Remediation Of Contaminated Land Research Articles

SCORE: A novel multi-criteria decision analysis approach to assessing the sustainability of contaminated land remediation

The multi-criteria decision analysis (MCDA) method provides for a comprehensive and transparent basis for performing sustainability assessments. Development of a relevant MCDA-method requires consideration of a number of key issues, e.g. (a) definition of assessment boundaries, (b) definition of performance scales, both temporal and spatial, (c) selection of relevant criteria (indicators) that facilitate a comprehensive sustainability assessment while avoiding double-counting of effects, and (d) handling of uncertainties. Adding to the complexity is the typically wide variety of inputs, including quantifications based on existing data, expert judgements, and opinions expressed in interviews. The SCORE (Sustainable Choice Of REmediation) MCDA-method was developed to provide a transparent assessment of the sustainability of possible remediation alternatives for contaminated sites relative to a reference alternative, considering key criteria in the economic, environmental, and social sustainability domains. The criteria were identified based on literature studies, interviews and focus-group meetings. SCORE combines a linear additive model to rank the alternatives with a non-compensatory approach to identify alternatives regarded as non-sustainable. The key strengths of the SCORE method are as follows: a framework that at its core is designed to be flexible and transparent; the possibility to integrate both quantitative and qualitative estimations on criteria; its ability, unlike other sustainability assessment tools used in industry and academia, to allow for the alteration of boundary conditions where necessary; the inclusion of a full uncertainty analysis of the results, using Monte Carlo simulation; and a structure that allows preferences and opinions of involved stakeholders to be openly integrated into the analysis. A major insight from practical application of SCORE is that its most important contribution may be that it initiates a process where criteria otherwise likely ignored are addressed and openly discussed between stakeholders.

Comparing the Adoption of Contaminated Land Remediation Technologies in the United States, United Kingdom, and China

In many locations across the world, land contamination poses a serious threat to human health and the wider environment. For instance, a report published on April 17, 2014, revealed that China now has 16.1 percent of its land contaminated by various organic and inorganic contaminants, posing a range of challenges from human health risk to food security. The innovation and adoption of suitable remediation technologies is critical for solving land contamination issues. However, little is known about the pattern of remediation technology adoption, as well as its determining factors. This study uses a questionnaire survey in the United States, United Kingdom, and China to examine the spatial variation of remediation technology adoption. It further explores the temporal trend of remediation technology adoption using secondary data from the U.S. Superfund program. The study identified significant differences in remediation technology adoption among these countries, which are attributed to the different environmental, social, economic, and regulatory contexts. It is argued that the full implications of remediation technology adoption to sustainable development should be further studied, and policy instruments should be designed accordingly to promote those remediation technologies that align the best with long‐term sustainability. Technology developers may also use these implications to adjust their research and development priorities. © 2014 Wiley Periodicals, Inc.

Transformation of anthracene on various cation-modified clay minerals.

In this study, anthracene was employed as a probe to explore the potential catalytic effect of clay minerals in soil environment. Clay minerals saturated with various exchangeable cations were tested. The rate of anthracene transformation follows the order: Fe-smectite >> Cu-smectite > Al-smectite ≈ Ca-smectite ≈ Mg-smectite ≈ Na-smectite. This suggests that transition-metal ions such as Fe(III) play an important role in anthracene transformation. Among Fe(III)-saturated clays, Fe(III)-smectite exhibits the highest catalytic activity followed by Fe(III)-illite, Fe(III)-pyrophyllite, and Fe(III)-kaolinite, which is in agreement with the interlayer Fe(III) content. Moreover, effects by two common environmental factors, pH and relative humidity (RH), were evaluated. With an increase in pH or RH, the rate of anthracene transformation decreases rapidly at first and then is leveled off. GC-MS analysis identifies that the final product of anthracene transformation is 9,10-anthraquinone, a more bioavailable molecule compared to anthracene. The transformation process mainly involves cation-π bonding, electron transfer leading to cation radical, and further oxidation by chemisorbed O2. The present work provides valuable insights into the abiotic transformation and the fate of PAHs in the soil environment and the development of contaminated land remediation technologies.

Sustainability: A new imperative in contaminated land remediation

Abstract Land is not only a critical component of the earth's life support system, but also a precious resource and an important factor of production in economic systems. However, historical industrial operations have resulted in large areas of contaminated land that are only slowly being remediated. In recent years, sustainability has drawn increasing attention in the environmental remediation field. In Europe, there has been a movement towards sustainable land management; and in the US, there is an urge for green remediation. Based on a questionnaire survey and a review of existing theories and empirical evidence, this paper suggests the expanding emphasis on sustainable remediation is driven by three general factors: (1) increased recognition of secondary environmental impacts (e.g., life-cycle greenhouse gas emissions, air pollution, energy consumption, and waste production) from remediation operations, (2) stakeholders’ demand for economically sustainable brownfield remediation and “green” practices, and (3) institutional pressures (e.g., social norm and public policy) that promote sustainable practices (e.g., renewable energy, green building, and waste recycling). This paper further argues that the rise of the “sustainable remediation” concept represents a critical intervention point from where the remediation field will be reshaped and new norms and standards will be established for practitioners to follow in future years. This paper presents a holistic view of sustainability considerations in remediation, and an integrated framework for sustainability assessment and decision making. The paper concludes that “sustainability” is becoming a new imperative in the environmental remediation field, with important implications for regulators, liability owners, consultants, contractors, and technology vendors.

Factor analysis and structural equation modelling of sustainable behaviour in contaminated land remediation

Contaminated land remediation has traditionally been viewed as sustainable practice because it reduces urban sprawl and mitigates risks to human being and the environment. However, in an emerging green and sustainable remediation (GSR) movement, remediation practitioners have increasingly recognized that remediation operations have their own environmental footprint. The GSR calls for sustainable behaviour in the remediation industry, for which a series of white papers and guidance documents have been published by various government agencies and professional organizations. However, the relationship between the adoption of such sustainable behaviour and its underlying driving forces has not been studied. This study aims to contribute to sustainability science by rendering a better understanding of what drives organizational behaviour in adopting sustainable practices. Factor analysis (FA) and structural equation modelling (SEM) were used to investigate the relationship between sustainable practices and key factors driving these behaviour changes in the remediation field. A conceptual model on sustainability in the environmental remediation industry was developed on the basis of stakeholder and institutional theories. The FA classified sustainability considerations, institutional promoting and impeding forces, and stakeholder's influence. Subsequently the SEM showed that institutional promoting forces had significant positive effects on adopting sustainability measures, and institutional impeding forces had significant negative effects. Stakeholder influences were found to have only marginal direct effect on the adoption of sustainability; however, they exert significant influence on institutional promoting forces, thus rendering high total effect (i.e. direct effect plus indirect effect) on the adoption of sustainability. This study suggests that sustainable remediation represents an advanced sustainable practice, which may only be fully endorsed by both internal and external stakeholders after its regulatory, normative and cognitive components are institutionalized.

The Development of Risk-Based Remediation Target Value for Lead Contaminated Soils

With the rapid economic development, China is experiencing increased land contamination and lead poisoning problem in recent years, which is no longer restricted to isolated incidents and locations. There is an urgent need to remediate the lead contaminated soils to protect the publics health. However, contaminated land remediation and determination of remediation target value has been neglected for years. In order to accommodate uncertainties within the conservative point estimation of remediation target value for lead contaminated soils, Monte Carlo simulation technique is integrated into the traditional calculation model from a probabilistic perspective. Risk-based remediation target values for lead contaminated soils of different land use types (including school/hospital, residential, business and industrial use) are developed preliminarily. Furthermore, this study highlights the necessity to determine the remediation target value on the basis of actual (i.e. site-specific) risks to humans and, besides, actual risks due to contaminant migration.

Quantitative Environmental Footprints and Sustainability Evaluation of Contaminated Land Remediation Alternatives for Two Case Studies

Since the US Environmental Protection Agency (US EPA) launched its “green remediation” program and EU member states began to reassess their national regulations for environmental remediation in order to reach a Europe‐wide consensus on policy and standards, the need and interest for sustainable remediation of contaminants from brownfields has grown considerably. Concomitantly, the ability to calculate and assess the suitability as well as the environmental footprints and associated risks of a growing number of remediation techniques has become a priority. The authors quantitatively evaluate the differences between various remediation techniques, and for this purpose, a number of ex situ and in situ remediation techniques are adapted to model 21 remediation scenarios for two contaminated sites in the Gothenburg region of Sweden: the Bohus Varv site on the Göta älv river bank and the Hexion site in Mölndal. A wide range of quantitative results for these models are presented, compared, and analyzed.Based on the results from both projects, it is concluded that: (1) remediation techniques requiring long distance residual transportation have significant footprints, except the transportation of contaminated residuals by train due to Swedish energy production conditions; (2) residual transportation by ship results in much higher SOx, NOx, and particle releases compared to the other alternatives; and (3) residual transporation by truck results in high accident risks. Finally, activities powered by electricity result in a reduced footprint compared to activities powered by fossil fuels, considering Swedish energy production conditions.The authors conducted a cross‐benefit analysis of SiteWiseTM applications which recognizes its potential as a tool for presenting life cycle assessment analyses with appropriate system boundary definitions and an easy inventory analysis process. Results from this tool provide valuable support to decision makers aiming at more sustainable remediation. © 2013 Wiley Periodicals, Inc.

Oxidation of anthracene using waste Mn oxide minerals: The importance of wetting and drying sequences

PAHs are a common problem in contaminated urban soils due to their recalcitrance. This study presents results on the oxidation of anthracene on synthetic and natural Mn oxide surfaces. Evaporation of anthracene spiked Mn oxide slurries in air results in the oxidation of 30% of the anthracene to anthraquinone. Control minerals, quartz and calcite, also oxidised a small but significant proportion of the anthracene (4.5% and 14% conversion, respectively) when spiked mineral slurries were evaporated in air. However, only Mn oxide minerals showed significant anthracene oxidation (5–10%) when evaporation took place in the absence of oxygen (N2 atmosphere). In the fully hydrated systems where no drying took place, natural Mn oxides showed an increase in anthracene oxidation with decreasing pH, with a conversion of 75% anthracene at pH 4. These results show both acidification and drying favor the oxidation of anthracene on Mn oxide mineral surfaces. It has also been demonstrated that non-redox active mineral surfaces, such as calcite, may play a role in contaminant breakdown during wetting and drying sequences. Given that climate changes suggest that wetting and drying sequences are likely to become more significant these results have important implications for contaminated land remediation technologies.

Effects of Chemical, Biological, and Physical Aging As Well As Soil Addition on the Sorption of Pyrene to Activated Carbon and Biochar

In this study, the suitability of biochar and activated carbon (AC) for contaminated soil remediation is investigated by determining the sorption of pyrene to both materials in the presence and absence of soil and before as well as after aging. Biochar and AC were aged either alone or mixed with soil via exposure to (a) nutrients and microorganisms (biological), (b) 60 and 110 °C (chemical), and (c) freeze-thaw cycles (physical). Before and after aging, the pH, elemental composition, cation exchange capacity (CEC), microporous SA, and sorption isotherms of pyrene were quantified. Aging at 110 °C altered the physicochemical properties of all materials to the greatest extent (for example, pH increased by up to three units and CEC by up to 50% for biochar). Logarithmic K(Fr) values ranged from 7.80 to 8.21 (ng kg(-1))(ng L(-1))(-nF) for AC and 5.22 to 6.21 (ng kg(-1))(ng L(-1))(-nF) for biochar after the various aging regimes. Grinding biochar to a smaller particle size did not significantly affect the sorption of d(10) pyrene, implying that sorption processes operate on the subparticle scale. Chemical aging decreased the sorption of pyrene to the greatest extent (up to 1.8 log unit for the biochar+soil). The sorption to AC was affected more by the presence of soil than the sorption to biochar was. Our results suggest that AC and biochar have a high sorption capacity for pyrene that is maintained both in the presence of soil and during harsh aging. Both materials could therefore be considered in contaminated land remediation.

Briefing: The Avenue site in the UK and the definition of waste code of practice

The demonstration of waste recovery is at the core of every contaminated land remediation project in which a soil treatment scheme is utilised. The definition of waste: development industry code of practice is a new voluntary approach by which recovery can be clearly established with its use providing an alternative to the complex regulatory regime of exemptions, permits and enforcement positions. This briefing describes how the code has been used at one of the most renowned remediation projects in the UK – the Avenue coking works in Chesterfield – where VSD Avenue (the joint venture contractor comprising VolkerStevin, Sita Remediation and DEC) is employing thermal desorption, bioremediation and complex sorting as proven remediation technologies.

Effects of biochar and the earthworm Eisenia fetida on the bioavailability of polycyclic aromatic hydrocarbons and potentially toxic elements

Polycyclic aromatic hydrocarbons (PAHs) and potentially toxic elements (PTEs) were monitored over 56 days in calcareous contaminated-soil amended with either or both biochar and Eisenia fetida. Biochar reduced total (449 to 306mgkg−1) and bioavailable (cyclodextrin extractable) (276 to 182mgkg−1) PAHs, PAH concentrations in E. fetida (up to 45%) but also earthworm weight. Earthworms increased PAH bioavailability by >40%. Combined treatment results were similar to the biochar-only treatment. Earthworms increased water soluble Co (3.4 to 29.2mgkg−1), Cu (60.0 to 120.1mgkg−1) and Ni (31.7 to 83.0mgkg−1) but not As, Cd, Pb or Zn; biochar reduced water soluble Cu (60 to 37mgkg−1). Combined treatment results were similar to the biochar-only treatment but gave a greater reduction in As and Cd mobility. Biochar has contaminated land remediation potential, but its long-term impact on contaminants and soil biota needs to be assessed.

Utilisation of Magnesium Phosphate Cements to Facilitate Biodegradation within a Stabilised/Solidified Contaminated Soil

Stabilisation/solidification (S/S) of heavy metals and a parallel biodegradation of an organic contaminant using magnesium phosphate cements (MPC) was investigated under laboratory conditions. The study was aimed at improving the robustness of S/S technology by encouraging biodegradation in order to bring about some form of contaminant attenuation over time. A silty sand soil, amended with compost was spiked with an organic contaminant, 2-chlorobenzoic acid (2CBA), and two heavy metal compounds, lead nitrate and zinc chloride. Two formulations of the MPC grouts based on different proportions of the cement constituents, with paste pH of approximately 6.5 and 10, were utilised for S/S treatment. The study involved treating the organic contaminant present in the soil with and without the heavy metals by employing the low and high pH MPC grout mixes, and using 10% and 25% compost content. Microbial activity was monitored using dehydrogenase assay, whilst the tests pertaining to the performance criteria such as contaminant concentration, unconfined compressive strength, elastic stiffness, permeability and batch leaching tests were evaluated at set periods. Contaminant recovery analysis after 140 days indicated a similar reduction in 2CBA concentration to approximately 56% in the different grout mixes. The cement constituents exhibited stimulatory and inhibitory effects on soil dehydrogenase activity. Heavy metal leachability as well as the engineering behaviour of the treated soils conformed to acceptable standards. The results of the investigations show considerable promise for the application of MPC in contaminated land remediation.

Effects of biochar and greenwaste compost amendments on mobility, bioavailability and toxicity of inorganic and organic contaminants in a multi-element polluted soil

Applying amendments to multi-element contaminated soils can have contradictory effects on the mobility, bioavailability and toxicity of specific elements, depending on the amendment. Trace elements and PAHs were monitored in a contaminated soil amended with biochar and greenwaste compost over 60 days field exposure, after which phytotoxicity was assessed by a simple bio-indicator test. Copper and As concentrations in soil pore water increased more than 30 fold after adding both amendments, associated with significant increases in dissolved organic carbon and pH, whereas Zn and Cd significantly decreased. Biochar was most effective, resulting in a 10 fold decrease of Cd in pore water and a resultant reduction in phytotoxicity. Concentrations of PAHs were also reduced by biochar, with greater than 50% decreases of the heavier, more toxicologically relevant PAHs. The results highlight the potential of biochar for contaminated land remediation.

Developing decision support tools for the selection of “gentle” remediation approaches

A range of tools have been proposed to support decision making in contaminated land remediation. From a European perspective it is clear, however, that there are considerable national differences in the decision support process, and more generally in the extent to which this process supports the selection of less invasive, alternative remediation options such as phytoremediation, in situ immobilisation etc. (referred to here as “gentle” remediation technologies). In this paper we present results from the recently completed European Union ERANET SNOWMAN project SUMATECS (Sustainable Management of Trace Element Contaminated Sites), and critically review available decision support tools in terms of their fitness for purpose for the application of gentle remediation technologies. Stakeholder feedback indicates a lack of knowledge amongst stakeholders of currently available decision support tools. We propose that decision support which focuses on gentle remediation is more strongly incorporated into existing, well-established (national) decision support tools / decision-frameworks, to promote more widespread use and uptake.

Sustainability of land remediation. Part 2: impact assessment

A comparative assessment was carried out of the technical/environmental sustainability of five different contaminated land remediation projects completed in the UK between 1997 and 2002. The remediation technologies employed in those projects were in situ stabilisation/solidification, soil washing, ex situ bioremediation, cover system, and excavation and disposal to landfill. A further objective of the assessment was to highlight areas of sustainability concerns for the individual technologies and projects. The assessment is based around four principal criteria defined by the authors. Each project was assessed using both an overall multi-criteria analysis, detailed in Part 1 of this paper, and a detailed impact assessment, detailed here in Part 2.

Sustainability of land remediation. Part 1: overall analysis

A comparative assessment was carried out of the technical and environmental sustainability of five different contaminated land remediation projects completed in the UK between 1997 and 2002. The remediation technologies employed were in situ stabilisation/solidification, soil washing, ex situ bioremediation, cover system and excavation, and disposal to landfill. A further objective of the assessment was to highlight areas of sustainability concerns for the individual technologies and projects. The assessment is based around four principal criteria defined by the authors. Each project was assessed using both an overall multi-criteria analysis, detailed in this paper (Part 1), and a study of the detailed impacts on an individual project basis, detailed in Part 2.

Improving petroleum contaminated land remediation decision-making through the MCA weighting process

Internationally petroleum contamination is widespread, posing serious environmental risks including surface and groundwater contamination, thus remediation is essential. The implementation of remediation options is becoming more complex with the increasing influence of stakeholders on the outcome of decision-making processes. Acceptance of remediation schemes during implementation can be increased by involving stakeholders and the public in the decision-making stage. In petroleum remediation involving multiple stakeholders, Multicriteria Analysis has been employed due to its ability to incorporate the preferences of each stakeholder through weighting. The research focused on investigating ways to improve the weighting process. The study demonstrated the utility of SWING, and determined which type of participant and how many participants to include in the decision process, through the application of ELECTRE III and Weighted Summation. It was recommended that a mixture of stakeholders, the public and experts be involved. The total number of participants will be limited by the choice of participatory and weighting methods. The careful selection of participants, as well as the choice of participatory and weighting methods, can minimize the subjectivity involved in MCA weighting, thereby lending decisions in petroleum remediation greater legitimacy.

A comparison of the technical sustainability of in situ stabilisation/solidification with disposal to landfill

Sustainability is becoming a very important issue in contaminated land remediation and should form one of the factors used in future selection of treatment technologies. In situ stabilisation/solidification (S/S) is a remediation technique that is increasingly being applied to the treatment of contaminated sites because of numerous advantages over other remediation techniques. This paper assesses and compares aspects of the technical sustainability of in situ S/S with landfilling. Criteria previously established for the assessment of the technical sustainability of the remediation of contaminated land are employed. The comparison is presented in the form of a case study based on a real remediation project in the UK. The analysis indicated that landfilling had a larger impact than S/S in the majority of areas investigated, such as waste production (1000 kg waste/t soil remediated for landfilling compared to none for S/S), transportation (12.9 km/t for landfilling, 0.4 km/t for S/S) and use of raw materials (1005.5 kg/t for landfilling, 88.9 kg/t for S/S), although S/S had high greenhouse gas emissions (12.6 kg/t for landfilling, 40.9 kg/t for S/S). In addition, a multi-criteria/cost-effectiveness analysis gave cost effectiveness scores of −34.2 to S/S and −138.1 to landfill (where more positive is better).

Assessing the true technical/environmental impacts of contaminated land remediation - a case study of containment, disposal and no action

Assessing the true technical/environmental impacts of contaminated land remediation - a case study of containment, disposal and no action

Electrokinetic iron pan generation in unconsolidated sediments: implications for contaminated land remediation and soil engineering

Electrokinetic remediation is an emerging technology that has generated considerable interest as a technique for the in situ remediation of clay-rich soils and sediments. Despite promising experimental results, however, at present there is no standardised universal electrokinetic soil/sediment remediation approach. Many of the current technologies are technically complex and energy intensive, and geared towards the removal of 90% or more of specific contaminants, under very specific field or laboratory-based conditions. However, in the real environment a low-tech, low-energy contaminant reduction/containment technique may be more appropriate and realistic. Such a technique, FIRS (Ferric Iron Remediation and Stabilisation), is discussed here. The FIRS technique involves the application of a low magnitude (typically less than 0.2 V/cm) direct electric potential between two or more sacrificial, Fe-rich, electrodes emplaced in, or either side of, a contaminated soil or sediment. The electric potential is used to generate a strong pH (and E h) gradient within the soil column (pH 2–13), and force the precipitation of an Fe-rich barrier or “pan” in the soil between the electrodes. Geochemical and geotechnical data for FIRS-treated sediments from the Ravenglass estuary, Cumbria, UK indicate that the technique can significantly reduce contaminant concentration in treated soil, by remobilisation of contaminants and concentration on, or around, the Fe-rich barrier. Arsenic, in particular, seems highly amenable to the FIRS treatment, due to its solubility under the high pH conditions generated near to the cathode, and its marked geochemical affinity with the freshly precipitated Fe oxides and oxyhydroxides in the Fe barrier. Geotechnical tests indicate that the Fe barrier produced by the technique is practically impervious (permeability = 10 −9 m/s or less), and has moderate mechanical strength (UCS ∼11 N/mm 2). Notably, a large increase in shear strength in the treated soil near to the anode electrode (due to Fe cementation and/or dewatering) is also observed, without significant loss of porosity. The data indicate that the FIRS technique shows considerable promise as an in situ method for contaminated land remediation and soil water containment, and for improving the mechanical properties of soils (contaminated or otherwise) for civil engineering purposes.