Got LNAPL? Technical Update and Strategic Management. Thank you for joining. This webinar will begin at 3pm BST, 4pm CEST and 10am EST.

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1 Got LNAPL? Technical Update and Strategic Management Thank you for joining. This webinar will begin at 3pm BST, 4pm CEST and 10am EST. Copyright 2015 by ERM Worldwide Limited and/or its affiliates ( ERM ). All Rights Reserved. No part of this work may be reproduced or transmitted in any form or by any means, without prior written permission of ERM.

2 Got LNAPL? Technical Update and Strategic Management Copyright 2015 by ERM Worldwide Limited and/or its affiliates ( ERM ). All Rights Reserved. No part of this work may be reproduced or transmitted in any form or by any means, without prior written permission of ERM.

3 Good Afternoon & Welcome Oliver Phipps EMEA Practice Leader Contaminated Site Management, Oliver worked in France for many years and now leads our Contaminated Site Management (CSM) practice across EMEA, comprising over 250 multi-disciplinary professionals (geologists, hydrogeologists, engineers, chemists, toxicologists). Tel: +44 (0) Alan Thomas Technical Fellow, Alan is a specialist providing technical support to the CSM Team developing and promoting sustainable risk based solutions for contaminated land and groundwater. Alan has over 20 years experience and has worked in a number of countries and industrial sectors including oil & gas, manufacturing, chemical and pharmaceutical industries. Alan was a co author on the recently published UK CL:AIRE illustrated handbook of LNAPL transport and fate in the subsurface. Tel: +44 (0) alan.thomas@erm.com David de Courcy-Bower Senior Engineer / LNAPL Technical Expert, David is a registered professional engineer with more than 15 years of experience providing contaminated site investigation and restoration services. He is a technical expert for sites impacted with light non aqueous phase liquids (LNAPL) and uses innovative LNAPL management approaches to optimize conceptual site models and remedial efforts to achieve site closure. He has worked on LNAPL projects across the globe and contributed to the development of ITRC LNAPL guidance and ASTM LNAPL standards. Tel: +1 (414) david.decourcybower@erm.com 3

4 Agenda LNAPL Vertical Distribution Where is LNAPL in the formation? LNAPL Transmissivity How practicable is LNAPL recovery? LNAPL Risks What are the risks and drivers to clean up LNAPL? Remedial Strategies What s the path towards closure? Natural Source Zone Depletion 4 Image Source: David de Courcy-Bower

5 LNAPL Release Release Source Vapor Phase LNAPL Saturated Zone Dissolved Phase Source: Modified from Huntley and Beckett,

6 Well Thickness vs Formation Saturation Visible Light UV Light LNAPL Groundwater 6 Source: Andrew Kirkman and API 2004

7 LNAPL Terminology Residual LNAPL Body not moving (not in wells) Groundwater / Vapor Phase Impacts Mobile LNAPL Body not moving (present in well) Does not indicate migration Migrating LNAPL Body Moving (appears in clean wells) Typically during new releases so confirm release has stopped Visual evidence (presence at receptors) Perimeter monitoring POTENTIAL RECOVERY Residual Mobile Migrating 7 Source: Garg, Shell 2011

8 LNAPL Vertical Distribution Visible Light UV Light Residual Saturation Limit (Sor) Shark s Fin Air - Oil Interface Theoretical Air - Water Interface Observed Monitoring Well Product Thickness Mobile Free LNAPL Product LNAPL Saturation Profile Oil - Water Interface Source: Andrew Kirkman Modified API, Oil Saturation (% Pore Space)

9 Well Thickness and Formation Distribution Bedrock Source: Modified from AFCEE,

10 LNAPL Thickness - WARNING Represent what is in the formation Predict the rate of LNAPL recovery Predict the volume of recoverable LNAPL Suggest lateral movement of LNAPL 10

11 LNAPL Management Process Maximum Extent Practicable Risk Based Approach LNAPL Conceptual Site Model (LCSM) LNAPL Transmissivity LNAPL Stability Dissolved Phase Vapor Phase Direct Contact Is the LNAPL Recoverable Yes Evaluate Recovery No Yes Is each risk understood Yes Is risk acceptable No No Remedial Metrics Evaluate Remediation Closure 11

12 LNAPL Management Process Maximum Extent Practicable Risk Based Approach LNAPL Conceptual Site Model (LCSM) LNAPL Transmissivity LNAPL Stability Dissolved Phase Vapor Phase Direct Contact Is the LNAPL Recoverable Yes Evaluate Recovery No Yes Is each risk understood Yes Is risk acceptable No No Remedial Metrics Evaluate Remediation Closure 12

13 Understanding Metrics for LNAPL Recovery 13 LNAPL Thickness Inconsistent between soil types Poor indicator of LNAPL recovery Inconsistent between hydraulic scenarios (perched, confined, unconfined) LNAPL Recovery Rate (Asymptotic Recovery / Decline Curve) Need recovery system or pilot test data - hard to predict recovery Operational variability and technology differences make it difficult to use across technologies and/or sites Need to normalize drawdown induced LNAPL Transmissivity Estimated with recovery data or field testing on monitoring wells Consistent across soil types Consistent across confined, unconfined or perched conditions Transmissivity proven metric with increased acceptance Source: ITRC, 2009, ASTM

14 LNAPL Transmissivity (Recoverability) Accounts for magnitude of the mobile interval Accounts for soil permeability Accounts for LNAPL properties Accounts for variability in K n across the mobile interval MW T n = K n over b n LNAPL K n ρ n g k k = µ n rn Highest LNAPL saturation has highest LNAPL conductivity Used as direct measure of changes in LNAPL saturation K n (S n ) varies across the mobile interval Residual LNAPL 14 Source: ITRC, 2009, ASTM

15 LNAPL Transmissivity - ASTM 2013 Methods Baildown Testing Remove LNAPL Volume from both well casing and borehole. Monitor recovery of LNAPL back into the well over time Analyze data using API Workbook - Manual Skimming Tests Repeated removal of LNAPL from wells Measure volume recovered until it is constant for given time interval Recovery System Data Total fluid pumping (oil/water recovery ratios) Water enhanced recovery Vacuum enhanced recovery 15 Source: AFCEE

16 LNAPL Thickness in Wells Where do you install recovery wells? Pink areas? Green? Source: ASTM, 2014

17 LNAPL Recoverability - Transmissivity Now where do you install recovery wells? Source: ASTM, 2014

18 Transmissivity as a Remedial Endpoint Defines endpoints of recovery Identifies when hydraulic/pneumatic recovery is complete Possible closure for sites where residual LNAPL does not pose a risk to receptors Refocuses remedial efforts for sites where residual LNAPL risk to receptors exists Referenced in ITRC LNAPL guidance (2009) Transmissivities between 0.1 and 0.8 ft 2 /day 0.01 to 0.08 m 2 /day Further reductions can be inefficient, costly, and may be of limited use in reducing LNAPL mass, migration potential, or longevity Increasing Regulatory Acceptance

19 Case Study: How evaluating LNAPL transmissivity supported site closure and reduced costs Previous consultant performed monthly LNAPL recovery efforts at site: 3 years of LNAPL recovery efforts Less than 100 gallon of LNAPL recovered from wells Gauged LNAPL thicknesses of between 0.001m and 1.3m were recorded. Assumed that regulator required LNAPL recovery due to erratic thicknesses. Recommended site excavation that required facility demolition (~$800k USD) ERM evaluated Existing Data and supplemented data gaps to revise LNAPL CSM: LNAPL diagnostic gauge plots perched LNAPL LNAPL transmissivity evaluation Low Tn max 0.1 ft 2 /day Vapour intrusion evaluation No VI issues Leveraged understanding of new regulatory guidance to propose no further action due to no risk receptors and low recoverability. Site NFA letter from agency received ~6 months after initial evaluation (~$40k USD spend).

20 LNAPL Management Process Maximum Extent Practicable Risk Based Approach LNAPL Conceptual Site Model (LCSM) LNAPL Transmissivity LNAPL Stability Dissolved Phase Vapor Phase Direct Contact Is the LNAPL Recoverable Yes Evaluate Recovery No Yes Is each risk understood Yes Is risk acceptable No No Remedial Metrics Evaluate Remediation Closure 20

21 Risk to Human Health & the Environment Evaluate the Risks to Receptors Immediate explosive conditions, human health / biological exposure Longer term evaluate future exposure pathways and hazardous conditions LNAPL Release Actual risk profile must be understood 1 Vapor Intrusion (explosive, human health) Impacted Utilities (explosive, migration) Impacted Supply Wells (explosive, human health) Surface Seeps (biological, human health) 5 5 Impacted Surface Water (biological, human health) 21

22 LNAPL Conceptual Site Model (LCSM) Major Components of LCSM: Site Setting Geology/Hydrogeology LNAPL Delineation Source Zone LNAPL Chemical/Physical Properties LNAPL Body Stability LNAPL Recoverability Dissolved Phase/Vapour Phase Natural Source Zone Depletion Increasing Site Complexity Increasing Risk Factors High Medium Low Level of LCSM Detail/Data The LCSM is the body of information describing aspects of the LNAPL and site setting necessary to satisfy the LNAPL remedial objectives 22 Source: ASTM E2531 Revision Committee, 2015, ITRC 2009

23 Case Study: How revised LNAPL CSM improved understanding and reduced costs Extensive investigations by a local consultancy, including: Borehole installation and collection of soil and groundwater samples at over 40 locations; and Installation of 4 wells to nearly 70m depth. Free-phase hydrocarbons with an apparent thicknesses of between 0.001m and 0.725m were recorded. Inferred that there was a significant pool of LNAPL in subsurface Client provisioned 3m for on-site impacts and 3m for off-site impacts. ERM used High Resolution techniques to revise LNAPL CSM: Rapid Optical Screening Tool (ROST ) Discrete interval vertical sampling via CMT wells Coupled with product assessment, chemical and geochemical data to demonstrate active natural attenuation. Following regulatory negotiation groundwater remediation has been avoided, although some soil removal will be required. Investigation and Remediation costs reduced to < 1m.

24 LNAPL Management Process Maximum Extent Practicable Risk Based Approach LNAPL Conceptual Site Model (LCSM) LNAPL Transmissivity LNAPL Stability Dissolved Phase Vapor Phase Direct Contact Is the LNAPL Recoverable Yes Evaluate Recovery No Yes Is each risk understood Yes Is risk acceptable No No Remedial Metrics Evaluate Remediation Closure 24

25 Remediation objectives and metrics Figure: CL:AIRE 2014

26 How does this fit in the EMEA regulatory framework Country/Region Regulatory Agency What LNAPL remedial critieria / endpoints are applied? Belgium Flanders: OVAM Are there LNAPL Specific Remedial Criteria Specific LNAPL Thickness Requirements X Maximum Extent Practicable X LNAPL Transmissivity X Other end point X Brussels: BIM/IBGE X X X X Wallonia: DPS X (no risk) France Germany Italy DREAL / DRIEE lower soil protection agency (normally at District level) X X X X X normally hydrocarbon concentrations in GW or soil vapor X X X X X Netherlands South Africa Spain Province, Municipality or Regional Environmental Authority X X X X, risk-based DEA, DWS X X National Agencies Hydrological Confederation of river basins. Catalonian and Basque Country have water competences X X X X UK EA X X Risk basis risk basis risk basis 26

27 LNAPL Remedial Technologies Excavation Physical containment In-situ soil mixing Natural source zone depletion (NSZD) Air sparging/soil vapor extraction (AS/SVE) LNAPL skimming Bioslurping/EFR Dual pump liquid extraction Multi-phase extraction, dual pump Multi-phase extraction, single pump Water/hot water flooding In situ chemical oxidation Surfactant- enhanced subsurface remediation Co-solvent flushing Steam/hot-air injection Radio frequency heating Three and six-phase electrical resistance heating 27 Source: ITRC, 2010

28 Natural Source Zone Depletion 28 Source: de Courcy-Bower, Zimbron, Stone, ANSR 2015

29 NSZD Quantification 29 Source: de Courcy-Bower, Zimbron, Stone, ANSR 2015

30 Chamber Method - Li-Cor 8100A 30 Source: Dylan Stankus ERM Portland, OR Rental Cost: ~ 1500 per month NSZD Rates ~2 mins for CO 2 flux Need background location LNAPL plume has higher CO 2 flux Stoichiometric calculations to covert into volume of LNAPL 5.5 to 55 m 3 /Ha-yr

31 NSZD Methods Overview Field Design Measurement Period Total Field Time (10 locations) Method Benefits Gradient Method Trap Method Chamber Method Wells / vapor points installed through vadose zone Install soil pipe collar into shallow soils Install soil pipe collar into shallow soils (background required) 1-4 hours 1-4 weeks 5-15 minutes 2-5 days once locations installed - Use of existing locations - Evaluation of deeper smear zone impacts 2 days 2 days - Accounts for temporal fluctuations - Includes analysis of 14 C carbon isotopes - Rapid delineation of CO 2 flux across source area Level of Training High Low Medium Data Analysis More complex data analysis and modern carbon evaluation Laboratory based analysis Relatively simple data analysis and correction for background Overall Cost $$$ $$ $ 31 Source: de Courcy-Bower, Zimbron, Stone, ANSR 2015

32 LNAPL Management Process Maximum Extent Practicable Risk Based Approach LNAPL Conceptual Site Model (LCSM) LNAPL Transmissivity LNAPL Stability Dissolved Phase Vapor Phase Direct Contact Is the LNAPL Recoverable Yes Evaluate Recovery No Yes Is each risk understood Yes Is risk acceptable No No Remedial Metrics Evaluate Remediation Closure 32

33 LNAPL Strategy Advances in the conceptual understanding of LNAPL behavior can have significant benefits for the sustainable and cost effective management of LNAPL impacted sites Develop LCSM that is right sized for the site risks and complexity Maximize use of existing data Update as additional data is obtained especially during remediation Define realistic objectives and goals for LNAPL recovery & remediation LNAPL thickness generally poor metric for evaluating LNAPL recovery Alternate LNAPL recovery metrics i.e. LNAPL transmissivity, Asymptotic Recovery, Oil/water Recovery Ratio At low risk sites consider the use of passive technologies such as the use of NSZD 33

34 Thank you for listening Any questions? Oliver will now facilitate some discussion and Alan and David would be pleased to answer your questions: Any further questions should be sent to who will ensure that they are issued to the correct person so that you can get a response. ERM Events Coming Soon: 20 th October: Contaminated Land Risk Assessment & Toxicology 17 th November: Evaluating and Managing Liabilities Associated with Potential Environmental Releases: A Holistic Review of Infrastructure Risk