Assessing effects of site characteristics on remediation secondary life cycle impact with a generalised framework

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  • This article was downloaded by: [Ams/Girona*barri Lib]On: 10 October 2014, At: 00:51Publisher: RoutledgeInforma Ltd Registered in England and Wales Registered Number: 1072954 Registeredoffice: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK

    Journal of Environmental Planning andManagementPublication details, including instructions for authors andsubscription information:http://www.tandfonline.com/loi/cjep20

    Assessing effects of site characteristicson remediation secondary life cycleimpact with a generalised frameworkDeyi Houa, Abir Al-Tabbaaa & Jian Luoba Department of Engineering, University of Cambridge,Trumpington Street, Cambridge CB2 1PZ, UKb School of Civil & Environment Engineering, Georgia Instituteof Technology, Mason 226, 790 Atlantic Drive, Atlanta, GA, USA30332-0355Published online: 16 Jan 2014.

    To cite this article: Deyi Hou, Abir Al-Tabbaa & Jian Luo (2014) Assessing effects of sitecharacteristics on remediation secondary life cycle impact with a generalised framework, Journalof Environmental Planning and Management, 57:7, 1083-1100, DOI: 10.1080/09640568.2013.863754

    To link to this article: http://dx.doi.org/10.1080/09640568.2013.863754

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  • Assessing effects of site characteristics on remediation secondary life

    cycle impact with a generalised framework

    Deyi Houa*, Abir Al-Tabbaaa and Jian Luob

    aDepartment of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ,UK; bSchool of Civil & Environment Engineering, Georgia Institute of Technology, Mason 226,

    790 Atlantic Drive, Atlanta, GA, USA 30332-0355

    (Received 13 July 2013; final version received 5 November 2013)

    The sustainable remediation concept has been broadly embraced by industry andgovernments in recent years in both the US and Europe. However, there is a strongneed for more research to enhance its practicability. In an attempt to fill this researchgap, this study developed a generalised framework for selecting the mostenvironmentally sustainable remedial technology under various site conditions. Fourremediation technologies were evaluated: pump and treat (P&T), enhanced in situbioremediation (EIB), permeable reactive barrier (PRB), and in situ chemicalreduction (ISCR). Within the developed framework and examined site conditionranges, our results indicate that site characteristics have a profound effect on the lifecycle impact of various remedial alternatives, thus providing insights and valuableinformation for determining what is considered the most desired remedy from anenvironmental sustainability perspective.

    Keywords: sustainable remediation; life cycle assessment; groundwater remediation;contaminated land

    1. Introduction

    Land contamination is a major challenge to modern society; with an estimated 294,000

    contaminated sites in the US (USEPA 2004) and over 300,000 ha of potential

    contaminated land in the UK (EA 2005). The land contamination issue can deteriorate

    due to other environmental-friendly practices such as recycling (Hou 2011; Hou et al.

    2012). Land remediation requires the investment of a significant amount of resources.

    The US Superfund clean-up programme alone is spending approximately $1.2 billion

    annually in the federal budget; and the requested reinstating of the Superfund tax would

    add over $20 billion in funding over the next decade (USEPA 2013). Historically,

    remediation was considered to be an inherently sustainable practice because it restores

    contaminated land and reduces urban sprawl and greenfield development. Modern green

    design standards, such as the Leadership in Energy and Environmental Design (LEED)

    programme, recognise brownfield remediation as a major credit towards sustainable

    development (USGBC 2011). However, remediation operations are also associated with

    adverse environmental effects throughout its life cycle. It is only in recent years that

    researchers and industrial practitioners have started to examine these secondary

    environmental impacts from a sustainability perspective, and using a life-cycle

    approach (Ellis and Hadley 2009).

    *Corresponding author. Email: deyi.hou@gmail.com

    2014 University of Newcastle upon Tyne

    Journal of Environmental Planning and Management, 2014

    Vol. 57, No. 7, 10831100, http://dx.doi.org/10.1080/09640568.2013.863754

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    mailto:deyi.hou@gmail.comhttp://dx.doi.org/10.1080/09640568.2013.863754

  • Sustainable remediation is an emerging field, with its concept first adopted by several

    organisations which are sponsored primarily by the industry. These organisations include

    the Network for Industrially Contaminated Land in Europe (NICOLE, founded in 1995 in

    Europe), the Contaminated Land: Applications in Real Environments (CLAIRE, founded

    in 1999 in the UK), and the Sustainable Remediation Forum (SURF, founded in 2006 in

    the US). Sustainable remediation, or its variant green remediation, is also increasingly

    supported by governments (CLARINET 2002; ITRC 2011; USEPA 2010a). Various US

    federal agencies, e.g. USACE (USACE 2010), AFCEE (AFCEE 2010), NAVFAC

    (NAVFAC 2011) and state governments, e.g. California-DTSC (DTSC 2009), have

    developed guidance, protocols and software packages in this field in the past few years.

    A number of research studies have been conducted relating to this field, and they have

    used life cycle assessment (LCA) (Lemming, Hauschild, and Bjerg 2010; Morais and

    Delerue-Matos 2010), multi-criterion analysis (Harbottle, Al-Tabbaa, and Evans 2008;

    Sparrevik et al. 2012) and footprint calculators (USEPA 2010b; Lubrecht 2012) in

    sustainability evaluation for remedy selection. Several early studies laid the foundations

    for conducting life cycle assessment (LCA) in the field of remediation, primarily to

    account for secondary impacts in order to support informed decision making (Diamond

    et al. 1999; Volkwein, Hurtig, and Klopffer 1999; Blanc et al. 2004). Two review paperspublished in 2010 summarised the findings and challenges based on a review of over 10

    remediation LCA studies (Lemming, Hauschild, and Bjerg 2010; Morais and Delerue-

    Matos 2010). Since 2010, over a dozen more LCA studies have been published

    (Owsianiak et al. 2013). These studies have rendered a wide range of findings and

    implications to assist researchers and industrial practitioners in taking a holistic view in

    remediation decision-making processes.

    As an International Organization for Standardization (ISO) standardised method,

    LCA can be used with other factors, such as cost and performance data, to select the most

    appropriate remedial alternative. However, performing an LCA can be resource and time-

    consuming (USEPA 2006), and may not be affordable by most remediation projects.

    Moreover, the incorporation of sustainability in remediation decision making is a

    continuous and iterative process (Holland 2011). As traditional LCA is a relatively static

    process (i.e. requiring solid definition of the system), it may need adaptation to

    accommodate the unique challenges in sustainable remediation decision making in a

    project life cycle where sigificant changes may occur in the system. One of the

    challenges is that most existing studies have used highly site specific data, which make it

    difficult to extend the implications from these studies to other sites with different site

    conditions.

    This study aims to explore the feasibility of using a generalised LCA model to derive

    knowledge that can be more broadly applicable than what traditional LCA renders. Four

    remediation technologies are assessed in this study: pump and treat (P&T), enhanced in

    situ bioremediation (EIB), permeable reactive barrier (PRB), and in situ chemical

    reduction (ISCR). This LCA has chosen chlorinated ethylene as the study subject because

    chlorinated solvents are the most prevalent organic contaminants in soil and groundwater

    (ATSDR 2007), due to their past extensive industrial use as cleaning and degreasing

    solvents, adhesives, coating solvents and as feedstock for other chemicals (Stroo and

    Ward 2010). Unlike most existing remediation LCA studies that are limited by highly site

    specific conditions and thus rendering mixed results (see Table S1 in the Supplementary

    Material available via the article website), the present generalised remediation life cycle

    assessment (GRLCA) studies the influence of broad-range varying site-specific

    parameters, including site location, plume dimension, hydrology, chemistry and

    1084 D. Hou et al.

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  • geochemistry. The present study also represents the first LCA of ISCR with in situ soil

    mixing, and one of only a few LCA studies on EIB.

    2. Materials and methods

    2.1. Generalised site conceptual model

    A generalised site conceptual model (GSCM) was established based on a review of

    remediation activities at four typical chlorinated solvent contaminated sites (see

    Supplementary Material available via the article website, section B). These sites are

    located in California, USA, with site size ranging from a few hectares to over 100 ha. The

    plume dimensions and hydrogeological properties show moderate to strong variation

    among these sites. A broad range of remediation activities have been conducted at these

    sites to treat contaminated groundwater, ranging from conventional P&T to innovative

    ISCR. The GSCM, as shown in Figure 1, was developed to encompass the site conditions

    encountered at these sites. The system parameter ranges were expanded to account for a

    wider range of site conditions (see Table 1).

    In the GSCM, the contaminated area consisted of a treatment zone that was the target

    of active remediation (e.g. chemical or biological treatment), and a monitored natural

    attenuation (MNA) zone, where there was no active remediation, where instead risks

    were managed through regularly monitoring the natural attenuation of the plume by

    dilution and natural degradation. A series of parameters depicted the location of the site,

    hydrogeology, extent and migration of contaminants, etc. The typical parameters

    observed at these four sites were used to generate a range of parameters that were used in

    the GSCM study. Section B of the Supplementary Material (available via the article

    website) includes a diagram of the GSCM and simulated parameter range. In this study,

    to simplify the analysis, tetrachloroethene (PCE) and its daughter products were selected

    Figure 1. A diagram of the generalised site conceptual model (Denotation: W1 widthof treatment zone [40 m]; W2 width of plume area for monitored natural attenuation [270 m];L1 length of treatment zone [60 m]; L2 length of MNA zone [260 m]; D depth to upperlimit of contaminated aquifer [4 m]; B thickness of contaminated aquifer [6 m]).

    Journal of Environmental Planning and Management 1085

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  • as the modelled contaminants in the GSCM. The present GRLCA framework is a

    parameterised LCA based on the GSCM.

    2.2. LCA functional unit and LCA boundaries

    The goal of the LCA was to compare the secondary life cycle impact from four

    remediation options for the GSCM. The functional unit was to reduce the levels of PCE

    and its daughter products (i.e. TCE, DCE and vinyl chloride) within the treatment zone of

    the GSCM (see Figure 1) to levels below the California Maximum Contaminant Level

    Table 1. Range of system parameters in the generalised site conceptual model.

    Key system parametersRange of parameter

    values Default values Basis

    Plume dimensionWidth of treatment zone 4 m to 200 m 40 m A factor of 1/2 or 2 was applied to

    the minimum/maximumvalues in Table S1 (in theSupplementary Materialavailable via the articlewebsite) to encompass andexpand the range of parametervalues being simulated in thisstudy, with the exception oftreatment zone width, forwhich the minimum value wasreduced to 4 m to encompass awider range of possible siteconditions. The default valueswere set at or near thegeometric mean of theminimum and maximumvalues.

    Length of treatment zone 15 m to 300 m 60 mAquifer starting depth 1 m to 18 m 4 mAquifer thickness 2 m to 18 m 6 mMNA plume width 60 m to 1200 m 270 mMNA plume length 50 m to 1400 m 260 m

    HydrogeologyHydraulic conductivity 0.5 to 100 m/day 7 m/day As aboveHydraulic gradient 0.0001 to 0.02 0.003 Reflect a wide range of

    possibilities based onhistorical data at the typicalsites (i.e. accounting fortemporal variation).

    Chemistry andgeochemistry

    Half-lives of PCE anddaughter products inZVI treatment

    0.1 hour to 10 hour 2.4 hour (USEPA 2000; Rabideau,Suribhatla and Craig 2005;Muegge 2008).

    ZVI longevity in PRB 5, 10, 15, and30 years

    15 years

    Native Electron AcceptorDemand (EIB)

    0.002 to 0.2 kgH2/m

    3 water0.02 kg

    H2/m3 water

    Information from typical sites.

    Native demand of ZVIdosage in soil mixing

    30 to 3,000 mgZVI/kg soil

    280 mg ZVI/kgsoil

    Information from typical sitesand Bozzini 2006; Sale andOlson n.d.).

    Site locationSite worker travel

    distance20 km to 500 km 100 km Information from typical sites.

    1086 D. Hou et al.

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  • (Cal-MCL) for drinking water (CDPH 2011), with a 30-year timeframe. The Cal-MCL is

    5 mg/L for PCE, 5 mg/L for TCE, 6 mg/L for 1.1-DCE and cis-1.2-DCE, and 0.5 mg/L for

    vinyl chloride. Groundwater monitoring and possibly supplemental remediati...

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