10/14. The CMC and USAID provided comments on 02/19/14, the IPTD Contractor submitted the revised O&M Manual on 04/01/14, and USAID approved the O&M Manual on 05/28/14.

5.9 Electrical Distribution System On 09/10/13, the Danang Power Company arrived on site to turn over the two transformer substations to the IPTD Contractor. The IPTD Contractor set the first six power containers on their foundation blocks on 11/01/13. The last two were set on 11/20/13 when a larger crane was available on site.

Novas installed conduit for the distribution of power to the treatment system in September 2013. In October 2013, Novas completed trenching and installation of conduit from the east and west substations to the power containers locations. In November 2014, Novas prepared power units 2, 4, 6, and 8 for testing by Kruger engineers.

On 10/24/13, ELA began installation of the conduit from the power containers to the IPTD structure. On 11/21/13, ELA began mounting the electrical wellhead boxes and heater elements on the IPTD structure. On 11/24/13, ELA began installing cable from the power units to the substations. ELA continued electrical work through January 2014, and finished their scope of work in February 2014. This included running cable from the transformer sub-stations to the power control units. This also included installation of wellhead electrical boxes, heater elements, ground jumper cables, communication cable to the control container and signal cable to transmit temperature data.

Kruger installed grounding systems for the power containers, control container, emergency backup generator and treatment plant equipment. Each grounding system consisted of six grounding rods

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buried in the subsurface, each connected by a grounding wire and leading to a main connection point where the above surface ground cable was connected. Thanh Khe power energized the overhead power lines to both transformer substations on 01/17/14.

5.10 As-Builts Section C.4.1.8 of the IPTD Contractor’s contract states: “As-built drawings of each treatment phase must be completed for submission with the O&M manual, which is due 2 weeks after shakedown. The as-built drawings must be based on the design drawings, approved changes to the design drawings, and as-built conditions of the site. The as-built drawings must be submitted in the O&M Manual and the Final Report (see Section F.5.2) for each treatment phase.”

The IPTD Contractor submitted and posted the as-built drawings to the CMC eRoom after the O&M Manual was submitted and the system was running. The as-built drawings were updated and submitted in compliance with the IPTD Contractor’s contract.

6 Phase 1 Thermal Treatment Operations This section describes the Phase I thermal treatment operations including O&M of the IPTD® pile and LVTP from startup through quenching, a discussion of the in-pile temperature progression, power usage, and status of the pile, pile manifold, and treatment system vacuum.

6.1 IPTD® Pile O&M This section describes O&M activities for the IPTD pile from start-up to quenching.

6.1.1 Startup Water treatment operations started on 05/21/14 with the opening of the leachate valves. The system treated leachate until 05/29/14 when flows from the leachate system diminished significantly. On 05/29/14, the well field was energized and idled to remove condensate from the well pipes. All circuits were set to automatic settings on 05/30/14 with a 50ºC set point. On 06/01/14 the circuits were set to 100°C. The IPTD Contractor start-up team kept control over operations, and handled all the minor problems and glitches that came from start-up and during early operations.

6.1.2 Steam Phase While loading the IPTD structure and installing the thermal treatment system in Fall 2013, a significant amount of water infiltrated the soils within the IPTD structure prior to the start of operations. It is unknown how much water infiltrated the pile at this time. Due to the significant amount of water in the IPTD structure, the production of steam started almost immediately after energizing the well field. In addition, in October 2014, rainwater infiltrated the IPTD structure through cracks in the LWIC cap. Again, it is unknown how much water infiltrated the pile at this time. The volume of steam lessened as heating progressed but continued for most of the Phase I heat up.

6.1.3 Heat up to 335oC The original requirement for heat up was for all thermocouples to reach a minimum of 335°C for 21 days. However, after challenges with rainwater infiltration and subsequent cooling and re-heating, the heating requirement was adjusted to be an average temperature of 335ºC in each 1 m layer with no

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thermocouples below 275ºC and with no more than 10% of thermocouples below 335ºC. The schedule for heat up was longer than originally expected. In the IPTD Contractor’s contract, the heating duration is specified as “approximately 4 months.” However, the actual heating duration for Phase I totaled 290 days (~9.5 months) from the start of treatment to the start of confirmation sampling on 03/16/15. The main reasons for schedule heat up delays are reviewed in the schedule section (Section 1.4). It should be noted that even without the rainwater infiltration problems that severely affected schedule, it is unlikely the original requirement of all pile soils reaching 335ºC could have been met on schedule, specifically in the deepest portion of the pile because the IPTD was loaded with the optimum moisture content for compaction, which was not as dry as originally modeled by the IPTD Contractor. The estimated delay associated with this change is between 2 and 2.5 weeks, all other delays attributable to water caused as much as 4 months of delay.

6.1.4 Thermal Treatment System Controlled Shutdown As described in Section 1.4.3, the treatment system and well field were temporarily shut down on 07/22/14 due to consecutive dioxin exceedances in the liquid effluent (additional information regarding the dioxin exceedances is provided in Section 6.4.2.4). The well field was kept at idle to ensure condensate would not build up in the heater cans. The CMC, the IPTD Contractor and USAID reviewed the issue and came up with appropriate corrections. The IPTD Contractor worked diligently to change out all the carbon and granular ferric hydroxide (GFH) in the treatment train. The system was re-started on 08/08/14.

6.1.5 Thermal Treatment System Re-start Reducing conditions in the GFH influent water caused the LVTP effluent water to have a red coloration. The GFH vessels were steam cleaned and new GFH was put back in the vessels. As noted above in Section 6.1.4 of, the system was re-started on 08/08/14. The water in the drainage ditch was circulated through a sand filter to remove the reduced iron causing the red coloration. A flocculent was also applied to the ditch water that worked well at precipitating the dissolved reduced iron from the ditch water.

6.1.6 Rainwater Infiltration Rainwater infiltration into the IPTD pile after start-up was due to not having an impermeable cover over the concrete. If cracking was anticipated and heavy rain was also anticipated, it would have been more appropriate to proceed with the original design which included an HDPE liner or other water barrier that did not need re-application in the event of extended heating.

The IPTD Contractor attributed the significant number of cracks in the LWIC to differential settlement and lateral movement. The CMC agrees that differential settlement and lateral movement were contributors to cracking; however, the lateral movement was noted after the middle depths of the pile had achieved temperatures much higher (up to 200⁰C higher) than treatment requirements and expectations. The following additional factors contributed significantly to rainwater infiltration in earlier stages of heating:

Iron oxide discolored water

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• Prior to installing the LWIC (completed 10/10/13), rainwater infiltrated the IPTD structure while both the ECC and the IPTD Contractor were constructing the IPTD structure and installing the thermal treatment system. Water infiltrated the IPTD structure while the ECC was filling the structure and installing the gravel plenum layer and while the IPTD Contractor was installing the wells and in plenum manifold system. The impact from this is approximately a 1 month delay to the overall schedule.

• After installing the LWIC, but prior to any indication of lateral movement, rainwater infiltrated the IPTD structure due to not having an impermeable cover over the LWIC. The IPTD Contractor installed an HDPE liner (i.e., impermeable cover) between 10/22/15 and 12/13/15. Cracking was anticipated by the IPTD Contractor and heavy rain was also anticipated; therefore, it would have been more appropriate to proceed with the original design, which included an HDPE liner or other water barrier that did not need re-application in the event of extended heating and that would protect the IPTD structure from water infiltration after cracking of the cap. The overall estimated delay from this event is approximately between 4 and 4.5 months.

The O&M Manual’s contingency matrix has a discussion of a contingency for minor surface cover cracking (<1-2 cm wide) and for significant surface cover cracking (>2 cm wide). This is important because cracking was always expected. The greatest number of cracks were 1-2 cm, or “minor” according to the definition in the O&M Manual, with only some being in the “significant” range of greater than 2 cm. The IPTD Contractor’s IPTD® Final Report - Phase I lists four potential reasons for the concrete surface cover cracks.

• Lateral movement of the IPTD pile.

• Thermal expansion of the IPTD pile.

• Uneven heating of the subsurface.

• Tipping forces of the IPTD pile structure walls.

The CMC recommends consideration of the following additional potential causes of cracking:

• Rapid heating of concrete in general.

• Thermal cycling of the concrete caused by cycles of IPTD heating and rain.

The IPTD Contractor’s daily reports prior to the October 2014 rain event indicated that the IPTD Contractor repaired cracks on a daily basis, and this maintenance was not out of the ordinary; according to the IPTD Contractor’s superintendent, the level and effort of the crack repair was consistent with other projects. The IPTD Contractor filled the annulus around the heater wells to keep water out of them and cracks were repaired with several methods depending on width. The crack repair was necessary from the beginning of IPTD operation until the end of heating.

Crack repair was an ongoing process and most of the cracks that were repaired needed repair on multiple occasions. Therefore, it is difficult to quantify the length of cracks in linear meters but from a construction perspective it does not matter as long as cracks were being repaired in a timely manner that prevented water infiltration. The heavy rains may have caused cracks to become larger and make it more difficult to repair the cracks in a timely manner. During the crack repair, different materials were used including:

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• Concrete – discontinued due to shrinkage during curing.

• Bitumen – discontinued due to odor problems.

• Bentonite –successfully sealed cracks. However, as cracks expanded, bentonite needed maintenance and additional bentonite had to be added to fill the additional space.

• HDPE –provided an impermeable cover over the pile and prevented water infiltrating through cracks.

6.1.7 Corrective Action The section describes corrective actions taken by the IPTD Contractor during Phase I to address some of the factors that contributed to the extended heating duration.

6.1.7.1 Supplemental Surface Cover

The IPTD Contractor’s original IPTD design (available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_1d8e1) included an HDPE cover at the top of the structure. This HDPE cover was later removed from the IPTD design (see CMC’s comments on the IPTD design for additional details, available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_3ef56). After the October 2014 rain events, the roll-on liner failed and an HDPE liner was installed across the top of the IPTD structure. Installation of the HDPE liner took approximately 2 weeks, and it took an additional 2 weeks to fully weld the cover due to rain. The CMC does not believe a supplemental concrete surface cover was necessary; however, it did not detract from system performance.

It is not possible to directly determine the effect of any individual mitigation measure while rainwater was still being boiled off since the majority of energy input is used to boil this water off. In retrospect, Phase 1 experience bore out the CMC’s initial concerns, that the HDPE should not have been removed from the IPTD design. After the HDPE cover was installed during the implementation of Phase I, it prevented further water infiltration and cooling such that the pile was able to heat to the required temperatures to complete treatment.

The IPTD Contractor notes that the additional LWIC surface cover improved heating in the uppermost portion of the IPTD pile, but the evidence given for that claim remains unclear. Upon analysis, a correlation between the installation of LWIC and better heating efficiency is not evident.

6.1.7.2 Raising Heaters

The IPTD Contractor raised heaters 50 cm to better deliver heat to the top 1 m of soil in the IPTD structure. Raising the heaters appeared to have helped temperatures in the upper portion of the pile, but was impeded by the high temperatures in the middle section of the pile, triggering safety overrides and shutting down the heaters to keep them from overheating and destroying treatment components.

6.1.7.3 Shortened Heaters and Increasing Thermal Set Point

The IPTD Contractor cut and shortened heaters to better deliver heat to the top 1 m of soil in the IPTD structure. The shortened heaters and raising the set point above 800ºC was likely responsible for the continuation of the heating curve and the successful heating of the upper 1 m layer of the IPTD pile.

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https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_1d8e1



6.1.8 335oC Average Temperature The 335ºC average target temperature was met in all layers. The last layer to meet this temperature was the 0-1 m depth, which achieved an average temperature of 335ºC on 03/25/15.

6.1.9 Cooling to 100oC Average (Quenching) The CMC reviewed the quenching AHA with the IPTD Contractor and their subcontractor on 05/11/15. The IPTD Contractor was directed to perform a test quench after the GVN was informed of the plan to start quenching (at the MND monthly meeting on 05/13/15). The IPTD Contractor began the test quench on 05/13/15 which was planned to include injecting a small quantity of water into the IPTD structure to test the amount of steam generated and the ability of the treatment system to capture and treat the vapors. The test quench was scheduled to be conducted for 1 week; however, on 05/14/15 (one day after the test quench began), the CMC directed the IPTD Contractor to stop injecting water into the pile after the development of large plumes of steam due to the high flow of water being applied by the IPTD Contractor. Afterwards, the IPTD Contractor was directed to follow their test quench plan and take a more measured approach for the initial quenching. The IPTD Contractor restarted quenching on 05/15/15, and executed their quench process. To meet the water pressure needs, the IPTD Contractor used an alternative pump to increase volume, and water injection points were moved regularly to help water soak in rather than run off. Hot spots were determined from TMP data and those locations were targeted during quenching, sometimes by making a hole in the LWIC. During quenching, the IPTD Contractor reacted quickly to daily visual observations and temperature data to adjust the quenching process as needed. Some amount of professional judgment and trial and error was required, but the goal of 100ºC average TMP temperature was reached in early July 2015, within the 2 month time goal set at the start of quenching.

The IPTD Contractor states that the average pile temperature reached approximately 87ºC on 07/07/15. For clarification, this was the average temperature of the TMPs, not the average pile temperature. As discussed above, it is likely that water had preferential pathways down vertical piping including TMPs. The water getting down around the TMPs caused false low readings. However, it did not seem to cause significant hardship or delays for the removal of hot soil and may have expedited the schedule as the ECC was able to finish quenching the treated soils efficiently during removal.

The CMC’s recommends that the same quenching strategy used for Phase 1 be used for Phase II quenching. Specifically, the IPTD Contractor should quench the pile to a maximum of 100ºC average TMP temperature prior to handing over the IPTD structure to the ECC.

6.2 In-pile Temperature Originally, the heating was estimated to take approximately 4 months (based on the IPTD Contractor’s modeling) – the temperature curves were expected to have been much flatter, the temperature in the top portion of the pile would have not lagged behind as much, and the middle portion of the pile would not have had as much heat saturation. As described above, during loading of the Phase I soils and the installation of the IPTD treatment system, more water was in the pile soils than originally modeled by the IPTD Contractor; therefore, more heating time was required to reach the boiling point. An unfortunate result of this delay was a large heat differential between the middle of the pile, which heated quickly, and the top and bottom portions of the pile, which heated more slowly. The bottom temperatures were more of a concern early in the heating process, as they were slow to heat up and

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lagged behind the rest of the pile when comparing daily rise in temperature after boil-off. The heat differential in the curve was noted and discussed on site by the IPTD Contractor and the CMC, but was not a significant concern until rain water infiltrated the top layers in October 2014. This exacerbated the heat differential and took temperatures back to boiling at many of the TMPs but had little effect in the middle portion of the pile. The slow heating of the bottom section of the pile, the safety shut down of heater circuits due to the heat differential (especially on the east and west perimeter), and the decrease in individual well temperatures due to rain events were the greatest concerns for the heat-up schedule as discussed on site in September and early October 2014, prior to the rain events and subsequent water infiltration into the IPTD pile.

The IPTD Contractor’s Final Report - Phase I ( d a t e d 1 0 / 2 9 / 1 5 ) , “On September 24, 2014 rain water was found to infiltrate the pile and reduce the temperatures locally in the infiltration areas.” The IPTD Contractor did not alert the CMC of an impact to IPTD pile temperatures due to rain in September 2014. The site experienced steady rain starting late on 09/23/14. The IPTD Contractor’s daily report for 09/24/14 notes: “Scanned TMP Logger to determine if rain was having an impact on shallow TC units, as of 11:00 hrs there is no discernable effect, TMP34 & 36 are the only two units with temps in the 100°C range and 36 has been that way for a while now.” The 09/25/14 daily report notes: “Scanned all TC’s from all TMP arrays, no impact from rain on upper units.” At the time of this event, the CMC and IPTD Contractor discussed the readings at TMP34 and it appeared that water had gotten into or around the TMP itself, giving a false reading. This was never verified, but no TMP effect was noted in daily reports during earlier rain events in September 2014 or in the early weeks of October 2014. As mentioned in Section 9 of this report there are several things being done in Phase II to mitigate this problem such as redesigned heaters, rolling tarp system and a robust cap redesign.

6.3 Pile Manifold Vacuum The pile vacuum was expected to keep fugitive emissions from escaping from the IPTD pile structure during heat-up and treatment. Based on pile vacuum data and observations of steam and dioxin concentrations in ambient air (see Section 6.4.4), this does not appear to be the case and is being reconsidered in design changes for Phase II. The CMC recommends adding additional vacuum capacity in order to keep the plenum layer under vacuum at all times.

6.4 LVTP O&M and Monitoring This section describes O&M activities for the LVTP. It provides an overview of the LVTP monitoring requirements and compliance criteria, discusses the liquid treatment and vapor treatment during Phase I, and provides a discussion of ambient air monitoring.

6.4.1 LVTP Monitoring and Compliance Overview Use of the LVTP for treatment of process water and vapor began on 05/21/14 and ended on 10/13/15. The IPTD Contractor began monitoring the influent, intermediate and effluent locations in the liquid and vapor treatment systems on 05/22/14 and 06/02/14, respectively. Samples were collected to check that the treatment system was effectively capturing and treating the emissions from the IPTD treatment and complying with the project action levels as presented in the Project EMMP and the IPTD Contractor’s SAP/QAPP. The CMC coordinated with the IPTD Contractor to perform oversight and quality control of sampling activities, receive and review results and recommend solutions to improve monitoring and operations.

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As described in Sections 1.4.3 and 6.1.4, the Phase I IPTD thermal treatment system was started on 05/29/14 and was temporarily shut down from 07/22/14 to 08/08/14 due to consecutive dioxin exceedances in the liquid effluent. This is further discussed in Section 6.4.2.

6.4.1.1 Monitoring and Compliance Criteria

Monitoring of the IPTD and LVTP was conducted in accordance with the FY 2014/FY 2015 Project EMMP (available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport- Remediation/0_30544) and the IPTD Contractor’s SAP/QAPP (available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_3e43c). The EMMP was revised after the IPTD Contractor’s original SAP/QAPP was submitted to include the IPTD Contractor’s monitoring requirements. The Project EMMP and the sampling portion of the IPTD Contractor’s SAP/QAPP both changed over the course the Phase I due to observations of site conditions and results of monitoring.

The parameters analyzed during Phase I operations are presented in Table 1 below.

Table 1. Monitored parameters during Phase I treatment

Parameter Discharge criteria Comments Vapor Dust 150 mg/m3 HCl 50 mg/m3 Dioxin TEQ 0.60 ng/m3 TEQ Phenol 19 mg/m3 Cresol 22 mg/m3

Benzene 5000 μg/m3

CMC recommended monitoring, operating and maintaining the treatment system (e.g., changing or rotating GAC more frequently) to comply with GVN standard on 11/14/14

Liquid pH 5.5 – 9.0 COD 150 mg/L Arsenic (As) 100 μg/L Phenols (total) 0.45 mg/L Oil & Grease 9.0 mg/L 2,4‐D 0.200 mg/L 2,4,5‐T 0.100 mg/L 2,3,7,8‐TCDD 24.01 pg/L

Turbidity 29 NTU

CMC recommended monitoring turbidity for the effluent of the treatment plant to determine whether turbidity was correlated with dioxin. No correlation was observed between dioxin and turbidity, and the turbidity was consistently below the discharge criteria so it was decided that additional turbidity sampling was not required.

Ammonia 9.9 mg/L CMC recommended monitoring and operating system to comply with GVN standard on 12/12/14.

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https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_3e43c


Acronyms: HCl = hydrochloric acid μg/L = micrograms per liter mg/m3 = milligrams per cubic meter mg/L = milligrams per liter ng/m3 = nanograms per cubic meter pg/L = picograms per liter TEQ = toxicity equivalence NTU = nephelometric turbidity unit μg/m3 = micrograms per cubic meter GVN = Government of Vietnam 6.4.1.2 Monitoring and Sampling Frequency

As noted above, the Project EMMP and the sampling portion of the IPTD Contractor’s SAP/QAPP both changed over the course the Phase I due to observations and results. The following provides a summary of those changes:

• The IPTD Contractor issued the 2012 SAP/QAPP in October 2012.

• The CMC recommended adding analytes (including liquid dioxin samples) and increasing sampling frequencies in October 2013. The IPTD Contractor made the recommended changes and discussed the increased costs with USAID in January 2014.

• The Draft FY 2014 EMMP was submitted to USAID on 01/11/14.

• The IPTD Contractor updated and submitted the SAP/QAPP Revision 1 (including frequency tables) in March 2014.

• The IPTD treatment system was temporarily shut down on 07/22/14 due to consecutive dioxin exceedances in the liquid effluent (see Section 6.4.2.4 for additional information).

• The IPTD Contractor updated the SAP/QAPP frequency tables in August 2014 and re-started the IPTD treatment system.

• The August 2014 sampling frequencies were followed until the completion of the confirmation soil sampling in April 2015, at which reduced monitoring commenced was agreed upon and followed.

• Increased monitoring began at the start of quenching operations in May 2015.

• After quenching was deemed complete, reduced monitoring commenced in September 2015.

• After decontamination of the IPTD and LVTP equipment was completed, the IPTD Contractor ceased sampling at the LVTP on 10/13/15.

6.4.2 Liquid Treatment This section provides a discussion of the liquid treatment in the LVTP during Phase I and the CMC’s analysis of the IPTD Contractor’s performance. One general comment/recommendation is provided here, and the following subsections (6.4.2.1 through 6.4.2.5) provide specific analysis/recommendations on different elements of the liquid treatment system.

General Comment: Per the IPTD Contractor’s Final Report - Phase I (dated 10/20/15), the IPTD Contractor suspected that suspended solids in the leachate water had contributed to the dioxin exceedances in June, 2014. The CMC agrees that the suspended particles likely contributed to dioxin exceedances by facilitating transport through the treatment system. However, during this period water was being recirculated through the system and the suspended solids may have originated from leachate water, LGAC fines, and/or GFH fines. Therefore the CMC recommends limiting or completely eliminating recirculation of process water through the LVTP.

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6.4.2.1 MPPE

The MPPE system was included in the design to reduce GAC consumption by adsorbing both chemical oxygen demand (COD) and dioxin concentrations to the synthetic media. After the MPPE media was changed, dioxin was measured in the media at a concentration of 291,000 ppt total TEQ as reported by MPP Systems, although no information was provided on the year of the World Health Organization (WHO) toxic equivalency factor (TEF) used (i.e., 1998 or 2005), or the non-detect (ND) calculations used (e.g., setting NDs equal to 1 or ½ times the detection level or 0). The non-aqueous phase liquid (NAPL) waste from the MPPE and OWS units contained an average concentration of 8,870,000 ppt total TEQ dioxin (mid-point, WHO 2005) as measured and reported by the IPTD Contractor. Based on the removal and concentration of dioxins in the MPPE and NAPL, the CMC recommends that the IPTD contractor investigate whether these waste streams are a continuous source of dioxin to process vapor, process water and/or ambient air in the LVTP.

6.4.2.2 LGAC

The LVTP also included LGAC vessels to remove contaminants from the liquid waste stream. The IPTD Contractor was responsible for LGAC maintenance and media replacement. On multiple occasions, the CMC recommended to USAID and the IPTD Contractor that additional LGAC should be purchased and delivered to the site for future use as more GAC was used than originally estimated due to more frequent change out based on effluent exceedances, biological growth and other factors. The LGAC did not remove contaminants as expected due to colloidal particle transport (as presented in Section 6.4.2.4) and substantial biological growth problems. The IPTD Contractor will modify their design and operate the LGAC differently (e.g., rinsing GAC of fines before use, more frequent GAC change outs, carefully dosing with nitrate and managing biological growth) during Phase II in order to improve the LGAC performance. The IPTD Contractor is expected to provide more detail about how they will manage this in their forthcoming revised O&M Plan. .

6.4.2.3 GFH and Arsenic

GFH was included in the Phase 1 treatment system to react with and remove arsenic from the liquid waste stream prior to discharge. The IPTD Contractor’s Final Report - Phase I (dated 10/20/15) implies a correlation between arsenic and other compounds coming from the pile near the 100°C milestone, likely driven by steam generation. The CMC agrees and recommends the IPTD Contractor perform a more detailed analysis of the correlation between arsenic and 2,3,7,8-TCDD in order to inform Phase II operations.

6.4.2.4 2,3,7,8-TCDD

Dioxin, and specifically 2,3,7,8-TCDD, is the primary contaminant of concern on this project. During Phase I operations, three consecutive 2,3,7,8-TCDD exceedances of the 24.01 pg/L project action level were measured in the liquid effluent of the LVTP on 06/23/14 (192 pg/L), 06/25/14 (133 pg/L) and 06/30/14 (354 pg/L). In response to these exceedances, the treatment system was shut down from 07/22/14 to 08/08/14 while the IPTD Contractor made operational modifications to the system. As described in Section 1.4.3, there was never a final conclusion on why the exceedances occurred; however, it is suspected that negatively charged colloidal particles were facilitating transport of dioxin through the treatment system. Particle size analysis did indicate significant dioxin mass associated with particles with small diameters (e.g., 1 micron). The source of these particles is not known conclusively,

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but it is expected that they could have originated as pile leachate, recirculated solids, small pieces or “dust” from the GAC media, or biologically-generated solids from within the LVTP.

Also, in response to both VRTC’s sharing of elevated dioxin results at the outfall of Sen Lake and additional dioxin exceedances observed in the LVTP liquid effluent, on10/27/14 the CMC recommended to USAID that samples be collected from the Sen Lake outfall on a weekly basis. A minimum of one sample was analyzed per month and additional samples were analyzed if deemed necessary based on the IPTD Contractor’s treatment system results. Also, on 10/30/14, the CMC recommended that the IPTD Contractor treat water in the outfall ditch through a sand filter to remove trace dioxin reported in samples collected from the ditch. The CMC believes that this treatment was helpful in removing particulates that might have been carrying dioxin from the water in the ditch, but that there was likely additional precipitate that settled or was flocculated to the bottom of the outfall ditch and was not removed by the treatment.

During quench, three consecutive samples, collected on 04/13/15, 04/20/15 and 04/27/15, showed elevated dioxin concentrations of 69.7, 43.5 and 43.9 pg/L, respectively, all of which exceed the project action level of 24.01 pg/L. The CMC agrees with the IPTD Contractor’s explanation that these exceedances were likely caused by a combination of factors, including: an increase in influent dioxin concentration, potential biological fouling of LGAC units, LGAC rotation, and/or insufficient LGAC replacement and MPPE regeneration. It is very likely that the increase in influent dioxin concentrations was caused by steam stripping of low levels of dioxin remaining in soil. The biological fouling and frequent LGAC rotation and insufficient MPPE regeneration may have reduced the liquid treatment train’s ability to reduce these elevated concentrations of dioxin below our project action level prior to discharge. The CMC believes that the following changes recommended for the Phase II will decrease the likelihood of such exceedances:

• Avoid pumping leachate to reduce solids (and colloidal) loading in the system;

• Avoid recirculation of treated water back through the LVTP to reduce solids loading;

• Pre-rinse unused LGAC to flush mobile GAC fines prior to placing the units in service;

• Improve OWS operation via improved skimming;

• Control biofouling (and biosolids generation) appropriately and aggressively when needed via redox manipulation (i.e., nitrate addition) as a primary option and pH control as a secondary option, and use inline nitrate sensors to minimize nitrate overdosage above what is needed to prevent sulfate reducing conditions in the GFH;

• Improve MPPE performance via more frequent regeneration as needed; and

• Improve GAC performance via replacement when needed, and do not rotate GAC vessels. Rotation is not typically implemented nor recommended by GAC vendors, as it disrupts predictable adsorption zone movement through the vessels, thus increasing chances of unexpected breakthrough. It also has the potential to contribute to inefficient GAC usage.

In general, elevated concentrations of 2,3,7,8-TCDD at the effluent of the LVTP did not show a strong correlation with concentrations measured at the outlet of Sen Lake as shown in Figure 2 below. Exceedances measured in the Sen Lake outfall during Phase I operations are presented in Table 2 The CMC believes that the IPTD Contractor operated and monitored the system to limit exceedances of 2,3,7,8-TCDD.

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Figure 2. Concentrations of 2,3,7,8-TCDD measured at the LVTP, Outfall Ditch and Sen Lake Outlet during Phase I operations.

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Table 2 Exceedances at Sen Lake Outfall During Phase I Operations

Sample ID Date collected Turbidity 2,3,7,8-

TCDD (pg/L) Dioxin TEQ

(pg/L) Benzo(a)pyrene

(ng/L) Zinc Arsenic

(mg/L) Sample Collection Notes

(mg/L)

Project EMMP Action Levels

> 29 NTU over

background 24.01 pg/L None

established 200 ng/L 3 mg/L 0.1 mg/L

1R‐SW‐0017 10/27/14 14.1 96.5 97.4 0.241 0.0207 0.00338 Inspection on 10/27/14 showed erosion of cap in DD1.

1R‐SW‐0018 11/04/14 3.4 25.3 26 ND 0.0097 0.00728 11/04/14: DD1 cap repaired. 1R‐SW‐0035 02/26/15 14 43.6 44.8 ND 0.007 0.0352 Sample 1R‐SW‐0036 indicates that 1R‐SW‐

0035 was an anomaly. 1R‐SW‐0036 03/09/15 10.7 7 7.77 Not analyzed 1R‐SW‐0037 03/19/15 15.5 50.4 51.4 0.213 0.0339 0.00027 No clear reason for elevated concentration

in 1R‐SW‐0037, but potential influences include: slightly elevated turbidity during pumping, potential for low levels of dioxin on colloidal particles during subsurface dewatering in SL‐2E, and/or elevated concentration in LVTP effluent. Concentrations in the next two samples show a decreasing trend.

1R‐SW‐0038 03/26/15 14.7 28.9 29.9 Not analyzed

1R‐SW‐0039 04/04/15 9.6 21.9 23.3 Not analyzed

1R‐SW‐0042 04/25/15 4.3 24.7 26.1 ND Not analyzed Slightly elevated concentration in 1R‐SW‐0042 during DD‐3 & DD‐6 subsurface dewatering. Halted on 05/18/15.

1R‐SW‐0043 06/25/15 20.5 26.5 29.1 0.501 0.0461 0.0175 No clear reason for elevated concentration in 1R‐SW‐0043.

Acronyms/Abbreviations:

DD = Drainage Ditch ng/L = nanograms per liter EMMP = FY 2014/FY 2015 Project EMMP Update NTU = nephelometric turbidity unit ID = identification pg/L = picograms per liter mg/L = milligrams per liter TCDD = tetrachlorodibenzo‐p‐dioxin ND = not detected TEQ = toxicity equivalence

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6.4.2.5 COD

COD concentrations were measured at the LVTP liquid effluent during Phase I operations in order to ensure compliance with the Vietnamese standard of 150 mg/L for permanent water treatment plants. COD measured in the LVTP effluent exceeded the Vietnamese standard multiple times throughout Phase I operations (concentrations ranged from <10 to >1900mg/L). The CMC recommended sampling to determine a baseline threshold value (BTV) for COD on 03/08/14 that might serve as a more appropriate COD discharge standard for the project. On 04/17/14, the CMC recommended locations in the Phu Loc River and on the Danang Airport property for this sampling. The results of the COD sampling indicated that COD concentrations in the Phu Loc River and on the Danang Airport property are lower than the 150 mg/L Vietnamese standard for permanent water treatment plants. Considering the LVTP is a temporary treatment system and the compliance point of the project is Sen Lake (i.e., point where water discharges offsite), the CMC recommends moving the discharge monitoring point to Sen Lake for Phase II and keeping the discharge standard at 150 mg/L.

6.4.3 Vapor Treatment This section provides a discussion of the vapor treatment in the LVTP during Phase I and the CMC’s analysis of the IPTD Contractor’s performance.

6.4.3.1 Dioxin

Dioxin was monitored in the vapor effluent of the LVTP to determine compliance with the project action level of 0.6 ng/m3. After the IPTD Contractor began sampling effluent vapor for dioxin, results indicated that the sampling volumes were too low to determine compliance with the project action level. In August 2014, the CMC recommended that the IPTD Contractor increase their dioxin sample volume in order to collect additional mass and provide higher certainty of the results received from the laboratory. Only one dioxin exceedance was noted during Phase I operations.

CC also collected vapor samples from the LVTP according to their schedule. Generally, they collected samples using a low-volume polyurethane foam (PUF) sampling apparatus. On 07/14/14, CC collected dioxin samples from the LVTP and reported to the CMC that their results were 0.65 ng/m3, which was above the discharge standard of 0.6 ng/m3. CC later hired the Dioxin Laboratory (DXL) to collect additional dioxin samples from the effluent of the LVTP using an isokinetic sampling method on 09/17/14 and 09/18/14. Results for this sampling event ranged from 1.5 to 2.1 ng/m3, also above the discharge standard of 0.6 ng/m3. However, the IPTD Contractor’s sample results from this same date showed dioxin results below 0.25 ng/m3. Due to these different results, ADAFC requested that DXL review their results and the CMC review the data from the IPTD Contractor’s sampling event. The CMC validated the IPTD Contractor’s results following Stage 2B validation requirements which are described by the United States Environmental Protection Agency (USEPA) as “A verification and validation based on completeness and compliance checks of sample receipt conditions and both sample-related and instrument-related quality control results.” The CMC completed validation on 10/31/14 and all of the IPTD Contractor data from this period was considered usable (i.e., no results should be rejected based on evaluation of the precision, accuracy, or representativeness of the information provided in the laboratory analytical data packages). After this point, the data was accepted by ADAFC and no further action was required.

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6.4.3.2 Benzene

The IPTD Contactor noted that PID screening continued to show elevated readings after the 100⁰C milestone, which is after the majority of initially present volatile organic compounds (VOCs) were expected to have volatilized from the pile. As a result, VOC samples were collected and analyzed and showed elevated concentrations of benzene and acetone. Benzene is a toxic compound, so the CMC recommended that operations and monitoring proceed to reduce benzene concentrations in effluent vapor. The IPTD Contractor began rotating GAC vessels on a weekly basis, as well as replacing carbon more frequently, which was effective in achieving this goal. As benzene is expected to be generated during Phase II thermal operations, the IPTD Contractor will install a Fourier transform infrared spectroscopy (FTIR) unit to provide real-time benzene data and tailor operations to minimize effluent concentrations. The CMC recommends that the IPTD Contractor focus on replacement when FTIR or analytical results indicate a need, and consider discontinuing vessel rotation. Rotation is not typically implemented nor recommended by GAC vendors, as it disrupts predictable adsorption zone movement through the vessels (thus increasing the risk of early breakthrough), and has the potential to contribute to inefficient GAC usage.

6.4.4 Ambient Air In September 2014, VRTC collected ambient air samples from the project site and shared results with USAID and the CMC on 10/07/14. Results indicated dioxin concentrations in ambient air were elevated above the project action level (i.e., greater than 0.414 picograms per cubic meter [pg/m3], based on the BTV) in locations on the ground near the IPTD structure (see Appendix A – VRTC results for samples collected between 06/15/14 and 09/12/14). At the time, neither the CMC nor the IPTD Contractor were collecting ambient air samples near the IPTD structure. In October 2014, VRTC, the CMC, and the IPTD Contractor jointly collected ambient air samples on the ground near the IPTD structure. Results for all parties were received in November 2014 and confirmed elevated levels of dioxin in ambient air between the LVTP and the IPTD structure (VRTC – 9.53 pg/m3, CMC – 3.28 pg/m3, and IPTD Contractor – 4.83 pg/m3). In addition, the CMC and IPTD Contractor collected ambient air samples on top of the IPTD structure near the southern end of the structure, but VRTC did not collect samples from this location as it was outside of their scope. Results from the top of the structure also showed elevated levels of dioxin in ambient air (CMC – 160.63 pg/m3, IPTD Contractor – 173.95 pg/m3) (see Appendix A – VRTC, CMC, and IPTD Contractor results for samples collected between 10/16/14 and 10/18/14).

After these results were received, the CMC, IPTD Contractor, and USAID implemented the following to address the elevated dioxin levels in ambient air:

• Reduced the release of dioxin emissions (i.e., source control) by increasing the vacuum to the IPTD pile and covering the top of the pile with HDPE.

• Established 10 pg/m3 as a project action level for dioxin in ambient air that triggers a requirement for upgraded PPE. This new project action level was determined through a risk evaluation conducted by the CMC using the available ambient air data and worker hours (i.e., time spent on the project site). As a result of this risk evaluation, the following actions were taken:

o The top of the IPTD pile was established as an exclusion zone that required upgraded PPE to conduct work (dioxin levels were greater than 10 pg/m3 on top of the pile).

o The LVTP was established as an exclusion zone that required upgraded PPE to conduct work (dioxin levels were greater than 10 pg/m3 in the LVTP).

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o Workers on the ground near the IPTD pile (i.e., support zone) did not require upgraded PPE (dioxin levels were less than 10 pg/m3).

• Collected the following additional ambient air samples to assess the extent of dioxin levels in ambient air and to adjust PPE requirements as needed throughout the site:

o Weekly ambient air samples from the top of the IPTD structure and from within the LVTP (IPTD Contractor collected).

o Weekly ambient air samples from the perimeter of the project site at the four compass points (north, south, east and west) (CMC collected). On 02/24/15, the frequency of perimeter sampling was reduced to once every 2 weeks. On 04/18/15, perimeter sampling ceased.

Additionally, due to concerns over fugitive emissions, the CMC collected ambient air samples from 05/17/15 to 07/08/15 at the perimeter of the IPTD structure (four samples) and the perimeter of the project site (four samples) every week during quenching operations. Concentrations of dioxin in ambient air in the sample locations ranged from 0.5 to 18.5 pg/m3 at the perimeter of the IPTD structure, and from 0.1 to 1.2 pg/m3 at the perimeter of the project site. The project action level of 0.414 pg/m3 was exceeded at the perimeter of the site in 13 of the 64 samples collected during quenching operations. Ambient air results for all samples collected on/near the IPTD structure and the perimeter of the project site are presented in Appendix A.

Considering the site activities that were taking place and the prevailing wind directions during sampling, it is likely that the elevated concentrations of dioxin in ambient air samples collected at the perimeter of the project site, as well as some of the samples collected around active excavation areas, were caused by dioxin vapor originating from the IPTD and LVTP.

In addition, dust released during the changing of spent vapor carbon is very likely related to elevated concentrations of dioxin in ambient air. Based on excavation monitoring results, presented in Table 3, the levels of dioxin observed around the excavation areas were lower than those observed in the LVTP and the levels of dust were also low. Therefore, it is unlikely that dust from other site activities caused significantly increased levels of dioxin within the LVTP.

Despite the procedural and housekeeping changes implemented by the IPTD Contractor, such as washing the LVTP, installing fans to promote air flow and using sprinklers to limit dust in the LVTP area, concentrations of dioxin in ambient air in the LVTP did not decrease. In addition, at the end of operations, the ambient air results from within the LVTP were still elevated. These results indicate that the source of dioxin is not related to dust from outside being deposited in the LVTP, but is instead a result of the dust generation, operations and associated equipment within the LVTP.

The results of ambient air monitoring indicated that fugitive emissions from the IPTD structure and LVTP had a measurable effect on dioxin concentrations in ambient air across the site. However, with the exception of one elevated reading at the top of the IPTD structure ramp where workers are required to wear appropriate PPE for exclusion zones, dioxin concentrations in ambient air did not exceed the risk assessment PPE upgrade level of 10 pg/m3 anywhere on site. Therefore, neither on-site workers outside the exclusion zone nor the surrounding community were at elevated risk due to dioxin in ambient air. Changes are being made to the design of the IPTD structure cover/cap and the planned operations for Phase II with the goal of reducing dioxin in ambient air to at or below background levels.

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Table 3. Dioxin (TEQ pg/m3) and Dust (µg/m3) Data Collected During Excavation Activities

Sample ID Location Sampling Date

Mean Dust Level

(µg/m3)

Maximum Dust STEL (µg/m3)

Dioxin TEQ (pg/m3)

Phase II Excavation

1R‐AR‐0062 West ‐ EW & EH 03/19/14 ‐ 03/20/14 34.54 78.16 0.1037

1R‐AR‐0063 South ‐ EW & EH 03/19/14 ‐ 03/20/14 22.73 58.73 0.0748

1R‐AR‐0064 East ‐ EW & EH 03/19/14 ‐ 03/20/14 30.76 75.11 0.0912

1R‐AR‐0066 West ‐ SL & EH 04/24/14 ‐ 04/25/14 22.38 48.3 0.1684

1R‐AR‐0067 North ‐ SL & EH 04/24/14 ‐ 04/25/14 26.77 62.41 0.0788

1R‐AR‐0068 East ‐ SL & EH 04/24/14 ‐ 04/25/14 29.4 58.56 0.0243

1R‐AR‐0069 South ‐ SL & EH 04/24/14 ‐ 04/25/14 20.87 45.82 0.0602

1R‐AR‐0070 South ‐ SL & TSSA 05/21/14 ‐ 05/22/14 14.36 26.65 0.0677

1R‐AR‐0071 East ‐ SL & TSSA 05/21/14 ‐ 05/23/14 19.27 38.59 0.1401

1R‐AR‐0072 North ‐ SL & TSSA 05/21/14 ‐ 05/22/14 17.52 73.22 0.1523

1R‐AR‐0073 West ‐ SL & TSSA 05/21/14 ‐ 05/22/14 12.59 40.3 0.1891

1R‐AR‐0076 South ‐ SL, EH & EW 06/24/14 ‐ 06/25/14 8.25 28.14 0.231

1R‐AR‐0077 East ‐ SL, EH & EW 06/24/14 ‐ 06/25/14 12.61 46.21 0.295

1R‐AR‐0078 North ‐ SL, EH & EW 06/24/14 ‐ 06/25/14 10.895 31.27 0.344

1R‐AR‐0079 West ‐ SL, EH & EW 06/24/14 ‐ 06/27/14 13.23 60.78 1.396

1R‐AR‐0080 South ‐ SL, DD & TSSA 07/23/14 – 07/24/14 7.15 58 0.043

1R‐AR‐0082 East ‐ SL, DD & TSSA 07/23/14 – 07/25/14 14.74 53.37 0.103

1R‐AR‐0081 West ‐ SL, DD & TSSA 07/23/14 – 07/24/14 20.21 72.15 0.282

1R‐AR‐0083 North ‐ SL, DD & TSSA 07/23/14 – 07/24/14 14.72 79.83 0.214

1R‐AR‐0084 North‐ SL, DD & TSSA 09/03/14 – 09/04/14 16.2 55.8 0.168

1R‐AR‐0085 East ‐ SL, DD & TSSA 09/03/14 – 09/04/14 12.64 97.55 0.015

1R‐AR‐0086 South ‐ SL, DD & TSSA 09/03/14 – 09/04/14 6.91 34.74 0.018

1R‐AR‐0087 West – SL, DD & TSSA 09/03/14 – 09/04/14 8.34 34.27 0.311

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Sample ID Location Sampling Date

Mean Dust Level

(µg/m3)

Maximum Dust STEL (µg/m3)

Dioxin TEQ (pg/m3)

1R‐AR‐0140 North – SL, DD 03/20/15 – 03/21/15 35.16 94.41 0.108

1R‐AR‐0141 West – SL, DD 03/20/15 – 03/21/15 20.73 82.61 0.52

1R‐AR‐0142 South – SL, DD 03/20/15 – 03/21/15 21.76 85.53 1.527

1R‐AR‐0143 East – SL, DD 03/20/15 – 03/21/15 20.91 86.21 0.186

1R‐AR‐0144 South – DD 05/14/15 – 05/15/15 20.94 40.86 1.01

1R‐AR‐0145 East – DD 05/14/15 – 05/15/15 15.26 43.84 1.03

1R‐AR‐0146 West – DD 05/14/15 – 05/15/15 15.18 40.16 1.56

1R‐AR‐0147 North – DD 05/14/15 – 05/15/15 25.02 167.84 5.38

1R‐AR‐0216 South – SL‐4 (TSSA‐2) 08/18/15 – 08/19/15 9.47 31.96 0.104

1R‐AR‐0217 North – SL‐4 (outlet) 08/18/15 – 08/19/15 7.19 48.35 0.086

1R‐AR‐0218 West – SL‐4 (road) 08/18/15 – 08/19/15 5 42 0.250

1R‐AR‐0219 East – SL‐4 (TSSA‐1) 08/18/15 – 08/19/15 14.19 30.07 0.128

Acronyms/Abbreviations: DD = Drainage Ditch EH = Eastern Hotspot EW = Eastern Wetland pg/m3 = picograms per cubic meter S L = S e n L a k e STEL = short-term exposure limit TEQ = toxicity equivalence TSSA = Temporary Soil Stockpile Area µg/m3 = micrograms per cubic meter

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6.4.5 Other Analysis Related To Phase I IPTD Operations Various other sampling occurred during the IPTD operations, as presented in this section.

6.4.5.1 Water Running out of the CMU Blocks

Four samples (1R-SW-IPTD-0001, 0002, 0003 and 0004) were collected from water running out of the concrete masonry unit (CMU) blocks of the IPTD structure. The flow during these events was sporadic and ranged from a trickle to a more steady flow, and many of these events were caused by heavy rains, making it even more difficult to determine flows. Results for these samples are discussed in the bullets below and presented in Table 4.

• 2013. IR-SW-IPTD-0001 was collected from water flowing out of the CMU blocks, believed to be stormwater, in the northeast corner of the IPTD on 09/19/13. This sample contained dioxins, herbicides and arsenic above project action levels, but the water had already run across the site and into the southeastern wetland (SEW) once sample results were received.

• 2013. TerraTherm attempted to inject blue dye into multiple AIPs in the southeast portion of the IPTD structure to help determine whether water inside the IPTD structure was leaking out of the pile walls. However, dye was found on top of the IPTD structure, indicating that it may have been spilled while trying to inject it, thereby allowing the dye to be washed down the IPTD structure along the walls. IR-SW-IPTD-0002 was collected from blue-dyed water discharging from the southeast corner of the IPTD structure on 11/7/13 (it is unsure whether the water originated from inside the IPTD structure or was flowing down the sides of the walls). Concentrations of dioxin, benzo (a) pyrene and arsenic were below the project action levels but zinc was above the project action levels. Like sample IR-SW-IPTD-0001, this water had already run across the site and into the SEW once sample results were received. However, the CMC collected soil samples from the area affected by this contaminated water which showed concentrations of dioxin below both the soil and sediment action levels (1000 ppt and 150 ppt, respectively) as presented in Section 6.4.5.2),

• 2014. 1R-SW-IPTD-0003 was collected from the Drying Pad on 01/16/14. This water was a mixture of rain water and water leaking out of the CMU blocks that had been collected and transported to the Drying Pad as a precaution. Concentrations of dioxin, benzo (a) pyrene, arsenic and zinc were below the project action levels, and this water was discharged without treatment.

• 2015. IR-SW-IPTD-0004 was collected from water flowing out of the CMU blocks near the northeast corner of the IPTD structure during quenching operations on 06/25/15. Concentrations of benzo (a) pyrene, arsenic and zinc were below the project action levels. However, the concentration of dioxins was elevated (measured at 464 pg/L 2,3,7,8-TCDD) more than 10 times the project action level of 24.01 pg/L. Again, this water had already run across the site and into the SEW once sample results were received. However, the CMC collected soil samples from the area affected by this contaminated water (see Section 6.4.5.2 below) and recommended that the IPTD Contractor capture such water during Phase II operations.

6.4.5.2 Soil Samples around the IPTD Structure

On 11/25/13, the CMC collected two 10-point composite soil samples along the north and east sides of the IPTD pile (IPTD-North and IPTD-East) where water was observed coming out of the CMU blocks. The results of the two samples are provided below.

• IPTD-North – 4.1 ppt dioxin TEQ

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• IPTD-East – 6.75 ppt dioxin TEQ

On 08/11/15, the CMC collected one 30-point composite soil sample (1R-SL-SPILL-0002) in the northeast portion of the IPTD laydown area where water was observed coming out of the CMU blocks during quench operations. The results of the sample show that the concentration of dioxin was 21 ppt dioxin TEQ.

The results for all soil samples around the IPTD were below both the soil and sediment action levels (1000 ppt and 150 ppt, respectively), indicating that the water coming out of the CMU blocks had not contaminated the soil surrounding the IPTD structure. However, the CMC provided recommendations to USAID and the IPTD Contractor that any future water out of the CMU blocks during Phase II filling or operations be captured in a drainage system already installed on the east and north sides of the IPTD structure and treated in the LVTP. No more water has discharged from the blocks after this recommendation was made.

6.4.5.3 Pre-treatment IPTD Soil Samples

In July and September 2013, CC collected discrete “grab” soil samples from the top 1.5 m in the north and west portions of the IPTD structure as these were the only portions of the structure that were completely filled at that time. The remainder of the IPTD structure was not yet completely filled at this time. CC collected 15 samples from 40 to 50 cm and 6 samples from 1.4 to 1.5 m using an electric drill with a 15 cm diameter coring attachment. Limited decontamination was performed during this sampling event. Each grab sample was placed into three ~100 milliliter (mL) plastic jars. CC kept two jars and provided one jar to the CMC.

On 12/20/13, the CMC composited the discrete samples collected by CC into two samples to represent the top two horizontal DUs of the IPTD pile (i.e., 0-1 m layer and 1-2 m layer). These samples were submitted for dioxin and total metals analyses; dioxin TEQ and arsenic results are provided below.

• CC IPTD 0.4-0.5m – 6,880 ppt dioxin TEQ, 40.3 milligrams per kilogram (mg/kg) arsenic

• CC IPTD 1.4-1.4m – 4,030 ppt dioxin TEQ, 37.7 mg/kg arsenic

6.4.5.4 Arsenic in IPTD water

On 12/16/14 and 12/17/14, the CMC collected samples from the AIPs across the IPTD structure (1R- DD-IPTD-0010 through 0016) to determine the average arsenic concentration of water in the IPTD structure prior to treatment. Total arsenic levels ranged from 1.06 to 9.81 milligrams per liter (mg/L) as presented in Table 4. The CMC requested the laboratory analyze sample 1R-DD-IPTD-0011 for arsenic speciation, but the results were inconclusive. As a result, the CMC recommended that additional samples of leachate water be collected and analyzed for arsenic speciation.

On 03/11/14, sample 1R-DD-IPTD-0017 was collected from the leachate collection pipe in the northeast sump of the IPTD structure. This sample was collected for the purpose of characterizing the concentration and speciation of arsenic in IPTD pile water. The total arsenic concentration was 0.394 mg/L, above the project action level of 0.1 mg/L (see Table), and arsenic speciation results showed that the majority of the arsenic (approximately 68%) was organic arsenic. Results were provided to USAID in the CMC’s “Arsenic Speciation Results of the IPTD Leachate and Recommendations” memo,

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dated 05/13/14. In the memo, the CMC proposed an alternate action level of 0.257 mg/L and recommended additional arsenic sampling from the effluent of the LVTP.

Samples of project-affected water were collected from the effluent of the LVTP for characterization of arsenic on 06/09/14 and 06/11/14, however these samples were only to be analyzed if the total arsenic results in the IPTD Contractor’s LVTP effluent water samples collected at the same time were observed above the project action level, which did not occur.

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Table 4. Results of IPTD Pile Water Sampling

Sample ID1 Date

collected Turbidity 2,3,7,8-



(ng/L) Total

Phenols 2,4-D2 2,4,5-T2 Zinc

(mg/L) Arsenic (mg/L) Sample Collection Notes Current Disposition of Water

Project EMMP Action Levels > 29 NTU over


established 200 ng/L 0.45-0.495

mg/L 0.2

mg/L 0.1 mg/L 3 mg/L 0.1 mg/L

1R‐DD‐IPTD‐0001 08/06/13 761.00 11400 11,600 35.4 NM NM NM 0.463 0.0997 Water collected from the sump within the IPTD structure before the structure was fully filled (i.e., rainwater runoff). Water was sampled in the sump, and then moved from the sump to a storage tank on the Drying Pad.

This water was treated as described to the left and discharged to the Drying Pad, which contained a significant amount of rain water from prior storm events. All Drying Pad water was then discharged into shallow, gravel‐filled infiltration galleries1 located in the Phase II excavation area east of the Drying Pad.

1R‐DD‐IPTD‐0002 08/21/13 <1 0.343 1.41 ND NM NM NM 0.446 0.0058 Same water as 1R‐DD‐IPTD‐0001 that was sampled after it was decanted into a separate storage tank and treated with aluminum sulfate flocculant and granular activated carbon.

1R‐DD‐IPTD‐0003 09/26/13 83.17 243 55 sample lost in shipping

2.34J 1.71J 0.152 0.294 5.08 Water collected from the sump at the northeast corner of the IPTD structure (i.e., dewatering water and rainwater infiltration). The water was sampled in the sump and then moved to the Drying Pad in a water truck.

1R‐DD‐IPTD‐0004 09/27/13 2.63 215 272 0.289 3.03 1.86 0.142 0.0101 4.27 Same water as 1R‐DD‐IPTD‐0003 that was sampled after it was treated with aluminum sulfate flocculant.

1R‐DD‐IPTD‐0005 09/27/13 0.34 ND 1 0.277 ND 0.0251 0.0031J 0.0039 3.72 Same water as 1R‐DD‐IPTD‐0003 that was sampled after it was treated with aluminum sulfate flocculant and one granular activated carbon unit. Sample collected after 1.5 cubic meters had been run through the treatment system.

1R‐DD‐IPTD‐0006 09/27/13 0.34 2.53 3.21 0.236 ND 0.0659 0.0012J 0.0044 3.82 Same water as 1R‐DD‐IPTD‐0003 that was sampled after it was treated with aluminum sulfate flocculant and one granular activated carbon unit. Collected after 3.5 cubic meters had been run through the treatment system.

1R‐DD‐IPTD‐0007 09/27/13 0.34 ND 1.15 0.158 ND ND 0.0003J ND 3.58 Same water as 1R‐DD‐IPTD‐0003 that was sampled after it was treated with aluminum sulfate flocculant and two granular activated carbon units. Collected after 3.5 cubic meters had been run through the treatment system.

1R‐SW‐IPTD‐0001 09/19/13 5.73 31.4 40.9 0.298 0.256J 0.253 0.102 ND 0.214 Sample collected from water flowing out of the ground near the northeast corner of the IPTD structure.

Not applicable; this water flows east toward the Eastern Wetland.

1R‐DD‐IPTD‐0008 11/7/13 8.0

13.6 (dissolved)

16.7 (dissolved)

1.18 NM NM NM

0.0299 0.428 IPTD water collected directly from leachate collection pipe in the NE sump. Subsequently treated in LVTP. 43.5

(on filter) 47.2

(on filter) NM NM NM

1R‐SW‐IPTD‐0002 11/7/13 1.0 17.3 19.2 ND NM NM NM ND 0.134 Blue‐dyed water discharging from the SE corner of the IPTD structure. Not applicable; this water flows east toward the Eastern Wetland.

1R‐GW‐IPTD‐0001 11/26/13 <1 7.91 8.86 0.627 NM NM NM 0.107 0.397 Water collected from 1.5‐2.5 m depth via a shallow piezometer well installed at the northeast corner of the IPTD structure.

Not applicable; this is groundwater collected at the northeast corner of the IPTD.

1R‐DD‐IPTD‐0010 12/16/13 blue dye

interference NM NM NM NM NM NM 2.28 1.59 IPTD water collected from air inlet well at south end of pile, east side.

Treated and discharged by IPTD Contractor.

1R‐DD‐IPTD‐0011 12/17/13 >100 NM NM NM NM NM NM 2.65 9.81 IPTD water collected from air inlet well at south end of pile, west side.


interference NM NM NM NM NM NM 2.66 4.96 IPTD water collected from air inlet well at center of pile, west side.

1R‐DD‐IPTD‐0013 12/17/13 >100 NM NM NM NM NM NM 1.95 1.16 IPTD water collected from air inlet well at center of pile, east side.


interference NM NM NM NM NM NM 6.77 4.57 IPTD water collected from air inlet well at north end of pile, east side.

1R‐DD‐IPTD‐0015 12/17/13 >100 NM NM NM NM NM NM 2.92 2.82 IPTD water collected from air inlet well at north end of the pile, west side.

1R‐DD‐IPTD‐0016 12/17/13 >50 NM NM NM NM NM NM 0.034 1.06 IPTD water collected directly from leachate collection pipe in the NE sump.

1R‐SW‐IPTD‐0003 01/16/14 6.14 3.89 6.8 7.45 NM NM NM 0.0080 0.0161 Collected from the Drying Pad Discharged to Sen Lake.

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Sample ID1 Date

collected Turbidity 2,3,7,8-



(ng/L) Total

Phenols 2,4-D2 2,4,5-T2 Zinc

(mg/L) Arsenic (mg/L) Sample Collection Notes Current Disposition of Water

Project EMMP Action Levels > 29 NTU over


established 200 ng/L 0.45-0.495

mg/L 0.2

mg/L 0.1 mg/L 3 mg/L 0.1 mg/L

1R‐DD‐IPTD‐0017 03/11/14 NM NM NM NM NA3 NA3 NA3 ND 0.394

Water collected from leachate collection pipe in the northeast sump for arsenic speciation: filtered through a 0.45 µm filter and preserved with HCl for As speciation analyses. Speciation results: As III (inorganic): 0.061 mg/L As V (inorganic): 0.066 mg/L MMA (organic): 0.046 mg/L DMA (organic): 0.211 mg/L Unknown (organic): 0.010 mg/L

Treated and discharged by IPTD Contractor

1R‐SW‐IPTD‐0004 06/25/15 1.25 464 474 16.9 NM NM NM 0.0306 0.0257 Sample collected from water flowing out of the blocks near the northeast corner of the IPTD structure.

Not applicable; this water flows east toward the Eastern Wetland.

Notes: Results shown in red exceeded the Project EMMP action levels. Samples shown in gray‐shaded rows were treated by some means prior to sampling. 1 ‐ Infiltration galleries were constructed by digging a shallow trench, placing a perforated pipe horizontally into the trench, filling the trench with gravel, and capping the trench with native soil.

Acronyms/Abbreviations: 2,4‐D = 2,4‐dichlorophenol NA = not applicable 2,4,5‐T = 2,4,5‐trichlorophenol ND = not detected E M M P = Environmental Mitigation and Monitoring Plan ng/L = nanograms per liter ID = identification NM = not measured IPTD = in‐pile thermal desorption NTU = nephelometric turbidity unit mg/L = milligrams per liter pg/L = picograms per liter

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6.5 Stakeholder Coordination Coordination with various stakeholders occurred during the Phase I thermal treatment operations to ensure that the project activities were transparent and proceeded with the support of the GVN. The following bullets provide an outline of key stakeholder coordination activities conducted by USAID, the CMC, IPTD Contractor and ECC during Phase I. Note that consultation with community stakeholders is being conducted by MND, and not USAID or the implementing contractors.

• 03/03/14 – The CMC and the IPTD Contractor held a meeting with CC to review the specification sheets for VGAC and LGAC.

• 03/14/14 – The CMC hosted a site briefing for CC to discuss system operations, schedule, sampling procedures, emergency action plan, IPTD O&M Manual and monthly reporting procedures.

• 06/04/14 – The CMC provided CC with an updated schedule of the IPTD Contractor’s IPTD operations sampling; and on 06/13/14, the CMC provided the IPTD Contractor with CC’s schedule for IPTD operations sampling.

• 03/15/14 – The CMC provided a site tour to representatives from DONRE and provided information on IPTD system operations.

• 03/26/14 – The CMC provided a site tour to Office 33 and Army Division 372 and provided information on IPTD system operations.

• 04/03/14 – The CMC reviewed a letter from VRTC concerning their specific sampling location and port size needs on the effluent stack, reviewed Vietnamese regulations regarding stack height requirements, and provided USAID with alternative options to the 20 m stack height that Office 33 suggested.

• 04/24/14 – The CMC hosted a site visit and tour for CC. The visit included a tour of the IPTD and LVTP and a discussion of the LVTP sample locations and sampling frequency.

• 06/18/14 – The CMC hosted an operations meeting for ADAFC, USAID, the IPTD Contractor, CC and DONRE.

• 07/14 through 07/15 – The CMC held 33 meetings with the IPTD Contractor, CC and DONRE to discuss on site activities and the IPTD Contractor’s weekly progress reports.

• 08/01/14 – The CMC held a site meeting and tour with USAID, MND, CC, the IPTD Contractor and the ECC. The IPTD operations and sampling schedule and the Vietnamese treatment standard for dioxin that applies to this project were discussed.

• 09/11/14 – The CMC provided VRTC with June and July 2014 air sample results and recommendations.

• 09/12/14 and 09/15/14 – The CMC provided CC with the IPTD Contractor’s 08/14/14 and 08/15/14 dioxin vapor data.

• 10/10/14 – The CMC received and provided USAID and the IPTD Contractor with CC/DXL’s results for effluent air from the LVTP.

• 10/10/14 – The CMC received a letter from ADAFC requesting that the CMC review the IPTD Contractor’s vapor results from 09/17/14 and 09/18/14, shorten the turn-around time for dioxin vapor samples, and maintain a daily vapor and liquid sampling frequency during this phase of IPTD operations.

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• 10/15/14 – The CMC met with Airport officials to hear their concerns regarding odor coming from the IPTD. The CMC provided a letter to the Airport regarding the odor on 10/23/14.

• 10/18/14 – The CMC provided CC with the IPTD Contractor’s updated sampling schedule.

7 Confirmation Soil Sample Results This section provides a description of the confirmation sampling the CMC conducted to determine effectiveness of the IPTD treatment.

7.1 Interim Soil Samples In order to determine the appropriate sampling methodology for the IPTD structure and to determine the status of thermal treatment, the CMC conducted two rounds of interim soil sampling.

The first interim soil sampling was performed 10/03/14, 10/06/14 and 10/08/14. During this event, traditional drilling equipment was used in an attempt to collect samples from the IPTD structure, including a split spoon sampler and simple limited access rotary drill rig. The goal was to collect discrete samples from six horizontal DUs, each 1 m thick (i.e., 0-1 m, 1-2 m, 2-3 m, 3-4 m, 4-5 m, and 5-6 m pile layers), as shown in Figure 3. However, due to the very fine particle size, high density and lack of moisture in the soil, the drilling crew experienced very high friction on the drill string and limited sample was recovered (<10 cm) with each attempt. On 10/08/14, the CMC’s drilling subcontractor attempted to use an aluminum core shaft to collect soil samples, which melted and broke in the hole. The borehole was abandoned and drilling operations were halted until an alternate method could be identified.

After the initial interim sampling event, the CMC worked to develop an innovative method and sampling apparatus that would vacuum soils out of the IPTD structure. On 12/09/14, the IPTD Contractor provided the CMC and USAID with information identifying cool, warm and hot locations of the pile that would be appropriate for interim sampling.

On 12/18/14, the CMC mobilized drilling crews to the top of the IPTD structure to conduct the second interim sampling event. All equipment was decontaminated prior to the start of drilling activities. The vacuum method was executed as follows:

• Advanced auger 1 m into the IPTD soils to break them up prior to vacuum extraction.

• Vacuumed and advanced extraction hose 1 m into the IPTD soils.

• Collected all evacuated soil from the collection drum (a.k.a. hopper or cyclone).

October, 2014 interim sampling event

December 2014 interim sampling event

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• Advanced casing 1 m into the IPTD soils.

• Decontaminated all equipment using water, soap, hexane and acetone.

• Repeated until samples had been collected from all six DUs.

The vacuum method proved successful in collecting the following samples:

• Six discrete samples (IPTD-COOL-0001, 0002, 0003, 0004, 0005 and 0006), one from each 1 m thick DU at the “cool” test hole location in the IPTD on 12/22/14.

• Six discrete samples (IPTD-WARM-0001, 0002, 0003, 0004, 0005 and 0006), one from each 1 m thick DU at the “warm” test hole location in the IPTD on 12/24/14.

• Six discrete samples (IPTD-HOT-0001, 0002, 0003, 0004, 0005 and 0006), one from each 1 m thick DU, at the “hot” test hole location in the IPTD on 12/26/14.

On 12/26/14 the drilling teams demobilized from the top of the IPTD. Samples were provided to the IPTD Contractor for analysis of dioxin and moisture content. Results are presented in Table 5, as provided by the IPTD Contractor.

Table 5. Interim soil results

INTERIM SAMPLE RESULTS - January 2015 Hot Warm Cool

Depth (m)

Dioxin TEQ

(pg/g)1

Temp (T48, °C)2

Dioxin TEQ

(pg/g)

Temp

(T23, °C)

Dioxin TEQ

(pg/g)

Temp (T09,

°C) 1 2283 352 8433 201 3503 98 2 1603 460 31.3 350 37 123 3 36.5 520 5.43 470 1.61 342 4 11.4 531 3.13 495 2.51 457 5 1.92 476 1.30 421 0.821 441 6 1.18 377 2.73 308 1.32 341

Notes: 1 - Dioxin results are reported as pg/g TEQ, using a mid-bound approach (1/2 of the detection limit when non- detect) and WHO 2005 toxic equivalency factors (TEFs). 2 - Temp listed is the temperature of the nearest thermocouple on the date of sample collection. 3 - Results in pink are above the 150 ppt project cleanup goal.

7.2 Improvements to Sampling Method after Interim Sampling

On 01/07/15, prior to receiving the results of the second interim sampling event, the IPTD Contractor presented a number of concerns with the interim sampling method and decontamination procedures. The following bullets summarize their primary concerns:

• The potential for cross-contamination between layers, and particularly the potential for material from the upper zone to be carried downward in the borehole and/or fall to the bottom of the borehole during the augering and sample collection process. The IPTD Contractor noted that they

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expected the confirmatory samples to be clean after exposure to an elevated temperature for an extended period of time; since the upper layer suffered significant cooling, these and may not have been exposed to these very hot temperatures for as long as some of the deeper intervals. If residual dioxin was present in the shallow soil and cross-contamination occurred between the shallow zone and deeper intervals, it may invalidate the confirmatory sampling.

• The exhaust of the vacuum apparatus may emit fine particulate into the sampling area. This could not only pose a H&S concern, but could also deposit potentially impacted dust or particulates on the nearby drilling and sample collection tools.

• Decontamination between vertical sample intervals and between sample boreholes. How are the cyclone separator, the extraction hose and related down-hole hardware decontaminated? How is proper decontamination inspected and verified?

As a result of these concerns, the CMC and the IPTD Contractor had a conference call on 01/09/15. The results of this call included the following:

• In order to reduce the need for decontamination, it would be beneficial to collect the confirmation samples using dedicated sampling equipment for each DU.

• To prevent cross contamination between the DUs, the casing will be advanced prior to vacuuming the sample out of the borehole.

• All sampling equipment touching the sample will be made of stainless steel to facilitate decontamination.

• The CMC and drilling subcontractor will work to improve the filtration on the vacuum exhaust to reduce the chance of dioxin dust release and cross contamination.

• All samples will be covered upon collection and processed in a controlled environment.

Once the results of the second interim sampling event were received, there was no evidence of cross- contamination. However, the above recommendations were still included in the Phase I IPTD confirmation sampling plan as presented in the CMC’s 03/16/15 SAP Addendum (available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_33816).

7.3 Final Soil Sample Results Following completion of IPTD treatment, USAID directed the CMC to begin collecting IPTD confirmation samples on 03/16/15. At this time, average temperatures at every depth monitored in the pile except the shallowest (30 cm) exceeded the original target temperature of 335ºC, although a number of individual thermocouples were still below the target. Post-treatment confirmation samples were collected from 03/17/15 to 05/11/15 and analyzed for dioxin to determine the effectiveness of IPTD treatment on the Phase 1 soil and sediment and ensure that the LWIC cap was not contaminated during treatment. Sampling was conducted in accordance with the 03/16/15 SAP Addendum (available on the CMC eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_33816). In addition to the six 1- m thick DUs described above and shown in Figure 3, an additional LWIC decision unit (60 cm thick) located above the treated soil was also sampled. Samples from eight sub-decision units were collected from the 0-1m decision unit, but sub-decision unit sampling was discontinued for deeper decision units to reduce the sampling schedule after positive sample results were received from the 0-1m layer. A Multi Increment Sampling (MIS) method was used for the post-treatment confirmation sampling. Each post-treatment MIS confirmation sample consisted of a 30-point

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composite sample to characterize the DU. In addition to the seven post-treatment MIS confirmation samples (six soil/sediment and one LWIC), two additional 30-point MIS samples were collected from the 2-3 m layer (DU) of treated soil/sediment to provide triplicate results and calculate the 95% UCL. Eight sub-DU samples were also collected from the 0-1 m DU (the plan view of the IPTD pile in Figure 3 shows the eight sub-decision units A-H). Dioxin results are presented in Section 7.3.1 and Table 6.

In addition to TCDD/TCDF analysis, the six soil/sediment 30-point MIS confirmation samples were analyzed for total arsenic (USEPA Method 200.2/6020A), in vitro bio-accessibility (IVBA), and Synthetic Precipitation Leaching Procedure (SPLP). The arsenic analytical results were used to determine if restrictions on reuse due to arsenic are required to protect human health. Arsenic, IVBA, and SPLP results are presented in Section 7.3.2 and Tables 7 and 8.

Representative material from the IPTD structure was collected during post-treatment confirmation sampling and submitted to ACC, a local geotechnical laboratory, for geotechnical property testing. Results are presented at the end of this section in Table 9. Further testing is required to determine whether the treated material is suitable for use as common fill on the project site.

7.3.1 Dioxin Results As shown in Table 6, post-treatment soil/sediment sample results indicated that dioxin levels in all DUs of the IPTD structure were below the project action level (150 ppt) and the treatment was considered complete. The 95% UCL for the 2-3 m triplicate sample was only 2.6 ppt. Samples of the LWIC contained dioxin at 1.85 ppt, below the project action level; therefore, the LWIC can be used or disposed of with no restrictions.

7.3.2 Arsenic Results Sample results for the soil within the IPTD structure indicated that arsenic concentrations range from 17.7 to 36.3 mg/kg (see Table 7) which is higher than the USEPA Industrial Regional Screening Level (RSL) of 3.0 mg/kg and one to two orders of magnitude higher than arsenic levels measured on the Danang Airport property outside the project site (0.947 mg/k to 2.16 mg/kg). In order to determine if restrictions needed to be placed on the reuse of treated soil/sediment due to arsenic levels, the CMC conducted SPLP and IVBA analysis and evaluated the results as follows:

• SPLP results were used to identify the leaching potential for arsenic to surface water or groundwater; results are shown in Table 7.

• The leaching potential data were then used in various models to estimate potential future arsenic concentrations in groundwater and surface water due to arsenic leaching from the treated soil/sediment.

• IVBA results were used to calculate the site specific relative bioavailability (RBA) of arsenic (i.e., what can be absorbed from the human gut); results are shown in Table 8.

• The RBA results and the estimated concentrations arsenic concentrations in groundwater and surface water were then used to calculate the cancer risk and non-cancer hazard index (HI) to human health under different exposure scenarios using USEPA-accepted toxicity factors. The data were also used to conduct a screening-level ecological risk evaluation.

• A future resident, a trespasser, and a construction worker were evaluated as receptors in the risk evaluation to span the possible range of exposures at the site.

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The CMC presented the results of this arsenic risk evaluation to USAID in the Arsenic Risk Evaluation Report and Arsenic Risk Evaluation and Risk Management Considerations for Reuse of Treated Soil and Sediment at the Danang Airport, Vietnam both submitted on 08/10/15. The evaluation estimated that cancer and non-cancer risks due to exposure to arsenic in soil and due to swimming were below USEPA’s acceptable risk level (i.e., not of concern). However, based on the risk estimates for exposure to arsenic via groundwater ingestion and exposure to arsenic via ingestion of fish in Sen Lake, the CMC recommended that the following restrictions be considered by USAID for the site:

• Prohibit the installation of drinking water wells in the uppermost Holocene aquifer on the site.

• Prohibit the installation of drinking water wells in the uppermost Holocene aquifer downgradient of the site unless clay is added to the cover placed on top of the treated soil/sediment.

• Prohibit fishing in Sen Lake until fish tissue data can be collected to demonstrate concentrations are acceptable for human consumption.

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Figure 3. IPTD Sampling Areas


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Table 6. IPTD Confirmation Sampling Results – Dioxin


Sample ID

Location Date

Sampled

Matrix

Action Level (pg TEQ/g)a

Dioxin Concentration (TEQ pg/gb [i.e., ppt])

1R‐SL‐P1‐IPTD‐0001 Phase I IPTD samples collected at A locations, 0‐1m 3/23/15 Soil/Sediment 150 51.5 P1‐IPTD‐A‐0001 IPTD, sub‐decision unit A, 0‐1m 03/20/15 Soil/Sediment 150 95.6 P1‐IPTD‐B‐0001 IPTD, sub‐decision unit B, 0‐1m 03/24/15 Soil/Sediment 150 36.3 P1‐IPTD‐C‐0001 IPTD, sub‐decision unit C, 0‐1m 03/23/15 Soil/Sediment 150 91.0 P1‐IPTD‐D‐0001 IPTD, sub‐decision unit D, 0‐1m 03/23/15 Soil/Sediment 150 1.9 P1‐IPTD‐E‐0001 IPTD, sub‐decision unit E, 0‐1m 03/24/15 Soil/Sediment 150 2.4 P1‐IPTD‐F‐0001 IPTD, sub‐decision unit F, 0‐1m 03/23/15 Soil/Sediment 150 1.1 P1‐IPTD‐G‐0001 IPTD, sub‐decision unit G, 0‐1m 03/20/15 Soil/Sediment 150 16.0 P1‐IPTD‐H‐0001 IPTD, sub‐decision unit H, 0‐1m 03/23/15 Soil/Sediment 150 143.0

1R‐SL‐P1‐IPTD‐0002 Phase I IPTD samples collected at B locations, 1‐2m 4/25/15 Soil/Sediment 150 0.332 1R‐SL‐P1‐IPTD‐0003

Phase I IPTD samples, 2‐3m decision unit, triplicate 4/25/15

Soil/Sediment 150 0.237 95%

UCL 2.6

1R‐SL‐P1‐IPTD‐0007 4/25/15 150 2.34 1R‐SL‐P1‐IPTD‐0008 4/25/15 150 0.27 1R‐SL‐P1‐IPTD‐0004 Phase I IPTD samples collected at B locations, 3‐4m 4/25/15 Soil/Sediment 150 0.304 1R‐SL‐P1‐IPTD‐0005 Phase I IPTD samples collected at B locations, 4‐5m 4/25/15 Soil/Sediment 150 0.0918

1R‐SL‐P1‐IPTD‐0006 Phase I IPTD samples collected at B locations, 5‐6m 4/25/15 Soil/Sediment 150 0.981 (lab dup 0.819)

1R‐SL‐P1‐IPTD‐0009 Phase I IPTD samples, 2‐3m decision unit, replicate 4/25/15

Soil/Sediment 150 0.264 1R‐SL‐P1‐IPTD‐0010 4/25/15 150 0.234 1R‐Concrete‐P1‐IPTD‐ 0001 Original 60cm IPTD LWIC cap decision unit 07/10/15 Concrete 150 1.85

Notes: a - Action level for dioxin in sediment is 150 ppt. Action level for soil is 1000 ppt. b - TEQ results are based on WHO 2005 TEFs and with NDs assigned a value of half the reporting limit.

Acronyms/Abbreviations: cm = centimeter LWIC = light weight insulating concrete TEQ = toxicity equivalence DD = Drainage Ditch pg/g = picograms per gram WHO = World Health Organization ID = identification ppt = parts per trillion ND = non-detect TEF = toxic equivalency factor

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Table 7. IPTD Confirmation Sampling Results – Arsenic


Sample ID 1R‐SL‐P1‐ IPTD‐0001

1R‐SL‐P1‐ IPTD‐0002





Sample Description1 0‐1 m

IPTD layer 1‐2 m

IPTD layer 2‐3 m

IPTD layer 3‐4 m

IPTD layer 4‐5 m

IPTD layer 5‐6 m

IPTD layer

Total arsenic2 20.4 mg/kg 20.3 mg/kg 23.1 mg/kg

18.7 mg/kg 17.7 mg/kg 36.3 mg/kg

Leachable Arsenic3 0.0395 mg/L 0.0639 mg/L 0.244 mg/L 0.250 mg/L 0.238 mg/L 0.142 mg/L

Notes: 1 – Each sample represents a different horizontal layer of the 6 m deep IPTD pile. The samples were collected using MIS methodology, by compositing 30 aliquots from the subject layer into one sample for analysis. The 30 aliquots for each sample were collected from a systematic random grid across the IPTD pile, each collected from the entire 1 m depth of the IPTD pile layer. 2 – Analyzed by USEPA Method 200.2/6020A (modified); Metals in Soil by collision-reaction cell inductively coupled plasma mass spectrometry. 3 – Analyzed by SPLP USEPA Method 1312M; extraction fluid to soil ratio of 2:1 (milliliter to gram); 4.2 pH extraction solution. Digest analyzed by USEPA Method 200.2/6020A.

Table 8. IPTD Confirmation Sampling Results – IVBA and RBA

Sample ID 1R‐SL‐P1‐ IPTD‐0001






Arsenic concentration (< 250 micron soil particle size fraction)1

23.7 mg/kg

25.0 mg/kg

26.9 mg/kg

23.6 mg/kg

25.8 mg/kg

34.8 mg/kg

Percent Arsenic IVBA 16% 38% 59% 50% 48% 40% Percent RBA, predicted based on Diamond et al., 2015 14% 30% 44% 38% 37% 31%

Note 1: The arsenic concentration used for the IVBA and RBA analysis represent the arsenic concentration for the fraction of soil particles that are less than 250 microns instead of the arsenic concentration for all the soil fractions. The < 250 micron soil particle size fraction is the portion that adheres to children’s hands and would be ingested.

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Table 9. Geotechnical Results – representative material from IPTD structure


Density1 CBR1

Optimal Moisture1 Atterberg Limits2

Blow count Wet Dry % Plastic limit Liquid limit

10 1.839 1.535 14.76 13.53 Too low to calculate 30 1.933 1.655 25.31

65 1.984 1.732 40.1 Notes: 1 – As measured by Proctor Compaction Test, Vietnamese Method 22TCN3332-06 2 – As measured by Vietnamese Method TCVN 4197:1995

Acronyms/Abbreviations: CBR – California Bearing Ratio

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7.3.3 Decontamination Procedures and Equipment Rinsate Results This section describes the decontamination procedures for equipment used during the IPTD post- treatment confirmation sampling investigation. It describes the different work zones that were established on-site to ensure sampling, decontamination, and support activities were conducted to international standards in order to prevent cross-contamination of samples collected and to reduce risk of contamination outside the sampling areas. Rinsate samples were collected during IPTD post-treatment confirmation sampling in the same way that soil samples were collected: by vacuuming approximately 2.5 liters (L) through the decontaminated sampling apparatus and collecting the water from the bottom of the cyclone. Each individual sample was collected into two, 1 L amber bottles, one of which was sent to and analyzed at the laboratory, the second was retained at the project site as a backup. Table 10 provides the results of equipment rinsate results that were collected to evaluate the decontamination effectiveness. These results, presented in pg/L, or parts per quadrillion (ppq), are more than 1,000 times lower than the concentrations measured in post-treatment confirmation soils, and therefore indicate successful decontamination of difficult-to-clean equipment (with many different fittings, joints, etc.). The remaining mass of dioxin measured in the rinsate samples is too low to affect the results of the post-treatment confirmation soil samples when compared with the total dioxin mass in soil.

7.3.3.1 Overview

All reusable stainless steel sampling equipment was decontaminated before and after the collection of a sample; initially between DUs and sub-DUs, and subsequently between DUs only (as sub-DUs were omitted). The general decontamination steps were as follows:

• Wash equipment with ambient water and metals-free soap (e.g., Alconox) to remove soil particles;

• Rinse equipment three times with environmental grade hexane to remove soil residues;

• Rinse equipment three times with environmental grade acetone to remove any residual materials and assist with hexane evaporation and equipment drying; and

• Wrap surfaces of the equipment that will be exposed to samples with aluminum foil.

Large reusable sampling equipment (e.g., drill rigs, large corers) required decontamination in a designated area that was large enough to fully contain the equipment (e.g., on one or more layers of heavy plastic sheeting to cover the ground surface).

As shown in Figure 4, a Decontamination Station (DS) was located at the top of the vehicular access ramp and adjacent to the foot access ramp to the IPTD. This was the first location where project personnel entered and exited the Contamination Reduction Zone (CRZ) in PPE. The decontamination line was established so that contaminated equipment came from the IPTD to the DS and was placed in a dedicated location, progressed through to the wash and rinse containers and then to a separate area for rinsing with environmental grade hexane and acetone. The fully decontaminated equipment was then wrapped in aluminum foil and transferred to an area adjacent (yet separated) from the DS for storage until required for sampling.

In addition to the DS, a High-Pressure Wash-Down Station (HPWDS) was set up to remove contaminated materials from large equipment including pipes, casing and cyclone hoppers. The HPWDS was located within the LVTP adjacent to the north end of the IPTD. The equipment washed at the HPWDS was transferred by flat-bed truck between the stations and when brought back to the DS at

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the IPTD. The washed equipment was placed in a dedicated location in the decontamination line, where it was rinsed with environmental grade hexane and acetone.

Brushes, soap and water were used in the wash containers for cleaning smaller equipment in the DS. Any larger equipment cleaned in the DS and HPWDS was elevated to prevent uncontrolled movement of contaminated water. In the DS, the equipment was elevated to ensure contaminated water drained into a collection barrel that was pumped to the water treatment facility adjacent to the IPTD. At the HPWDS, equipment was elevated over a grated sump structure. This sump structure drained into the water treatment facility.

All personnel working in the DS were required to wear Level C PPE which included full Tyvek suits, two layers of gloves which included heavy duty wash gloves that extended up the forearm, rubber boots, hard hats, and eye protection in the wash and rinse area. Personnel performing the hexane and acetone rinse were required to wear half face respirators.

7.3.3.2 Work Zones

The CRZ, located between the Exclusion Zone and the Support Zone, was established for the decontamination of workers and equipment. Decontamination of workers was performed by washing boots and equipment with a three step system: 1) clean with soap and water; 2) rinse with water; and, 3) second rinse with water. The work zones for decontamination of equipment included two distinct areas: DS with Storage; and HPWDS.

7.3.3.3 Quality Control

Quality control of washed and decontaminated equipment included the inspection for soil or oil on the surfaces of equipment. This included a glove test in which a clean rubber glove was run across the surface of the equipment and checked for any residue. The glove test for casing included inserting a glove covered hand into the casing to check for residue. Stainless steel stingers and hoses which could not be glove-tested beyond their opening were visually inspected to the extent possible.

Personnel working in the DS cleaned the plastic sheeting at least twice daily to minimize entry of soil into the decontamination line and storage area and to reduce the potential of cross-contaminating already-decontaminated equipment. The plastic sheeting and fabric material were extended around the decontamination line and storage area to provide shelter from winds and to minimize the uncontrolled movement of personnel not involved in the decontamination process.

7.3.4 Investigation-Derived Waste Investigation-derived waste (IDW) from the DS and HPWDS included contaminated water used for equipment decontamination and disposable PPE (e.g., gloves and Tyvek suits). Contaminated water was treated in the LVTP adjacent to and north of the IPTD. All disposable PPE including gloves, Tyvek suits and worn-out cleaning equipment such as brushes used for sampling and decontamination was collected in a designated IDW plastic bag and disposed of several times through each day and at the end of each day in a designated facility on site.

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Exclusion Zone

Figure 4. Decontamination Station Layout on the IPTD structure

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Support Zone

Exclusion Zone


Table 10. Equipment Rinsate Results

Sample ID Date Collected

2,3,7,8-TCDD (pg/L)

Dioxin TEQ (pg/L) Notes

1R‐Rinsate‐0013 03/17/15 3.96 4.72 Collected prior to the start of drilling into the IPTD structure.

1R‐Rinsate‐0014

03/26/15

6.13

7.19

Equipment previously used for A locations 0‐1m. Repurposed for C locations, 2‐3m.

1R‐Rinsate‐0015

03/26/15

0

1.06

Equipment previously used for A locations 0‐1m. Repurposed for A locations, 2‐3m.

1R‐Rinsate‐0016

03/26/15

4.34

6.24

Equipment previously used for A locations 0‐1m. Repurposed for B locations, 1‐2m.

1R‐Rinsate‐0017

04/06/15

155

169

Equipment previously used for A locations 0‐2m. Repurposed for B locations, 1‐2m.

1R‐Rinsate‐0018

04/06/15

37.9

40.5

Equipment previously used for C locations 2‐3m. Repurposed for B locations, 2‐3m.

1R‐Rinsate‐0019

04/06/15

135

140

Equipment previously used for C locations 2‐3m. Repurposed for B locations, 3‐4m.

Note: These results, presented in pg/L, or parts per quadrillion (ppq), are more than 1,000 times lower than the concentrations measured in post-treatment confirmation soils, and therefore indicate successful decontamination. The remaining mass of dioxin measured in the rinsate samples is too low to affect the results of the post-treatment confirmation soil samples when compared with the total dioxin mass in soil.

Acronyms/Abbreviations: ID = identification pg/L = picograms per liter TCDD = tetrachlorodibenzo‐p‐dioxin TEQ = toxicity equivalence

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7.4 Dioxin Mass Balance Estimate for Phase 1 The confirmation soil sampling data were used in conjunction with other data collected before and during Phase 1 to estimate the following:

• The amount of dioxin mass present in the pile prior to heating;

• The amount of dioxin mass removed from the pile during operations; and

• The amount of dioxin mass destroyed in the pile.

Because it is not feasible to trace dioxin destruction to specific degradation byproducts, the estimation of dioxin mass destroyed in the pile must be made by inference, by subtracting from the initial dioxin mass all other identifiable amounts of dioxin mass measured elsewhere. This approach introduces some degree of uncertainty in these calculations, but is unavoidable given the complexity of organic compounds present in the vapor and liquid streams from the IPTD structure. All data presented in this section are based on WHO 2005 TEFs and dry weights, and assume congeners that are not detected are present at half of their respective detection limits (mid-point analysis).

The pile was not sampled prior to operation in the same careful manner as it was sampled after treatment, and therefore any estimate of pre-treatment mass is uncertain. There are two methods that can be used to estimate this mass:

• The same approach described in Section 7.1.3 of the ITPD Contractor’s IPTD® Final Report - Phase I can be used: as documented in the IPTD Contractor’s 100% Design Report Section 4.4.4, Table 14, the Master Soil Composite sample could be assumed to be representative of Phase I pile contents. This sample had a total TEQ of 56,000 picograms TEQ per gram (pg TEQ/g). The estimated dry soil volume in the Phase I pile was 44,100 m3 (70 m wide by 105 m long by 6 m tall). The maximum soil density was determined to be 1,821 kilograms per cubic meter (kg/m3) (Tech Memo to Jamey Watt, USAID COR, dated 04/23/12), which is very close to the average of the measurements made during filling of the pile (1.827). In the estimate made by the IPTD Contractor, it was assumed that the soil was placed at 90% compaction, which was the minimum requirement and is a reasonable and conservative assumption for this mass balance. Multiplying the soil volume, 90% of the maximum density, and Master Soil Composite concentration yields an initial dioxin mass of 4.05 kilograms (kg) TEQ.

• Alternatively, the composited pre-treatment samples collected by CC (described in Section 6.4.5.3) could be assumed to be representative of the pile. These samples were collected at two depths (40 cm and 1.4 m) and composited from the north and west areas of the pile only while the pile was in the process of being filled. As noted above, these samples comprised contributions from 6 and 14 subsamples, respectively. The results were 6,880 and 4,030 pg TEQ/g, both roughly an order of magnitude lower than the Master Soil Composite sample. Using the average of these two results, and all the other parameters used in the first method, results in an estimated initial dioxin mass of only 0.394 kg TEQ.

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Unfortunately, neither of these two methods provides a certain estimate of pre-treatment dioxin mass. The Master Soil Composite sample was collected as a 10-gallon mixture of 14 subsamples from various parts of the site, proportioned to expected remediation volumes. However, variability in dioxin soil concentrations in site soils and deviations in actual excavation volumes from expectations may mean this result is not completely representative of Phase 1 pretreatment concentrations. It is thought that this sample may biased high because of the amount of additional unplanned over excavation, which was not included in the composite, which would result in an overestimate of pre-treatment mass. The representativeness of the composited 20 pre-treatment subsamples collected by CC are even more questionable since the samples were collected from only two discrete depths in the pile, the deepest of which only penetrated the top quarter of the pile, and only from the northern and western portions of the pile. While the limitations of the samples collected from the pile by CC are therefore more obvious, there exist no field duplicate data to characterize the representativeness of either data set or estimate. For the purposes of this mass balance estimate, the Master Soil Composite is used, but both pre-treatment data sets should be considered uncertain, inadequate, and less definitive than the post-treatment confirmation soil samples described in Section 7.3.

The following quantities of dioxin mass were measured during and after Phase I treatment:

• Based on the IPTD confirmation sampling results, the final average dioxin concentration remaining in the pile at the time of sampling was 9.3 pg TEQ/g. Multiplied by the same dry soil mass as estimated initially provides the following: 9.

• 3 pg TEQ/g x 72,275,490 kg x 1000 g/kg x 1 g/1x1012 pg = 0.672 g = 6.7 x 10-4 kg TEQ. It should be noted that some amount of initial soil mass was removed during treatment in the form of volatile organic material. The amount of soil removed is not known, but any removal would reduce the apparent mass of dioxin remaining in the pile, and thus increase estimates of in situ destruction in the pile.

• Section 7.1.13 of the IPTD Contractor’s IPTD® Final Report - Phase I estimates the total dioxin mass coming into the liquid-phase portion of the LVTP by multiplying the maximum amount of flow observed over specific operational periods by the amount of dioxin measured in samples collected during each period. The result is 3.36 x 10-3 kg TEQ. This approach is generally reasonable, but two aspects of this should be noted:

o The samples used for this analysis were collected at the effluent of the OWS. As a result, care must be taken to avoid double-counting dioxin mass associated with NAPL removed by the OWS (see below).

o The period used in this analysis extended from 6/9/2014 through 3/23/2015. As noted in the weekly reports provided by the IPTD Contractor, dioxin concentrations remain elevated outside of this date. Heating of the pile continued past this date, and although confirmation sampling started on 03/17/15, it was not completed until 05/11/15. Because is not possible to collect a complete “snapshot” of the pile system instantaneously, some uncertainty is introduced.

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• Using the same method, the amount of dioxin mass that flowed through the vapor-phase side of the LVTP was estimated by the IPTD Contractor: 9.00 x 10-5 kg TEQ. This estimate is also reasonable.

• Some dioxin mass also left the pile and was quantified as NAPL, removed by the LVTP. As noted above, some NAPL was removed from the OWS and some was generated by the operation of the MPPE system. The exact volumes were not measured. These two wastes were combined prior to sampling, thus complicating a complete mass balance, given the LVTP “influent” samples from SP-L006 were measured downstream of the OWS. This complication is not addressed in the IPTD Contractor’s final report. However, the NAPL data do allow for some assessment:

o 28 totes were each filled with 1,000 L of NAPL from the OWS and MPPE and stored in four shipping containers. Of those 28 total totes, only the four totes closest to the container doors were sampled. Samples were collected on 05/29/15, using a paint mixer attached to a drill motor to mix each tote. Four 250-mL samples (one from each tote) were extracted and then mixed into one 1-L master sample. Aliquots from the master sample were placed in two 40 mL volatile organic analyte (VOA) vials, and analyzed.

o The lab reported two separate phases in the sample: an “organic” phase, and an “aqueous” phase, each with dioxin concentrations of 14,500,000 and 3,240,000 nanograms TEQ per kilogram (ng TEQ/kg), respectively. The lab estimated that the organic phase comprised approximately 10% of the volume in the sample. A volume- weighted average concentration of this sample is therefore 4,366,000 ng TEQ/kg.

o Multiplying this by the density of the NAPL (assumed to be 1 kilogram per liter [kg/L], conservatively, given the NAPL floated on water), and the volume in the totes (28,000 L) results in 0.122 kg TEQ.

o While it is expected that the mixing achieved during sampling improved the sample’s representativeness of the four totes, it is not known how reproducible these data are of those four samples. The volumetric ratio of phases present in the totes could be different than observed by the lab.

o More importantly, it is not known how representative those four totes are of all 28 totes. It is known the LVTP influent was highly variable and influenced by the type of heating occurring in the pile. The two 40-mL VOAs analyzed may not represent an accurate average of 28,000 L of NAPL. As such, the NAPL data provide a very uncertain representation of this waste stream.

o The IPTD Contractor’s IPTD® Final Report - Phase I documents a variety of assumptions that lead to the conclusion that 0.098 kg TEQ of dioxin mass is present after treatment, in the form of NAPL from the MPPE units. This assertion is problematic, because it is contradicted by the estimation that only 3.36 x 10-3 kg TEQ flowed into the MPPE units. As such, some of the assumptions made must be incorrect. Among these is the assumption that 80% of dioxin mass in the 28 NAPL totes was from the MPPE units. The dioxin concentrations measured at SP- L006 do not indicate the level of variability necessary to support this statement.

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o Given the hydrophobicity of dioxin, it is more reasonable to assume that more of the dioxin was removed by the OWS.

o Additional sampling of the OWS NAPL was conducted on 08/13/15, months after the confirmation samples were collected and after quench water had been added to the pile. Similar to the previous sample, two phases were observed: a lighter “organic” phase, and a denser “aqueous” phase, with dioxin concentrations of 24,500,000 and 138,000 ng TEQ/kg, respectively. It is not known what fraction of the samples was represented by each phase, or how representative the sample was of the NAPL present in the OWS. If the volumetric fractions were assumed to be similar to the previous sample, the volume-weighted average concentration would be of similar order of magnitude to the previous average: 2,574,200 ng TEQ/kg.

o These results are similar to the previous, but also indicate the amount of variability potentially present in this system.

o Because of this uncertainty, it is not possible to quantify the NAPL dioxin mass confidently. For example, if the true average dioxin concentration in the 28 totes of NAPL is close to 3,240,000 ng TEQ/kg, the NAPL dioxin mass would be 0.094 kg TEQ. If the 0.0034 kg of TEQ detected at SP-L006 is subtracted from that amount, thus assuming (for the sake of estimation only) that all the dioxin detected at SP- L006 was removed as NAPL (and concentrations downstream of the MPPE were all non-detect), that would mean that the total additional dioxin mass in this waste stream was 0.091 kg TEQ. If the true average was closer to the 14,500,000 ng TEQ/kg result, and it was assumed that all of the mass originated from OWS, the total additional dioxin mass would be approximately 0.41 kg TEQ.

Using the average dioxin concentration in the 05/29/15 sample, and conservatively assuming the NAPL mass is all from the OWS, the total dioxin mass removed from the pile is 3.36 x 10-3 kg TEQ + 9.00 x 10-5 kg TEQ + 0.122 kg TEQ = 0.125 kg TEQ. However, there are other miscellaneous items that may not be included in this total. For example, this estimate does not include any dioxin mass removed by the bag filters located both upstream of the OWS (033-FBW 501/502 and 601/602) and downstream of the OWS on the Quench/Spray Tower (033-FEW 603/601), as those waste streams were not quantified during operations. Additionally, any dioxin mass discharged through the liquid-phase after 3/23/2015 (e.g. as a result of cleaning activities), or still present in the LVTP (especially upstream of the OWS) are likely not included in this estimate either. Any dioxin escaping from the pile as fugitive steam is also not included. As a result, the total amount of mass removed from the pile may be higher than estimated.

Although this is similar to the IPTD Contractor’s estimate, this estimate is very uncertain for the reasons noted above. These sources of uncertainty are not detailed sufficiently in the IPTD Contractor’s IPTD® Final Report - Phase I.

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7.5 In Pile Destruction Using the Master Soil sample pre-treatment estimate, and the post-treatment estimates from section above, the amount of dioxin destroyed in the pile can be estimated: 4.05 kg TEQ (original amount) - 0.125 kg TEQ (amount removed) - 6.7 x 10-4 kg TEQ (amount remaining) = 3.9 kg TEQ, or 97%. However, as noted above, this estimate is very uncertain as it depends on the accuracy of all the estimates upon which is based. This includes the estimate of how much mass was removed from the pile, which is uncertain given the estimate derived in the previous section assumes no other losses from the system (including fugitive steam, mass removed via bag filters, or residue in the LVTP), and given the uncertain NAPL mass dominates this estimate. If the four totes sampled were not representative of all 28 totes, and a higher average dioxin concentration was actually removed, the NAPL mass could have been higher. For example, if the additional dioxin mass in the NAPL was 0.41 kg TEQ (i.e., per similar to the “organic” phase in the 05/29/15 sample), the in situ destruction would have been approximately 90%.

The estimate of in pile destruction is also dependent on an accurate estimate of pre-treatment mass. If the pre-treatment mass is instead estimated based on the CC samples described in Section 6.4.5.3, the amount destroyed in the pile changes significantly: 0.394 kg TEQ (original amount) - 0.125 kg TEQ (amount removed) - 6.7 x 10-4 kg TEQ (amount remaining) = 0.27 kg TEQ, or approximately 68%. If a larger dioxin mass is estimated to be associated with the NAPL, the amount of in-pile destruction drops further. However, it is not expected that these data are as representative of pre- treatment mass. As described above, this sampling event was not comparable to the confirmation sampling conducted, especially in terms of subsamples/aliquots contributing to the final sample. None of the samples were collected from lower than 1.4 m in the pile, and the amount of soil composited was substantially less than what was used to generate the Master Soil sample. Furthermore, this amount of in-pile destruction is significantly lower than what was observed in earlier studies referenced in the IPTD Contractor’s 100% Design Report, or in the treatability study performed using the Master Soil sample. Therefore, the CC data are not expected to be as representative of the initial dioxin mass. However, as noted above, it is not known if the Master Soil sample is completely representative either, as it was comprised of 14 large-volume grab samples collected throughout the site, and not 30-point MIS samples collected from the pile (like the confirmation samples). If the Master Soil sample is biased high, as may be the case as described above, that would also bias high any estimate of in pile destruction efficiency.

Rather than report this estimate without qualification (see Section 7.1.4 of the IPTD Contractor’s IPTD® Final Report - Phase I), it would be more appropriate to indicate that the data collected during Phase 1 suggest in situ destruction in the pile may have been over 90%, and perhaps as high as 97%. However, as outlined above, these estimates have very significant uncertainty, and should only be used with appropriate caveat and qualification.

Although it is not possible to address all of the sources of uncertainty from Phase I listed above now, it is still possible to reduce uncertainty in some parts of the mass balance. Specifically, additional samples could be collected from the NAPL totes, both to analyze the 24 totes that were not analyzed, and to collect duplicate samples to understand the variability of the dioxin concentrations

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sampled. Additionally, if any solids from bag filter operations, or any other residuals, are still present onsite and can be sampled, that would improve mass balance also.

To achieve a greater degree of confidence in the Phase II mass balance, the project team should consider the costs and benefits of the following:

• Pre-treatment dioxin mass could be characterized better. This could be done either via use of existing stockpile concentrations data and surveyed volumes, or by implementing the confirmation soil protocol on the Phase II pile prior to treatment.

o Some stockpiles, such as TSSA1, have been characterized using MIS techniques and DUs similar or smaller in size to those that would be in the Phase II pile. It is not expected that additional sampling of those same materials, once loaded in the Phase II pile, would lead to greater confidence in pretreatment dioxin mass.

o Other stockpiles, such as DP-1, have been sampled less intensively on a volumetric basis, and could be characterized more using MIS techniques to reduce uncertainty in pretreatment dioxin concentrations.

o The dioxin concentrations in TSSA2, which was generated solely from over-excavation activities, could be estimated based on a volume-weighted average of pre- and post-excavation samples. This method is less accurate than direct measurement, and would insert uncertainty into any estimate of pre-treatment dioxin mass. If this approach was used, this uncertainty would translate to uncertainty regarding the mass balance in general. Therefore, this option is not recommended.

o It would be most directly comparable to post-treatment confirmation sampling to implement the same confirmation sampling protocol, with the same pre-selected DUs, prior to treatment. This would result in a pre-treatment mass estimate that would be much more certain. This would be more expensive and time-consuming, but measures could be implemented to maximize sampling efficiency.

o If additional certainty is desired in the estimates of dioxin mass and destruction, then a cost benefit analysis should be done to balance the two best options: additional stockpile MIS sampling, or pre-treatment MIS sampling of the loaded Phase II pile. Either sampling approach would need to use similar DU sizing (or smaller) compared to the planned post-treatment DUs. Although some of the stockpiles have already been sufficiently sampled, it may be best to sample soil as it is loaded into the IPTD structure. That option would not involve drilling and should have the lowest cost and least schedule impacts.

• It is already planned to use only one MPPE unit during Phase II. This will make mass balance calculations simpler than in Phase I, when MPPE units were arranged in parallel and then in series. Most operational changes are made out of necessity, but if the IPTD Contractor identifies other opportunities to maintain operational consistency, such changes will simplify the mass balance.

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• Uncertainty in the Phase II mass balance could be reduced through careful characterization of all LVTP waste streams that are not otherwise included in the mass balance.

o The exact determination of which waste streams require characterization depends on which sample ports are used.

o Dissimilar waste streams should be kept separate if feasible. If it is necessary to combine dissimilar wastes, the wastes should be well characterized first to prevent variability in the combined material to lead to future uncertainty.

o Waste characterization should be done so as to achieve statistical confidence in the results, through the use of compositing to reduce the impact of small-scale heterogeneity and duplicate samples to assess variability in the results. The level of effort required for this depends on the amount of waste requiring characterization.

• The sampling and O&M programs should be scrutinized by the CMC and the IPTD Contractor to verify that all dioxin mass in the LVTP can be included in the mass balance one way or another. Sampling points should be selected to verify no dioxin mass is accidentally excluded or counted twice, and then used as consistently as possible during operations. System recirculation loops should be identified and considered in this context. This effort should require minimal effort.

o If possible, process samples should be collected at locations where sample variability is lowest. For example, sampling upstream of the OWS is not recommended because entrained NAPL mass may result in variability in results or even bias towards the aqueous portion of the flow.

o Sampling could therefore be conducted either downstream of the OWS (at SP-L06, as during Phase I), or downstream of the MPPE unit. If sampling is done downstream of the OWS, the NAPL mass from the MPPE unit can be used to double-check the MPPE influent mass. If sampling is done downstream of the MPPE unit, the NAPL from the OWS and MPPE unit should be characterized separately.

7.6 Destruction and Removal Efficiency (DRE) The removal efficiency with respect to the soil is easier to calculate, as it simply compares the initial soil concentrations against the treated soil confirmation sampling data. Similar to how it was calculated in the IPTD Contractor’s IPTD® Final Report - Phase I, the destruction removal efficiency in the soil is estimated to be ([4.05 kg – 6.7 x 10-4 kg]/4.05 kg} * 100 = approximately 99% or better for Phase I. Again, as outlined above, these estimates have very significant uncertainty, and should only be used with appropriate caveat and qualification. The only difference between this result and the result presented in the IPTD Contractor’s IPTD® Final Report - Phase I is that the IPTD Contractor uses four significant figures; this level of precision is not warranted given the very significant uncertainty discussed above and the precision provided in some of the confirmation sampling data. As described above, if the pre-treatment mass estimate is biased high, as may be the case, this estimate of DRE would also be biased high.

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8 IPTD® Pile Decommissioning The IPTD Contractor started decommissioning the above surface pipe and accoutrements in May 2015 before the CMC had finished the sampling of the IPTD pile. After sampling finished, the vertical pipes were then extracted from the IPTD pile.

9 Lessons Learned USAID, the CMC, the IPTD Contractor and the ECC conducted a two-part lessons learned workshop to learn from the implementation of Phase I and allow incorporation of any appropriate changes into the design and implementation for Phase II. The workshop was broken into two separate sessions, Lessons Learned I and Lessons Learned II. The Lessons Learned I workshop was held in Danang from 04/14/15 through 04/16/15 and the Lessons Learned Workshop II was held in Danang on 09/22/15 and 09/23/15.

9.1 Lessons Learned Process The Lessons Learned I workshop agenda was designed to evaluate Phase I, produce a list of action items for the project team to evaluate for Phase II, and reach agreement on a preliminary Phase II schedule, with consideration to risks and appropriate contingencies. The team used data from a pre- meeting survey and brainstorming to develop a list of all deviations from the intended results of Phase I. Attendees prioritized and grouped the deviations and used root cause analysis techniques to develop a list of root causes, with potential solutions for each, as described in the following section. The following key group conclusions/decisions for Phase II were reached:

• It is problematic for both the IPTD Contractor and the ECC to operate in the rainy season. It is less risky to heat into the dry season instead of into the rainy season. However, not all work can be postponed until periods of no moisture, even during the dry season. Therefore, the team should expect, plan and design to operate at least partially in the rainy season.

• Additional measures are needed to keep the IPTD structure dry and well insulated. The existing surface cover of the IPTD structure must be improved to prevent infiltration of rainwater and direct rain off the pile. Improvements to temporary cover during loading may also be necessary. Inspection of the IPTD structure is necessary to confirm insulation functionality and/or determine appropriate repairs prior to Phase II.

• The heater design should be modified to improve heating in the shallowest portion of the pile, and away from the middle of the pile where thermal losses are lowest.

• Improvement of the LVTP treatment process, such as membrane filtration, may be necessary to address discharge exceedances.

• Faster analytical turnaround time and/or real-time monitoring would also help improve O&M decision making.

• Additional IPTD structure modifications, such as an expansion of the gravel plenum layer to the outer vertical layers of the pile, may be necessary to reduce dioxin emissions from the pile and ambient air concentrations.

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• Strategic loading of the pile will be helpful. Soils with the highest concentrations and highest moisture content should be loaded in the middle of the pile.

• VGAC and LGAC from Phase I should not be placed in the Phase II pile because of uncertainty with regard to potential treatment impacts, potential difficulties in measuring dioxin concentrations on the GAC versus soils, potential concerns associated with use of the treated soil if contained GAC, and limited available volume in the Phase II pile.

At the conclusion of the Lessons Learned I meeting, each of the three contractors was tasked with evaluating potential solutions to root causes identified during the meeting. In between the two meetings, all contractors worked to resolve their respective action items.

The Lessons Learned II meeting was held to discuss and develop group consensus regarding action items that had not yet been resolved during conference calls, and to develop the Phase II schedule further based on the design changes resulting from resolution of the action items. Other additional topics not covered in detail in Lessons Learned I were discussed, including H&S and environmental sampling and compliance.

9.2 Action Items Each of the three contractors was tasked with evaluating potential solutions to root causes identified during Lessons Learned I. The action items and their current status are summarized below by the responsible contractor. The major changes to the IPTD design are described in the IPTD Contractor’s IPTD® Final Report – Phase I and will be submitted as DCRs for review and approval by USAID before implementation.

9.2.1 IPTD Contractor Action Items The following actions were assigned to the IPTD Contractor:

• Identify the most appropriate method to keep the IPTD structure dry and insulated during operation. The IPTD Contractor evaluated constructability and conceptual costs for a roof, but this was deemed too expensive. As an alternative, the team developed an alternative cover design with additional structural concrete to help control cracking, a greater slope, no penetration collars, and a more robust waterproof HDPE cover that will shed rainwater off the pile. The IPTD Contractor and the CMC are currently still collaborating on remaining details regarding the cover design. Additional collaboration will occur with the ECC to develop an appropriate method, such as a rolling tarp system, to keep soils dry during pile filling and cap construction. It is believed that additional insulation beyond the original design is not needed; the improved cap only needs to keep water out. It is also thought that additional structural concrete on top of the cover is probably not necessary either.

• To improve the uniformity of heating throughout the IPTD structure given expected heat loss and potential upset conditions, modify the heater design to include a boost at the top and more balanced energy output to maximize efficiency. Multiple rounds of modeling and cost/benefit analysis were performed to optimize the design, minimize

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expected heater maintenance, determine that the gravel layer on the bottom was still needed, and verify that the heaters could not be lowered.

• Following inspection of the IPTD structure and measurement of existing insulation properties (R-value), consider performing additional modeling and IPTD structure modifications, such as replacement and/or additional LWIC, to optimize the pile design.

• Install air injection per design (evaluate after quenching).

• Evaluate use of leachate system for air inlet/circulation.

• Evaluate membrane filtration as a potential means to improve dioxin removal via control of colloidal particles thought to facilitate dioxin transport. It was determined that the additional system complexity and costs involved would be too significant, and the decision was therefore made to not move forward with this change, and to control this as well as feasible using other techniques, such as management of biological growth on the LGAC media using redox and pH control, little to no treatment of pile leachate and recirculated flow, and improved skimming in the OWS. It should be noted that the monitoring data do not support the IPTD Contractor’s assertions in their IPTD® Final Report - Phase I that the exceedances were “very few and isolated”, and it is expected that the potential implementation of membrane filtration would have been fully capable of controlling dioxin exceedances. Further, the use of biocide, as is recommended in their IPTD® Final Report - Phase I, is not appropriate for biofouling control for the reasons outlined in the CMC’s memorandum on biofouling, dated 08/29/15.

• Conduct emission dispersion modeling for dioxin and benzene. The IPTD Contractor will evaluate both worker and community exposure.

• Determine an alternative laboratory that can conduct dioxin analysis faster, so as to allow for faster decision making during operation. The IPTD Contractor will implement a FTIR multi-point sampler to allow for real time decision making regarding VGAC efficiency.

• Evaluate the amount of adsorption media (MPPE and LGAC) necessary and most appropriate for Phase II, given life-cycle costs.

• In conjunction with the CMC, reevaluate the need to treat leachate in the pile versus boiling it and then treating condensate via the LVTP. It will also be necessary to consider operational simplicity, risk of dioxin exceedances, and other factors as part of this decision. (Note: this has already been done and the leachate piping has already been eliminated.)

• Evaluate blower capacity for Phase II, and determining if additional equipment is needed. The vacuum utilized during Phase I was often minimal, and fugitive steam emissions from the pile were frequent during heating. It is understood that if vapor recovery is too extensive, vapors drawn into the pile will cool the pile, but a better balance between cooling and fugitive emissions is likely achievable.

• In conjunction with the CMC, reevaluate the target treatment temperature and duration at the target temperature. During Phase I, successful results were achieved even though the pile was not maintained at 335°C for 21 days.

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• In conjunction with the CMC, develop a high iron contingency plan.

• Modify the task-specific HASP to require more PPE during high-risk activities such as VGAC replacement. As described above, additional measures are needed to prevent additional exposure during these activities.

9.2.2 CMC Action Items The following actions were assigned to the CMC:

• Finalize and implement the stockpile sampling plan to determine which stockpiles or stockpile portions require thermal treatment to fulfill GVN turnover requirements related to geotechnical specifications and other compounds of potential concern in the soil (e.g., arsenic), and to facilitate Phase II LVTP design improvements. This item was completed and results were sent to USAID on 09/03/15.

• Assess the depth of groundwater and potential effect of groundwater on cooling of the IPTD floor. The CMC has completed this action item and determined that groundwater is not present at sufficient elevation to cause any cooling of the pile. Any loss of heat through the bottom of the IPTD structure is instead thought to be the result of wet LWIC at the bottom of the structure. This item was completed and a memo was sent to USAID with the CMC’s recommendations on 09/11/15. The CMC will continue to monitor water levels weekly during the 2015 rainy season.

• Finalize the IPTD structure survey report and inspection method/criteria. The inspection criteria were provided to USAID in a technical memo dated 09/21/15. The IPTD structure was inspected in accordance with the technical memo. Currently, the CMC is preparing a follow up memo with final recommendations, but it appears that the IPTD structure needs very few repairs in order to function for Phase II thermal treatment. The biggest change will be the elimination of the leachate collection piping.

• Review the background COD monitoring data and evaluated the potential change of discharge monitoring points for COD. The CMC has completed this action item and recommends against changing the monitoring point. COD exceedances to date have not been a significant issue, and monitoring COD at the Sen Lake outfall is not expected to provide a significant benefit to the project. This has been evaluated with the review of the IPTD Contractor’s Phase II Sampling Plan and is still under consideration.

• Work with the IPTD Contractor to update the IPTD Contractor’s Phase II Sampling Plan for the LVTP, using Phase 1 analytical data and operational lessons learned to guide adjustments. The IPTD Contractor has submitted their proposed Phase II Sampling Plan and the CMC has provided comments on the plan.

• Coordinate LGAC, VGAC and NAPL disposal. The CMC worked with Holcim and a local vendor for onsite plasma destruction to provide pricing and logistics for each option. USAID worked with the IPTD Contractor directly for information on shipping and re-use of the LGAC, VGAC and destruction of the NAPL.

• Develop an improved sampling approach for Phase II confirmation sampling.

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9.2.3 ECC Action Items The following action items were assigned to the ECC:

• With input from the IPTD Contractor, design a rolling tarp/cover system to use when placing soil in the pile and prior to installation of the heater cans and new cap.

• Install vertical gravel plenum along sidewalls with input from the IPTD Contractor. If deemed appropriate. (This is no longer being considered due to volume constraints within the IPTD structure for Phase II.)

• Agree with the IPTD Contractor on compaction percentage and moisture content percentage to be achieved during Phase II. Following this agreement, the ECC is responsible for identifying and mitigating high water content in stockpiles as needed. The CMC took proctor and compaction tests from the stockpile areas and performed a stockpile survey to determine that the Phase II soils would fit into the Phase II treatment.

10 Assessment – Measurement and Evaluation of Project Indicators The IPTD Contractor had one indicator for their measurement and evaluation (M&E) reporting for Phase I. Their goal was to treat 38,852 m3 of dioxin contaminated soil and sediment to levels below 150 ppt. The IPTD Contractor met this goal.

The CMC had several M&E goals for Phase I. These can be referenced on USAID’s AidTracker+ website and are also available on the CMC’s eRoom: https://team.cdm.com/eRoom/ca2/USAIDDanangAirport-Remediation/0_301e8

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Appendix A Ambient Air Sample Results

Ambient Air Sample Results On/Near IPTD Structure and from Project Site Perimeter

Sample ID Sample date Sampling Party Sample Method/Equipment Location Sample Result (mm/dd/yy) TEQ (pg/m3)

Project action level for dioxin in ambient air = 0.414 pg/m3 (based on BTV) – values shown in red exceed the project action level 0614DN KK04 06/15/14

VRTC

Kimoto 120SL ambient air sampler. Collection: 4 hrs, ~80 m3/hr

Near the IPTD pile 0.13 0714DN KK04 07/14/14 Near the IPTD pile 0.13 0814DN KK04 08/15/14 Near The CMC office 0.27 0814DN KK07 08/15/14 Near the stack of IPTD pile 0.52 0914DN KK01 09/11/14 North end of MLA 2.19 0914DN KK04 09/12/14 Near The CMC office 1.47

0914DN KK07 09/12/14 Between IPTD pile and treatment plant 8.73

1014DN KK01 10/16/14 VRTC Kimoto 120SL ambient air sampler.

Collection: 4 hrs, ~80 m3/hr

Near MLA2 and apron area 4.11 1014DN KK04 10/17/14 South end of site – entrance gate 0.1 1014DN KK07 10/17/14 Between LVTP and IPTD 9.53

GROUND‐NW PILE‐ AMBIENT 10/17/14

IPTD Contractor SKC Leland Legacy sampling pumps, low volume PUF cartridge. Collection: 24 hrs,

~5L/min

Between LVTP and IPTD 4.83

PILE‐TOP SOUTH‐ AMBIENT 10/17/14 Top of IPTD – south end 173.95

1R‐AR‐0088 10/18/14 CMC Tisch TE‐1000 ambient air sampler.

Collection: >24 hrs, ~ 0.2 m3/min

South end of site – entrance gate 0.394 1R‐AR‐0089 10/18/14 Between LVTP and IPTD 3.279 1R‐AR‐0090 10/18/14 Top of IPTD – south end 160.634

Values shown in red exceed the project action level. Cells shaded in grey identify site perimeter samples with an action level of 0.414 pg/m3. Non-shaded cells identify samples collected on/around the IPTD structure with an action level of 10 pg/m3 requiring upgraded PPE. GROUND‐NW PILE‐

AMBIENT 10/20/14

IPTD Contractor SKC Leland Legacy sampling pumps, low volume PUF cartridge. Collection: 24 hrs,

~5L/min

Between LVTP and IPTD 1.8

PILE‐TOP SOUTH‐ AMBIENT 10/20/14 Top of IPTD – south end 79.7

NW PILE ‐ GROUND 10/27/14

IPTD Contractor

Tisch TE‐1000 ambient air sampler. Collection: >24 hrs, ~0.2 m3/min

Between LVTP and IPTD 36 SOUTH PILE ‐ TOP 10/27/14 Top of IPTD – south end 6.2

NW PILE ‐ GROUND (1406) 10/30/14 Between LVTP and IPTD 6.35

SOUTH PILE ‐ TOP (1404) 10/30/14 Top of IPTD – south end 7.39

LVTP 11/04/14 In LVTP, next to treated water buffer tank 45.8

IPTD Pile 11/04/14 Top of IPTD – middle 5.4


1R‐AR‐0092 11/06/14 CMC Tisch TE‐1000 ambient air sampler. Collection: >24 hrs, ~0.2 m3/min Just north of The CMC trailer 0.233

LVTP 11/10/14

IPTD Contractor

Tisch TE‐1000 ambient air sampler.

Collection: >24 hrs, ~0.2 m3/min

In LVTP, next to treated water buffer tank and OWS 37.5

IPTD Pile 11/10/14 Top of IPTD – middle 1.8 LVTP 11/14/14 In LVTP, southeast side of OWS 19.4

IPTD Pile 11/14/14 Top of IPTD – middle 2.8 1R‐AR‐0093 11/19/14

CMC



Perimeter of project site – west 0.205 1R‐AR‐0094 11/19/14 Perimeter of project site – east 0.566 1R‐AR‐0095 11/19/14 Perimeter of project site – north 0.429 1R‐AR‐0096 11/19/14 Perimeter of project site – south 0.086

LVTP 11/21/14

IPTD Contractor



LVTP ‐ Northeast corner of OWS 33.3 IPTD Pile 11/21/14 Top of IPTD – middle 11.2

LVTP 11/25/14 LVTP ‐ Northeast corner of OWS 33.4 IPTD Pile 11/25/14 Top of IPTD – middle 6

1R‐AR‐0097 11/28/14

CMC



Perimeter of project site – west 1.128 1R‐AR‐0098 11/28/14 Perimeter of project site – north 0.908 1R‐AR‐0099 11/28/14 Perimeter of project site – east 0.686 1R‐AR‐0100 11/28/14 Perimeter of project site – south 0.289

LVTP 12/02/14

IPTD Contractor



LVTP ‐ Northeast corner of OWS 26.2 IPTD Pile 12/02/14 IPTD Center of pile 19.4

LVTP 12/09/14 LVTP ‐ Southeast corner of OWS 13.1 IPTD Pile 12/09/14 IPTD Center of pile 27.4



Perimeter of project site – east 0.372 1R‐AR‐0103 12/06/14 CMC Perimeter of project site – north 0.378 1R‐AR‐0104 12/06/14 CMC Perimeter of project site – west 0.363 1R‐AR‐0105 12/06/14 CMC Perimeter of project site – south 0.819

LVTP ‐ EAST 12/12/14 IPTD Contractor


East side of LVTP in center of PGAC bank 5.1

LVTP ‐ MPPE V 12/12/14 IPTD Contractor Inside of MPPE V ‐ next to columns 4.4

LVTP ‐ SOUTH 12/12/14 IPTD Contractor LVTP ‐ South at sump where MPPE's drain to 6

LVTP ‐ WEST 12/12/14 IPTD Contractor West side of LVTP in center of VGAC bank 3.7




Perimeter of project site – west 0.296 1R‐AR‐0107 12/17/14 CMC Perimeter of project site – south 0.385 1R‐AR‐0108 12/17/14 CMC Perimeter of project site – east 0.266 1R‐AR‐0109 12/17/14 CMC Perimeter of project site – north 0.237

LVTP 12/19/14 IPTD Contractor Tisch TE‐1000 ambient air sampler. Collection: >24 hrs, ~0.2 m3/min

West side of pile 4.6 IPTD Ramp 12/19/14 IPTD Contractor South east of OWS 1.2 1R‐AR‐0110 12/24/14 CMC


Perimeter of project site – east 0.321 1R‐AR‐0111 12/24/14 CMC Perimeter of project site – north 0.354 1R‐AR‐0112 12/24/14 CMC Perimeter of project site – west 0.258 1R‐AR‐0113 12/24/14 CMC Perimeter of project site – south 0.261


LVTP 7.5 IPTD Ramp 12/26/15 IPTD Contractor Perimeter of project site – west 3.4 1R‐AR‐0114 12/31/14 CMC


Perimeter of project site – west 0.272 1R‐AR‐0115 12/31/14 CMC Perimeter of project site – east 0.309 1R‐AR‐0116 12/31/14 CMC Perimeter of project site – north 0.26 1R‐AR‐0117 12/31/14 CMC Perimeter of project site – south 0.232


LVTP N. of OWS 9 IPTD Pile 01/02/15 IPTD Contractor IPTD Center of pile 3.2



Perimeter of project site – north 0.362 1R‐AR‐0120 01/08/15 CMC Perimeter of project site – east 0.271 1R‐AR‐0121 01/08/15 CMC Perimeter of project site – south 0.067 1R‐AR‐0122 01/08/15 CMC Perimeter of project site – west 0.187


LVTP N. of OWS 5.4 IPTD Pile 01/12/15 IPTD Contractor IPTD Center of pile 0.4



Perimeter of project site – west 0.21 1R‐AR‐0125 01/15/15 CMC Perimeter of project site – north 0.19 1R‐AR‐0126 01/15/15 CMC Perimeter of project site – east 0.32 1R‐AR‐0127 01/15/15 CMC Perimeter of project site – south 0.15


LVTP S. of OWS 4.1 IPTD Pile 01/19/15 IPTD Contractor IPTD Center of pile 0.8



Perimeter of project site – north 0.4 1R‐AR‐0129 01/22/15 CMC Perimeter of project site – east 0.31 1R‐AR‐0130 01/24/15 CMC Perimeter of project site – south 0.21


LVTP 01/29/15 IPTD Contractor Tisch TE‐1000 ambient air sampler.



LVTP 02/02/15 IPTD Contractor LVTP S. of OWS 7.7 IPTD Pile 02/02/15 IPTD Contractor IPTD Center of pile 6.7



Perimeter of project site – east 0.16 1R‐AR‐0132 02/06/15 CMC Perimeter of project site – south 0.16 1R‐AR‐0133 02/06/15 CMC Perimeter of project site – north 0.19 1R‐AR‐0134 02/06/15 CMC Perimeter of project site – west 0.11

LVTP 02/12/15 IPTD Contractor



LVTP 02/16/15 IPTD Contractor LVTP N. of OWS 9.3 IPTD Pile 02/16/15 IPTD Contractor IPTD Center of pile 9.8

LVTP 02/24/15 IPTD Contractor LVTP N. of OWS 14.8 IPTD Pile 02/24/15 IPTD Contractor IPTD Center of pile 7.6



Perimeter of project site – south 0.06 1R‐AR‐0136 02/26/15 CMC Perimeter of project site – east 0.41 1R‐AR‐0137 02/26/15 CMC Perimeter of project site – west 1.05 1R‐AR‐0138 03/04/15 CMC Perimeter of project site – north 0.28






LVTP 03/16/15 IPTD Contractor LVTP S. of OWS 17 IPTD Pile 03/16/15 IPTD Contractor IPTD Center of pile 6.8



LVTP 04/08/15 IPTD Contractor LVTP S. of OWS 3 IPTD Pile 04/08/15 IPTD Contractor IPTD Center of pile 7.6


LVTP 04/22/15 IPTD Contractor LVTP S. of OWS 21.8 IPTD Pile 04/22/15 IPTD Contractor IPTD Center of pile 2





LVTP 05/07/15 IPTD Contractor LVTP S. of OWS 18.8 IPTD Pile 05/19/15 IPTD Contractor IPTD DU A/B 3.5 LVTP‐N 05/19/15 IPTD Contractor LVTP‐ N. of OWS 25.5 LVTP‐S 05/19/15 IPTD Contractor LVTP‐ S. of OWS 42.2

1R‐AR‐0148 05/22/15 CMC


South ‐ Site Perimeter 0.8 1R‐AR‐0149 05/22/15 CMC West ‐ Site Perimeter 0.9 1R‐AR‐0150 05/22/15 CMC East ‐ Site Perimeter 0.4 1R‐AR‐0151 05/22/15 CMC North ‐ Site Perimeter 0.8 1R‐AR‐0152 05/24/15 CMC South ‐ IPTD Perimeter 0.8 1R‐AR‐0153 05/24/15 CMC East ‐ IPTD Perimeter 1.8 1R‐AR‐0154 05/24/15 CMC West ‐ IPTD Perimeter 1.6 1R‐AR‐0155 05/24/15 CMC North ‐ IPTD Perimeter 1 1R‐AR‐0156 05/26/15 CMC North ‐ Site Perimeter 0.2 1R‐AR‐0157 05/26/15 CMC East ‐ Site Perimeter 0.2 1R‐AR‐0158 05/26/15 CMC West ‐ Site Perimeter 0.3 1R‐AR‐0159 05/26/15 CMC South ‐ Site Perimeter 0.2

IPTD Pile 05/28/15 IPTD Contractor Tisch TE‐1000 ambient air sampler. Collection: >24 hrs, ~0.2 m3/min

IPTD Center of pile 2.6 LVTP 05/28/15 IPTD Contractor LVTP‐ N. of OWS 29.8

1R‐AR‐0160 05/28/15 CMC


West ‐ IPTD Perimeter 1.2 1R‐AR‐0161 05/28/15 CMC North ‐ IPTD Perimeter 0.7 1R‐AR‐0162 05/28/15 CMC East ‐ IPTD Perimeter 1.5 1R‐AR‐0163 05/28/15 CMC South ‐ IPTD Perimeter 0.8 1R‐AR‐0164 06/03/15 CMC West ‐ Site Perimeter 0.8 1R‐AR‐0165 06/02/15 CMC South ‐ Site Perimeter 0.1 1R‐AR‐0166 06/02/15 CMC East ‐ Site Perimeter 0.1 1R‐AR‐0167 06/02/15 CMC North ‐ Site Perimeter 0.2


IPTD Center of pile 2 LVTP 06/04/15 IPTD Contractor LVTP‐ N. of OWS 23.3



West ‐ IPTD Perimeter 0.8 1R‐AR‐0169 06/04/15 CMC South ‐ IPTD Perimeter 1 1R‐AR‐0170 06/04/15 CMC East ‐ IPTD Perimeter 0.6 1R‐AR‐0171 06/04/15 CMC North ‐ IPTD Perimeter 1.4




West ‐ Site perimeter 0.3 1R‐AR‐0177 06/10/15 CMC South ‐ Site perimeter 0.1 1R‐AR‐0178 06/10/15 CMC North ‐ Site perimeter 0.2 1R‐AR‐0179 06/10/15 CMC East ‐ Site perimeter 0.1





North ‐IPTD Perimeter 0.5 1R‐AR‐0181 06/13/15 CMC West ‐IPTD Perimeter 1.5 1R‐AR‐0182 06/12/15 CMC South ‐IPTD Perimeter 1.6 1R‐AR‐0183 06/13/15 CMC East ‐ IPTD Perimeter 0.2


IPTD Center of pile‐‐"worst case" near steam 1.4



East ‐ Site perimeter 0.1 1R‐AR‐0186 06/16/15 CMC West ‐ Site perimeter 0.1 1R‐AR‐0187 06/16/15 CMC South ‐ Site perimeter 0.4 1R‐AR‐0188 06/18/15 CMC North ‐ Site perimeter 0.1





North ‐ IPTD Perimeter 0.4 1R‐AR‐0190 06/19/15 CMC West ‐ IPTD Perimeter 9.7 1R‐AR‐0191 06/19/15 CMC South ‐ IPTD Perimeter 0.5 1R‐AR‐0192 06/19/15 CMC East ‐ IPTD Perimeter 0.6





West ‐ Site perimeter 0.8 1R‐AR‐0195 06/23/15 CMC East ‐ Site perimeter 0.4 1R‐AR‐0196 06/23/15 CMC South ‐ Site perimeter 0.4 1R‐AR‐0197 06/23/15 CMC North ‐ Site perimeter 0.3 1R‐AR‐0198 06/25/15 CMC


West ‐ IPTD Perimeter 1.3 1R‐AR‐0199 06/25/15 CMC East ‐ IPTD Perimeter 2.0 1R‐AR‐0200 06/25/15 CMC South ‐ IPTD Perimeter 0.5 1R‐AR‐0201 06/25/15 CMC North ‐ IPTD Perimeter 1.6




West ‐ Site perimeter 0.3 1R‐AR‐0204 06/30/15 CMC North ‐ Site perimeter 0.3 1R‐AR‐0205 06/30/15 CMC South ‐ Site perimeter 0.2 1R‐AR‐0206 06/30/15 CMC East ‐ Site perimeter 0.1



1R‐AR‐0207 07/02/15 CMC


West ‐ IPTD Perimeter 18.5 1R‐AR‐0208 07/02/15 CMC North ‐ IPTD Perimeter 0.5 1R‐AR‐0209 07/02/15 CMC South ‐ IPTD Perimeter* 1.6 1R‐AR‐0210 07/02/15 CMC East ‐ IPTD Perimeter* 1.3 1R‐AR‐0212 07/07/15 CMC West ‐ Site Perimeter 0.5 1R‐AR‐0213 07/07/15 CMC East ‐ Site Perimeter 0.2 1R‐AR‐0214 07/07/15 CMC South ‐ Site Perimeter 0.7 1R‐AR‐0215 07/07/15 CMC North ‐ Site Perimeter 0.2

IPTD Pile 07/09/15 IPTD Contractor Tisch TE‐1000 ambient air sampler.


IPTD Center of pile 1.9 LVTP 07/09/15 IPTD Contractor LVTP Between MPPE V and TWBT 10.9

LVTP (Center) 07/16/15 IPTD Contractor Center of LVTP (next to OWS/MPPE) 11.7

LVTP ‐ NE 07/16/15 IPTD Contractor


NE corner of LVTP 2.7 LVTP ‐ NW 07/16/15 IPTD Contractor NW corner of LVTP 1.0 LVTP ‐ SE 07/16/15 IPTD Contractor SE corner of LVTP 4.7 LVTP ‐ SW 07/16/15 IPTD Contractor SW corner of LVTP 1.4

WEST‐OWS 07/23/15 IPTD Contractor West of OWS, in between OWS and VGAC beds 4.5

LVTP ‐ CENTER 07/23/15 IPTD Contractor Center of LVTP (next to OWS/MPPE) 15.3




LVTP ‐ CENTER 08/12/15 IPTD Contractor


Center of LVTP (next to OWS/MPPE) 9.6

Decon Area 08/12/15 IPTD Contractor Immediately next to Decon area/floor drain 5.2

NAPL Waste Tank 08/12/15 IPTD Contractor Immediately next to MPPE NAPL tank 7.4



LVTP ‐ SE 08/27/15 IPTD Contractor SE corner of LVTP 4.4 Between BT & OWS 08/27/15 IPTD Contractor Between buffer tank and OWS 65.8


BOTTOM OF CYCLONE 09/03/15 IPTD Contractor Low volume PUF/sampling pump.

5L/min for 300 min. Bottom of cyclone 35.4

Top of Carbon VGAC 1 09/03/15 IPTD Contractor Low volume PUF/sampling pump.

5L/min for 300 min. Top of carbon VGAC 1 8.5

WEST PERIMETER BETWEEN VGAC 3 &

4

09/04/15

IPTD Contractor Tisch TE‐1000 ambient air sampler.

Collection: >24 hrs, ~0.2 m3/min WEST PERIMETER BETWEEN VGAC 3 & 4

132.8

8hr LGAC #1 09/11/15 IPTD Contractor Tisch TE‐1000 ambient air sampler. Collection:8 hrs, ~0.2 m3/min

Near LGAC #1 during change out 1.9

Between BT & OWS 09/17/15 IPTD Contractor Tisch TE‐1000 ambient air sampler.


Between buffer tank and OWS 21.1



Acronyms/Abbreviations: BTV – baseline threshold value min – minute TEQ – toxicity equivalence hr – hour MLA – former Mixing and Loading Area VGAC - vapor granular activated carbon IPTD – in-pile thermal desorption MPPE - Macro-Porous Polymer Extraction VRTC – Vietnam Russia Tropical Center L – liter LGAC – liquid granular activated carbon

PGAC - pressure granular activated carbon pg/m3 – picograms per cubic meter

LVTP – liquid vapor treatment plant m3 – cubic meter

PUF - polyurethane foam OWS – oil water separator

APPENDIX F

CONSTRUCTION SC

76

US Agency for International Development 1300 Pennsylvania Avenue, NW

Washington, DC 20523 Tel: (202) 712‐0000 Fax: (202) 216‐3524

www.usaid.gov

http://www.usaid.gov/

Documents

Activity Completion Report No. 2