frontiers in remediation innovation balance experience e book spreads

Imagine the result

www.arcadis-us.com

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Innovation. Balance. Experience.

Imagine the result


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frontiers in remediation-Innovation Balance Experience.indd 1 5/7/2012 8:32:38 PM


For ARCADIS, everything begins with a passion to help clients achieve success. We focus on

understanding our clients’ most complex environmental challenges, and we generate value by

creating balanced solutions. It’s how we do business.

What sets us apart are our core principles of technical innovation and excellence in project

delivery. Our scientists and engineers are pushing frontiers in remediation by improving the

application of existing technologies or by developing next generation technologies.

What results can you expect? The best possible! While everyone is talking about closing sites and

turning liabilities into assets, we’re achieving it. We’ve got the track record to prove we translate

our global experience into execution.

Imagine the result.

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frontiers in remediation



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Suthan S. Suthersan, PhD, [email protected]

Rula A. Deeb, PhD, [email protected]

Kurt A. Beil, [email protected]

Denice Nelson, PhD, [email protected]

Eric M. Nichols, [email protected]

Carol S. Mowder, [email protected]

Craig E. Divine, PhD, [email protected]

Scott T. Potter, PhD, [email protected]

Elisabeth L. Hawley, [email protected]

Karen Hohe Suchomel, [email protected]

www.arcadis-us.com

ARCADIS U.S., Inc.630 Plaza Drive, Suite 100Highlands Ranch, CO 80129tel 720 344 3500

© 2012 ARCADIS U.S., Inc. All Rights Reserved

While we believe the information presented in this document to be accurate, the information is not intended as legal or other advice but, rather, as general information not specific to a particular project. You should always formally engage the services of a lawyer or professional consultant of your choosing before taking action on matters referenced in this document.

Editing and editorial services: Chrissy Murphy (ARCADIS U.S., Inc., Newtown, PA), Rosario Varella (ARCADIS U.S., Inc., Emeryville, CA)

Design and layout: Andrew Lewandowski (ARCADIS U.S., Inc., Syracuse, NY)

Printing by: Eastwood Litho, Inc., 4020 New Court Avenue, Syracuse, NY 13206

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Case Studies

Case Study #

Project Name COCs Technology Location

Frontiers in Remediation: Sustainability by Design

1Artesian Treatment Vessels: A Sustainable In Situ Remediation System

TCE Artesian Treatment Vessels Georgia

2Sustainable Remediation: The Johnson Space Center Mulch Biowall Project

PCE, TCE, DCE, VC Mulch Biowall Barrier Texas

3 Sustainable Approach to Product RecoveryNAPL (crude oil, diesel, gasoline)

Hydrocarbon Recovery, Sustainable Remediation

Confidential

Frontiers in Geochemistry: Metals, Radionuclides and Inorganics

4Cost Effective Closure of a Former Chemical Manufacturing Facility

Cadmium, Lead, ZincIn Situ Stabilization/Solidication, Wetlands Construction, Soil Capping, Monitored Natural Attenuation

Virginia

5In Situ Remediation of a Mixed Uranium and PCE Plume

Uranium, PCE Anaerobic Bioremediation Southeastern US

6Remedy Optimization to Achieve Site Closure at a Large Former Mill Tailing Site

Uranium, Metals Thermal (ERH-VR) Confidential

7Groundwater and Soil Remediation for Hexavalent Chromium

Chromium Bioremediation, Excavation Western US

8Innovative and Sustainable Treatment of Metals Impacted Water in a Mine Pit Lake

Metals Water Treatment Confidential

9Biological Treatment of Mine Water Containing Nitrogen Compounds, Sulfate and Metals

Ammonium, Nitrate, Sulfate, Trace Metals

Biological Water Treatment South America

10In-Situ Bioremediation of Nitrate, Ammonia and Chlorinated Solvents at a Fertilizer Manufacturing Facility

Nitrate, Ammonia, CVOCs

Bioremediation Georgia

Case Study #


Pioneering Solutions: Large Diffuse Plumes

11Closure of a 3-Mile TCE Plume at Reese Air Force Base

TCEEnhanced Reductive Dechlorination, Directed Groundwater Recirculation, Monitored Natural Attenuation

Texas

12Leveraging Next Generation Characterization Techniques to Support Flux Focused Remediation

TCE Bioremediation California

13Use of Phytoremediation to Correct Groundwater Hydraulics Upgradient of a Permeable Reactive Barrier

TCEPhytoremediation, Permeable Reactive Barrier

Missouri

Pioneering Solutions: NAPL Management

14Remediation of an 8-Acre Residual LNAPL Source and an MTBE/TBA Plume

LNAPL (gasoline, diesel), BTEX, MTBE, TBA

Soil Vapor Extraction, Excavation, Groundwater Extraction and Treatment, Hydraulic Control, Dewatering

California

15In Situ Soil Mixing and Enhanced Reductive Dechlorination for DNAPL Source Treatment

VOCs, DNAPL

In Situ Soil Mixing with Zero Valent Iron and Clay, Enhanced Reductive Dechlorination, Monitored Natural Attenuation

Missouri

16Managing NAPL Seepage at the Pine Street Canal Superfund Site

Coal Tar, PAHs, NAPL Reactive Cap Construction Vermont

17Thermal Remediation of DNAPL at a Former Bicycle Manufacturing Site

PAHs, Chromium, Xylene, Vinyl Chloride, TCE

Excavation, Thermal Remediation and Vapor Recovery, Engineered Cap Installation

Illinois




Case Study #


Pioneering Solutions: Vapor Intrusion

18Vapor Intrusion Assessment and Mitigation at a Former Industrial Facility

PCE, TCE

In Situ Reactive Zone, Air Sparge/Soil Vapor Extraction, Enhanced Reductive Dechlorination, In Situ Chemical Oxidation

Indiana

19Base Activated Persulfate Oxidation of VOCs to Meet Indoor Air Inhalation Criteria

CVOCs, BTEX, MIBK, MEK

In Situ Chemical Oxidation, Excavation and Stabilization

Michigan

20Remediation of a Fractured Bedrock Aquifer Impacted by Chlorinated Solvents

TCA, DCE, TCE Enhanced Reductive Dechlorination Colorado

21USEPA Applied Research Program: Assessing Vapor Intrusion Temporal and Spatial Variability using Radon and Volatile Organic Compounds

PCE, TCE, Chloroform, Radon

Research Program, Vapor Intrusion Assessment

North Carolina

Pioneering Solutions: Emerging Contaminants

22Enhanced Sulfolane Removal using a Biological Granular Activated Carbon Treatment System

Sulfolane Biological GAC California

23In Situ Chemical Oxidation to Remediate an Industrial Site Contaminated with Tetrahydrofuran

Tetrahydrofuran ISCO The Netherlands

Pioneering Solutions: Site Closure and Other Strategies

24Thermal Remediation of a Former Dry Cleaner Site

PCE, CVOCs Thermal (ERH) Illinois

25 Former Tank Battery RemediationPetroleum Hydrocarbons, Produced Water/Brine

Landfarming, Monitored Natural Attenuation

Kansas

26In Situ Chemical Oxidation and Stabilization via Soil Mixing for BTEX Remediation

BTEXExcavation, In Situ Chemical Oxidation, Stabilization

Georgia

Case Study #


27Stabilization and Solidification to Address Coal Tar Contamination

Coal Tar In Situ Stabilization/Solidification Minnesota

28Minimizing Landfill Impacts on an Adjacent Wetland

MetalsHydraulic Containment (sheet pile wall, interceptor trench), pH Adjustment, Filtration

Michigan

29 Active Bulk Terminal RemediationVOCs, Ketones, Aromatic Hydrocarbons

Soil Vapor Extraction, Multi-Phase Extraction, Groundwater Extraction, Treatment, Amendment and Reinjection

Minnesota

30Development of Site-Specific Target Soil Concentrations to Reduce Remediation Costs at a Pesticides Contaminated Site

Pesticides (hexachlorocyclohexane, toxaphene, chlordane)

Excavation Florida

31 Remediation of a Former Natural Gas Plant SiteVOCs, SVOCs, Arsenic, Lead, Mercury, PCBs, Produced Water/Brine

Excavation, Landfarming, Soil Vapor Extraction, Biosparge, Air Sparge

Kansas

32 Produced Water Brine Plume Control Produced Water Groundwater Extraction Kansas

Fostering Innovation: Technology Development and Demonstration

33Tailored Granular Activated Carbon Treatment of Perchlorate in Drinking Water

Perchlorate, TCE Tailored Granular Activated Carbon California

34Comparison of Advanced Geophysical Sensors for Classifying Buried Munitions

Buried MunitionsTechnology Development and Demonstration

US

35Advanced Ground Water Treatment Research Program for Hexavalent Chromium Removal from Drinking Water

Chromium Water Treatment Research Program California

36Alternative Endpoints for Groundwater Remediation at Highly Complex Sites

Various Various US

Case Studies




Case Study #


Industry Leadership: Performance Based Remediation

37 Remediation of a Retail Portfolio of 775 SitesPetroleum Hydrocarbons, Fuel Oxygenates, LNAPL

Various US

38Accelerating the CERCLA Process at 30 Areas of Concern at Lake City Army Ammunition Plant

CVOCs, Petroleum Hydrocarbons, Lead, Explosives

Various Missouri

39Performance Based Remediation of a Site Impacted by PCE

PCESoil Vapor Extraction, Enhanced Reductive Dechlorination, In Well Sparging

Massachusetts

40Plume Management Zone for Soil and Groundwater Semi-Volatile Exceedances

SVOCs, Methylnaphthalene, Benzo(a)pyrene, TPH

Institutional Controls, Plume Management Zone

Texas

41Mass Flux Focused Remediation of a Chlorinated Solvents Plume

CVOCs Enhanced Reductive Dechlorination California

Building World Class Teams: Academic Partnerships

42Evaluating NAPL Source Longevity at Contaminated Sites

NAPLThermally Enhanced Extraction, Innovative Tools/Models

Arizona

43Development of USEPA Conceptual Model Scenarios for the Vapor Intrusion Pathway

VOCsVapor Intrusion Pathway 3-D Modeling

US

44Field Evaluation of Point Velocity Probes (PVPs), a New Groundwater Characterization Technology

Arsenic, Lead Point Volicity Probes Carolina

Case Study #


Frontiers in Remediation: Global Expertise

45In Situ Chemical Oxidation for Carbon Disulfide Treatment

Carbon Disulfide In Situ Chemical Oxidation United Kingdom

46Xiawangang Canal Sediment Remediation Project

Cadmium, Arsenic, Lead, Mercury, Copper, PCBs, Pesticides, PAHs

Multiple Sediment Remediation Technologies

China

47Enhanced Reductive Dechlorination of a High Concentration CVOC Plume

CVOCs Enhanced Reductive Dechlorination Belguim

48Bioprecipitation of Hexavalent Chromium and Enhanced Reductive Dechlorination of TCE in Groundwater

Chromium, VOCs, Petroleum Hydrocarbons

Bioremediation France

49 Oil and Gas Well Site Reclamation Program Petroleum Hydrocarbons, PCB, Arsenic, Mercury

Various Canada

Safety First: Integrating Health and Safety into Remediation Projects

50Health and Safety: Time Critical Removal Action in Arroyo with 30 Degree Slope

Various Time Critical Removal Action California

Case Studies

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At ARCADIS, our mission is to improve quality of life by providing sustainable solutions that enhance the built and natural environment. This enables us to produce exceptional value for our clients, employees, shareholders, and society. To fulfill our mission, we strive to reach the delicate balance between the creative and the functional, the innovative and the proven, ecology and economy, and between present needs and future legacy.

We envision a better world – then we engineer it. At ARCADIS, we are committed to leaving the environment and the places we touch better than we found them. With this vision, we approach our work differently from other consultants – we’re the singular firm with the focus, local capabilities and global expertise to meet our clients’ current and future needs. Ranked a top provider of environmental services by ENR, and with a track record of successful world-class projects, we have unparalleled resources, experience, and technical knowledge to follow through with our commitments.

This booklet presents 50 Case Studies that were selected to illustrate our breadth of global remediation experience as well as our capacity for remedial success through the effective design and deployment of ex situ technologies, in situ technologies, or combinations thereof, to address a wide range of soil and groundwater contaminants. These Case Studies are organized in this booklet around key technical differentiators that best demonstrate ARCADIS’ thought leadership in the industry.

Frontiers in Remediation: Sustainability by DesignRecognizing that every project is directly linked to the global environment, we continually invest in technologies, processes, products, and services that create and maintain sustainability. We carefully consider the environmental impacts of site cleanup activities to maximize net benefits by keeping in mind the triple bottom line. To better support sustainable remedial decision making, we developed a quantitative tool to evaluate individual metrics, such as energy, water, greenhouse gas, and carbon as a whole, and aggregate this diverse set of relevant parameters into a single unit of measurement. This proprietary tool, called The BalancE3™ Tool, can support corporate goals in achieving social equity and economic and environmental sustainability. To learn more about how we’ve integrated sustainability in our remediation projects, see Case Studies 1 through 3.

Frontiers in Geochemistry: Metals, Radionuclides and InorganicsThe multi-national community of talented scientists and engineers that staff our geochemistry practice provide unique expertise at sites impacted with metals, radionuclides, and non-metal inorganics. Based on advanced geochemical characterization methods and data evaluation techniques, our geochemists have the ability to build accurate conceptual site models that support remedial decision making. By employing a comprehensive understanding of biogeochemical systems, we have developed effective and sustainable solutions to our clients’ most challenging problems as demonstrated in Case Studies 4 through 10.

Pioneering SolutionsOur technical experts change industry paradigms, patent innovative technologies, and regularly author state-of-the-science articles, presentations, and books on cost-effective solutions to today’s toughest site investigation and remediation challenges. The following are a few technical challenges that necessitated us to pioneer creative remedial solutions:

• Large Diffuse Plumes (Case Studies #11 through 13)

• NAPL Management (Case Studies #14 through 17)

• Vapor Intrusion (Case Studies #18 through 21)

• Emerging Contaminants (Case Studies #22 through 23)

• Site Closure and Other Strategies (Case Studies #24 through 32)



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Fostering Innovation: Technology Development and DemonstrationAt ARCADIS, innovation is a cornerstone of our culture. We promote an entrepreneurial spirit within our technical communities, and emphasize the importance of identifying and demonstrating new and innovative technologies that can support more effective, efficient, and sustainable restoration of environmentally impacted sites. We are currently working on new technologies for metals remediation, perchlorate and chromium removal from drinking water, geophysical sensors for classifying buried munitions, and more (see Case Studies #33 through 36). When we implement a new or innovative approach, we dedicate our own resources to develop a deep understanding of the fundamental principles that control process and performance, and bring our experience in other areas to bear on implementation.

Industry Leadership: Performance Based RemediationARCADIS developed the concept of guaranteed fixed-price remediation decades ago and grew it into a highly successful business model. Today, many commercial and federal clients are awarding environmental restoration projects using performance based remediation contracts. The result is not only cost savings to clients, but also freedom from future remediation responsibilities and regulatory uncertainty. ARCADIS is an industry leader in the successful execution of performance based remediation for the Department of Defense, with over 30 projects either completed or in progress at a value exceeding $430 million. We have also demonstrated successes for commercial clients both in terms of our ability to utilize innovative remedial strategies to drive sites to closure, and in working with regulatory agencies to negotiate optimum endpoints and keep remedial progress on schedule (see Case Studies #37 through 41).

Building World Class Teams: Academic PartnershipsAt ARCADIS, we believe that knowledge drives successful outcomes. We break the barriers erected through the “knowledge is power” mindset and reward staff for knowledge sharing. Our environmental professionals from different business units and global offices are encouraged to collaborate and push boundaries to deliver optimal client-focused solutions. Our unique and global Technical Knowledge and Innovation (TKI) program provides a formal framework for knowledge exchange,

technical collaboration, training, and quality assurance — all embedded within a culture of continuous improvement and innovation. In our quest to build world class teams to better serve our clients, we often partner with researchers at universities if we lack internal resources and associated technical knowledge. Academic partnerships provide unique training opportunities for our employees on leading edge technical advancements and next generation technologies (see Case Studies #42 through 44).

Frontiers in Remediation: Global ExpertiseToday, ARCADIS maintains its dedication to innovation and excellence as we continue to build our global footprint to more effectively serve our clients. With 16,000 employees and more than $2.7 billion in revenues, ARCADIS has an extensive international network supported by strong local market positions. For examples of how we leverage our global expertise to meet client needs internationally, see Case Studies #45 through 49.

Safety First: Integrating Health and Safety into Remediation ProjectsProviding a healthy and safe work environment is an integral part of our values and a key element of the solutions we provide for our clients. We believe that health and safety on the job is a major concern of our clients, who demand robust programs involving continuous improvement, strong leadership, and employee engagement. We address these concerns through our risk and behavior-based health and safety management program. We proactively identify and prioritize risks in our work, and develop robust approaches to eliminate or minimize these risks. As a result, work-related injury and illness rates are currently below industry benchmarks (see Case Study #50).

Please contact us if you have any questions, require additional information, or if we can be of assistance to you.

Suthan S. Suthersan, PhD, PE

Chief Technical Officer

[email protected]

Rula A. Deeb, PhD, BCEEM

Technical Director - Outreach

[email protected]

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Frontiers in Remediation:Sustainability by Design

1frontiers in remediation



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1

The ChallengeHistorical TCE impacts in groundwater at the Fort Gordon Military Reservation resulted from waste solvent disposed in a drain that discharged to a sump and clay tile leach field. The TCE plume migrated under ambient groundwater conditions from the original source area to approximately 1800 feet downhill toward a receiving tributary. The shallow impacted soils in the source area were removed by excavation as an Interim Measure in 2005. However, significant groundwater impacts remained after this action.

The water table aquifer is 100 to 200 feet thick, has low to medium permeability, and yields very low volumes of water due to its high clay content. At the base of the hill, artesian groundwater conditions exist that result in upward plume transport toward the stream and surrounding flood zone. An active remediation approach was initially requested by the regulatory agencies to address the remaining groundwater impacts and to ensure long-term protectiveness of the tributary. However, the remoteness of the site, combined with a mature native forest overlying the groundwater plume and sensitive ecological receptors presented significant access limitations.

The ApproachARCADIS screened remediation options for their overall efficacy in eliminating plume migration to the unnamed tributary and the anticipated impacts of construction activities to the native forest habitat and the ecological receptors that reside in the area. A carbon footprint analysis for each remediation alternative was completed using the ARCADIS BalancE3® Tool to compare the overall potential benefits of the selected remedy. The ARCADIS BalancE3® Tool provides a quantitative means to determine environmental, social, and economic impacts associated with remediation decisions that will be made throughout the lifecycle of a remedy.

The selected remedy was a novel artesian treatment vessel that functions effectively in these challenging site conditions. The vessels require zero energy input. ARCADIS installed a network of passive artesian “extraction” wells along the flood plain of the receptor stream. The wells are screened in the core of the plume to fully capture impacted groundwater. Upon surfacing under natural artesian conditions, the impacted groundwater is directed to customized vessels that contain liquid phase granular activated

ClientFort Gordon Military Reservation

Scope of ServicesGuaranteed Fixed Price Performance-based Remediation, Innovative Sustainable Remedy Development, Sustainability Evaluation

Performance Period2009 through Present

ContaminantsTCE

Project GoalEliminate the discharge of TCE-contaminated groundwater to a tributary while minimizing impacts to the native forest habitat in a remote area of Fort Gordon.

ARCADIS StrategyExploit naturally occurring artesian conditions at the site to design a totally passive (zero energy input) remedy which can meet cleanup objectives.

Project AccomplishmentsARCADIS designed and implemented an elegant passive and sustainable remedy that leveraged natural site hydrogeologic conditions and fully met remedial objectives. The final remedy design minimized disturbance to the natural habitat, requires no moving mechanical parts, consumes no external power source or water, and has no direct air emissions or operational noise. All stakeholders collaborated through the remedy selection and design thereby maximizing support for the implementation of the final remedy.

Artesian Treatment Vessels: A Sustainable In Situ Remediation SystemAugusta, Georgia

Artesian Treatment Vessels: A Sustainable In Situ Remediation System

Augusta, Georgia

carbon. The vessels are installed below the land surface to minimize habitat impacts. The natural ambient hydraulic gradient is sufficient to convey the impacted water through the vessels where it undergoes full treatment. The treated water is then discharged to a gravel apron in the flood plain. This approach requires no energy input, pumps or other mechanical equipment, and results in no consumptive use of water. The operation and monitoring activities can be conducted during regularly scheduled groundwater monitoring events, and carbon change-outs are expected only once every 5 to 7 years.

The ResultA detailed remedy evaluation, a highly accurate understanding of the site hydrogeology, and a life cycle approach to remedy design guided the ARCADIS team to develop an innovative and simple strategy that minimized resource consumption and reduced ecological impacts. The reliance on natural hydraulic gradients and gravity resulted in a sustainable remediation system and a minimal impact on the environment while providing protection to a sensitive riparian zone. Our innovative remedy resulted in savings of approximately 50 metric tons of CO2 equivalent over the 30-year remedial lifecycle. Throughout the design process, stakeholders were engaged to ensure that the final design met their expectations. This collaboration gained both stakeholder support and maximized acceptance the final remedy implementation.

Conceptual schematic presenting extraction well and ATV configuration (at left). Groundwater extraction is facilitated via differential pressure differences and funneled to a vertical liquid phase carbon vessel prior to discharge

Conceptual geological cross section showing location and vertical interval of artesian extraction wells. Twenty total wells and five total ATVs provide plume capture along the unnamed tributary floodplain. Red dashed line represents the water elevations along plume flow path in deeper monitoring wells

TREATMENT WELL DEEP WATER LEVELS




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2

The ChallengeIn 2008, Hurricane Ike caused extensive damage to the Gulf Coast region including the NASA Johnson Space Center (JSC) campus in Houston, Texas. In an effort to avoid landfill disposal of waste and debris, many of the trees downed by the hurricane were chipped into 1,500 cubic yards of mulch and retained for future use at the site. ARCADIS developed a strategy that uses the mulch in a permeable reactive barrier (PRB) for the biological treatment of chlorinated solvents in groundwater at the site. The use of downed trees and debris from Hurricane Ike as mulch material for the biowall has increased sustainability for the groundwater remediation at the site, reduced waste generation from the site, and lowered restoration costs for the Client.

The ApproachResults from baseline groundwater sampling and a bench scale test indicated that site conditions are conducive to chlorinated solvent degradation stimulated by the addition of a mulch biowall. To fulfill NASA’s interest in incorporating sustainable practices during site remediation, the ARCADIS team integrated sustainable remediation practices into the design and operation of five proposed remedial alternatives. The remedial alternatives included four biowall designs and monitored natural attenuation, and incorporated best practices such as the use of onsite renewable biological resources as reactive media (the onsite mulch), re-use of extracted water in a biowall alternative with recirculation of groundwater, use of onsite injectable substrate, and reliance on local vendors.

Sustainable Remediation: The Johnson Space Center Mulch Biowall ProjectHouston, Texas

Sustainable Remediation: The Johnson Space Center Mulch Biowall Project

Houston, Texas

ClientNational Aeronautics and Space Administration (NASA)

Scope of ServicesSite Investigation, Treatability Testing, Remedy Selection, Sustainability Evaluations


ContaminantsPCE, TCE, DCE, VC

To further minimize the environmental footprint and to identify opportunities to enhance the environmental outcome, a quantitative sustainability assessment was performed for the remedial alternatives using the BalancE3® Tool. This comprehensive analysis included five metrics energy consumption, air emissions, water requirements, material consumption/waste generation, and land impacts. Metric quantification included onsite activities as well as transportation associated with the movement of materials to and from the site. The selected alternative is a mulch biowall PRB with installed horizontal piping for injectable substrate delivery. The addition of installed piping allows for the periodic renewal of the carbon content of the wall, eliminating the need for biowall replacement once the mulch carbon content is exhausted, thereby significantly decreasing overall environmental impacts.

The ResultThe plan for the JSC mulch biowall PRB was presented to the Texas Commission on Environmental Quality in a formal Remedial Action Plan in 2011 and will be implemented in 2012.

Project GoalIncorporate sustainable remediation practices as requested by the Client into a response action to address chlorinated solvents in groundwater.

ARCADIS StrategyEvaluate multiple sustainable remedial alternatives, including the use of mulch from trees downed by Hurricane Ike at the site in a subsurface biowall to avoid landfill disposal of waste. Identify opportunities to maximize the environmental outcome by incorporating best practices for sustainable remediation and by using sustainability tools to evaluate the design and operation of different remedial alternatives.

Project AccomplishmentsBench scale testing indicated that site conditions are conducive to enhanced chlorinated solvent degradation stimulated by the addition of a mulch substrate. The proposed remedy, which incorporates a subsurface mulch biowall as a permeable reactive barrier for chlorinated solvents in groundwater, was approved by the Texas Commission on Environmental Quality (TCEQ) and is currently scheduled for implementation.

Downed trees at JSC following Hurricane Ike

Proposed location of parallel mulch biowalls at JSC (in orange) and approximate extent of the groundwater plume (in yellow).




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3

The ChallengeHistorical operation of the hydrocarbon recovery facility and an adjacent large petroleum refinery impacted groundwater with approximately 2 million gallons of free product. An environmental forensics analysis and detailed assessment of existing site data revealed the distribution of crude oil, diesel, and gasoline within several distinct and commingled areas. Additional site investigation efforts led to the identification of onsite sources. Once the impacted areas were fully delineated, a sustainable approach to petroleum product recovery was developed and implemented.

The ApproachMultiple renewable energy technologies and resources were integrated over time to develop an adaptive design that met the increasing energy demands of the recovery system. Phase I, installed in 2001, consisted of six fluid pneumatic pumps powered by four windmills. A fiberglass gathering system was constructed to collect and convey free product and groundwater to the adjacent oil refinery which purchased the recovered oil. The refinery had an existing wastewater treatment system which was used to treat the groundwater, thereby eliminating the need to construct and operate a new system. These cost savings and the re-use of existing infrastructure added additional sustainable elements to the project. The treatment system has performed consistently well, with minor down time for maintenance

Project GoalRecover non-aqueous phase liquids (NAPL) from groundwater at a RCRA site and fully incorporating sustainable practices into the selected remedy.

ARCADIS StrategyUse sustainable design principles to develop a recovery system for free product with minimal waste generation, air emissions, and grid electricity consumption.

Project AccomplishmentsTo date, around 367,000 gallons of free product have been reclaimed, which amounts to 30% of total estimated releases. Recovered petroleum product was transferred to an adjacent oil refinery, generating revenue and avoiding transportation-related air emissions and waste. The petroleum recovery system uses renewable energy instead of grid electricity, thus further reducing air emissions.

ClientConfidential Client

Scope of ServicesHydrocarbon Recovery, Sustainable Remediation


ContaminantsNAPL (crude oil, diesel, gasoline)

Sustainable Approach to Product RecoverySt. Croix, U.S. Virgin Islands

Sustainable Approach to Product RecoverySt. Croix, U.S. Virgin Islands

despite highly corrosive local conditions. Phase II was installed in summer 2004 and consists of six solar panels and six downhole submersible electric pumps powered exclusively by solar panels. The Phase III system expansion occurred in summer 2007 with the goal of increasing hydrocarbon production by installing additional power sources and by adding additional recovery wells screened over a larger vertical distance to enhance oil recovery. Four additional solar panels and three electric wind turbines were installed to power the new downhole submersible pumps and floating oil skimmers.

The ResultTo date, approximately 367,000 gallons of free product have been reclaimed. This accounts for approximately 30% of the total estimated release volume. The transfer of recovered petroleum product to an adjacent oil refinery for re-use as a feed stock avoided offsite transfer and disposal, thereby reducing air emissions and waste generation. The sale of the recovered product also helped reduce overall project costs. This project was highlighted on the cover of USEPA’s publication

“Green Remediation: Incorporating Sustainable Environmental Practices into Remediation of Contaminated Sites” dated April 2008.

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Frontiers in Geochemistry:Metals, Radionuclides and Inorganics




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4

The ChallengeHistorical activities associated with metal smelting, metal concentration operations, and zinc sulfate manufacturing resulted in the presence of cadmium, lead, and zinc in site soils and lagoon sludges at concentrations that rendered the materials hazardous. Elevated concentrations of zinc were also present in groundwater as well as surface water discharging through site outfalls. Due to multiple property transactions over time, environmental liabilities and obligations were distributed among multiple former owners and remedial activities had to be completed with the cooperation of the current property owner.

The ApproachThe strategy for site closure included several elements First, ARCADIS placed an asphalt cap over a large area with contaminated soils to eliminate direct contact with the metals-bearing soils, reduce leaching of metals from soil to groundwater by limiting infiltration, and povide additional parking for the facility. Second, ARCADIS performed a risk assessment and developed a groundwater fate and transport model to gain acceptance of monitored natural attenuation as a remedy for the zinc groundwater plume. Third, following a decision to stabilize all lagoons to achieve certain bearing strengths and allow the construction of stormwater treatment cells on the footprint of the former lagoon area, a total of 35,000 cubic yards of sludge was stabilized in place using 10% Portland Cement (by weight).

Cost-Effective Closure of a Former Chemical Manufacturing FacilityPortsmouth, Virginia

Cost-Effective Closure of a Former Chemical Manufacturing Facility

Portsmouth, Virginia

ClientConfidential Chemical Client

Scope of ServicesSite Investigation, Risk Assessment, Groundwater Modeling, Soil Remediation, Groundwater Remediation, Regulatory Negotiation, Surface Water Treatment

Performance Period1999 through 2009

ContaminantsCadium, Lead, Zinc

The ResultFive wastewater treatment basins and one sludge drying bed existed at the facility. ARCADIS was successful in classifying four of the lagoons with metals-bearing sludges as non-hazardous through a statistical evaluation of analytical data. All the lagoons at the facility were stabilized to achieve certain bearing strengths and to allow the construction of stormwater treatment cells on the footprint of the former lagoon area. Following stabilization and grading, a man-made wetlands system consisting of a stormwater pond, two vertical flow cells, and a polishing pond was constructed on top of the stabilized area for surface water treatment. Impacted stormwater was pumped to the stormwater pond, distributed to the vertical flow cells for treatment, released to the polishing pond, and then discharged to the Elizabeth River. The Consent Order resulting from periodic NPDES exceedances of zinc was closed at the completion of this project.

Project GoalCost-effective closure of a former chemical manufacturing facility with metals-impacted soils and lagoon sludges, and elevated levels of zinc in groundwater and surface water.

ARCADIS StrategyConstruction of an asphalt cap to limit direct contact with metals-impacted soils. In Situ stabilization/solidification of metals-impacted lagoon sludges and construction of a passive surface water treatment system on top of the stabilized area. Monitored natural attenuation for metals in groundwater.

Project AccomplishmentsRemediation activities were successfully conducted in cooperation with the current property owner and a Consent Order was closed at the completion of the project.

A total of 35,000 cubic yards of sludge present in the lagoons was stabilized




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5

The ChallengeThis facility has been historically operated for the processing of uranium. ARCADIS was contracted to design and implement an anaerobic In situ Reactive Zone (IRZ) to expedite the remediation of uranium-impacted groundwater and to significantly reduce the time required to achieve groundwater standards. ARCADIS was also contracted to handle regulatory negotiations to achieve approval and acceptance of the remedial approach.

The original size of the uranium plume at this site was just under 0.75 acre with concentrations ranging from 30 to 2,700 micrograms per liter. The uranium plume is located in an unconsolidated alluvium aquifer comprised of silt, clay, clayey sand, gravel, and cobbles. In addition, a primary source of uranium contamination is located underneath one of the site buildings, a complication that ARCADIS was able to account for in the remedy design.

Project GoalRemediation of chlorinated solvents (PCE) and radionuclides (uranium) in groundwater utilizing enhanced in situ anaerobic reductive dechlorination/precipitation to treat the plume area and prevent the off-site migration of impacted groundwater.

ARCADIS StrategyDesign and implement a remedy to simultaneously treat both PCE and uranium. ARCADIS’ approach consisted of a phased implementation of an anaerobic In situ Reactive Zone (IRZ) to stimulate the microbial precipitation of uranium and the reductive dechlorination of PCE through the delivery of a carbon susbstrate followed by the addition of ferrous sulfate to promote the formation of an insoluble mineral form of uraninite.

Project AccomplishmentsPCE and uranium concentrations in the treatment areas have been reduced by approximately 90% to levels below the MCLs for the target constituents of concern. The ARCADIS team successfully implemented an injection-based strategy to promote reductive dechlorination of PCE while at the same time reductively precipitating uranium. The final polishing element of the remedy incorporated an engineered in situ chemical stabilization step to mitigate potential uranium dissolution after completion of the biological treatment phase.


Scope of ServicesPilot Testing, Full Scale Remedy Implementation, Regulatory Negotiation, Confirmation Sampling

Performance PeriodJanuary 2000 through Present

ContaminantsUranium, PCE

In Situ Remediation of a Mixed Uranium and PCE PlumeSoutheastern United States

In Situ Remediation of a Mixed Uranium and PCE PlumeSoutheastern United States

The ApproachARCADIS developed a remedial strategy involving the phased implementation of an in situ anaerobic IRZ® technology to reductively dechlorinate TCE tetrachloroethene and to precipitate uranium. The first phase consisted of a pilot demonstration and was followed by a full scale implementation. Monthly injections of organic carbon were performed to establish and maintain the reactive zone. Under reducing conditions, soluble uranium is converted to the insoluble mineral form uraninite. Injections were augmented with ferrous sulfate to promote the formation of reduced ferrous sulfide minerals which coat aquifer grains to physically encapsulate the uraninite and maintain reducing conditions for significant time periods (thereby protecting the uraninite from re-oxidation).

Microbial precipitation of uranium

The Result Based on the results of the pilot test, the implementation of the full scale remedy was initiated in June 2002. The system consisted of up to 24 injection wells for application of reagent mixtures, and up to 16 monitor for performance monitoring. Performance monitoring began in December 2002 and continued through 2011. Performance monitoring of the full-scale demonstration has confirmed the continued destruction and precipitation of chlorinated volatile organic compounds (CVOCs) and uranium, respectively. The expanded area of reagent injection has resulted in a substantially smaller impacted area (defined as having concentrations greater than the maximum contaminant level [MCL]). Uranium stabilization via ferrous sulfate was initiated in 2007 with a pilot test and then expanded in subsequent years. The addition of ferrous sulfate for stabilization has continued through 2011 to prevent the resolubilization of uranium as oxygen reenters the aquifer (i.e., oxygen reacts with the excess iron).

As of 2011, full scale remedial injections have added a total of 76,834 pounds of organic carbon and 42,363 pounds of ferrous sulfate. The impacted area for uranium has been reduced by approximately 90% of the baseline impacted area to below the MCL. Initiation of closure monitoring in approximately 0.4 acres of the treatment zone took place in 2009 after monitoring results showed sustained CVOC and uranium concentrations below MCLs. To date, CVOCs and uranium concentrations have been observed to rebound. Currently, the closure monitoring area is being expanded to include additional areas where contaminant concentrations have decreased below MCLs.




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6

The ChallengeHistorical operations at a former mill site affected a groundwater aquifer system with uranium, molybdenum, selenium, and other metals. The site is in the process of restoring and hydraulically containing contaminated groundwater using a pump and treat system. While pump and treat has been successful at containing the plume, performance data do not provide a clear indication about the timeframe needed to meet remedial goals. Alternative restoration approaches are needed to aggressively reduce the remedial timeframe and drive the site to closure. In addition, the current treatment system requires an evaluation to improve the performance of ex-situ water treatment.

The ApproachARCADIS developed a comprehensive program to assist with source evaluation, alternative approaches to groundwater restoration, and water treatment system optimization. The project utilized key resources from across ARCADIS to meet Client needs. This included pilot testing of in situ groundwater treatment approaches for uranium and metals, and detailed tracer studies of water movement through mill tailings. The groundwater geochemical environment is challenging due to high concentrations of dissolved solids. ARCADIS performed a detailed evaluation of the geochemistry to develop more efficient remedial strategies. Malcolm Pirnie, the Water Division of ARCADIS, also provided operational assistance with the water treatment plant, and has diagnosed and addressed limitations to treatment processes.

Project GoalAdvance a former uranium mill site towards site closure by addressing groundwater contaminated with uranium and other metals.

ARCADIS StrategyDevelop a comprehensive program to evaluate and identify sources, perform geochemical analyses to assess soils and groundwater, optimize the water treatment system, and develop alternative approaches for groundwater restoration.

Project AccomplishmentsThrough process optimization, ARCADIS is has decreased the projected remedial timeframe and has improved the performance of the existing treatment system. We are currently developing an innovative in situ remediation strategy to augment the existing pump and treat system.

ClientConfidential Mining Client

Scope of ServicesSite Investigation and Remediation, Water Treatment, Geochemistry


ContaminantsUranium, Metals

Remedy Optimization to Achieve Site Closure at a Large Former Mill Tailing SiteConfidential Location

Remedy Optimization to Achieve Site Closure at a Large Former Mill Tailing Site

Confidential Location

The ResultRemedial timeframes and limitations of the existing remedial strategy have been identified and are being addressed through process optimization. Our multi-disciplinary team is developing an innovative approach for the in situ treatment of groundwater to augment the existing pump and treat system, and where appropriate, replace the system to provide sustained long-term treatment capacity. Through close collaboration between scientists and engineers, our team has improved site operations, enhanced stakeholder communication, and is working to achieve optimized remedial performance to advance the site to closure.




Page 28 Page 29

7

The ChallengeExtensive historical operations contaminated soil and groundwater with Cr(VI) at a former wood pressure-treating facility. A groundwater extraction, treatment, and re-injection system was installed in 1995 in an attempt to remove Cr(VI) from groundwater and soil via flushing. However, the treatment plant was expensive to operate and the approach required several decades to meet remedial objectives.

The ApproachHydrogeologic evaluations and groundwater modeling were conducted to optimize the performance of the groundwater extraction system. Using the MODALL application, ARCADIS demonstrated that plume capture could be enhanced by focusing extraction. Field studies tested the effectiveness of in situ anaerobic bioremediation to further treat groundwater at the site. Following excavation of shallow source area soil, anaerobic bioremediation studies in the deep vadose zone were conducted.

Project GoalObtain closure at a former wood pressure-treating facility where groundwater and soil are contaminated with hexavalent chromium.

ARCADIS StrategyFocus groundwater extraction to enhance plume capture and significantly reduce treatment costs. Implement an in situ remedial technology combined with excavation of shallow source area soil to expedite remedial timeframes.

Project AccomplishmentsIn situ bioremediation reduced Cr(VI) concentrations in groundwater by three orders of magnitude to less than 1 µg/L. ARCADIS’ comprehensive remedial approach has reduced treatment costs at the site by approximately $20 to $30 million. We expect to receive regulatory closure within 8 years.


Scope of ServicesGroundwater and Soil Investigation, Fate and Transport Modeling, Remediation, Regulatory Negotiations, Site Closure

Performance PeriodNovember 2005 through November 2015 (anticipated)

ContaminantsCr(VI)

Groundwater and Soil Remediation for Hexavalent Chromium Western United States

Groundwater and Soil Remediation for Hexavalent Chromium

Western United States

The ResultWithin 18 months of contract award, site regulators approved full scale in situ anaerobic bioremediation for groundwater treatment. After four years of injecting electron donors, Cr(VI) was eliminated from the upper groundwater system. Active remediation in the deeper saturated zone was conducted in 2011 and 2012, and the area is currently being assessed to determine if closure criteria have been met. Remediation of Cr(VI)-impacted deep vadose zone soils using high-pressure direct push injections and 40 gravity-fed injection wells is expected to be completed by mid-2012. By optimizing the remedy and moving from ex-situ to in situ treatment, ARCADIS’ remedial approach has saved $20 to $30 million in restoration costs, and has reduced remedial timeframes to approximately 8 years.

© 2010 ARCADIS3 May 20121

Figure 2

3,00

0 FT

Former Source Area (~200 ft x 200 ft)

10 µg/L

Upper Sand Unit Cr(VI) Plume 2012

© 2010 ARCADIS3 May 20121

Figure 1Site Map with Baseline Chromium Plume

3,00

0 FT

Former Source Area (~200 ft x 200 ft)




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8

The ChallengeAn existing pit from prior hard rock mining has resulted in a large pit lake. The concentrations of metals in the lake have increased over time, resulting in the need for treatment. Conventional water treatment through pumping the water then treating using ion exchange resins is not favorable due to residuals management concerns and challenging geochemical conditions resulting in very stable soluble metal form in the pit lake.

The ApproachARCADIS performed a detailed study of pit lake chemistry, including an investigation of the temperature and water chemistry profile with depth. A team of geochemists, remediation engineers, and water treatment experts developed an in-lake treatment approach based on a better understanding of the water chemistry. The approach was vetted through proof-of-concept testing at the bench scale level, followed by intermediate scale testing using 3,000-gallon test vessels that were assembled at the mine. A preliminary engineering design followed.

Project GoalDesign and test a cost-effective treatment alternative for a mine pit lake

ARCADIS StrategyDevelop an in-lake treatment strategy to precipitate metals from surface water in a stable form and provide treated water for re-use in mining processes.

Project AccomplishmentSuccessfully completed bench scale and intermediate-scale testing, and a preliminary engineering design. The alternative treatment approach was proven to be economical, technically sound, and preferable to conventional pump and treat approaches from a sustainability perspective.


Scope of ServicesWater Treatment, Remedy Design, Geochemistry


ContaminantsMetals

Innovative and Sustainable Treatment of Metals-Impacted Water in a Mine Pit Lake Confidential Location

Innovative and Sustainable Treatment of Metals-Impacted Water in a Mine Pit Lake

Confidential Location

The ResultThe alternative treatment strategy developed by ARCADIS is an in-lake treatment approach. The approach is economical, technically-sound, and proven through extensive testing, for full scale treatment of the pit lake. Chemical amendments were identified that could selectively react with and facilitate the precipitation of targeted dissolved metals. The in-lake treatment strategy replaces conventional water treatment and avoids the need for residuals management. The end result involves stable metal precipitates that are resistant to leaching over the long-term. Once implemented at the full scale, this sustainable strategy will provide treated water for re-use in mine operations processes.




Page 32 Page 33

9

The ChallengeA large precious metal mine in the Southern hemisphere uses large volumes of water for ore beneficiation processes, including milling. Mine process water, and water produced through pit dewatering activities, is currently being treated by reverse osmosis and acid neutralization. These treatment processes are unable to efficiently meet surface water discharge requirements. A more efficient and cost-effective approach was needed to reduce concentrations of nitrogen species, sulfate, and trace metals.

The ApproachARCADIS scientists, microbiologists, and engineers worked closely to develop an innovative treatment concept for impacted water associated with mine operations. The team developed a biological treatment approach based upon sequenced reactions, then tested the concept at the bench scale at the ARCADIS Treatability Laboratory in Durham, North Carolina. The approach involves an aerobic process, followed by anaerobic treatment to accomplish nitrification, denitrifcation, sulfate reduction, and metal sulfide precipitation. Bench scale tests included an evaluation of carbon sources and treatment kinetics. Results were scaled to develop treatment plans for full scale implementation, with the potential of treating thousands of gallons per minute of mine process water.

Project GoalDevelop and test an efficient and cost-effective method to reduce concentrations of nitrogen species, sulfate, and trace metals in water impacted by mine processes.

ARCADIS StrategyCombine expertise in biogeochemistry and surface water treatment from two ARCADIS business units and two operating companies to develop a sequenced biological treatment approach capable of degrading a mixture of the contaminants of concern.

Project AccomplishmentARCADIS developed and bench tested an innovative biological treatment concept that successfully removed contaminants of concern to below local discharge standards. We are currently designing and optimizing a full scale field implementation for the technology.


Scope of ServicesWater Treatment, Engineering Design, Geochemistry


ContaminantsAmmonium, Nitrate, Sulfate, and Trace Metals

Biological Treatment of Mine Water Containing Nitrogen Compounds, Sulfate and MetalsSouth America

Biological Treatment of Mine Water Containing Nitrogen Compounds, Sulfate and Metals

South America

The ResultARCADIS developed an innovative and cost-effective treatment process for removing ammonium, nitrate, sulfate, and metals from impacted mine process water to meet stringent local discharge standards. Nitrogen species and sulfate concentrations are reduced to the low parts per million range. Trace metals including cadmium, copper, manganese, and zinc that were initially present at tens of parts per million were reduced to less than 0.1 parts per

million. Cyanide that was initially present was destroyed through oxidation and did not affect the biological treatment process. A significant aspect of this work was achieving optimal biological treatment in the presence of high total dissolved solids (>5,000 parts per million). The next step is to demonstrate successful process scale-up through field evaluation, and then optimize the process for high-altitude cold environments. This effort will be co-led by ARCADIS U.S. and local ARCADIS personnel in South America.

Sulfate reduction bench study, early in experiment Sulfate reduction bench study, end in experiment

-60

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-20

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ents

rem

oval

(%)

NH4-N

NO3-N

SO4

mixing andpH adjustment

Nitrification

Denitrification Sulfate reduction

Initial




Page 34 Page 35

10

The ChallengeRemediation of chlorinated solvents in groundwater beneath a major fertilizer manufacturing facility in Georgia is complicated by the presence of elevated concentrations of nitrate and ammonia, which create unique geochemical conditions in the aquifer. Offsite impacts from two neighboring properties are contributing chlorinated solvent the groundwater plume underlying the site. Low hydraulic gradients at the site through shallow unconsolidated sands result in slow advective transport and delay remedial progress.

The ApproachARCADIS conducted a facility investigation, pilot test, and a Corrective Action Plan (CAP) to remediate chlorinated solvents and nitrate in groundwater. The 12-month pilot test using enhanced reductive dechlorination (ERD) began in January 2008. After successfully demonstrating ERD performance in a pilot test at three different areas of the site with different geochemical and hydrogeologic settings, ARCADIS prepared a CAP that included a conceptual design for a full scale implementation of the proposed remedy. While regulatory approval of the CAP was still pending, ARCADIS submitted a workplan to implement two ERD applications as Interim Measures to accelerate source depletion and expedite remediation.

Project GoalRemediate groundwater impacted by chlorinated solvents and nitrate at a major fertilizer manufacturing facility.

ARCADIS StrategyEnhanced in situ biodegradation of contaminants by periodically injecting a carbohydrate solution (whey and molasses) to sustain an anaerobic reducing environment.

Project AccomplishmentsPilot test results showed a greater than 90 percent reduction in concentrations of chlorinated compounds and nitrate. The study demonstrated that enhanced reductive dechlorination (ERD) was feasible and effective in this challenging geochemical environment.


Scope of ServicesSite Investigation, Pilot Test, Full Scale Remedy Implementation

Performance PeriodJanuary 2008 through Present

ContaminantsNitrate, Ammonia, CVOCs

In-Situ Bioremediation of Nitrate, Ammonia and Chlorinated Solvents at a Fertilizer Manufacturing FacilityAugusta, Georgia

In-Situ Bioremediation of Nitrate, Ammonia and Chlorinated Solvents at a Fertilizer Manufacturing Facility

Augusta, Georgia

The ResultUsing the in situ reactive zone (IRZ®) technique, the enhanced reductive dechlorination pilot study established anaerobic conditions in order to overcome and reduce energetically-favorable electron acceptors, specifically nitrate, and also degrade chlorinated solvents to non-toxic endproducts (ethene and ethane). Results from the pilot test indicated a greater than 90 percent reduction in CVOC concentrations over a 12-month period. Overcoming the elevated background nitrogen concentrations required adjustments to the carbon loading and injection frequency. Following optimization of these parameters (increased carbon concentration and frequency of carbon injections), background concentrations of nitrate were also reduced by over 90 percent. Active remediation will continue using the ERD technology until the remedial goals are achieved or contaminant concentrations are low enough to allow transition to a passive remedy like monitored natural attenuation.

Results of the ERD pilot test after 12 months of carbon injections indicated greater than 90% reduction in CVOC concentrations. Further, the background concentrations of nitrate were also reduced by over 90%

Page 37



Pioneering Solutions:Large Diffuse Plumes




Page 38 Page 39

11

The ChallengePast aircraft maintenance operations resulted in a 3-mile by 1-mile TCE plume (known as the Tower Plume) in the Ogallala Aquifer, a primary source of water for the surrounding community in Lubbock, Texas. Tower Plume impacts resulted in groundwater use restrictions requiring client funding of a large wellhead treatment program. Remedial goals included reduction of contaminant concentrations to less than MCLs, preventing plume migration, and restoring offsite groundwater to unrestricted use. A groundwater pump and treat (P&T) system began operation in 1996 with subsequent investigations resulting in system expansions. However, the P&T system performance was limited with the plume failing to contract significantly over time.

The ApproachAfter being awarded a performance based contract in 2004, ARCADIS characterized mass flux through the groundwater system. Operation of the groundwater extraction system was adjusted to focus on high mass flux areas while achieving plume control. In addition, an enhanced reductive dechlorination (ERD) approach incorporating groundwater recirculation was implemented to address high concentration zones. ARCADIS followed an adaptive design process and aggressively made system adjustments based on performance monitoring data. Directed groundwater recirculation (DGR) and monitored natural attenuation (MNA) were implemented to address the remaining plume areas. DGR is based on remediation hydraulics concepts, including the principles that the plume will always migrate through the coarsest fractions of the aquifer, and that high flow zones will have the highest contaminant concentrations and largest mass flux. DGR was thus

Project GoalRegulatory closure by restoring onsite and offsite TCE-contaminated groundwater by 2014.

ARCADIS StrategySystematically use mass flux data to optimize remediation and achieve site closure. Apply combination remedies including enhanced reductive dechlorination (ERD), directed groundwater recirculation (DGR), and monitored natural attenuation (MNA) to address residual contaminant sources, control the plume, and complete remediation to regulatory goals.

Project AccomplishmentsAll compliance point concentrations are below regulatory standards. Post-remediation monitoring has been initiated. DGR accelerated remediation while reducing groundwater extraction rates from approximately 900 to 300 gpm, significantly reducing operating costs. The projected remediation timeframe was reduced from more than 50 years to approximately 10 years, with a projected reduction greater than $20M in total restoration cost. The surrounding community and regulator have been highly supportive of the revised remedial approach. Site closure is anticipated in 2014.

ClientAir Force Real Property Agency (AFRPA)

Scope of ServicesPerformance Based Remediation, Regulatory Negotiations, Regulatory Closure


ContaminantsTCE

Closure of a 3-Mile TCE Plume at Reese Air Force BaseLubbock, Texas

Closure of a 3-Mile TCE Plume at Reese Air Force BaseLubbock, Texas

focused on these zones, and performance data was used to adaptively design and install a comprehensive yet focused system of injection, extraction, and monitoring wells. This approach was successfully negotiated with the regulators and initially implemented in 2006 with adaptive adjustments made through 2011.

The ResultThe combination of ERD, DGR, and MNA has dramatically accelerated groundwater remediation at the site. The Tower Plume has contracted at a rate of 2 to 3 acres per week from 2006 through 2012. Concentrations of TCE in all compliance wells have declined below the MCL. Stakeholder satisfaction best reflects success to date. As remediation has progressed, wellhead treatment is no longer required, and private residences and farms continue to regain unrestricted use of the groundwater.

2004

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12

The ChallengeHistorical operations at a freeze-drying facility at the site resulted in TCE impacts to soil and groundwater. TCE leaked into the underlying groundwater and formed a large plume extending half a mile. The plume underlies several active industrial properties, including a railway corridor. The complex hydrogeology at the site necessitated remediation-driven investigations to construct a robust conceptual site model.

The ApproachAfter signing the project contract for performance based remediation, ARCADIS conducted a detailed evaluation of existing site data, past remedial actions, and two enhanced reductive dechlorination (ERD) pilot tests in key areas of the plume. Based on the evaluation of site data and pilot test results, ARCADIS developed a full scale in situ bioremediation system and negotiated with the California’s Regional Water Quality Control Board (RWQCB), San Francisco Bay Region, to amend the Board order and approve the use of ERD as the final remedy for groundwater. At the time, this site was the largest full scale ERD application in California.

Project GoalAchieve short-term remedial goals (Tier 1 surface water criteria, groundwater screening levels for aquatic habitat impacts) during active remediation with a long-term objective of site closure.

ARCADIS StrategyAn approach utilizing enhanced reductive dechlorination through flux focused and adaptive remedial design was applied.

Project AccomplishmentsShort-term goals for groundwater were achieved in many areas of the site. Our team successfully negotiated with third-party property owners to install injection wells throughout the length of the plume. By focusing treatment on higher permeability zones, a rapid reduction in TCE mass flux was observed.

ClientConfidential Commercial Client

Scope of ServicesSite Investigation, Performance Based Remediation, Regulatory Negotiations, Site Closure


ContaminantsTCE

Leveraging Next Generation Characterization Techniques to Support Flux Focused RemediationSan Leandro, California

Leveraging Next Generation Characterization Techniques to Support Flux Focused Remediation

San Leandro, California

For the implementation of a full scale ERD remedy, a point injection approach was used. Permanent injection points were installed in strategically placed transects across the length of the plume, and a dilute organic carbon solution was injected at these points. In 2007, performance monitoring data evaluations indicated that additional investigation is warranted to understand the source and transport pathways for the remaining TCE mass. Remedial-driven investigations were executed that relied primarily on Cone Penetrometer Testing/ Membrane Interface Probe (CPT/MIP) technologies. The high-resolution data were then displayed and interpreted using 3-D geologic modeling software. These focused investigations resulted in an updated and more robust conceptual site model. Adjustments were then made to the ERD system. The performance monitoring data continues to be evaluated, and provides a basis for adapting the remedy as needed.

Variable Transmissivity

The ResultFocused remediation-driven investigations and a refined understanding of the hydrogeology at the site allowed us to address the remaining contaminant mass flux in groundwater, and greatly improved the performance of the selected remedy. Based on current contaminant trends, active remedial efforts are expected to finish by 2015, and the project completion is anticipated in 2018.




Page 42 Page 43

13Use of Phytoremediation to Correct Groundwater Hydraulics Upgradient of a Permeable Reactive BarrierIndependence, Missouri

Use of Phytoremediation to Correct Groundwater Hydraulics Upgradient of a Permeable Reactive Barrier

Independence, Missouri

ClientU.S. Army

Scope of ServicesPerformance Based Remediation, Groundwater Modeling


ContaminantsTCE

Project GoalTo achieve TCE cleanup goals for groundwater downgradient of a permeable reactive barrier (PRB).

ARCADIS StrategySupplement existing groundwater remedy with a phytoremediation system using hybrid poplar and willow trees to prevent TCE impacted groundwater from bypassing a PRB.

Project AccomplishmentsTCE concentrations in areas where the plume was previously migrating around the PRB have decreased by as much as 90%. The footprint of the TCE downgradient of the PRB has reduced from 9.6 acres in 1999 to 0.7 acres in 2011. Groundwater elevations within the area of the phytoremediation system have declined an average of 5 feet over the last 4 years.

The ChallengeIn 2000, a 450 foot-long zero valent iron (ZVI) permeable reactive barrier (PRB) was installed at the Lake City Army Ammunition Plant (LCAAP) as an Interim Remedial Action (IRA) to prevent the migration of TCE impacted groundwater to a downgradient paleochannel aquifer, a prolific groundwater resource at LCAAP. Immediately following PRB installation, groundwater began mounding behind the PRB due to construction activities and created a significant head differential (up to 10 feet) that caused a portion of the TCE impacted groundwater to migrate around the northeast end of the PRB.

The ApproachGroundwater modeling was performed to evaluate the effectiveness of the PRB in treating groundwater with the observed mounding. Modeling output indicated that only 50% of the groundwater flux was migrating through the PRB and subsequently being treated, with another 50% remaining untreated as it migrated around the end of the PRB. Output from the groundwater model also indicated that a 1.5 gallons per minute (gpm) removal rate upgradient of the PRB would successfully prevent TCE impacted groundwater from bypassing the PRB. An analysis was performed to evaluate how to correct the hydraulics. The installation of a phytoremediation system upgradient of the PRB was recommended as a solution. In response, a 1.5-acre phytoremediation system consisting of approximately 750 hybrid poplar and willow trees was installed directly upgradient of the PRB in 2008.

The ResultThe groundwater mounding upgradient of the PRB has steadily declined since the trees were planted 4 years ago. The average water table reduction observed following the most recent growing season was 5 feet. TCE concentrations in the two monitoring wells located where the groundwater was previously bypassing the PRB have decreased by up to 90% since the installation of the phytoremediation system . To date, the combined technologies are providing a protective, passive, and cost-effective remedy in treating TCE impacted water prior to reaching the paleochannel aquifer. The TCE impacted groundwater extent downgradient of the PRB has decreased from 9.6 acres in 1999 to 0.7 acres in 2011.

Wet conditions near the PRB May 2008 Dry conditions near the PRB 2012

August 1999Pre-PRW Installation

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River, stream or ditchGroundwater Elevation Contour Line(feet above mean sea level)TCE Extent in groundwater (>5 µg/L)Phyto-System

Page 45



Pioneering Solutions:NAPL Management




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14

The ChallengeRemedial investigation of the off-property area defined an approximately 8-acre residual LNAPL body and a 7,000 foot long MTBE and TBA plume. The site was given a very stringent cleanup order for the removal of off-property LNAPL to the extent practicable by 2010 and groundwater cleanup water quality goals consistent with beneficial uses by 2013. This second cleanup goal effectively required the cleanup of residual LNAPL in soil such that it will not affect groundwater at concentrations above MCLs.

The ApproachA conceptual site model (CSM) was developed for residual LNAPL distribution including lines of evidence for LNAPL immobility. Additionally, the CSM defined MTBE and TBA distribution, transport, and biodegradation in groundwater. A multi-faceted remedial strategy was implemented at the site. Removal of residual LNAPL and depletion of the risk-driving components in the residual LNAPL were accomplished by dewatering the LNAPL smear zone and applying soil vapor extraction (SVE) intensively. Multiple metrics of remedial performance and progress, including tracking the depletion of lighter-end hydrocarbons, were used to evaluate dewatering effectiveness and to predict SVE remedy progress. Based on these evaluations, the remediation system was adaptively modified to increase the pace of cleanup in recalcitrant areas. To assure complete confidence of compliance, target areas of residual LNAPL were carefully identified and excavated by large diameter

auger. The affected groundwater downgradient of the LNAPL source zone was treated by a combination of extraction and natural attenuation informed, by groundwater modeling and site-specific assessment of MTBE and TBA intrinsic biodegradation rates. Finally, the off-property area was hydraulically isolated from the operating terminal to prevent any further migration of contaminants.

The ResultRemediation of the initially targeted off-property LNAPL zone has met the 2010 cleanup deadline and resulted in the removal of more than 99% of LNAPL mass. The LNAPL zone has been depleted of BTEX, MTBE and TBA, and therefore further threats to groundwater were eliminated. Cut off from the source, combined with groundwater extraction and natural attenuation, led to significant reductions in mass for MTBE (over 99.8%) and TBA (about 89%). Additionally, MTBE concentrations in 163 of 165 off-property groundwater monitoring wells decreased below the remedial goals two years before the groundwater remediation deadline.

Remediation of an 8-Acre Residual LNAPL Source and an MTBE/TBA PlumeSouthern California

Remediation of an 8-Acre Residual LNAPL Source and an MTBE/TBA Plume

Southern California


Scope of ServicesRemedial Investigation, Residual LNAPL Source Remediation, Hot-spot Excavation, Groundwater Modeling, Groundwater Remediation, Natural Attenuation


ContaminantsLNAPL (gasoline and diesel), BTEX, MTBE, TBA

Project GoalIn the off-property area, remove the residual LNAPL source zone by 2010 to the extent practicable and achieve groundwater cleanup criteria by 2013.

ARCADIS StrategyAn LNAPL and general conceptual site model was developed to identify risk-based and other concerns. The LNAPL smear zone was demonstrated to be immobile then dewatered to allow for an intensive application of soil vapor extraction. Groundwater extraction and treatment were performed in areas of the highest MTBE and TBA concentrations. Groundwater extraction was also used as a hydraulic barrier at the property boundary.

Project AccomplishmentsSuccessfully implemented residual LNAPL remediation and received regulatory concurrence that the 2010 deadline was met throughout the targeted LNAPL zone. Successfully implemented groundwater remediation and reduced MTBE concentrations to below the cleanup criteria throughout nearly all of the compliance area two years ahead of schedule.

Predicted Hydrocarbon Fraction in SVE Flow

Jun 30, 2008

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-291 74 440 805 1170 1535 1901

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15

The ChallengeARCADIS was hired under a guaranteed fixed-price contract to implement comprehensive treatment of a source area containing approximately 1.25 million pounds of mixed VOCs (including DNAPL), the saturated soil, and the resulting dissolved phase plume. Mixed solvent waste materials were placed in this former disposal area in approximately 30 to 45 feet of highly plastic clay that is underlain by a narrow weathered bedrock zone. This weathered zone allowed transport of dissolved-phase VOCs downgradient into a high-permeability paleochannel supply aquifer.

The ApproachThe primary components of the multi-faceted source area remedy include zero valent iron (ZVI) and clay soil mixing, enhanced reductive dechlorination (ERD), and monitored natural attenuation (MNA). ARCADIS implemented DNAPL, saturated soil, and groundwater remediation utilizing a ZVI and clay soil mixing approach in three separate locations covering a total area of 4,500 square feet. A seven-foot-diameter auger equipped with a drilling shroud for vapor

capture and control crane were used to advance mixing columns to a total depth ranging from 32 to 47.5 feet below ground surface, or to the encountered bedrock surface. During advancement, the ZVI-clay slurry was injected into the drilling augers to facilitate mixing of ZVI and clay. The clay material served to reduce the overall hydraulic conductivity of the soils such that the ZVI material could facilitate both abiotic and biotic destruction of target contaminants.

In addition to the source area soil mixing approach, an ERD approach was implemented to facilitate treatment of saturated soil and dissolved-phase impacts outside of the source area. A total of 41 injection wells, arranged in five separate transects, were installed to target the weathered bedrock interval at the base of the clay that serves as the predominant mass flux conduit away from the source area. Individual wells were connected via below-grade piping to the treatment system building where storage and mixing of the dilute organic carbon injection solution was conducted. Following construction completion in Fall 2007, periodic injection events were completed on a quarterly to a semi-annual basis to

sustain total organic carbon concentrations within the primary flow interval and to enable treatment along the plume flow path.

ARCADIS provided turnkey services for this project, allowing the Client to focus on their primary mission. Our team developed the remediation approaches, prepared workplans for Agency approval, secured all required permits, solicited bids from qualified contractors, provided construction management and remediation operation monitoring during site remediation activities, maintained communications with regulatory agencies, and adaptively managed the complex regulatory framework to gain approval of milestone documents as part of remedial implementation. Within a period of 4 years, ARCADIS completed the Remedial Investigation and Feasibility Study (RI/FS), Record of Decision (ROD), and Remedial Design/Remedial Action Workplan (RD/RA WP) documents as required by the three-party Federal Facilities Agreement between the Army, USEPA, and the Missouri Department of Natural Resources stakeholders.

The ResultImplementation of the ZVI-clay soil mixing successfully achieved the project objectives. After 4 years of ERD system operation, VOC concentrations beyond the downgradient injection transect have been reduced by up to 95%. The ERD system has successfully stopped plume migration prior to discharge in the public supply aquifer. Currently, ERD operation and MNA continue to reduce VOC mass within the vicinity of the source area.

In Situ Soil Mixing and Enhanced Reductive Dechlorination for DNAPL Source TreatmentIndependence, Missouri

In Situ Soil Mixing and Enhanced Reductive Dechlorination for DNAPL Source Treatment


ClientU.S. Army

Scope of ServicesIn Situ Remediation, Performance Based Remediation

Performance PeriodSeptember 2003 through September 2012

ContaminantsMixed VOCs, DNAPL

Project GoalProvide treatment for a DNAPL source area and resulting dissolved groundwater plume.

ARCADIS StrategyUse a multi-faceted source area remedy including in situ soil mixing with zero valent iron and clay, enhanced reductive dechlorination, and monitored natural attenuation to provide treatment and control migration.

Project AccomplishmentsThe zero valent iron and clay soil mixing remedy successfully obtained its objectives. The enhanced reductive dechlorination remedy continues to reduce contaminant concentrations in groundwater and to control downgradient mass migration.




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The ChallengeThe 2002 cleanup of the Pine Street Canal Superfund Site culminated in the placement of a 3-foot-thick sand cap in the 1,500-foot-long canal to isolate NAPL associated with a former manufactured gas plant. Subsequent monitoring of the cap’s performance revealed the presence of NAPL on approximately 5% of its surface area. The challenge was to develop cost-conscious, targeted measures to address a limited area of NAPL seepage under difficult site conditions without compromising the existing multi-acre sand cap.

The ApproachARCADIS executed a field program to fill data gaps regarding NAPL mobility within an extensive peat layer in an aggressive action to control and locate NAPL seepage. ARCADIS then went on to design and construct an effective NAPL control strategy including a reactive cap and NAPL recovery wells. The investigation was conducted using TarGOST™ (tar-specific green optical screening tool), which detects coal-tar NAPL using laser-induced fluorescence. TarGOST™ yields real-time, high-resolution data, allowing for

a rapid, comprehensive, and cost-effective investigation. Key elements of the investigation and design included the following:

• A phased NAPL field investigation conducted over three seasons (spring, summer, winter) and including diver surveys of NAPL seepage, gas ebullition, and subsurface testing of NAPL extent and mobility.

• During the winter field investigation, it was necessary to cross fragile wetlands and the highly compressible canal banks under frozen conditions; therefore, low ground weight equipment and techniques were employed to minimize damage to sensitive environments and to prevent NAPL from being forced out of the spongy peat.

• NAPL residual saturation testing and bench scale column testing were conducted to confirm the basis of design for the recommended NAPL control system.

• The design phase included both a NAPL controls analysis followed by a final remedy design which incorporated micro-dredging, a reactive cap, and NAPL recovery wells.

Project GoalControl the continued seepage of NAPL through an existing capping remedy into a surface water (canal).

ARCADIS StrategyPerform a detailed engineering evaluation of the previously implemented capping remedy in order to develop an enhanced approach to complement the existing remedy and effectively control the continued discharge of NAPL to surface water.

Project AccomplishmentsThe use of creative and innovative techniques facilitated targeted measures to address a limited area of NAPL seepage in an otherwise effective existing sand cap. Our highly functional and cost-effective solution employed cutting-edge investigation techniques and remediation technologies.

ClientGreen Mountain Power

Scope of ServicesField Investigation, Data Interpretation, Design and Construction of NAPL Controls Including a Reactive Cap and NAPL Recovery Wells


ContaminantsCoal Tar, NAPL, PAHs

Managing NAPL Seepage at the Pine Street Canal Superfund SiteBurlington, Vermont

Managing NAPL Seepage at the Pine Street Canal Superfund SiteBurlington, Vermont

Construction, including site preparation, micro-dredging of the existing sand cap, and placement of capping materials, was completed in fall 2010. ARCADIS constructed a reactive cap made of sorbent organoclay material over an aerial extent of 46,000 square feet using approximately 165,000 square feet of reactive core mat (RCM) to control and sequester NAPL. Passive NAPL recovery wells were installed in winter 2011 along the banks of the canal in the vicinity of the reactive cap. Key elements of the construction included micro-dredging to remove the top of the existing sand cap, where necessary, while avoiding the need to dewater the canal. Another key element was the placement of the amended cap which included the following layers from bottom to top:

• A geocomposite layer composed of a geotextile heat bonded with a geonet to ensure stability.

• Multiple layers of RCM deployed across the canal after the geocomposite layer was placed.

• A turf reinforcement mat consisting of intertwined steel wire mesh for protection and stability of the underlying the RCM layers. The turf reinforcement mats were connected on land using heavy-duty rings floated into place along the sections of canal and then sunk in place along the capping area.

• Amended cap layers were secured along the steeper bank with an anchor trench and along the shallower bank using rebar pins.

The ResultARCADIS overcame the challenges of soft sediment and highly mobile NAPL to design and construct an innovative reactive cap, currently the largest of its kind in the world. With the investigatory work, design, and construction now complete, ARCADIS is currently optimizing the long-term monitoring and maintenance requirements of the cap.




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The ChallengeThe 71-acre former bicycle manufacturing plant was impacted by polyaromatic hydrocarbons (PAHs), chromium, xylene, vinyl chloride (VC), and TCE. DNAPL was discovered during site remediation activities and attributed to a release from a former above ground TCE storage tank.

ARCADIS was hired to lead a voluntary cleanup project to remediate the contaminated soils. Project objectives included eliminating potential contaminant exposure pathways as well as attempting in situ remediation of free product TCE in a very tight clayey soil.

The ApproachARCADIS developed a cost-effective remediation strategy after a previous consultant at the site failed to negotiate site-specific remediation objectives with the Indiana Environmental Protection Agency (IEPA) in a timely manner despite significant

expenditures. After ARCADIS was selected to take over all remedial activities, our team quickly and successfully conducted negotiations with the IEPA, submitted a remedial action workplan, and retained contractors to implement the approved remedy.

Contaminated soils were excavated in 8 discrete areas for offsite disposal and engineered barriers were installed to eliminate potential exposure pathways per IEPA requirements. The engineered barriers integrated existing concrete slabs with clay caps to ensure a minimum one-foot cap. The clay portions of the barriers were covered with at least 6 inches of topsoil.

During the site remediation process, ARCADIS discovered that TCE was present as a NAPL in a localized area to approximately 35 feet below grade in a very tight clayey soil formation. After conducting a feasibility study, ARCADIS proposed to use Electrical Resistance Heating with Vapor Recovery (ERH/VR) to remediate the NAPL-impacted soils. ARCADIS obtained approval from the IEPA, retained

Thermal Remediation of DNAPL at a Former Bicycle Manufacturing SiteOlney, Illinois

Thermal Remediation of DNAPL at a Former Bicycle Manufacturing Site

Olney, Illinois

Project GoalComplete remediation of soils and receive a no further remediation (NFR) letter from the Illinois EPA (IEPA).

ARCADIS StrategyThe strategy included a clear understanding of Client objectives, the selection of appropriate remediation technologies capable of meeting cleanup objectives, careful management of all remedial activities, and successful negotiations with the regulatory agency.

Project AccomplishmentsSuccessfully completed soil remediation activities under budget and received an NFR letter from the IEPA.

ClientCity of Olney, Illinois

Scope of ServicesSite Investigation and Remediation, Regulatory Negotiations, Confirmatory Closure Sampling

Performance PeriodSeptember 2003 through May 2006

ContaminantsPAHs, Chromium , Xylene, Vinyl Chloride, TCE

contractors to bring power supply to the remediation area, conducted site preparation, security fencing, well installation, remediation monitoring, and all air and soil sampling. The ERH/VR remedy was successfully completed after 8 weeks of operation and achieved cleanup results several times lower than the site soil remediation objective. ARCADIS prepared a remedial action completion report to document all remediation activities and confirmatory sampling results, and received a No Further Remediation (NFR) letter from the IEPA for the site.

The ResultARCADIS provided turnkey services for this project including the development of all remediation approaches, preparation of remediation workplans, securing all required permits, soliciting bids from qualified contractors, providing construction management during site remediation activities, preparing as-built drawings for engineered caps and barriers, maintaining communications with the regulatory agency, and provided technical solutions during the overall remediation process. ARCADIS saved at least 15% of the total remediation budget for the Client and achieved the remediation goals on schedule. In addition, ARCADIS provided technical support the Client to secure a brownfield grant to finance part of the remediation cost.

Figure1. Soil boring locations and remediation areas.

Shallow Impacts

Deep Impacts

Figure1. Soil boring locations and remediation areas.

Shallow Impacts

Deep Impacts

Figure 2. Cross-section and TCE analytical results. Figure 4. Average subsurface temperature versus TCE vapor stream concentration.

Soil boring locations and remediation areas

Average subsurface temperature vs. TCE vapor stream concentrationCross-section and TCE analytical results

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© John Foxx

Pioneering Solutions:Vapor Intrusion




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The ChallengeThe facility was used for a wide variety of manufacturing purposes from 1906 through July 2009. Historical operations led to the presence of PCE and TCE in groundwater at elevated concentrations extending from the north/northwestern portions of the facility to approximately 1,900 feet offsite to the south/southeast below a residential neighborhood. Offsite PCE and TCE concentrations exceeded Indiana Department of Environmental Management (IDEM) residential screening levels beneath approximately 137 residential and 26 commercial properties. Soil gas investigations suggested that PCE and TCE vapor intrusion (VI) exposure pathways existed in the adjoining residential areas. Past remediation efforts were limited to soil excavation (53 tons of hazardous soil and 232 tons of non-hazardous soil) and an air sparge/soil vapor extraction (AS/SVE) pilot test in a source area in the northwestern part of the site to mitigate the migration of PCE vapors to the adjacent western residential homes.

The ApproachWe assembled a multi-disciplinary team of experts in vapor mitigation, risk communication, and in situ remediation to address Client needs. Within one week, a conceptual site strategy for addressing potential VI issues was developed. The sampling plan used scientific methods to limit the number of homes/businesses sampled based on subsurface concentrations, geology, building construction, etc. A comprehensive VI investigation plan included the generation of public relations materials and a neighborhood “door knock” event where ARCADIS employees visited the neighborhood to openly discuss the proposed sampling with residents. Over a period of three months, the team completed the collection of sub-slab soil gas and/or indoor air samples at 36 residential homes, and installed active vapor mitigation systems at eight homes based on analytical results.

Within one month of project award, the team designed and installed an in situ reactive zone (IRZ) system in the southern portion of the industrial property to treat TCE in groundwater, and an SVE system just north of the southern residential neighborhood. The groundwater

Vapor Intrusion Assessment and Mitigation at a Former Industrial FacilityIndiana

Vapor Intrusion Assessment and Mitigation at a Former Industrial Facility

Indiana


Scope of ServicesVapor Intrusion Assessment and Mitigation, Soil and Groundwater Investigation and Remediation, Groundwater Modeling, Risk Communication

Performance PeriodOctober 2010 through Present

ContaminantsPCE, TCE

Project GoalImplement vapor intrusion investigation and mitigation measures in a residential neighborhood impacted by historical activities at a former industrial facility, and to perform source remediation at the facility to limit offsite liability.

ARCADIS StrategyRapidly integrate a multi-faceted team of experts to develop and implement a vapor intrusion assessment and mitigation approach while managing regulatory and media challenges.

Project AccomplishmentsA strategy was developed one week after the start of the project. Within three months, a vapor intrusion investigation and mitigation plan was fully implemented, and source area remediation efforts were initiated. Rapid and definite project progress reversed media coverage from negative to positive and vastly improved regulatory relationships.

monitoring network was expanded in 2011 to delineate the distribution of contaminants at the site. Several onsite industrial sewers were located and investigated. A groundwater model was developed to understand source areas and their contributions to downgradient plumes. Additional remedies were implemented based on these results.

Multiple divisions within ARCADIS worked together to ensure that project objectives were met within short timeframe. An electronic information portal was established to allow immediate Client access to project progress and deliverables and schedule, and also to facilitate team members from 12 offices to share information.

The ResultAdditional investigation results identified three unknown areas within the facility that were contributing sources of PCE and TCE to groundwater. Through additional sampling, data analysis and groundwater modeling, groundwater along the southern property boundary was determined to be unrelated to the degradation of upgradient PCE, which was an element of prior conceptual site models.

Concurrent with controlling offsite liability, source remediation was initiated in December 2010 and is anticipated to continue through December 2012. Several industrial sewers identified as potential sources of PCE and TCE were properly closed, and roof drains that previously discharged stormwater through impacted soils below the building were rerouted. Groundwater remediation applications in 2011 included AS/SVE, in situ chemical oxidation, and enhanced reduction dechlorination (ERD). In 2012, ERD (including bioaugmentation) and SVE will continue as the only active remedies at the site.

In May 2011, IDEM issued a letter indicating that further offsite investigation of the VI pathway was not warranted. Given the project progress, Client’s actions to protect the community, and the risk communication efforts conducted by the project team, media coverage shifted dramatically and became much more positive. Both IDEM and the Client have been extremely complimentary of our work with the head of the Client’s Global Environmental Operations thanking ARCADIS for “diligence and hard work in getting us to this point”.




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The ChallengeA former above ground storage tank (AST) facility located near Detroit, Michigan, required remediation of soils and groundwater to reduce contaminated soil and groundwater concentrations to less than target remediation goals for the following: indoor air soil volatilization criteria, direct contact criteria, and NAPL C-sat criteria. VOC concentrations in soil suggested the presence of NAPL. The treatment area was approximately 90 feet in length by 80 feet in width, with a depth varying from 4.5 to 6 feet below ground surface (bgs). The treatment area included approximately 1,600 in-place cubic yards of soil. An excavation/disposal approach would have required soil to be disposed in a hazardous waste landfill.

The ApproachDue to the complex mixture of VOCs to be treated (MEK, MIBK, TCE, cis-1,2-DCE, BTEX, and tri-methylbenzenes), ARCADIS selected in situ chemical oxidation (ISCO) using base-activated persulfate and soil mixing. The treatment area was divided into 35 15-foot square grid treatment cells, with treatments applied one cell at a time. A two-step application process was implemented. The first step

involved using an excavator to mix in calcium oxide to increase the soil pH above 8 standard units. The second step involved mixing persulfate into the pH-conditioned soil. A total of 25 tons of sodium persulfate was used for soil treatment. Confirmation soil samples were collected from each grid at depths of 3 and 6 feet bgs using the excavator bucket, and soil samples were analyzed using an onsite laboratory. Soils in the individual grid cells were re-treated if confirmation soil sample results exceeded the target cleanup criteria.

In addition to the ISCO/soil mixing treatment, an innovative cap was placed over the entire northern extent of the property. The cap cover was placed over the entire northern extent of the property. The cap over the conditioned portion of the site (9,000 square feet) will reduce infiltration, control perched groundwater flow, and provide continued reduction of VOCs in groundwater over time. It was composed of 4 inches of topsoil, 6 inches of compacted clay and geotextile fabric over the treated soil. Areas east and west of the treated soil area were covered with 4 inches of topsoil and grass to provide a walking area. The entire southern length of the treated area was asphalt paved to a width of 15 feet to provide an additional truck traffic lane.

The ResultSoil conditioning activities were successful at reaching the target remediation goals for all of the treatment cells. Starting concentrations of cis-1,2-DCE (65 mg/kg), ethylbenzene (1,300 mg/kg), MIBK (760 mg/kg), toluene (4,000 mg/kg), TCE (550 mg/kg), 1,2,4-trimethylbenzene (393 mg/kg), and 1,3,5-trimethylbenzene (121 mg/kg) were reduced to below detection limits. Confirmation soil samples were collected and analyzed in March 2011. All samples collected were below the detection limits for VOCs.

Two replacement monitoring wells were installed in the treatment area during February 2011 and are included in the groundwater monitoring plan for the site. Four quarterly monitoring events were

completed (June, September and December of 2011; February 2012) to monitor the effectiveness of treatment. Groundwater monitoring results indicate that the treatment was effective at reducing groundwater concentrations to remedial goals. Starting groundwater concentrations of MEK (400 mg/L), cis-1,2-DCE (93 mg/L), MIBK (9,700 mg/L), toluene (120 mg/L), trichloroethene (130 mg/L), 1,2,4,-trimethylbenzene (120 mg/L), 1,3,5-trimethylbenzene (120 mg/L), xylenes (250 mg/L), and vinyl chloride (30 mg/L) were reduced to below detection limits.

The project was performed as a lump sum that carried a guarantee. In the event that the treatment was ineffective at reducing VOC concentrations to below set goals, ARCADIS would remove and dispose of the impacted soil at no extra cost to the Client.

Base-Activated Persulfate Oxidation of VOCs to Meet Indoor Air Inhalation CriteriaMichigan

Base-Activated Persulfate Oxidation of VOCs to Meet Indoor Air Inhalation Criteria

Michigan


Scope of ServicesSite Remediation, Construction Management, Regulatory Negotiation, Closure Sampling

Performance PeriodJuly 2010 through November 2011

ContaminantsCVOCs, BTEX, MIBK, MEK

Project GoalReduce soil and groundwater impacts (mixed VOCs) to below the indoor air inhalation criteria and address likely presence of NAPL at the site.

ARCADIS StrategySodium persulfate (an oxidant) and agricultural lime (an activator) were blended into shallow soils using an excavator. A mobile laboratory was used to determine whether the soil treatment objectives were reached after each cell was treated. Mixing was repeated as required until all the cells met treatment objectives. Groundwater monitoring was conducted quarterly following soil treatment to evaluate performance.

Project AccomplishmentsThe project exceeded the set goals of reducing concentrations to below the indoor inhalation criteria by reducing contaminant levels to non-detectable limits in soil. Following remedy implementation, groundwater contaminant concentrations also remain at levels substantially below set goals.

Treatment area

Final green cap




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The ChallengeHistorical operations and waste management practices at a materials testing laboratory resulted in a 2000-foot long chlorinated volatile organic compound (CVOC) plume in a fractured bedrock aquifer beneath a residential neighborhood. ARCADIS’ responsibilities entailed directing all aspects of ongoing investigation and remediation efforts both onsite and downgradient of the site within a residential area. The remedial activities addressed indoor air, soil, and groundwater impacted by TCE; 1,1,1-TCA, and 1,1-DCE. All activities are being conducted in accordance with a Correction Action Order on Consent (CAOC) from the State of Colorado.

The ApproachSource Zone: For approximately 13 years (1998 - 2011), a DNAPL source zone comprising of CVOCs including 1,1,1-TCA; 1,1,-DCE, and TCE was addressed primarily by hydraulic containment using more than 20 recovery wells. Although the containment system was sufficient in preventing offsite contaminant migration, an enhanced reductive dechlorination (ERD) pilot test was conducted in 2003. Based on promising results from the pilot study, the ERD system was subsequently expanded across the entire source area in 2009. Contaminant concentrations across much of the source area have been significantly reduced by several orders of magnitude from near-solubility concentrations to the parts per billion range. In addition, contaminant mass flux has been reduced by several orders of magnitude. By 2011, all recovery wells were taken offline, representing a complete transition for the source area treatment strategy from hydraulic capture to an enhanced in situ

Project GoalMitigate immediate offsite vapor intrusion risks, and achieve regulatory closure for a fractured bedrock site contaminated with chlorinated volatile organic compounds.

ARCADIS StrategyMitigate potential vapor intrusion risk through active remediation and monitoring. Operate an existing site-wide groundwater remediation system, and optimize system performance system by incorporating multiple technologies and a flux focused and adaptive philosophy. Address immediate indoor air impacts at offsite residences.

Project AccomplishmentsImmediate vapor intrusion concerns were addressed through the installation of a vapor mitigation system using a tiered indoor air monitoring program for more than 100 residences. ARCADIS demonstrated the effectiveness of conventional radon mitigation systems in apartment buildings. The overall site remedy addressed both source zone and dissolved phase contamination through in situ approaches thereby saving the client an estimated $4M in restoration costs.

ClientColorado Department of Transportation, Materials Testing Laboratory

Scope of ServicesRemediation, VI Mitigation, Regulatory Closure


ContaminantsTCA, DCE, TCE

Remediation of DNAPL and Chlorinated Solvents in Fractured BedrockDenver, Colorado

Remediation of DNAPL and Chlorinated Solvents in Fractured Bedrock

Denver, Colorado

biodegradation approach. This resulted in lower costs for the Client and dramatically shortened anticipated cleanup timeframes.

Offsite: In order to address immediate concerns regarding vapor intrusion, offsite sub-slab depressurization (SSD) systems and radon-style systems were installed to remediate indoor air impacts at apartment complexes and single-family homes, respectively. Offsite groundwater containing parts per million levels of 1,1,1-TCA; 1,1,-DCE, and TCE was originally treated in fractured bedrock via in situ cometabolic aerobic biodegradation (AB) for 8 years (2001 – 2008). Although the AB system supported enhanced CVOC destruction, the contaminant degradation rates were modest. Therefore, an anaerobic in situ ERD remedy was pilot tested. The results confirmed the following: (1) areas previously treated via aerobic techniques could be readily converted to anaerobic conditions within a reasonable timeframe; (2) complete reductive dechlorination of CVOCs could be achieved; and (3) CVOC degradation rates by ERD system are approximately five times greater than those by the AB system. Site-wide conversion of the groundwater treatment system from an aerobic to an anaerobic biological remedy was completed in early 2009. The system treatment performance was highly successful and supported regulatory concurrence to terminate all active offsite treatment by early 2012.

The ResultARCADIS successfully implemented in situ technologies to address CVOC treatment in a complex fractured rock aquifer. This resulted in the termination of the onsite pump-and-treat system and all active offsite remediation. We also enhanced the effectiveness of the overall site remedy, which resulted in substantial time and cost savings over the lifecycle of the project.

To manage offsite VI issues at apartment buildings, we recommended converting to radon-type systems similar to those used at the single-family homes. This is expected to save the client an estimated $90,000 per year over the cost of operating and maintaining the previous sub-slab depressurization (SSD) systems.

Finally, our efforts to improve stakeholder relations and addressing concerns of building occupants regarding potential vapor intrusion and health concerns were successful. Negotiations with the regulatory agency to reduce indoor air sampling frequency resulting in reduced sampling costs for the Client.

During onsite ERD injections, a dye tracer was added to allow for a better understanding of the site hydrogeology, map injected fluid distribution, and to monitor offsite flow of groundwater




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The ChallengeThe management of vapor intrusion (VI) issues has long been complicated by the temporal and spatial variability in indoor air and soil gas concentrations. Relatively few datasets have been collected with detailed long-term monitoring information on VOC VI. The USEPA’s objectives for this applied research project were therefore as follows:

• Determine if radon would be a useful tracer for VI

• Quantify the relationship between subslab/subsurface soil gas and indoor air concentrations

• Examine if near-building external samples can be used as alternatives to subslab samples

• Identify any seasonal fluxes in radon and VOCs related to HVAC use

• Evaluate the duration over which solvent-extracted passive samplers can be used

• Determine the impacts on VI conditions associated with usage of simple fan systems

The ApproachTo perform this intensive VI study, we established a data collection infrastructure in a pre-1920 Indianapolis duplex including differential pressure monitoring, multi-interval groundwater monitoring, and external and internal soil gas monitoring in a dense array directly beneath and adjacent to the house. We selected an unoccupied structure which minimizes the potential for indoor VOC sources. The dataset collected also includes a series of independent variables that affect VI: barometric pressure, soil moisture (monitored in situ), soil temperature, water level, HVAC operation, and wind speed/direction. Each of these variables operates on different time cycles ranging from hourly to seasonal. Monitoring data was gathered for 56 weeks, and included VOC and radon concentrations in indoor air, external air, and subslab soil gas.

Project GoalObtain insight to the causes and resulting degrees of temporal and spatial variability in vapor intrusion of VOCs.

ARCADIS StrategyEstablished a study site at a historic duplex in Indianapolis to collect a comprehensive dataset with long-term monitoring for VOC vapor intrusion parameters. The study site was extensively instrumented and cost-effectively operated as a test facility continuously for one year.

Project AccomplishmentsGenerated an extensive dataset that allowed ARCADIS to address many key questions important to the development of vapor intrusion study guidance. This work has led to more than ten presentations at national and international conferences.

ClientUSEPA (Research Triangle Park, NC)

Scope of ServicesVapor Intrusion Research Program in Collaboration with USEPA and Academia

Performance PeriodMay 2010 through Present

ContaminantsPCE, TCE, Chloroform, Radon

USEPA Applied Research Program: Assessing Vapor Intrusion Temporal and Spatial Variability using Radon and Volatile Organic CompoundsIndianapolis, Indiana

USEPA Applied Research Program: Assessing Vapor Intrusion Temporal and Spatial Variability using Radon

and Volatile Organic CompoundsIndianapolis, Indiana

The Result

Spatial and Temporal Variability: Implications for Sampling GuidanceCurrent VI site evaluation practice and regulatory guidance typically relies on a limited number of rounds of 24-hour indoor air extractive samples with Summa™ canisters, and 15-minute duration soil gas samples. Guidance frequently calls for sampling in two seasons and refraining from sampling after heavy rain events. The USEPA has expressed interest in allowing more flexibility in this standard practice by incorporating sampling methods with longer and shorter durations into VI investigations. In this study, we collected side-by-side VOC data using onsite gas chromatography with a time cycle of one hour and passive samplers with integration times of one day, week, month, and quarter. Differing temporal trends for two key VOCs, PCE and chloroform, were observed. From this dataset, we drew practical conclusions regarding various integration periods of indoor and soil gas sampling, implications of sampling in various seasons and after major rain events, and the potential utility of publicly-available near-real time datasets such as meteorology, soil moisture content, and groundwater levels for selecting sampling times.

Evaluation of this robust dataset provided useful insights including the following:

• Seasonal variability is not just a function of differing effects across the building envelope (driven by stack effect) but also reflects seasonal trends in shallow soil gas concentrations

• Accumulation of higher concentrations of contaminants

of concern under a basement floor limits the diagnostic strength of shallow soil gas

• Climactic differences in the severity of winters can effect worst case vapor intrusion

• In some cases, radon can have a very different distribution in shallow soil gas then VOCs

Uptake Rate Variance in Passive Samplers Employed For Indoor Air MonitoringPassive sorbent-based methods are an emerging technology for VI assessment. The current practice for indoor air VOC monitoring includes the use of Summa™ canisters for sampling with 8- to 48-hour integration times. Passive samplers are capable of much longer times. Concentration measurements using passive samplers require that the uptake rate characteristic of the sampler design for a given compound to be accurate and constant. Previous studies have shown that the uptake rate of passive samplers varies with temperature, exposure duration, and concentration ranges. Passive samplers were tested with 1, 7, 14, 28, 91, 182, and 364 day exposure times. Samples were collected at multiple stations subject to different temperatures and different degrees of temperature variability. Concentrations obtained over long integration periods were compared to those measured with multiple sequential samples of shorter durations at the same location to estimate the uptake rate variance. Excellent agreement was seen between averages of concentrations measured over short durations (i.e., one week) with single co-located long-term samples (up to one year for some compounds).

Test duplex in Indianapolis, IN

420: Not heated 422: Heated

Variability in VOCs in week-long samples during one year of sampling

3-D representation of chloroform in soil gas superimposed on stratigraphy, note higher concentrations beneath house

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Pioneering Solutions:Emerging Contaminants




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The ChallengeSulfolane is a petrochemical solvent that was used during historical pesticide manufacturing operations. Sulfolane has limited volatility and adsorption potential, but is readily biodegradable under aerobic conditions. A groundwater extraction, treatment, and re-injection system has been operating for the past 20 years to remove sulfolane and prevent plume migration. Although sulfolane concentrations have decreased in some wells, concentrations are still two to three orders of magnitude above the site-specific health-based cleanup goal.

The ApproachARCADIS conducted a technical evaluation of key process parameters affecting sulfolane biodegradation, followed by a full scale optimization test to enhance the performance of the existing treatment system. The existing influent aeration system was replaced with a temporary in-line hydrogen peroxide injection system to supply excess oxygen (up to 15 mg/L versus the previous maximum of 7 mg/L) into the biological granular activated carbon (BioGAC) bed. Configurational changes were made to optimize conditions for biological treatment of sulfolane and adsorption of fumigant co-contaminants. Adjustments to the system design were made based on performance monitoring data. Optimization test conditions resulted in more reliable and better distribution of oxygen throughout the bed to support a more uniform biomass distribution. As a result, test conditions increased sulfolane mass removal and improved the reliability of effluent quality. Overall treatment capacity and hydraulic loading rates also increased.

Project GoalAccelerate groundwater remediation and achieve site closure by 2020 at a former pesticide manufacturing facility in the Central Valley, California.

ARCADIS StrategyExpand treatment system capacity and focus on groundwater extraction from areas with the highest contaminant concentrations. The primary groundwater contaminant is sulfolane, which can biodegrade under aerobic conditions. In order to successfully enhance sulfolane treatment capacity, ARCADIS optimized the existing biological granular activated carbon (BioGAC) treatment system by modifying the process configuration and increasing the dissolved oxygen content.

Project AccomplishmentsARCADIS enhanced the sulfolane treatment capacity by 150%, from 2.1 to 5.2 lbs/day, which increased the treatment system hydraulic loading from 3.2 to 4.7 gpm/ft2. In addition, treatment system reliability improved as a result of changing the process configuration. These changes also reduced day-to-day operation and maintenance requirements.


Scope of ServicesRemediation, Regulatory Closure


ContaminantsSulfolane

Enhanced Sulfolane Removal using a Biological Granular Activated Carbon Treatment SystemCentral Valley, California

Enhanced Sulfolane Removal using a Biological Granular Activated Carbon Treatment System

Central Valley, California

The ResultDuring the optimization test, the treatment capacity for sulfolane was enhanced by more than 150%. The optimization test demonstrated the system’s capacity to treat sulfolane at higher concentrations and process water flow rates. Based on the success of the optimization test, ARCADIS is currently implementing full scale system upgrades to further increase sulfolane mass removal and improve the reliability of effluent quality. Following completion of the full scale system upgrades, including hydraulic upgrades and the installation of a permanent oxygenation system, the treatment system will be able to treat high concentrations of sulfolane at the flow rates needed to achieve remedial goals within 10 years.

1

10

100

1000

28-Dec-08

7-Apr-09

16-Jul-09

24-Oct-09

1-Feb-10

12-May-10

20-Aug-10

28-Nov-10

8-Mar-11

16-Jun-11

24-Sep-11

2-Jan-12

Port A- Influent Port C- Effluent

Health based criterion = 57ppb

Sulfo

lane

con

cent

ratio

n (p

pb)

Note: Half of reporting limit (10 ppb) used to represent non-detect values.

Post-enhancement treatment performance

2009-2011 Treatment Performance

Increased Treatment Capacity

0

1

2

3

4

5

6

2-Apr-11

12-Apr-11

22-Apr-11

2-May-11

12-May-11

22-May-11

1-Jun-11

Mas

s re

mov

al ra

te (l

b/da

y)

Single bed mass removal threshold - parallel operation

System mass removal threshold - parallel operation

Series configuration

Total system treatment capacity enhancement ~30%

Treatment System Effluent ReliabilityNormal - 95% CI

Perc

ent

Effluent sulfolane concentration (ppb)

VariablePre-enhancementPost-enhancement

Mean23.229.95

StDev20.96

0.9554

N7236

AD8.425

11.811

P<0.005<0.005

99.9

99

9590

80706050403020

105

1

0.1-50 -25 0 25 50 75 100 125

Note: Half of reporting limit (10 ppb) used to represent non-detect values.




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23

The ChallengeAt an industrial site in Dordrecht, the Netherlands, the groundwater was found to be contaminated with Tetrahydrofuran (THF). THF is cyclic ether used in commercial applications for the production of synthetic fibers. Due to the physical and chemical properties of THF, it is believed to be difficult to treat THF using in situ remediation techniques. THF is highly soluble and does not readily degrade biologically.

The ApproachAn understanding of the Client’s needs by ARCADIS combined with a good knowledge of site conditions, literature reviews, laboratory studies, and a tiered investigation of the site lead to a very successful remediation effort at the site.

A literature and laboratory study was designed to assess the feasibility of THF biodegradation and its potential for destruction by chemical oxidation. A series of laboratory tests showed a strong reduction of THF concentrations in water using a number of chemical oxidants. These preliminary results were used as a basis of additional bench scale studies to select the most effective chemical oxidant formulation. Additional laboratory tests suggested that THF degrading bacteria were present at the site. Bioremediation and ISCO were then tested in the field during a pilot study in 2008, and ISCO was selected for full scale implementation.

Project GoalTo develop an in situ remediation approach capable of tetrahydrofuran (THF) treatment at an industrial site.

ARCADIS StrategyCombining an understanding of Client needs with a literature review and laboratory studies, an effective remediation strategy was developed involving in situ chemical oxidation.

Project AccomplishmentsA significant reduction (99%) in THF concentrations was observed as a result of remedy application.


Scope of ServicesLaboratory Testing, Pilot Study, Site Investigation and Remediation


ContaminantsTetrahydrofuran

In Situ Chemical Oxidation to Remediate an Industrial Site Contaminated with TetrahydrofuranDordrecht, The Netherlands

In Situ Chemical Oxidation to Remediate an Industrial Site Contaminated with Tetrahydrofuran

Dordrecht, The Netherlands

The full scale ISCO was combined with a thorough investigation to accurately define the extent of THF impacts at the site. Injection wells that were used to deliver reagents were also used for delineation of the groundwater plume. In cooperation with the Client, who had the ability to review the groundwater samples within hours of collection, a stepwise installation of the injection wells and complete delineation of groundwater contamination was possible thereby reducing installation costs. The results showed that the THF contamination was more limited in extent but that concentrations of THF were higher than anticipated (above 1 mg/L). These findings led to the identification of contaminant migration towards neighboring sites.

The full scale ISCO application targeted THF zones of the highest concentrations and mass flux. It was comprised of four injection events,

with each event requiring 4 to 6 weeks to deliver the necessary volume of oxidant, followed by a period of 3 to 4 months for treatment. The full scale remediation was executed between April 2009 and December 2010.

The ResultsAfter two injection phases, the mass flux of THF toward neighboring sites diminished, and at the completion of the full scale remedy, a 99.7% reduction was achieved. Site groundwater concentrations declined from an average of 140,000 µg/L to 434 µg/L. One year following active remediation, the concentrations continued to decrease and the maximum groundwater concentration was 31 µg/L.

1

10

100

1000

10000

100000

1000000

0 2 4 6 8 10 12

Amount of reagent (# x stoichiometric)

Water

Soil + Groundwater

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

12/18/2008 7/6/2009 1/22/2010 8/10/2010 2/26/2011 9/14/2011 4/1/2012

The Netherlands

Dordrecht

Page 71



Pioneering Solutions:Site Closure and Other Strategies




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24Project GoalAchieve a No Further Action designation from the regulatory agency for soils and groundwater impacted by former dry cleaning operations.

ARCADIS StrategyThermal remediation using electrical resistance heating with vapor recovery to remove contaminant mass while minimizing impacts to business operations.

Project AccomplishmentsThe remedy operated successfully in a high traffic area, breaking down contaminants while minimizing impacts to the shopping center business activities. The site received a No Further Remediation letter from the regulatory agency.

ClientDominick’s Finer Foods/Safeway, Inc.

Scope of ServicesThermal Remediation, Confirmatory Closure Sampling

Performance PeriodJune 2006 through March 2008

ContaminantsPCE

Thermal Remediation of a Former Dry Cleaner SiteChicago, Illinois

Thermal Remediation of a Former Dry Cleaner SiteChicago, Illinois

The ChallengeARCADIS led a voluntary cleanup project for soil remediation in an alleyway behind a shopping center. The overburden soils and bedrock aquifer beneath the alleyway were impacted by chlorinated CVOCs due to previous release(s) of dry cleaning chemicals. The main contaminant of concern is PCE with concentrations in site soils at approximately 5,370 mg/kg.

The ApproachTo address the contaminant source without significantly impacting business operations at the Parkway Plaza Shopping Center, ARCADIS implemented a soil remedy consisting of electrical resistance heating (ERH) with vapor recovery. Due to heavy traffic involving frequent delivery vehicles, all horizontal wells for vapor recovery, electrical lines, drip lines, and other piping were buried. Fifteen weeks after ERH remediation operations were initiated, ARCADIS implemented a confirmatory sampling program to evaluate remedy success.

ARCADIS provided turnkey services for this project. We developed all remediation approaches, prepared remediation workplans for agency approval, secured all required permits, solicited bids from qualified contractors, provided construction management and remediation operation monitoring during site remediation activities, provided technical oversight and support during the remediation process, implemented a confirmatory sampling program to evaluate remedy success, and maintained communications with the regulatory agencies.

The ResultAll confirmatory soil sampling results were below the site specific soil remediation objectives, and all detected PCE concentrations were less than 0.5 mg/kg. In addition, the remediation achieved the Tier 1 residential soil remediation objectives for all samples and contaminants with the exception of one sample which slightly exceeded the Tier 1 residential remediation objective for PCE. The system was shut down after approximately 4 months with approval from the regulatory agency since the implemented remedy successfully achieved site soil remediation objectives. The site received a No Further Remediation (NFR) letter from the agency.

Installation of sub-grade vapor recovery system

Vapor recovery piping, drip lines, temperature monitoring cables, and electrical connections installed on rooftop

Remediation area after installing electrodes, drip lines, and vapor recovery system

Vapor recovery piping from the condenser to the rooftop during system construction

Vapor recovery piping from the condenser to the rooftop




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25

The ChallengeARCADIS was retained to perform investigation and remediation of a former petroleum storage and liquids separation facility in southwestern Kansas. The former tank battery site was impacted by petroleum hydrocarbons and produced water as a result of historical operations at the facility spanning a period of 40 years. The facility was decommissioned in 2004. ARCADIS was tasked to complete site characterization, develop cleanup objectives, and remediate the site to meet Kansas Corporation Commission and Kansas Department of Health and Environment regulatory closure requirements before returning the lease to the United States Department of Agriculture, Forest Service.

The ApproachARCADIS conducted the initial subsurface site characterization following facility decommissioning. Groundwater and soil

impacts were observed across the site. Following evaluation of applicable remedial alternatives and site specific data, ARCADIS developed a land farming and site reclamation plan to address remediation of approximately 10,000 cubic yards of impacted soil. Land farming was performed in phases. Given the volume of soils and limited space, soils were excavated and treated using a batch excavation, material management, and backfilling process. MNA was selected as the groundwater remedy. ARCADIS worked with the regulatory agencies to minimize the required groundwater monitoring frequency and timeframe, with the result that groundwater was sampled biennially for 4 years.

To further minimize costs and streamline efforts, the Client’s operating field personnel were trained and supervised by ARCADIS to implement elements of the remedial plan. We also recommended methodologies that emphasized the use of readily available and inexpensive materials and equipment.

Former Tank Battery RemediationSouthwestern Kansas

Former Tank Battery RemediationSouthwestern Kansas

Project GoalCharacterize the site, develop cleanup objectives, and perform remediation to meet regulatory closure requirements.

ARCADIS StrategyTo minimize treatment costs, ARCADIS characterized the site and developed a land farming and site reclamation plan to remediate approximately 10,000 cubic yards of impacted soils. Land farming was performed in phases given the volume of soils and limited treatment space. MNA was selected as the groundwater remedy for effectiveness and cost efficiency. ARCADIS worked with the regulatory agencies to minimize the required groundwater monitoring frequency and timeframe, and to further reduce costs.

Project AccomplishmentsAll soil remediation goals have been met. Current groundwater monitoring data meet the State’s Tier 2 residential groundwater standards. An unrestricted NFA determination was obtained for subsurface soil and groundwater impacts. Additional surface reclamation efforts (revegetation) by the Client’s field operation staff are ongoing.

ClientConfidential Oil & Gas Client

Scope of ServicesSite Characterization, Remediation, and Reclamation Services.


ContaminantsPetroleum Hydrocarbons, Produced Water/Brine

The ResultARCADIS’ implemented remedy has successfully met all soil remediation goals. Current groundwater monitoring results indicate that the Kansas Department of Health and Environment Tier 2 residential groundwater standards are met. We obtained a NFA determination for the Client for subsurface soil and groundwater impacts at the site. Additional surface reclamation efforts (revegetation) are ongoing.




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26

The ChallengeIn Situ chemical oxidation (ISCO) was initially the selected approach to remediate BTEX impacts and meet an aggressive redevelopment schedule at a former manufacturing facility in Georgia. An oxidant injection pilot test was conducted to aid in the design of a full scale approach. The results of the pilot study demonstrated that the geologic complexity of the saprolite and fractured bedrock aquifer significantly hindered the injectability and uniform distribution of the oxidant solution in the subsurface. Therefore, a full scale application of conventional ISCO as cost prohibitive and unlikely to meet the required remedial objectives and project schedule.

The ApproachAlthough chemical oxidation was still a viable approach for contaminant mass removal, ARCADIS needed to rapidly and cost-effectively adapt the delivery technique to meet the Client’s schedule and budget. ARCADIS revised the ISCO remedy from an injection-

based approach to one that included excavation of the overburden soil and direct mixing of oxidant and binder into the upper portion of the saturated interval. The direct mixing approach eliminated the uncertainty of adequate oxidant distribution observed during the pilot study and streamlined the remediation timeframe by utilizing heavy machinery already in use for redevelopment activities at the site.

Prior to field mixing, ARCADIS conducted bench scale tests to verify the effectiveness of mechanical oxidant mixing and to assess various binding agents and required concentrations to restore the bearing capacity of the post remediation soils. Sodium persulfate was selected to reduce BTEX concentrations to the required remedial objectives and Portland Cement was used to act as both activator and binder to meet the post remediation geotechnical requirements. Bench scale test results were used to design the full scale soil mixing remedy to treat the top 13 feet of saturated soils, account for bulking of the materials, and allow for sufficient post remediation soil strength and bearing capacity to support construction equipment after short curing times.

In Situ Chemical Oxidation and Stabilization via Soil Mixing for BTEX RemediationHapeville, Georgia

In Situ Chemical Oxidation and Stabilization via Soil Mixing for BTEX Remediation

Hapeville, Georgia


Scope of ServicesExcavation, In Situ Chemical Oxidation, and Stabilization of Impacted Soils

Performance PeriodOctober 2009 through June 2010

ContaminantsBTEX

Project GoalAggressively reduce benzene concentrations in groundwater to less than 10 mg/L in a source area with detected free product to facilitate the redevelopment of site.

ARCADIS StrategySince the originally approved remedy was shown to be ineffective during pilot testing, the strategy included combining technologies to minimize costs, meet the aggressive remediation schedule, and provide suitable soil strength for redevelopment activities. Elements of the remedy included excavation, mixing of chemical reagents into the upper portion of the saturated interval, followed by in situ stabilization of the soils.

Project AccomplishmentsARCADIS demonstrated agility in changing remedial approaches mid-project while still meeting aggressive schedule requirements. We met soil and groundwater objectives using soil mixing activities, and reduced costs by taking advantage, wherever possible, of onsite equipment.

The treatment zone was located approximately 25 feet below grade.

Prior to soil mixing, excavations were advanced to the water table and collection trenches were constructed in the saturated zone at the bottom of the excavation to collect any LNAPL. Soil mixing was completed in treatment cells using a hydraulic excavator. The design mix ratio of sodium persulfate and Portland Cement was amended, as needed, based on encountered field conditions (contaminant readings, visual observation on soil classification, consistency, moisture content) to achieve remedial and soil improvement goals. Hand augured temporary monitoring wells were also installed in selected cells to collect groundwater samples and determine initial BTEX concentrations following mixing.

The ResultAt total of approximately 8,200 cubic yards of saturated soil was treated in 45 mixing days. Post-treatment groundwater samples showed that BTEX concentrations were reduced to below the target levels within 24 days of treatment. The unconfined compression tests collected from each treatment cell indicated that the required post remediation soil strength was achieved across the treatment areas. Additionally, in place density and moisture testing showed that the required compaction and moisture content was also achieved.

By adapting the original injection-based ISCO approach to a soil mixing and stabilization approach, ARCADIS was able to achieve the remedial objectives for the site while maintaining the geotechnical integrity of the soils. The aggressive schedule of the adaptive remedial approach facilitated the redevelopment of the site and satisfied all project stakeholders.

Reagent staging and soil mixing

The site: Excavation R-1 and R-2




Page 78 Page 79

27 Stabilization and Solidification to Address Coal Tar Contamination

Duluth, Minnesota

The ResultA comprehensive construction quality assurance program was developed and implemented as part of the RAP to demonstrate remedy performance and characteristics of the stabilized mass to the agency and the public. In situ and laboratory testing were conducted throughout the implementation of the project which successfully demonstrated that the permeability, strength, and mix homogeneity met the project requirements. The successful implementation of the in situ stabilization/solidification remedy saved the Client more than $30,000,000.

Stabilization and Solidification to Address Coal Tar ContaminationDuluth, Minnesota

ClientU.S. Steel, Duluth Works

Scope of ServicesInvestigation, Treatability Studies, Alternatives Analysis, In Situ Stabilization and Solidification


ContaminantsCoal Tars (PAHs)

Project GoalEffectively stabilize coal tar impacted sediments present at the site, thereby preventing contaminant leaching into a nearby stream.

ARCADIS StrategyNegotiate stabilization/solidification remedy with regulatory stakeholders in lieu of excavation and offsite disposal.

Project AccomplishmentsSuccessful implementation of an in situ stabilization/solidification remedy which saved the Client more than $30,000,000.

The ChallengeARCADIS was hired to perform a limited investigation and treatability testing at a former integrated steel mill contaminated with coal tar. ARCADIS had to first demonstrate to the Client and the regulatory agencies that in situ stabilization/solidification techniques can effectively remediate an area of coal tar and coal-tar affected sediments along an unnamed stream at the site. Subsequently, ARCADIS completed the design and oversaw the implementation of the in situ stabilization/solidification remedy.

The ApproachARCADIS was responsible for preparing and conducting a focused, design-related investigation, several treatability studies, an alternatives analysis, a Response Action Plan (RAP), complete construction plans and specifications, a Contingency Plan, and a construction certification report. The project was coordinated to ensure the following: (1) the unnamed stream, which discharges to a major river that is a tributary to Lake Superior, was protected at all times from oily discharges during the in situ stabilization/solidification process; (2) the optimum soil-additive reagent mix was utilized for proper stabilization/solidification via the incorporation of laboratory-phase and field-phase treatability studies prior to full scale implementation; and (3) the final stabilized/solidified mass was protected from destructive elements by an appropriate cover system following completion.

Onsite batch plant for mixing reagents

Overview of stabilization activities




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28

The ChallengeThe Michigan Department of Environmental Quality (MDEQ) requested that ARCADIS’ Client evaluate the relationship and possible connection between surface water quality in an onsite wetland and groundwater impacted by an adjacent permitted hazardous waste landfill. The ultimate project goal was to prevent impacted groundwater from discharging to the adjacent wetland. The groundwater is characterized by elevated pH (9 to 12 pH units) and metals exceeding acute toxicity levels and State groundwater - surface water interface (GSI) criteria.

The remedy selection was compounded by several key drivers including the following: a listed hazardous waste designation for the source material making some of the technically-viable and/or state-preferred remedial alternatives cost prohibitive, the landfill’s proximity to the wetland, and an aggressive remedial action schedule mandated by the State.

The ApproachARCADIS faced the cost-effectiveness challenge by developing an alternative remedial approach that met the objectives of both the Client and MDEQ. In support of remedy implementation, ARCADIS conducted pilot tests, designed the remediation system, performed construction management and oversight, and supported the startup of a remediation system that consisted of several key components. First, a 1,800-linear foot hydraulic barrier (sheet-pile wall) was constructed around the downgradient perimeter of the landfill and source areas. Second, a groundwater interceptor trench immediately upgradient of the hydraulic barrier was designed and constructed to capture groundwater that flows through the landfill and source areas by inducing an inward hydraulic gradient. Finally, a groundwater treatment system was designed to remove metals of concern through pH adjustment and an innovative filtration system capable of removing solids larger than 1 micron in size and producing an order of magnitude less sludge than a conventional filtrations system thereby reducing the hazardous waste disposal costs associated with sludge disposal

Project GoalPrevent impacted groundwater associated with a landfill from discharging to an adjacent wetland.

ARCADIS StrategyInstall a cost-effective subsurface hydraulic barrier and interceptor trench to cutoff the migration of groundwater contamination from the landfill and associated source areas.

Project AccomplishmentsImplemented a cost-effective remedy to address listed wastes to satisfy the needs of both the State and the Client. The system currently exceeds the design parameters and the Client is realizing significant operational savings. Other project benefits include minimized treatment system waste products and improved relationships between the State and the Client.

ClientConfidential Steel Manufacturing Client

Scope of ServicesSite Investigation and Remediation, Regulatory Negotiations, Permitting and Compliance, Wetland Evaluation, Construction Management, Remedial Performance Monitoring


ContaminantsMetals, High pH

Minimizing Landfill Impacts on an Adjacent WetlandJackson, Michigan

Minimizing Landfill Impacts on an Adjacent WetlandJackson, Michigan

ARCADIS also provided additional services at the site. Regulatory negotiations were conducted with MDEQ’s Remediation and Redevelopment Division in Jackson District. ARCADIS fostered an open and respected relationship with agency staff, which led to development of a remedial alternative that was supported by all parties and implemented on schedule. During this process, ARCADIS was also able to build a stronger relationship between the District and the Client. With Jackson district support, ARCADIS streamlined the regulatory compliance and permitting process objectives for the project which included the Surface Water (NPDES permitting), Hazardous Waste, Land and Water Management (Joint Permit Application), and Groundwater Permit divisions. ARCADIS also obtained conditional approval from the Jackson District on an innovative Performance Monitoring Plan for the remedial action that is a combination of compliance standards and hydraulic monitoring.

The ResultARCADIS completed the remedy construction expeditiously and within budget, meeting both the Client and the State’s expectations. Construction oversight efforts were completed at 20% below budget and overall construction costs were 25% below anticipated proposed capital budget estimates. ARCADIS delivered these cost savings by adjusting the hydraulic barrier material during the design phase which substantially reduced capital and construction costs. The groundwater treatment system is currently meeting NPDES requirements and is substantially exceeding performance targets. The system is generating fewer solids than anticipated thereby leading to costs savings by minimizing hazardous waste management actions. ARCADIS underwent a process optimization phase of the project which entailed evaluating the dewatering operations to minimize the amount of water treatment required. This ultimately lowered the yearly chemical demands and operations and maintenance requirements.




Page 82 Page 83

29

The ChallengeThe site has been used by a wholesale distributor of industrial solvents, alcohols, esters, ketones, ethers, glycols, industrial oils, and allied products since 1946. Groundwater constituents of concern include chlorinated solvents, ketones, and aromatic hydrocarbons. Close coordination of all phases of the remedial evaluation, pilot testing, design, and implementation were required at this site due to ongoing facility operations and space limitations. The majority of the work also required isolation of an active rail spur, which posed a logistical challenge. Site constraints and the complexity of the remedial alternatives required a collaborative approach among all regulatory (Minnesota Department of Health, Minnesota Pollution Control Agency, Metropolitan Council, and City of St. Paul) and other stakeholders.

The ApproachFollowing a remedial alternatives analysis to select applicable and feasible remedial technologies, ARCADIS conducted a soil vapor extraction (SVE) pilot test and three in situ technologies to address constituents of concern in soil and groundwater at the site. Based on the relative success of the SVE pilot test, the selected remedial strategy included SVE and multi-phase extraction for shallow groundwater and source area soils. Deep groundwater is extracted at the downgradient property boundary, treated (using activated sludge), amended with electron acceptors and donors to facilitate in situ treatment, and re-injected upgradient of the source area.

Prior to and during treatment system installation, ARCADIS worked closely with the regulatory stakeholders, site stakeholders, and subcontractors to procure all necessary permits and site access agreements. The full scale remediation system was implemented in two phases. First, extraction and injection

Project GoalAchieve risk-based regulatory closure by evaluating remedies, developing a remedial strategy, and remediating contaminated soil and groundwater at an active commodity chemicals storage and distribution terminal in Minnesota.

ARCADIS StrategyAn evaluation of remedial alternatives was conducted to select feasible technologies that could address soil and groundwater contamination with the objective of achieving a risk-based regulatory closure of the site. In support of this evaluation, a series of pilot tests were conducted followed by the development of a full scale remedy with multiple treatment systems including soil vapor extraction, multi-phase extraction, and groundwater extraction, treatment, amendment and re-injection.

Project AccomplishmentsTreatment systems at the site have been successfully installed and have begun operating. The soil vapor extraction system has been removing significant mass since September 2007. Following groundwater extraction, treatment, and re-injection, a marked decline in ketone concentrations has been documented to date.

ClientConfidential Chemical Client

Scope of ServicesPilot Testing, Remediation Design and Implementation


ContaminantsVOCs, Ketones, Aromatic Hydrocarbons

Active Bulk Terminal RemediationSaint Paul, Minnesota

Active Bulk Terminal RemediationSaint Paul, Minnesota

wells, and associated subsurface conveyance piping were constructed in 2008. Second, the above grade treatment system was initiated in September 2009 and is ongoing.

The ResultThe SVE system began operating in September 2010. As of spring 2012, contaminant mass removal is still significant, and as a result, the multi-phase extraction system has neither been needed nor operated. Groundwater extraction and treatment began in December 2010. The regulatory agencies approved re-injection of the treated water after steady-state operating conditions were achieved and treatment limits were met for a sustained period of time. In July 2011, the treated effluent from the groundwater treatment system was amended with methanol and re-injected into the injection wells upgradient of the source areas. The recirculation loop established by the groundwater remedy significantly lowered ketone concentrations due to the flushing induced by upgradient injections.

Ketone concentration declines in two wells at the site following treatment (groundwater extraction, amendment with methanol, and re-injection)




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30

The ChallengeDue to historical pesticide formulation operations, soil and groundwater at a confidential site were impacted by chlorinated pesticides including hexachlorocyclohexane (BHC), toxaphene, and chlordane. Based on groundwater monitoring data, BHC appears to be the primary contaminant of concern (COC) since BHC concentrations in groundwater were found to be above groundwater cleanup levels. Site-specific groundwater cleanup levels for BHCs were established in the Record of Decision (ROD); however, site-specific BHC cleanup levels in soil had not been established, and there was uncertainty regarding appropriate soil cleanup levels for protection of groundwater for the soil leaching to groundwater pathway. Source reduction in the form of soil excavation is expected to mitigate this transport pathway and thereby sufficiently reduce the loading of BHC from soil to groundwater to meet groundwater remedial objectives. Therefore, site-specific soil clean-up goals needed to be developed so that a cost-effective protective remedy can be implemented.

The ApproachSynthetic precipitation leach test (SPLP) data were used to derive site-specific target soil concentrations (TSCs) (i.e., numeric cleanup goals) for BHC that are protective of groundwater for the soil leaching to groundwater pathway. TSCs were derived by calculating site-specific partition coefficients, Kd, for BHC based on SPLP results for soil samples collected across a range of expected BHC soil concentrations and sample depths. The calculated site-specific Kd values were orders of magnitude higher than default Kd values derived from literature, indicating that the BHC would preferentially sorb onto site soils rather than be transported to groundwater. This information resulted in substantially higher TSCs than would be derived using the default Kd values. Site-specific TSCs were then used in an area-weighted average (AWA) approach for designing a source reduction program involving excavation. The AWA approach provides a method for estimating total mass of COCs in soil, estimated mass removed, estimated mass remaining, and average COC concentrations that will remain in soil after source reduction activities have been completed. The source reduction program targeted the removal of soil with the highest COC concentrations while minimizing the total excavated volume. The program was designed so that BHC AWAs of the remaining soil were below their respective site-specific TSCs.

Project GoalDevise and implement a remedy to protect groundwater from pesticides that could leach from impacted soil at the site.

ARCADIS StrategyDevelop site-specific target soil concentrations for pesticides in soil for use in a source reduction program to protect groundwater.

Project AccomplishmentsSuccessfully negotiated site-specific target soil concentrations for hexachlorocyclohexanes (BHCs) that were then used in a comprehensive source reduction remedy involving soil excavation. This resulted in cost savings on the order of $5 million for the Client.


Scope of ServicesDevelopment of Site-specific Soil Cleanup Levels, Regulatory Negotiations, Development and Execution of Source Reduction Plan


ContaminantsPesticides (hexachlorocyclohexane, toxaphene, chlordane)

Development of Site-Specific Target Soil Concentrations to Reduce Remediation Costs at a Pesticides Contaminated SiteOrlando, Florida

Development of Site-Specific Target Soil Concentrations to Reduce Remediation Costs at a

Pesticides Contaminated Site Orlando, Florida

The ResultSource reduction activities consisted of the excavation of approximately 3,100 cubic yards (approximately 4,800 tons) of soil impacted with BHC, toxaphene, and chlordane resulting in estimated removal of 91% of the total BHC mass, 89% of the total toxaphene mass, and 92% of the total chlordane mass estimated to be present in soil in the 0 to 7 feet below ground surface (bgs) depth interval. The proposed soil excavation volume is significantly less than soil excavation volumes estimated using other approaches. Our approach will result in overall site remediation cost savings on the order of $5,000,000. The overall cost of the investigation and development of the remedial work plan was approximately $75,000.

Site map and soil and groundwater BHC impacts

Site conceptual model showing soil and groundwater impacts and groundwater discharge zones

Soil ß-BHC concentrations and Theissen polygons

Soil excavation and EHC™ backfill areas




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31

The ChallengeARCADIS was retained to perform site investigation and remediation activities at a former gas plant in southwestern Kansas. Investigation and cleanup of this facility were performed under the auspices of the Kansas Department of Health and Environment (KDHE) Voluntary Cleanup and Property Redevelopment Program (VCPRP) agreement. Constituents of concern include volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), arsenic, lead, mercury, chlorides, and PCBs.

The ApproachARCADIS conducted a number of site assessment activities at the decommissioned natural gas plant. This was followed by the preparation of a Voluntary Cleanup Investigation Report that summarized findings from all previous investigations at the site, as well as the findings from our investigation. ARCADIS then prepared a Conceptual Site Model (CSM) and a Remedial Alternatives Evaluation (RAE) in order to help facilitate regulatory discussions. Collectively, the CSM and RAE were used to demonstrate that the remaining delineation uncertainties bore little significance on the effectiveness of the anticipated cleanup approach.

Soil remediation efforts entailed excavation and disposal of approximately 800 cubic yards of soils contaminated with PCB and metals, onsite land farming of shallow soils impacted by hydrocarbons, and the installation of a full scale soil vapor extraction (SVE) system for treating deeper soils. Groundwater remediation efforts included vacuum enhanced recovery of LNAPL and the installation of a biosparge/air sparge system to remove aqueous phase hydrocarbons and to immobilize dissolved arsenic. Innovative design elements included the conversion of existing wells to biosparge wells and the use of above-ground piping.

The ResultIn spite of the complexities posed by the nature and extent of contamination, ARCADIS’ strategy was integral in navigating this

project through the VCPRP in a cost-effective manner. ARCADIS developed a phased approach for implementing the cleanup to satisfy all remaining KDHE concerns over the adequacy of early characterization efforts performed by others, and helped the Client negotiate approval to proceed with interim removal action and subsequent source area treatment, concurrent with efforts to resolve upgradient source responsibilities.

ARCADIS also convinced the stakeholders to agree to address produced water impacts which were determined to be pervasive in the area under the auspices of Kansas Corporation Commission guidelines, pending further evaluation of upgradient sources.

Remediation of a Former Natural Gas Plant SiteSouthwestern Kansas

Remediation of a Former Natural Gas Plant SiteSouthwestern Kansas


Scope of ServicesSite Characterization and Remediation, and Reclamation Services


ContaminantsVOCs, SVOCs, Arsenic, Lead, Mercury, PCBs, Produced Water/Brine

Project GoalConduct site assessment activities at a decommissioned natural gas plant located on a US Department of Agriculture (USDA) Forest Service land lease in southwest Kansas. Perform remediation and reclamation activities as appropriate to obtain an unrestricted closure determination from all applicable regulatory stakeholders.

ARCADIS StrategyThe Client had struggled to advance the project beyond the investigation phase and had been through several iterations of investigation efforts at the request of the State to fully delineate areas of concern. Once ARCADIS became involved, we recommended preparing a Conceptual Site Model (CSM) and a Remedial Alternatives Evaluation (RAE) in order to help facilitate regulatory discussions. Collectively, the CSM and RAE were used to demonstrate that the remaining delineation uncertainties bore little significance on the effectiveness of the anticipated cleanup approach.

Project AccomplishmentsARCADIS developed a phased approach for implementing cleanup in a manner that satisfied all remaining Kansas Department of Health and Environment (KDHE) concerns over the adequacy of early characterization efforts performed by others, and helped the Client negotiate approval to proceed with interim removal action, and subsequent source area treatment, concurrent with efforts to resolve upgradient source responsibilities.




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32

The ChallengeARCADIS was retained to perform investigation and remediation of a produced water spill in southwestern Kansas. The site, located on private property adjacent to USDA Forest Service land, was impacted by approximately 55,000 gallons of produced water released into the Ogallala Aquifer through a breached injection well casing at a saltwater disposal well. Following a decade of active pumping with inadequate results, ARCADIS was hired to initiate advanced hydrogeologic studies and optimize the groundwater recovery system to meet Kansas Corporation Commission closure standards.

The ApproachAfter evaluating zone-specific aquifer characteristics, ARCADIS also performed electrical resistivity surveying at the site to aid in plume delineation. Results were used to update and refine the conceptual site model and support capture zone analyses to redesign the groundwater recovery system.

ARCADIS installed two new recovery wells in the shallowest water bearing zone, with a combined groundwater extraction rate of 10 gpm. A third recovery well spanning all three zones was installed near the original source zone. Optimization of the third well provided steady state operational conditions at approximately 20 gpm and created a larger capture zone. ARCADIS subsequently received regulatory agency approval to expand the existing site infrastructure to accommodate disposal of recovered brine in a repaired saltwater disposal well. Finally, in the summer of 2012, we will install a fourth recovery well spanning all three zones in a critical area downgradient to expedite site closure.

Produced Water Brine Plume ControlSouthwestern Kansas

Produced Water Brine Plume ControlSouthwestern Kansas


Scope of ServicesSite Characterization, Remediation, and Reclamation Services.


ContaminantsProduced Water/Brine

Project GoalPerform hydrogeologic studies and optimize the groundwater recovery system to obtain site closure for a private landowner lease site impacted by a release from an oilfield disposal well.

ARCADIS StrategyARCADIS evaluated aquifer characteristics and updated the conceptual site model to support advanced capture zone analyses to optimize the groundwater recovery and treatment system and drive the site to regulatory closure. ARCADIS also pursued regulatory agency approval to dispose recovered brine in a repaired saltwater disposal well.

Project AccomplishmentsThe optimized recovery system has proven effective at controlling offsite plume migration, and is projected to meet project-specific groundwater cleanup objectives in 2015. As a result of our efforts, the Client has been able to reduce the projected environmental reserve budget for this project.

The ResultThe optimized recovery system has proven effective at controlling offsite plume migration and is projected to meet project-specific groundwater cleanup objectives in 2015. ARCADIS continues to perform semi-annual monitoring on behalf of the Client and has continued to work with regulatory agencies to drive towards site closure. ARCADIS has been integral in the planning, scoping, evaluation, design, and costing components of the project and has successfully coordinated a multidisciplinary team of personnel and various subcontractors to implement the project on schedule and within budget requirements.

Page 91



Fostering Innovation:Technology Development and Demonstration




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33

The ChallengeCurrently, ion exchange (IX) is the established and most commonly applied drinking water treatment technology for perchlorate. As a result of recent technological and process improvements, the treatment cost of conventional IX systems has steadily declined since 2000. This makes it difficult for a new, innovative technology to displace a widely used and accepted alternative. Additionally, TGAC and IX resins generally treat water for at least six months and up to 1.5 years before they require replacement, which makes demonstrating their effectiveness very time consuming. The time allotted by Fontana Water Company (the host facility) to conduct the field demonstration phase of the project was approximately one year.

The ApproachDue to the limited time available in the field to conduct the testing, two field tests were conducted simultaneously. The first set-up consisted of three 50 cubic feet capacity vessels connected in series

to treat a flow of 38 gpm. The second set-up consisted of six smaller-scale treatment systems that treated 1.5 gpm each. The six systems were used to test the technology with varied influent conditions: (1) a control bed, and beds spiked with (2) perchlorate, (3) nitrate, (4) total dissolved solids [sulfate], (5) TCE [as a co-contaminant], and (6) pre-disinfected/oxidant. To supplement the field data, 17 rapid small-scale column tests (RSSCTs) were performed in a laboratory at Pennsylvania State University using Fontana groundwater.

The ResultThe TGAC system was effective in reducing perchlorate concentrations below current MCLs for approximately 15,000 bed volumes (BVs) per bed (four- to five-month bed life), for a total treated volume of approximately 30,500 BVs (approximately 11.5 million gallons) with two beds in series. TGAC also successfully reduced perchlorate and TCE simultaneously to concentrations below current MCLs, although the perchlorate capacity was reduced by approximately 10 to 20%

Project GoalTo demonstrate the application of tailored granular activated carbon (TGAC) to cost-effectively remove perchlorate from drinking water to below regulatory limits. A secondary goal was to demonstrate that TGAC could also simultaneously remove perchlorate and TCE to below regulatory limits.

ARCADIS StrategyPerform the demonstration at an existing, operating perchlorate treatment facility in conjunction with the technology developer (Pennsylvania State University), the technology implementer (Siemens Water Technologies), and the developer of the technology’s analytical prediction software (The Air Force Institute of Technology).

Project AccomplishmentsDemonstrated that TGAC simultaneously removed perchlorate and TCE below drinking water regulatory limits (MCLs).

ClientEnvironmental Security Technology Certification Program (ESTCP)

Scope of ServicesPerform a Drinking Water Treatment Technology Demonstration at the Laboratory, Pilot and Field Scale.


ContaminantsPerchlorate, TCE

Tailored Granular Activated Carbon Treatment of Perchlorate in Drinking WaterFontana, California

Tailored Granular Activated Carbon Treatment of Perchlorate in Drinking Water

Fontana, California

when TCE was present. The 38 gpm field-scale TGAC demonstration system operated nearly continuously for 318 days and treated over 16.2 million gallons of perchlorate-impacted groundwater. The six 1.5 gpm test beds were operated for approximately six months.

As expected, data from two different scales of testing suggest that increases in nitrate and perchlorate influent concentrations reduce breakthrough time. Increases in the concentrations of other anions appear, at worst, to only moderately decrease system performance. TGAC testing with Fontana groundwater showed a shorter bed life to initial perchlorate breakthrough than predicted with proportional-diffusivity-based RSSCTs. Laboratory studies indicated that when using RSSCTs to predict perchlorate removal, the best fit to field-scale data relative to initial breakthrough can be obtained using a mathematical approach intermediate between proportional and constant diffusivity.

Main demonstration system manifold

Challenge vessels manifold and metering pumps

Half of the small-scale 1.5 gpm challenge vessels

TGAC demonstration vessels with Fontana Water Company’s full scale IX vessels in background

Four of the small-scale 1.5 gpm challenge vessels with manifold




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34

The ApproachARCADIS has partnered with NAEVA Geophysics, Inc. on this technology demonstration for DoD. Our approach includes the use of multiple advanced EMI sensors, such as the Geometrics MetalMapper and the TEMTADS, to collect data in production environments at two different demonstration sites, and then analyze the data in Geosoft UX-Analyze to determine the classification effectiveness of these sensors. Both qualitative and quantitative performance objectives will be developed for each phase of the test site demonstration. The project will involve several activities including the following: (1) collection and processing of EM61-MK2 data; (2) reacquisition of EM61-MK2 targets and cued target investigation with the advanced EMI instruments; (3) classification of advanced EMI data using multiple classification methods; and (4) intrusive investigation of all targets to determine the effectiveness of the classification process.

The ResultThe results of the study will provide the Department of Defense with an enhanced ability to leave pieces of metal in the subsurface that pose no explosive threat while still removing all munitions and explosives of concern. This has the potential to greatly reduce restoration costs at sites with buried military munitions.

The ChallengeThe Department of Defense (DoD) is responsible for investigating and cleaning up thousands of sites comprising millions of acres that are potentially impacted by military munitions. Current industry standard practice includes excavating a large number of buried metallic objects that are not munitions and explosives of concern (MEC) and pose no hazard because the ability of current sensors to discriminate these objects from MEC is limited. Next-generation electromagnetic induction (EMI) sensors and advanced software algorithms are able to successfully classify subsurface anomalies into feature classes that differentiate between MEC, non-hazardous Munitions Debris (MD), and scrap metal. While previous DoD research and development studies have demonstrated the ability of these advanced technologies to significantly decrease the number of targets that require intrusive investigation, additional classification demonstrations are still required to further evaluate the effectiveness of classification technologies on a broad range of project sites, to transfer the technology to production-level companies for widespread use within the munitions response industry, and to gain further regulatory concurrence on the use of classification.

Project GoalTo demonstrate/validate multiple advanced electromagnetic induction (IM) sensor technologies in the classification of munitions and explosives of concern (MEC) from non-MEC sources. Provide sensor performance data in an actual production environment on “live” munitions sites to determine the ability of the sensors to classify between MEC and metallic objects that pose no explosive hazard (i.e., “classification”).

ARCADIS StrategyUtilize next-generation sensors such as the Geometrics Metal Mapper and the TEMTADS to collect data in production environments at two different demonstration sites, and then analyze the data with advanced anomaly classification methods to determine the classification effectiveness of these sensors. Field demonstration efforts will be conducted in summer 2012.

Project AccomplishmentsNew sensor technology to accurately and reliably provide classification capability will allow the Department of Defense to focus its remediation efforts on MEC and reduce the need to dig up buried metallic objects that pose no explosive hazard, thereby reducing cost and minimizing the impacts to the environment and the public who must evacuate impacted areas during intrusive operations.


Scope of ServicesTechnology Development and Demonstration, Munitions Response

Performance Period2012 through 2014 (anticipated)

ContaminantsBuried Military Munitions

Comparison of Advanced Geophysical Sensors for Classifying Buried MunitionsUnited States

Comparison of Advanced Geophysical Sensors for Classifying Buried Munitions

United States

Stop Digging Point (i.e., Potential MEC to the left and non-hazardous metal to the right)

Total Number of Targets

Government Savings

Advanced EMI Sensor: Metal Mapper (Partners in Environmental Technology Conference & Workshop, December 2009)

Example of classification and interpretation of advanced EMI data (ESTCP Classification Workshop Presentation, 2011)

Example of potential cost savings to the government




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35

The ChallengeThe Advanced Water Treatment Research Program for Hexavalent Chromium in Drinking Water at the City of Glendale, California, was designed to provide technical feasibility and cost information for removing hexavalent chromium, Cr(VI), from groundwater supplies. The program provides water utilities effective treatment options in response to USEPA and California Department of Public Health (CDPH) pending action to establish a Maximum Contaminant Level (MCL) for Cr(VI) that could be significantly lower than the current MCL for total chromium. The program has lasted for a decade and has been supported by an extensive list of local, state, and national partners including the following:

• Water utilities from the cities of Los Angeles (LADWP), Burbank, and San Fernando; and the Metropolitan Water District of Southern California (Metropolitan)

• Industry groups such as the Water Research Foundation, Association of California Water Agencies, National Water Research Institute, and the San Fernando Valley Business Group

• Regulatory agencies such as the USEPA, the California Department of Water Resources (DWR) and the California Department of Public Health (CDPH)

The ApproachTo achieve the research program’s objectives, the ARCADIS project team used an innovative approach to testing and assisting the City of Glendale in obtaining funding through competitive grant mechanisms. Malcolm Pirnie, the Water Division of ARCADIS, prepared successful proposals for funding from a range of sources including the Federal Science and Technology grant program, the California State and Tribal Assistance Grant, Water Research Foundation Tailored Collaboration Grants, and the California Proposition 50 Water Bond.

Project GoalTo develop and test treatment technologies for the removal of hexavalent chromium, Cr(VI), from water to low parts-per-billion levels or below.

ARCADIS StrategyTechnical leadership of the chromium treatment research program involved developing the technical scope of successive projects comprising the research program (i.e., bench, pilot, and demonstration levels). ARCADIS also provided technical solutions, data analysis, and report preparation for each research project administered under the overall program, and performed bench and pilot testing of new technologies.

Project AccomplishmentsOur team identified and tested more than a dozen technologies for Cr(VI) removal. We fully demonstrated two new technologies for chromium removal including weak base anion exchange and reduction/coagulation/filtration, and developed treatment cost curves for use by regulatory agencies and water utilities.

The scientific and engineering approach employed by the project team was also unique in several ways. Towards the end of the initial pilot studies phase, an unknown mechanism of chromium removal was discovered. Weak-base anion (WBA) exchange resins demonstrated an extraordinary capacity for Cr(VI) removal (50+ times that of ordinary strong-base anion exchange resins). The mechanism for removal by the WBA resin (e.g., adsorption, precipitation, or encapsulation in the resin material) was evaluated using several highly technical geochemical methods. Findings of these studies demonstrated to the California Department of Public Health (CDPH) regulators and the project advisory committee that the Cr(VI) removed by the resin was relatively stable and unlikely to be released in a large mass to the distribution system.

The ResultThree technologies have been identified, and two tested at the demonstration scale for more than two years, that can remove Cr(VI) to low single-digit ppb levels in drinking water. Water treated with the new technologies is being served by the City of Glendale to its drinking water customers. This project offers the broader drinking water and industrial water treatment industries a range of Cr(VI) treatment options and treatment technology design criteria to consider when weighing the type of filtration technology to select. The large number of utilities that would be impacted by a decrease in the Cr(VI) MCL even as low as 10 ppb (4 to 5%) highlights the importance of this project to the industry.

ClientCity of Glendale, California

Scope of ServicesTechnical Leadership of the Chromium Treatment Research Program


ContaminantsCr(VI)

Advanced Ground Water Treatment Research Program for Hexavalent Chromium Removal from Drinking WaterGlendale, California

Advanced Ground Water Treatment Research Program for Hexavalent Chromium Removal from Drinking Water

Glendale, California




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The ChallengeSeveral factors make alternative endpoints beneficial and/or necessary. There are underlying technical limitations to groundwater cleanup, as well as factors that would be considered during a comprehensive analysis of the costs and benefits to society of removing residual contamination (e.g., lifecycle costs, sustainability, resource consumption). Examples include sites with residual DNAPL or multiple contaminants at depth, in fractured rock or karst environments, or widespread low-level contamination throughout a region. In addition, DoD site managers face programmatic expectations regarding site cleanup progress. Sites must therefore establish near-term cleanup objectives that are attainable and must consider alternative or intermediate performance goals as well as phased remedial actions.

Project GoalTo provide Department of Defense (DoD) environmental managers and regulators with tools, metrics, and case studies illustrating alternative remedial objectives for complex groundwater remediation sites, such as those where maximum contaminant levels (MCLs) or other numeric cleanup goals will not likely be achieved in the next hundred years or more.

ARCADIS ApproachResearch and compile case studies that illustrate the appropriate use, value, and acceptability of alternative endpoints for groundwater remediation at highly complex sites, including sites with extended timeframes to achieve cleanup goals. Examples include technical impracticability (TI) waivers, Applicable or Relevant and Appropriate Requirements (ARAR) waivers based on “greater risk”, Alternate Concentration Limits (ACLs), state designations for groundwater management zones, the use of monitored natural attenuation (MNA) over long timeframes, adaptive site management, and low-risk site closure.

Project AccomplishmentsThrough significant technical outreach and as reflected in a widely-distributed project report, this project broadened DoD and regulator knowledge of alternative endpoints and metrics, particularly the technical analyses used to formulate and document the cost, timeframe, and measurable impact of potential remedial approaches and endpoints.


Scope of ServicesReview of Case Studies Nationwide, Preparation of Guidance Report, Technical Outreach


ContaminantsVarious

Alternative Endpoints for Groundwater Remediation at Highly Complex SitesUnited States

Alternative Endpoints for Groundwater Remediation at Highly Complex Sites

United States

The ResultAs a result of this project, DoD personnel, state regulators and other environmental professionals that span federal, municipal, and private sectors have a valuable resource to understand the relevance and how to effectively apply various types of alternative endpoints, institutional controls, groundwater management strategies, and other approaches that have been used for groundwater at complex sites, as well as examples of tools and metrics used to demonstrate their appropriateness. As a follow-up to this project, ARCADIS has conducted significant outreach on this effort including a book chapter, conference presentations, workshops and short courses. We participated in the Interstate Technology and Regulatory Council (ITRC) Remediation Risk Management team and co-authored an

overview document on groundwater management approaches at highly complex sites, thereby increasing regulatory familiarity and acceptance of alternative approaches. ARCADIS staff also led six training courses for Navy Remedial Program Managers (RPMs) and contractors through the Fall 2010 RITS seminar series, conducted two Air Force workshops, and presented over 30 conference presentations and publications on this topic.

The project report is publicly available at www.serdp.org/Program-Areas/Environmental-Restoration/Contaminated-Groundwater/Persistent-Contamination/ER-200832. Although this project was developed in support of the DoD, the findings are highly adaptable to commercial, industrial, and municipal clients alike.

The ApproachARCADIS identified case studies through a comprehensive search of a CERCLA Record of Decision (ROD) database. As of November 2010, 77 CERCLA sites with technical impracticability (TI) waivers were identified. Examples of sites using other approaches were identified by internet searches, discussions with DoD personnel, state regulators, and other environmental professionals. As all alternative endpoints must be protective of human health and the environment, and must comply with existing regulations, regulatory requirements for groundwater cleanup under CERCLA, RCRA, and state-led programs were described in project deliverable report.

http://www.serdp.org/Program-Areas/Environmental-Restoration/Contaminated-Groundwater/Persistent-Contamination/ER-200832



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Industry Leadership:Performance Based Remediation




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The ChallengeIn an effort to reduce ongoing environmental liabilities associated with legacy and former retail stations, a major oil company explored methodologies to bring a significant portion of their retail portfolio to closure within a relatively short timeframe. This required a change in strategy and corporate mindset from low cost maintenance to an aggressive pursuit of closure. Previously, site closure across the portfolio was hindered by an uncoordinated effort involving different consultants using varied regulatory and remedial approaches to analogous problems and a corporate culture that valued cash flow management over closure. The oil company organized a significant portion of their liabilities into a portfolio and challenged their consultants to come up with a guaranteed and aggressive solution to close 775 sites in 15 states for a firm fixed price in 10 years. The most significant challenge posed by executing such a large portfolio of work, other than the sheer magnitude of the project, is working within a maze of regulations and cleanup standards that varied from state to state and, in some states, from county to county.

The ApproachARCADIS is an industry leader in executing performance based contracts. Our Guaranteed Remediation Program (GRiP®) team used a probabilistic cost model to develop a compelling offering that took into account the various levels of risk associated with a project of this magnitude while providing a cost-savings sharing option to the Client upon project completion. In executing the project, ARCADIS focused on devising an overall strategy with the following components:

• Logistical efficiencies: We dedicated program and project management resources, technical leadership, and execution teams to work seamlessly across the entire portfolio.

• Regulatory advocacy and innovation: We established precedent setting agreements with regulatory agencies to facilitate the rapid review and approval of critical documents.

• Technical efficiency and decisiveness: We leveraged common technical solutions for multiple sites, and designed trailer-mounted remediation systems that could be moved from site to

Project GoalAchieve site closure for 775 legacy and former retail sites on behalf of a major oil company looking to reduce environmental liabilities.

ARCADIS StrategyDeveloped a compelling offering with a guarantee to achieve site closure for all portfolio sites in 15 states within 10 years for a fixed price with shared cost savings upon contract completion.

Project AccomplishmentsARCADIS has closed approximately 20% of the sites within 2 years of contract award. With eight years remaining on the contract, we are on track to close all sites on time and within budget.


Scope of ServicesPerformance Based Remediation, Remedy Optimization, Regulatory Advocacy, Site Closure

Performance PeriodSeptember 2009 through September 2019 (anticipated)

ContaminantsPetroleum Hydrocarbons, Fuel Oxygenates, LNAPL

Remediation of a Retail Portfolio of 775 SitesUnited States

Remediation of a Retail Portfolio of 775 SitesUnited States

site thereby reducing remediation capital costs across the portfolio. We leveraged lessons-learned and best practices throughout the portfolio using a common group of technical experts.

• Web-based tools: We developed and used web-based project management, data management, and data reporting tools that can be accessed by ARCADIS staff nationwide and the Client. We also implemented the use of hand-held electronic systems for the real-time uploading of operations and maintenance data thereby reducing the time required to tabulate and generate reports.

In an unprecedented effort to accelerate cleanup timeframes, ARCADIS entered into the first Multi Site Agreement (MSA) between a regulatory agency and an engineering and consulting firm. We agreed to accelerate the study and cleanup of sites under a joint portfolio management strategy with the Washington State Department of Ecology (Ecology). ARCADIS placed sites into Ecology’s Voluntary Cleanup Program (VCP) which enables site owners to meet cleanup standards independently and to receive technical guidance from Ecology

during the process. ARCADIS is using similar regulatory advocacy approaches in other jurisdictions to facilitate regulatory responsiveness with the ultimate objective of rapidly driving sites to closure.

ARCADIS also developed a standard method of screening sites to identify those where cost-efficiencies could be realized by optimizing the groundwater sampling program. Optimization efforts included removing wells that provided repeat or redundant data (e.g., non-affected wells, multiple stable source zone wells), reducing the number of analytes, reducing the sampling frequency, and selectively switching from purge sampling methods to no-purge sampling methods.

The ResultARCADIS has closed approximately 20% of the sites within 2 years of contract award. To date, we have closed 140 sites for less than our cost model predictions. Any cost savings realized upon contract completion will be shared with the Client.

State Closed Sites Total SitesPercent Closed

California 52 201 26%

Florida 1 10 10%

Georgia 18 48 38%

Illinois 2 10 20%

Indiana 19 72 26%

Kansas 2 6 33%

Michigan 4 155 3%

New Jersey 1 30 3%

New York 1 17 6%

Ohio 32 151 21%

Oregon 2 12 17%

Washington 8 60 13%

Missouri, Utah, Pennsylvania

0 3 0%

Portfolio Total 140 775 18%

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The ChallengeRemediation at Superfund sites with extensive soil and groundwater contamination has historically been a lengthy and arduous process, taking decades to complete the various regulatory and administrative steps included in the CERCLA process. However, the Army set aggressive schedule and cost goals for environmental restoration at the Lake City Army Ammunition Plant (LCAAP). LCAAP sites include abandoned disposal pits, sumps, firing ranges, old lagoons and dumps, and closed RCRA lagoons and burning grounds. Primary environmental concerns are two operable units with large chlorinated solvent groundwater plumes impacting the principal drinking water source for LCAAP. These challenging source areas contain mixed liquid waste of more than 1,000,000 pounds of chlorinated solvents and petroleum hydrocarbons including non-aqueous phase liquids.

The ApproachTo meet the Army’s aggressive schedule and cost goals, ARCADIS executed a guaranteed fixed price remediation approach under a performance based contract for environmental restoration

services. Upon contract award in 2003, ARCADIS drew upon its technical, regulatory, and project management experts to execute CERCLA actions in three operable units comprised of over 30 areas of concern (AOCs). These included remedial investigations (RI), feasibility studies (FS), records of decisions (ROD), proposed plans, remedial designs and final Remedies In Place.

The large number of identified AOCs combined with the complexity of environmental problems and hydrogeologic constraints required the preparation of over 50 detailed technical reports. To meet the aggressive schedule performance goal for Remedy In Place (RIP), ARCADIS was adaptive in navigating the CERCLA process, streamlining the completion of many activities to expedite the overall project schedule. ARCADIS staff from more than 20 offices nationwide participated in the project, initiating all field investigations and completing 21 removal actions, field pilot studies for groundwater treatment, and human health and ecological risk assessments at every area. The ARCADIS team completed and achieved approval for 32 RI/FS reports, and worked cooperatively with the regulatory authorities to finalize proposed plans and RODs for three operable units within four years.

The ResultThe fixed price, performance-based contract vehicle provided the Army with schedule and cost certainty. The schedule success of the LCAAP project is the result of collaboration between ARCADIS, Army, and regulatory agencies (USEPA and the Missouri Department of Natural Resources).

Final remedies-in-place, which were achieved in 2008 or within 5 years of contract award, included the following components:

• In situ reactive zone systems

• Zero valent iron-clay soil mixing

• Vegetative cover placement

• NAPL recovery

• Phytoremediation

• Utilization of the existing pump and treat system and permeable reactive barrier

• In situ stabilization of lead in soils

• Soil excavation and offsite treatment

• Monitored natural attenuation

• Land use controls

The resulting restoration effort, with a contract value of approximately $53 million, is on schedule for completion in late 2012.

Accelerating the CERCLA Process at 30 Areas of Concern at Lake City Army Ammunition PlantIndependence, Missouri

Accelerating the CERCLA Process at 30 Areas of Concern at Lake City Army Ammunition Plant


ClientU.S. Army

Scope of ServicesPerformance Based Remediation, Site Investigation, Post-remedial Monitoring


ContaminantsCVOCs, Petroleum Hydrocarbons, Lead, Explosives

Project GoalTo accelerate completion of remedial investigations, feasibility studies, records of decision, proposed plans, remedial designs, and remedies in place under CERCLA at more than 30 areas of concern at Lake City Army Ammunition Plant.

ARCADIS StrategyTo meet the Army’s aggressive schedule and cost goals, ARCADIS executed a guaranteed fixed price remediation approach under a performance based contract for environmental restoration services. Upon contract award in 2003, ARCADIS drew upon its technical, regulatory, and project management experts to execute CERCLA actions in three operable units comprised of over 30 areas of concern.

Project AccomplishmentsClient objectives, including reaching Remedy in Place (RIP) designations at all areas of concern were met within 5 years of contract award. ARCADIS’ innovative remediation planning, design, and implementation has saved the Army more millions of dollars in overall site restoration costs.




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39

The ChallengeBoth soils and groundwater at the site were impacted with tetrachloroethene (PCE) as a result of historic parachute cleaning activities. The PCE plume in groundwater stretched approximately 3,000 feet to a river bordering the air field, and averaged approximately 400 feet in width, and 50 to 60 feet in thickness. The top of the plume dipped approximately 70 feet in the source area to a depth of 120 feet below ground surface (bgs) before turning upward and discharging into the river. The geology underlying the site represents a remnant plateau characteristic of kame-and-kettle topography formed by glacial lake sedimentation.

The ApproachARCADIS was contracted to complete a remedial investigation/feasibility study (RI/FS), obtain regulatory concurrence on a final remedy through a Record of Decision (ROD), and operate the selected remedy for a period of five years. In support of the FS, ARCADIS prepared a three dimensional groundwater flow and solute transport model to assist in the development, evaluation, and comparison of remedial alternatives. Public participation was solicited in the selection of the final remedy for groundwater. The final selected remedy involved the use of soil vapor extraction (SVE) to remove adsorbed phase CVOCs present in the source area, along with the in situ treatment of the majority of the groundwater plume using enhanced reductive dechlorination (ERD). The ERD technology

Project GoalAddress chlorinated volatile organic compounds in the source area and associated groundwater plume that was discharging to a nearby river. Meet the performance based goal of regulatory approved remedy in place (RIP) under CERCLA with five years of remedial system operations, maintenance, and monitoring.

ARCADIS StrategyRefine the conceptual site model, complete site remedial investigation (RI) and feasibility study (FS), obtained regulatory approval of the Record of Decision, and design a multi-faceted remedial approach to treat CVOCs in the source area and the distal plume.

Project AccomplishmentsARCADIS quickly and successfully treated the source area and significantly reduced the PCE footprint reducing the cleanup timeframe by as much as 60% and achieving greater than 90% reduction in contaminant mass in five years. We successfully protected the river by intercepting and treating impacted water prior to discharge.

ClientU.S. Army Forces Command (FORSCOM)

Scope of ServicesPerformance Based Remediation, Groundwater Modeling

Performance PeriodSeptember 2001 through June 2008

ContaminantsCVOCs

Performance Based Remediation of a Site Impacted by PCEFort Devens, Massachusetts

Performance Based Remediation of a Site Impacted by PCEFort Devens, Massachusetts

included five treatment areas along the length of the plume and injections of a degradable organic carbon substrate. Concurrently, an in well sparging (IWS) barrier was employed at the downgradient edge of the plume to protect the river through the removal of CVOC mass and the creation of a zone of oxidizing conditions.

The ResultWithin a period of three years, project documents including RI/FS, ROD, and Remedial Design/Remedial Action Work Plan (RD/RA WP) were completed and approved. An ERD pilot study being conducted concurrently reduced PCE concentration by up to 90% within a year of operation. Based upon the success of the pilot, a full scale ERD system was designed and constructed to achieve significant reductions in total contaminant mass within the treatment areas. In turn, the ERD system resulted in a considerable reduction in the size of the plume.

Reduction in PCE concentrations in the source area allowed for the shutdown of the SVE system after less than a year of operation, saving long-term operation and maintenance costs. The IWS wells operated with a PCE treatment removal efficiency of approximately 90%. PCE concentrations downgradient of the IWS system fell by 85%. The IWS system met its remedial objective of being protective of the downgradient river. Community and regulatory support and trust were gained through the continued successful treatment of the PCE plume.




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The ChallengeThirty years after a contaminant release at a former aboveground storage tank (AST) facility used for fuel oil storage, concentrations of SVOCs, 2-methylnaphthalene, and Total Petroleum Hydrocarbons (TPH) were still above residential Texas Tier 1 Protective Concentration Levels (PCLs). In 2008, a revised PCL for 1-methylnaphthalene was published, causing this constituent to exceed commercial/industrial screening levels in soil. Soil exceedances occurred deeper than six feet below ground surface (bgs) and were likely the result of seasonal groundwater fluctuations. Groundwater concentrations of TPH, 1-methylnaphthalene, 2-methylnaphthalene, and benzo(a)pyrene were initially above both residential and commercial/industrial PCLs, indicating that groundwater remediation would be needed.

The ApproachAfter beginning the performance based remediation project in 2006, ARCADIS conducted a detailed evaluation of existing soil and groundwater site data. Based on this evaluation, ARCADIS determined that the upper five to six feet of soil were not contaminated. Exceedances deeper than six feet bgs coincided with seasonal groundwater fluctuations and were limited to a small area beneath the former AST. Monitoring wells within the AST area had SVOCs detections. Outside the affected area, wells were free of impact. Groundwater at the site was determined to be Class 2, which allowed for the implementation of a Plume Management Zone, an institutional control that prevents exposure to contaminated groundwater above cleanup levels.

Project GoalAchieve closure for a site where soil and groundwater contaminant concentrations exceed Texas Tier 1 Protective Concentration Levels.

ARCADIS StrategyUsed Plume Management Zone guidance under the Texas Risk Reduction Program to eliminate the need for active remediation of soils, and focused instead on managing contaminated groundwater. Established a strong working relationship with the Texas Commission on Environmental Quality to accelerate approval of strategy and subsequent site closure.

Project AccomplishmentsSuccessfully demonstrated plume stability and a non-continuous source resulting in site closure. Gained regulatory acceptance of accelerated closure based on one annual groundwater event rather than three annual events as originally requested.

ClientConfidential Power & Utility Client

Scope of ServicesPerformance Based Remediation, Interim Removal Actions, Regulatory Negotiations, Regulatory Closure


ContaminantsSVOCs, 1-Methylnaphthalene, 2-Methylnaphthalene, Benzo(a)pyrene, TPH

Plume Management Zone for Soil and Groundwater Semi-Volatile ExceedancesTexas

Plume Management Zone for Soil and Groundwater Semi-Volatile Exceedances

Texas

The ResultARCADIS proposed establishing a Plume Management Zone with appropriate institutional controls in areas where soil and groundwater exceeded cleanup levels, due to the limited extent of contamination, biodegradable nature of the fuel oil constituents, and the declining and/or stable contaminant concentrations as evidenced by several years of monitoring. The Texas Commission on Environmental Quality (TCEQ) approved a Plume Management Zone and requested an additional three years of annual groundwater monitoring to demonstrate plume stability. ARCADIS met with the TCEQ, presented several lines of evidence demonstrating plume stability, and suggested that monitoring for three additional years was unnecessary. TCEQ agreed and conceded to one additional year of monitoring to fully demonstrate plume stability. Closure was granted in 2011.




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41

The ChallengeAfter completing source area remediation and significantly reducing downgradient contaminant mass, recalcitrant zones of elevated contaminant concentrations were still evident in a groundwater plume underneath the Del Monte Center, an active shopping center in Monterey, California. Additionally, low concentration contaminant impacts to an adjacent creek remained as a source of concern. Stakeholders agreed that some zones of residual mass may not require treatment at this site due to low contaminant mass flux. However, a predictive conceptual site model (CSM) was needed to connect residual contaminant mass to receptor risk, guide final remedial efforts, and support contractually-required regulatory closure.

Project GoalAchieve regulatory closure of a chlorinated solvents plume beneath an active shopping center in Monterey, California.

ARCADIS StrategyRefine the conceptual site model (CSM) using groundwater and contaminant mass flux information developed from focused studies. Use the revised CSM to obtain regulatory concurrence on remaining required remedial actions. Use an approach based mass flux to guide remediation and focus data collection to continue refining the CSM.

Project AccomplishmentsARCADIS leveraged high-end characterization techniques to produce a predictive CSM to successfully refocus remedial efforts in a challenging hydrogeologic environment. Source mass flux was reduced at the site, and discharge zones driving potential receptor risk were identified and remediated. The revised predictive CSM strengthened regulatory concurrence for no further active remediation. Additional confirmatory monitoring is underway to support a request for site closure under a risk-based framework.

The ResultThe targeted expansion of the existing ERD remedy controlled contaminant mass flux to the creek. Concentrations of chlorinated solvents were shown to decline in high flux zones thereby addressing the true contaminant flowpaths driving risk. Regulatory concurrence has been strong because the site has been well characterized, the remedy optimized, and remaining potential risks controlled. As a result, the groundwork was laid for site closure, and post-remediation monitoring has been initiated.

The ApproachAfter a top to bottom review of previously completed restoration efforts at the site, ARCADIS came to the conclusion that the hydrogeologic environment was much more complex than previously thought. Although significant mass had been removed, we came to believe that the drive to closure required a mass-flux-based understanding of the site. Accordingly, ARCADIS completed 2-D and 4-D geophysical surveys and multi-dye tracer tests. Using results from these tests together with historical site data, we created a numerical groundwater flow and transport model and then evaluated contaminant mass flux. The revised CSM led us to a better understanding of the hydrogeology at the site: (1) many low flow zones existed; (2) most of the flow was occurring in a thin horizon; (3) flow direction changed abruptly in some areas; and (4) aquifer to creek discharge occurred in specific zones. The revised CSM supported expanding an existing enhanced reductive dechlorination (ERD) system in a focused area of the site to control residual contaminant flux to the creek, continuing ERD in zones of higher contaminant flux across the site, and ceasing remediation in low flow/flux zones despite lingering elevated contaminant concentrations in many wells.

ClientAmerican Assets

Scope of ServicesPerformance Based Remediation, Regulatory Closure


ContaminantsCVOCs (PCE, TCE, DCE, VC)

Mass Flux Focused Remediation of a Chlorinated Solvents PlumeMonterey, California

Mass Flux Focused Remediation of a Chlorinated Solvents Plume

Monterey, California

Page 113



Building World Class Teams:Academic Partnerships




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42

The Challenge In many cases, innovative NAPL treatment technologies have an unclear benefit (in terms of reduced risk or cost) because of the difficulty associated with measuring and quantifying remedial performance and predicting long-term outcomes. Using Williams Air Force Base (Williams AFB) as a demonstration site, ARCADIS led a national team of academic and industry experts in the development of an innovative approach to more accurately predict the longevity of NAPL sources. The project was funded by the Department of Defense (DoD) through its Environmental Security Technology Certification Program (ESTCP).

At Williams AFB, a rising water table over the last two decades created a submerged smear zone of NAPL (jet fuel), resulting in a long-term source of benzene and other compounds to groundwater. Without treatment, concentrations of groundwater contaminants were predicted to remain elevated for hundreds of years. A pilot test involving thermally enhanced extraction (TEE) was conducted to reduce the footprint of the source. At the time of remedy selection and evaluation, it was not clear what tools can be used to make a decision about the benefits of transitioning from a thermal treatment pilot test to a full scale implementation.

Evaluating NAPL Source Longevity at Contaminated SitesMesa, Arizona

Evaluating NAPL Source Longevity at Contaminated SitesMesa, Arizona


Scope of ServicesTechnology Development and Demonstration, Groundwater Modeling


ContaminantsLNAPL

Project GoalUsing Williams Air Force Base as a field demonstration site, develop a methodology to more accurately predict the longevity of NAPL sources to groundwater to improve the evaluation of source treatment benefits and risks.

ARCADIS StrategyAt team of ARCADIS experts, together with industry and academic specialists, designed an innovative field measurement program. This program included integrated pumping tests and the deployment of passive flux meters both before and after a thermal remediation pilot test within a NAPL source area. The resulting data was then synthesized into a quantitative model.

Project AccomplishmentsThe field measurement program resulted in a methodology to more accurately characterize NAPL source zone depletion, thereby allowing for a robust prediction of source longevity and the impact of partial source reduction.

The ApproachTo better estimate NAPL persistence at Williams AFB, novel tools were applied to measure and analyze mass dissolution in the source zone before and after a thermal treatment pilot test. These tools included integral pumping tests combined with Passive Flux Meters™ deployment and multicomponent modeling using the model SEAM3D (Sequential Electron Acceptor Model, 3D). SEAM3D is a reactive transport model used to simulate complex biodegradation problems involving multiple substrates and multiple electron acceptors. The model was developed by Professor Mark Widdowson at Virginia Polytechnic Institute and State University (Virginia Tech).

The Result The combined tools measured mass transfer characteristics on length scales varying from a few to 70 feet. Our team synthesized the data collected on the various scales before and after the pilot test into a working model of NAPL geometry and mass dissolution in SEAM3D. SEAM3D was then used to evaluate various remedial strategies and the resulting predictions of source and plume longevity.

The methodology developed and refined during our field demonstration at Williams AFB allows for better estimates of NAPL mass and persistence coupled with accurate predictions of source mass reduction. The use of this tool will allow DoD to make scientifically defensible decisions related to when and to what degree active remediation efforts should be pursued. This has the potential to significantly improve the evaluation of source treatment benefits and risks, resulting in time and cost savings at NAPL-affected sites nationwide.

“We are seeking to improve decisions regarding when and to what extent NAPL sources should be remediated”




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43Project GoalProvide practitioners and regulators with a way to visualize the key processes associated with vapor intrusion.

ARCADIS StrategyUse a 3-D mathematical vapor intrusion model to perform simulations and provide visualizations for a number of conceptual scenarios to delineate potential VOC migration pathways.

Project AccomplishmentsModeling results were presented in a technical report titled “Conceptual Model Scenarios for the Vapor Intrusion Pathway”. The report was released by USEPA as one of a series of documents supporting the revision of USEPA’s Vapor Intrusion Guidance.

ClientUSEPA via EnviroGroup and RTI

Scope of Services3-D Modeling of Vapor Intrusion Pathways, Technical Guidance Preparation

Performance PeriodOctober 2009 through February 2012

ContaminantsVOCs, CVOCs

Development of USEPA Conceptual Model Scenarios for the Vapor Intrusion PathwayUnited States

Development of USEPA Conceptual Model Scenarios for the Vapor Intrusion Pathway

United States

The ChallengeThe potential for vapor intrusion has forced many sites to remediation, sometimes resulting in significant expenditures to although risk and exposure may not exist. The goal of this project was to develop a guidance document that provides a theoretical framework for the complex conditions that can be encountered at vapor intrusion (VI) sites, and illustrates how different site conditions may influence the distribution of VOCs in soil gas and indoor air of structures near soil or groundwater contaminant sources. The goal of the technical document is provide practitioners with better guidance on plan site investigations and interpreting associated results.

The ApproachARCADIS technical expert, Dr. Lilian Abreu, together with Professor Paul Johnson of Arizona State University, developed 3-D mathematical model that was used to simulate a variety of conceptual scenarios

to illustrate potential vapor migration pathways as VOCs travel from contaminated soil and groundwater through the subsurface and potentially into buildings. The Abreu and Johnson 3-D model was used to simulate several processes that cannot be simulated with the 1-D Johnson and Ettinger model such as effects of lateral source-building separation, finite sources, laterally-discontinuous soil layers, and coupled oxygen and chemical transport and biodegradation. The Abreu and Johnson 3-D model calculates the chemical vapor concentration in the subsurface, mass flow rates into buildings, and the indoor air concentration due to vapor intrusion.

The ResultThe final technical document presenting the results of the modeling work described above was released by USEPA in February 2012. Dr. Abreu was the primary author with Dr. Henry Schuver of USEPA’s Office of Resource Conservation Recovery as a supporting author. Several members of the USEPA Vapor Intrusion team

provided review and suggestions for the document including Professor Paul Johnson. RTI International managed document reviews, editing, and preparation. SRA International, Inc., managed the external peer reviews. The report is available and can be downloaded, free of charge, from the USEPA Vapor Intrusion public website at http://www.epa.gov/oswer/vaporintrusion/documents/vi-cms-v11final-2-24-2012.pdf.

Dr. Lilian Abreu, ARCADIS U.S., Inc. and Dr. Henry Schuver, USEPA ORCR, have made extensive presentations to educate the community of

practitioners on the use of the scenarios and visualizations derived from this modeling

-8

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(95% water saturation)

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Model specific inputs

Chlorinated VOCs

NAPL SourceSource Vapor: 200 mg/L TPH

[λ = 0.18 h-1]

Results suggest that there may be a critical depth beyond which VI is of little concern for NAPL sources as long as a clean aerobic soil layer is present.

Dissolved GW SourceSource Vapor: 2 mg/L TPH

[λ = 0.18 h-1]

Results suggest that for dissolved groundwater sources, VI may be of little concern even for relatively shallow source depths.

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Hydrocarbon Oxygen

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Aerobic Biodegradation of Petroleum Hydrocarbons

Effect Of Source Depth & Vapor Concentration

Effect of building type, source positioning, ground cover and

geologic vapor barrier.

http://www.epa.gov/oswer/vaporintrusion/documents/vi-cms-v11final-2-24-2012.pdf

http://www.epa.gov/oswer/vaporintrusion/documents/vi-cms-v11final-2-24-2012.pdf




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44

The ChallengeConventional groundwater velocity measurement methods are largely insensitive to local-scale heterogeneities that control advective flow rate and direction. To address this need, Point Velocity Probes (PVPs), an instrument capable of measuring transient and local-scale groundwater flow velocity and direction in situ, was recently developed by researchers at the University of Kansas.

The general efficacy of the PVP concept had been previously confirmed in laboratory and simple field settings. The objective for this study was to assess the practical implementability and performance of this technology at field sites with complex hydraulic conditions and where groundwater-surface water interactions are difficult to characterize using conventional methods.

The ApproachThe PVP utilizes a small volume of salt tracer and inexpensive sensors to directly measure groundwater flow direction and velocity in situ at discrete times. The probes are installed in conventional borings, rather than in wells, thus minimizing the changes and biases in the local flowfield caused by well construction. For this study, a new PVP prototype was developed using a three-dimensional plastic printer, and included both horizontally- and vertically-oriented detectors. The new PVPs were tested in a laboratory sand tank and then five PVPs were installed at a tidally-influenced site in North Carolina to evaluate their implementability, performance, and potential value as a new site characterization tool. A site-specific testing protocol was developed to account for the spatially- and temporally-variable hydraulic conditions and groundwater salinity.

Project GoalPartner with the University of Kansas to evaluate the implementability and performance of Point Velocity Probes (PVPs), a new site characterization technology.

ARCADIS StrategyConduct a research and development project to test Point Velocity Probes at a tidally-influenced site in Wilmington, North Carolina, characterized with spatially- and temporally-variable groundwater flow conditions.

Project AccomplishmentsLeveraged relationships with the University of Kansas to implement a cost-effect field demonstration to test and validate a promising new characterization technology. The study clearly identified the relative strengths and limitations of Point Velocity Probes, and our recommendations were used by the University of Kansas to improve the design of this technology.


Scope of ServicesDevelopment of a New Characterization Technology, Research and Development


ContaminantsArsenic, Lead

Field Evaluation of Point Velocity Probes (PVPs), a New Groundwater Characterization Technology Wilmington, North Carolina

Field Evaluation of Point Velocity Probes (PVPs), a New Groundwater Characterization Technology

Wilmington, North Carolina

The PVPs were tested multiple times and the results were compared to results from a number of other groundwater flux and velocity estimation tools and methods, including a heat-pulse flowmeter, passive flux meter, single-well tracer testing, and high resolution gradient analysis.

The ResultIn general, the PVP concept was validated, and measurements of groundwater velocity and direction were shown to be reliable in ideal settings using this technology. Our results suggest that PVPs may be useful for characterizing groundwater flow systems that are

complex but exhibit relatively modest transient behavior. Additionally, it was demonstrated that PVPs can be successfully installed using conventional methods in non-cohesive sands. We were able to identify some aspects of the current PVP design and testing protocol that needed improvements and researchers at the University of Kansas have since modified the design PVPs based on the results of this study.

By identifying the relative strengths and limitations of this technology, we provided the Client with a better understanding of its use at other sites within its environmental restoration portfolio.

Page 121



Frontiers in Remediation:Global Expertise




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45

The ChallengeCS2 was historically used in textile production at a manufacturing facility (the site) in the United Kingdom. The site was subsequently redeveloped as a housing estate. Later investigations identified CS2 contamination beneath property footprints on the estate resulting in the potential for substantial restoration costs. Remediation of CS2 poses multiple technical difficulties due to the chemical properties of this contaminant (volatility and a low flash point). Conventional treatment options for CS2 include excavation, stabilization, and landfill disposal. ARCADIS was approached to design and implement a more sustainable, cost-effective, safer, and less disruptive remediation approach.

The ApproachThe ARCADIS approach included the following key elements:• Develop a safe, sustainable, cost-effective in situ approach

for the remediation of CS2 in soil and groundwater.• Prove the effectiveness of the technology during laboratory

testing and in a limited field demonstration, and achieve regulatory agreement for a full scale implementation.

• Develop methodologies and health and safety procedures to safely oxidize CS2 in situ.

• Reduce the concentrations of CS2 in soil and perched groundwater

and demonstrate that the remaining concentrations do not pose a significant risk to human health at a 95% confidence level.

• Undertake the work in a manner considerate of the local community and minimize the effect of remediation activities on the neighboring residents.

Prior to development of this remedy, there were no known safe or effective in situ technologies available in the United Kingdom for remediation of this compound in soil and groundwater. The concept of using persulfate for oxidizing CS2 was conceived in collaboration with our Client which led ARCADIS to perform fundamental research in its European Treatability Facility. The treatability study represented a world first assessment of in situ chemical oxidation of CS2 using persulfate. ARCADIS designed experimental equipment to demonstrate that CS2 destruction could be achieved without a significant rise in temperature and with no production of harmful vapors. Health and safety was the primary driver in the laboratory evaluation of this technology, as temperature increases or the production of gases could lead to the migration of CS2 in the vadose zone in the field.

The first stage of full scale implementation was a field scale pilot trial undertaken to provide confidence in the remediation and validation approach to the stakeholders.

Project GoalTo develop and implement an in situ remediation strategy on an existing housing estate, reduce levels of CS2 in the subsurface to levels acceptable to all stakeholders, in a manner considerate to the local community.

ARCADIS StrategyDevelopment and bench testing of an innovative but safe remediation approach, drawing on the strengths of the ARCADIS global knowledge transfer network, before implementing a full scale remedy.

Project AccomplishmentsThe project involved the first application of in situ chemical oxidation of CS2 using persulfate worldwide. In November 2011, it was voted as the Best In Situ Treatment Project at the prestigious UK Brownfield Briefing Awards. The use of this innovative in situ approach resulted in an estimated £15 million to £20 million cost saving to the Client.


Scope of ServicesSite Investigation, Remediation using Direct Injection and In Situ Soil Mixing of Chemical Oxidants, Soil Gas and Air Sampling, Risk Evaluation


ContaminantsCarbon Disulfide (CS2)

In Situ Chemical Oxidation for Carbon Disulfide TreatmentWolverhampton, United Kingdom

In Situ Chemical Oxidation for Carbon Disulfide TreatmentWolverhampton, United Kingdom

Delineation investigations were undertaken using a Multiple Lines of Evidence approach including non-intrusive geophysics (electromagnetic survey), a Membrane Interface Probe (MIP) investigation, and soil and groundwater sampling. A network of dedicated injection wells was installed at the site. The well installations were designed based on contaminant distribution and to target the permeable subsurface zones. The activated persulfate solution was pumped to the well network using injection pipework and custom built distribution manifolds which allowed solutions to be applied to up to 24 wells simultaneously. The resulting zone of influence of the oxidant was assessed using the proprietary persulfate test kits developed by the ARCADIS Treatability Laboratory.

In conjunction with oxidant injection using wells, a series of surgical injections were undertaken. Direct push rods were used to apply activated persulfate solutions to discrete horizons, zones of high contamination, and areas of low permeability. A soil mixing approach

was designed and implemented for selected areas of particularly low permeability. Soil mixing was undertaken using an excavator or via the use of a bespoke shrouded modified augering system.

The ResultThe results from confirmatory sampling events following remedy implementation indicated that mean concentrations of CS2 in soil (at the 95% confidence limit) decreased from 4.9 mg/kg and 2.3mg/kg, to 0.64mg/kg and 0.082mg/kg, respectively, in two areas of concern at the site. Concentrations in groundwater decreased from a maximum of 13,000µg/L to a maximum of 12µg/L following remediation.

By implementing an innovative and novel approach for managing CS2 impacts in soil and groundwater, ARCADIS has remediated the site safely, rapidly and in a sustainable manner. The work was undertaken with disturbing neighboring residents and with full co-operation of the regulatory authorities. It also resulted in significant restoration cost savings to the Client (£15 to £20 million).

UK

Wolverhampton

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Geophysical survey results

Oxidant distribution network

CS2 concentrations over time from the treatability study

Temperature and off-gas experiment set up at ARCADIS’ facility

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46

The ChallengeThe Xiawangang Canal Sediment Remediation project is located within the historic Qingshuitang Industrial Zone in the city of Zhuzhou, Hunan Province, China. The Xiawangang Canal has been contaminated primarily with heavy metals due to decades of discharges from heavy industries (e.g., smelters, steel plants, chemical plants, and rail and auto car manufacturing plants). The Canal discharges to the Xiang River which serves as a drinking water source for the region. The project objectives were to develop an overall sediment remediation strategy involving the removal of heavy metal contaminated sediments for offsite disposal and the production of a conceptual remedial design for local engineers to ultimately execute the remedy.

The ApproachARCADIS, including ARCADIS-US and ARCADIS-China, provided global technical expertise and local delivery support to our Client, OTEK (an ARCADIS Alliance Member Partner based in Australia with several offices in China) in execution this complex and highly visible project. ARCADIS played a key role in the project’s success through a collaborative partnership with OTEK early on in the project pursuit phase when we presented our world-class sediment management capabilities to project stakeholders at a meeting hosted by the Australia Trade Commission in Australia. Immediately

following project award, ARCADIS mobilized five staff to the site over a 3-week period in order to obtain site-specific information necessary to develop the strategy and basis for remedial design.

ARCADIS led stakeholder engagements and site reconnaissance activities in order to document the site conditions and set the groundwork for successful project execution. Key observations and site challenges included the following:

• The canal has very limited access, and to further complicate access, the site is defined by steep side slopes consisting of bedrock, vertical brick or stone walls, and vegetated and non-vegetated (eroded) surfaces.

• The site is situated within a highly industrial area and is surrounded by chemical plants, smelters, steel plants, water treatment plants, and other industrial operations.

• The work area had numerous obstructions including pipes, concrete covers, bridges, and debris.

ARCADIS provided technical expertise and guidance on the field investigation which was conducted by others and consisted of surveying, sediment probing, sediment sampling, and a modified Standard Penetration Test (SPT), and bench scale solidification and stabilization (S/S) and water quality treatability tests which were

Project GoalProvide a conceptual design for the remediation of 4 km industrial canal.

ARCADIS StrategyDeploy a highly experienced field engineering team to site in order to collaborate with the Client and owner’s representative to field-engineer an appropriate technical solution.

Project AccomplishmentsMobilized a project team, including virtual international team members and in-country resources, to deliver a complex conceptual design in less than 2 months, providing the basis for the Client to complete a final design and construction of the remedy within an aggressive timeline and under budgetary constraints.

ClientOTEK

Scope of ServicesSite Investigation, Bench Scale Testing, Remedial Strategy Development, Conceptual Remedy Design

Performance Period2011

ContaminantsCadmium, Arsenic, Lead, Mercury, Copper, PCBs, Pesticides, PAHs

Xiawangang Canal Sediment Remediation ProjectZhuzhou, Hunan, China

Xiawangang Canal Sediment Remediation ProjectZhuzhou, Hunan, China

conducted by laboratories in China. Additionally, a HEC-RAS model (River Analysis Systems, version 4.0; 2008) was calibrated to describe Canal hydraulics during base flow and base flow plus storm-related runoff for existing and for post-removal conditions.

Based on the highly variable site conditions along the 4 km length of the canal, the remedial strategy was to implement a segment-based approach to systematically address sediments in 8 discrete segments from upstream to downstream in the treatment area. The key design and implementation elements are as follows:

• Water will be diverted in each segment of the Canal. Segments will then be dewatered to allow sediment removal under “dry” conditions. The wastewater will be collected and treated prior to discharge at one of two wastewater treatment plants adjacent to the Canal.

• Approximately 28,500 cubic meters of sediment will be removed following water diversion to a target depth up to 1 meter below the existing sediment surface or to bedrock.

• Sediment will be removed from most sections using long-reach excavators from the banks and tracked excavators and crawlers in the Canal. Covered sections require specialty removal methods.

• Following gravity dewatering, sediment will be treated using S/S to allow disposal at a Class I landfill for normal industrial waste.

• Backfill and erosion protection will provide a stable physical barrier between residual contaminated sediments and the environment after sediment removal.

• The conceptual design included turbidity controls and water quality monitoring to address the concern that the remediation itself may negatively affect downstream water quality and as well as water quality in the Xiang River.

The ResultARCADIS and its partner OTEK demonstrated agility in a collective rapid response to address the Zhuzhou Municipal Economic Authority’s immediate needs and aggressive schedule to complete a conceptual remedy design. The ARCADIS team was able to execute the site visit, investigation, and conceptual design completed within two months to allow accelerated construction schedule. ARCADIS’ remedial strategy and conceptual design were used to gain Client (investor) and regulatory approval for the project, and provided the basis for the detailed design and remedy construction which were completed by a local engineering firm in early 2012.

Zhuzhou




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47

The ChallengeA high-concentration CVOC plume (20 - 200 mg/L total CVOCs) was identified below a former production facility and has migrated vertically to a depth of 13 meters below ground surface (bgs). The plume extends laterally below a residential area. COVC concentrations indicate that DNAPL is present at some locations. Although the Client no longer owns the facility, this site is currently occupied by three independent companies and therefore the activities inside the buildings cannot be interrupted during the corrective action creating new and complex challenges to the project. The Client’s goal was to reduce the timeframe of remediation from 30 to 5 years by increasing the aggressiveness of the existing remedial strategy.

The ApproachA remedy based on enhanced reductive dechlorination (ERD) was selected for the site since geochemical analyses supported the potential

to stimulate anaerobic biodegradation. To minimize disruption of operations at the site, an automated injection system for carbon substrate (molasses) delivery was designed and constructed at the site. The system included a network of 171 injection wells completed at different depths and target treatment intervals. The flexible design of the system made it possible to optimize and adapt the operation in real-time during remediation. For example, injection volumes and concentrations have been adjusted throughout remedy implementation in order to maximize the treatment performance of the system and to focus the efforts of the remedy in areas that yield the greatest benefits. The downgradient pump and treat system was kept to limit offsite migration. The treated water from this system was reused to mix the injection solution thereby minimizing waste generation. Additionally, a soil vapor extraction system was installed to capture the vapors associated with the CVOCs in groundwater and secondary gases generated through the engineered biological reactions.

Project GoalAdapt an existing pump and treat system to a more efficient remedy to reduce the remedial timeframe from 30 to 5 years.

ARCADIS StrategyRe-design the groundwater remedy with a focus on more aggressive and rapid site cleanup, while maximizing the use of existing infrastructure from an onsite pump and treat system.

Project AccomplishmentsARCADIS designed a treatment system based on the injection of a carbon source to stimulate natural biodegradation processes. Downgradient pumping wells from the former pump and treat system were used to contain the contamination. Following implementation of the revamped remedy, concentrations in the deep part of the aquifer decreased by 99% over a period of 3 years. As a result, injections have ceased and the contaminant plume has been reduced to 3 shallow areas. In the following 2 years, remediation actions in these remaining zones will be increased with a focus on achieving the 5-year cleanup goal for the site.

ClientEastman Chemicals

Scope of ServicesProject Management, Stakeholder Involvement, Regulatory Negotiations, Risk Management, In Situ Remediation, Groundwater Modeling


ContaminantsCVOCs, BTEX

Enhanced Reductive Dechlorination of a High Concentration CVOC PlumeAntwerpen, Belgium

Enhanced Reductive Dechlorination of a High Concentration CVOC Plume

Antwerpen, Belgium

The ResultA rapid conversion of CVOCs to harmless degradation byproducts (ethene and ethane) was observed. In the deep part of the aquifer, a 99% reduction in contaminant concentrations was achieved after 3 years of operation and the overall remediation of this entire area is anticipated to be completed within the target 5-year timeframe. In order to achieve the cleanup goals for the site, additional wells will be installed in the remaining source zones to speed up remediation in these areas over a period of 2 years. The re-designed remedy represents a more effective solution based on overall performance, cleanup timeframe, and cost while the in situ ERD remedy utilizes fewer resources. Specifically, water and energy consumption at the site were reduced by 95% and 77%, respectively, while the generation of waste was reduced by 92%. The adaptive design has allowed for regular adjustments of the system as necessary in order to achieve the cleanup objectives within 5 years.

P&T ERD Reduction (%)Water

pumped (m³) 630,000 52,500 92reinjected (m³) 0 22,500discharge (m³) 630,000 30,000 95

EnergyElectricity (kWh) 220,000 51,000 77CO2 (ton) 44 10 77

Waste and materialsSludge (ton) 111 9 92Activated carbon (ton) 63 5.25 92Molasses (ton) 0 279

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48

The ChallengeLocated on a chalk plateau in Dreux, France, Perfect Circle Europe operated an automotive parts manufacturing facility that included a chromium plating operation which was active from 1962 until the facility was closed in 2005. Prior to 1970, the plant disposed its wastes in an onsite landfill. Investigations showed that the soil and groundwater at the site were impacted with several contaminants: hexavalent chromium (CrVI), chlorinated solvents (CVOCs), and petroleum hydrocarbons (TPH). In addition to the landfill, the former plating area and a storage area were also identified as source areas, contributing LNAPL and elevated concentrations of constituents to the groundwater (300 to 700 mg/L of CrVI, and >1,000 mg/L TCE). After operations ceased at the site in 2005, the Client entered into a Prefectural Order with the French administration to remediate the site. The primary objective of the authorities was to reduce the flux of constituents moving offsite.

Hydrogeological conditions at the site pose unique remedial challenges. The surficial geology of the site consists of clay to approximately 5 meters below ground surface (bgs), and overlays a fractured chalk limestone aquifer which extends to 100 meter bgs.

The ApproachHistorically, approximately 1,700 tons of CrVI and TPH impacted soils were consolidated and disposed onsite in a containment cell. In 2006, after operations ceased at the facility, the 1,700 tons and an additional 2,500 tons of soil were stabilized and disposed offsite to facilitate site redevelopment. Additional areas were capped with concrete to mitigate direct contact exposure pathways and to minimize CrVI leachate impacts to groundwater.

Groundwater fate and transport modeling was used to support a human health risk assessment. The results of the model were used to evaluate remedial options and negotiate remedial endpoints. Remediation targets for groundwater were established using offsite sentinel wells as points of compliance.

A total of 8 extraction wells were used for hydraulic containment and LNAPL recovery between 2000 and 2008. The objective of the system was to provide source control and reduction as an interim remedial measure prior to in situ treatment. The treatment system consisted of total fluids recovery, oil/water separation, air stripping, and activated

Project GoalCost-effective remediation of soil and groundwater at a site impacted by chromium and chlorinated solvents to facilitate property redevelopment and reuse.

ARCADIS StrategyInvestigations focused on delineating chromium and TCE in soil and chalk bedrock, while gathering pre-design data to evaluate in situ remedial options and support a risk assessment used to derive site specific cleanup goals. An existing groundwater extraction system was optimized to provide hydraulic containment and enhance mass removal, while in situ oxidant were applied to the subsurface to precipitate chromium and dechlorinate TCE in groundwater.

Project AccomplishmentsRemedial goals were achieved in approximately 2 years. Chromium and TCE concentrations were reduced by over 90% and 95%, respectively.

ClientPerfect Circle Europe

Scope of ServicesSite Investigation, Pilot Studies, Soil Removal, NAPL Recovery, Groundwater Modeling, Hydraulic Containment, Risk Assessment, Post-Remedial Monitoring


ContaminantsHexavalent Chromium, Chlorinated Solvents and Petroleum Hydrocarbons

Bioprecipitation of Hexavalent Chromium and Enhanced Reductive Dechlorination of TCE in GroundwaterDreux, France

Bioprecipitation of Hexavalent Chromium and Enhanced Reductive Dechlorination of TCE in Groundwater

Dreux, France

carbon polishing. The onsite wastewater treatment plant which was used to treat chromium wastewater during plant operations was used to treat the chromium in the extracted groundwater. More than 3.6 tons of CrVI, 815 kilograms (kg) of chlorinated solvents, 423 kg of TPH (equivalent to 330 liters of LNAPL), and 1,200 liters of LNAPL were recovered prior to implementation of the in situ remedy.

In situ Reactive Zones (IRZ) were established onsite and offsite in 2006 and operated until 2008 to address the comingled CrVI and TCE plumes. The IRZ was established by periodic injection of a carbon source and iron in order to facilitate desorption and reductive dechlorination of TCE, as well as bio-precipitation of CrVI. In the short term, TCE was desorbed from the bedrock matrix at elevated concentrations and then removed via the existing groundwater extraction system. As source concentrations were reduced, biological activity further reduced concentrations of TCE and its daughter products. The reducing environment that was established was conducive to the conversion of hexavalent chromium to trivalent chromium, thereby causing the chromium to precipitate out of the dissolved phase. The bioprecipitation of chromium was catalyzed by the periodic addition of ferrous sulfate into chromium source areas.

The adaptive design of the IRZ included a total of 38 bedrock injection wells installed in 3 phases, with 10 of these wells installed offsite to prevent any further migration of the plume. Molasses was

used as the electron donor in the IRZ. A total of 11 injection events were conducted on a quarterly basis. The groundwater extraction system facilitated the distribution of molasses by increasing hydraulic gradients, and was phased out as in situ biological processes became the dominant mass removal mechanism.

The ResultFollowing stabilization and offsite disposal of heavily contaminated soils in 1997 and hydraulic containment of the groundwater between 2000 and 2008, ARCADIS implemented the IRZ technology to successfully treat a comingled plume of CrVI and TCE. The remedial goals for groundwater were achieved in approximately 2 years. In situ bioprecipitation reduced CrVI concentrations by 90% to 99% (with 60% removal for a well in the plating area), and enhanced reductive dechlorination reduced TCE concentrations by 93% to 99%.

The French administration agreed to cease active treatment at the end of 2008. The site was subsequently sold and redeveloped. Currently, post-remedial monitoring of groundwater is being conducted. Skimming of LNAPL is continuing, and ARCADIS is conducting a soil gas survey to update the human health risk assessment to further negotiate a favorable LNAPL remedial endpoint. No rebound in groundwater concentrations has been observed in three years following the last injection event.

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Reduction of Cr(VI) in source area monitoring well




Page 130 Page 131

49

The ChallengeARCADIS’ Client acquired 16 inactive well sites in the province of Alberta and their associated environmental liabilities through an acquisition agreement. Resolution of these liabilities necessitated satisfying a variety of landowner and agency reclamation requirements as regulated through the Alberta Sustainable Resource Development, Alberta Environment, and the Energy Resources Conservation Board. ARCADIS was contractually required to address a variety of environmental issues and facilitate well site reclamation activities to obtain regulatory closure in a cost-effective and expeditious manner.

The ApproachARCADIS developed a portfolio approach to driving closure at these sites and assembled a multidisciplinary team of environmental professionals with applicable well site reclamation experience in the Province of Alberta. The management team also leveraged investigation and remediation expertise from offices in the United States.

Oil and Gas Well Site Reclamation ProgramAlberta, Canada

Oil and Gas Well Site Reclamation ProgramAlberta, Canada


Scope of ServicesSite Characterization, Remediation, and Reclamation Services


ContaminantsPetroleum, Hydrocarbons, PCB, Arsenic, Mercury, Produced Water/Brine

Project GoalConduct well site assessment and reclamation activities, and obtain Reclamation Certificates from Alberta Environment for 16 inactive oil and gas production wells in central and northern Alberta

ARCADIS Strategy ARCADIS utilized a portfolio approach to manage and streamline assessment and reclamation activities, beginning with a thorough evaluation of historical data by a multi-disciplinary team of soil scientists, hydrogeologists, and engineers. We characterized potential risks, identified data gaps, scoped further investigation needs, and prioritized field efforts. The team focused on defining the tasks required to satisfy Alberta Environment reclamation guidelines, while considering landowner considerations and seasonal constraints.

Project Accomplishments ARCADIS executed the supplemental field characterization and applied for Reclamation Certificates on the majority of sites within 2 years. We also advised the Client on transferring environmental liability for one site to a new operator. ARCADIS is currently helping the Client to mitigate residual stray gas migration concerns before applying for closure on the remaining well site.

The ResultReclamation Certificate applications were prepared, submitted and approved for eleven NFA sites within two years. ARCADIS advised the Client on transferring the liability for one site to a new operator interested in further exploration. ARCADIS implemented supplemental risk characterization and revegetation inspections at the remaining four well sites. Reclamation Completion certificates were subsequently obtained for three of these sites. ARCADIS is currently mitigating residual/stray gas migration issues and performing final site restoration activities before applying for a certificate at the one remaining site. Final closure objectives will be achieved in 2014.

Photos from a Phase 2 ESA and DSA investigation in northern Alberta

The remote location of the site required use of a helicopter to perform visual inspections of the former access roads and to mobilize drilling equipment to the site for subsurface investigationsAdministrative reviews of existing reports (Phase 1, Phase 2, and

Detailed Site Assessments) were conducted to identify supplemental investigation and remediation needs at all 16 sites. Following this review, the team coordinated multi-site investigation and reclamation efforts to minimize costs, accelerate schedules, and accommodate seasonal constraints. Additional programmatic planning and coordination efforts associated with fieldwork execution were also implemented to streamline and accelerate the program (i.e., health and safety planning, subcontracting, and access agreements). Upon completing all the necessary investigation and field inspection requirements, ARCADIS categorized reporting and closure expectations and assigned priority levels based on current status.

Alberta

Page 133



Safety First:Integrating Health and Safety into Remediation Projects




Page 134 Page 135

50

The ChallengeThe site is located in San Bernardino County, California, approximately 15 miles to the southeast of Needles in the Mojave Desert. ARCADIS Client was directed by the Department of the Interior to perform a Time Critical Removal Action (TCRA) at a location onsite designated as an Area of Concern (AOC). The project was performed in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).

The AOC comprises a narrow, steep-sided arroyo (greater than 30-percent slope) that drains into a National Wildlife Refuge. In addition to National Wildlife Refuge and endangered species concerns, the area is considered sacred by local Native American tribes. Over the years, fill material and debris were deposited throughout the arroyo.

This project provided ARCADIS with a unique opportunity to involve a number of business groups internally with the intent to merge culture and exchange ideas on both an operational level and related to health and safety practices. In addition to the ARCADIS Health and Safety behavioral based approaches, the Client had many additional requirements and safe work practices as a result of working in an active facility. ARCADIS worked collaboratively with other Client consultants to ensure that the project plan set the stage for success.

The ApproachIn order to meet the project demands, a crew of up to 15 operators and laborers with ARCADIS management and technical personnel underwent significant training in a designed program to have all field staff of one mind prior to any field implementation. Over a period of two weeks, Health and Safety training, as well as cultural sensitivity and operational training, were performed. The training was based on the hazards anticipated at the site, Client requirements, agreements with project stakeholders, as well as Federal, State, and Local requirements.

An evaluation of health and safety risks mandated that the work be performed in Level C Personal Protective Equipment (PPE). Of extreme concern was conducting work in Level C PPE in the middle of summer in the Mojave Desert. Temperatures during the summer months were routinely over 110°F and exceeded 120°F on a number of days. Measures used to address this hazard included work scheduling, crew rotations, heat monitoring stations that included work area WBDBGT (wet bulb, dry bulb, and globe temperature) monitoring, and personnel heart rate monitors. To meet the Client’s deadlines under the TCRA Action Memorandum issued by the Department of Interior and our obligation to provide a safe work place, up to three crews were used on 20 minute shifts with 40 minute recovery times to complete the

activities at times during June and July. Personnel’s vital signs were monitored consistent with the site specific Heat Stress Plan (HSP). As a result, the work was successfully performed with no incident.

One of the primary hazards was the removal of impacted soils that were loosely consolidated from historic dumping from the access roads located at the top of the ravine. There were significant logistical challenges to safely position equipment, generate no visible dust, work in Level C PPE, coordinate with a number of team members, and remove materials to transportation bins for offsite disposal as a Class I hazardous waste. To remove wastes from the site, transportation of the bins required navigating a large number of plant process equipment obstacles all while working directly over a high pressure gas main.

Great care was taken with these main keys to success which turned a high risk endeavor to a manageable risk for ARCADIS and our Client. A geotechnical evaluation was performed for safety considerations of working heavy equipment on up to 1:1 slopes. Traffic patterns of equipment and personnel were clearly defined and physical hazards, pinch points, and potential unsafe or unstable hoisting or loading were continuously evaluated and charged as everyone’s responsibility at the site. In addition, spotters were used at all times during construction. A construction supervisor was continuously stationed across the arroyo with radio contact to the operators and laborers.

Any unsafe condition was immediately reported and corrected. Every day the tailgate meeting ended with a supervisor asking “Who has stop work authority?” with a unanimous response of “I DO”.

The ResultAt the onset of the project, significant risks were identified by ARCADIS, other consultants, the Client, and stakeholders on the project. As a result, a significant effort and attention to safety and mitigation of risks was built into the execution plan from day one. Over two weeks of health and safety and related training was performed before the first bucket of debris and soil was removed from the site. The implementation was intentionally designed to include multiple consultants and contributions from multiple business units at ARCADIS in an effort to bring the best practices forward. The entire ARCADIS, subcontractor and Client teams were committed to a safe work place as demonstrated by the large upfront plan to train, set expectations, and maintain a health and safety incentive program which was conducted throughout the lifetime of the project.

Team members were fully invested into a safety culture and given the tools to succeed. The results of melding multiple health and safety cultures and the hard work of the project team has yielded a project that has implemented over 36,000 man-hours in extreme conditions and challenging terrain without a loss time or reportable accident.

Health and Safety: Time Critical Removal Action in Arroyo with a 30 Degree SlopeCalifornia

Health and Safety: Time Critical Removal Action in Arroyo with a 30 Degree Slope

California


Scope of ServicesTime Critical Removal Action

Performance PeriodNovember 2004 through February 2010

ContaminantsVarious

Project GoalPerform a Time Critical Removal Action in a manner that meets regulatory expectations without interruption or incident.

ARCADIS StrategyBuild a collaborative team comprised of Client consultants and ARCADIS experts from different business units to best manage health and safety risks during project implementation.

Project AccomplishmentsSuccessfully responded to regulatory directive, and in the process, completed 36,000 man-hours of labor under challenging conditions without incident.

Field personnel being trained to use ropes, harnesses, and a rescue litter

Field personnel hand-picking debris and conducting vacuum removal of soil and debris on the slope

Page 137




Glossary of Acronyms

Acronym Definition/meaning

ATV Artesian Treatment Vessel

AST Aboveground Storage Tank

bgs Below Ground Surface

BOD Biochemical Oxygen Demand

BTEX Benzene, Toluene, Ethylbenzene and Xylenes

CAP Corrective Action Plan

CaSx Calcium Polysufide

CERCLA Comprehensive Environmental Response Compensation and Liability Act

cis-DCE cis-1,2-dichloroethene

CSM Conceptual Site Model

COC Contaminant of Concern Constituent of Concern

CPT Cone Penetrometer Testing

Cr(VI) Hexavalent Chromium

CT Carbon Tetrachloride

CVOCs Chlorinated Volatile Organic Compounds

DNAPL Dense Nonaqueous-Phase Liquid

DO Dissolved Oxygen

DoD Department of Defense


ERD Enhanced Reductive Dechlorination

ERH Electrical Resistance Heating

ESTCP Environmental Security Technology Certification Program

ft Foot or Feet (unit of distance measurement)

gpm Gallons per Minute

Hg Mercury

HSU Hydrostratigraphic Units

IRA Interim Remedial Action

IRZ In Situ Reactive Zone

ISCO In Situ Chemical Oxidation

LIF Laser-Induced Fluorescence

LNAPL Light Nonaqueous-Phase Liquid

MCL Maximum Contaminant Level

MEK Methyl Ethyl Ketone

MIKB Methyl Isobutyl Ketone

mg/L Milligrams per Liter

mg/kg Milligrams per Kilogram

MGP Manufactured Gas Plant


µg/L Micrograms per Liter

µg/kg Micrograms per Kilogram

MIP Membrane Interface Probe

MNA Monitored Natural Attenuation

NFA No Further Action

NFR No Further Remediation

MTBE Methyl Tertiary Butyl Ether

NAPL Nonaqueous-Phase Liquid

NPDES National Pollutant Discharge Elimination System

O&M Operation and Maintenance

PAH Polyaromatic Hydrocarbons

PCB Polychlorinated Biphenyl

PCE Tetrachloroethene

PDA Personal Digital Assistant

PDB Passive Diffusion Bag

PPE Personal Protective Equipment

PRB Permeable Reactive Barrier

RCRA Resource Conservation and Recovery Act


RAE Remedial Alternatives Evaluation

RAP Response Action Plan

SPH Six Phase Heating

SVE Soil Vapor Extraction

SVOC Semi-Volatile Organic Compound

TBA Tert Butyl Alcohol

TCE Trichloroethene

TEE Thermally Enhanced Extraction

TOC Total Organic Carbon

TPH Total Petroleum Hydrocarbons

USEPA United States Environmental Protection Agency

USDA United States Department of Agriculture

UST Underground Storage Tank

VOC Volatile Organic Compound

ZVI Zero Valent Iron

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Documents

remediation frontiers

situ remediation

frontiers insuthan

situ bioremediation

tba treatment

sustainable approach

chromium bioremediation

situ stabilizationsolidication