This session focuses on how to make decisions regarding the remedial strategy for contaminated sites and associated information requirements above and beyond the assessment data required to implement a management or active remediation strategy. Australia has been developing national guidance on the remediation of contaminated sites; this involves consideration of how other countries approach the problem, and how concepts such as risk-based land management and sustainable remediation should be included.
The concepts presented in this session should be of interest to many countries, particularly those that are grappling with how to achieve the greatest return from the investment in remediation of contaminated sites.
The session includes speakers who are highly experienced in remediating contaminated sites and have a good understanding of international approaches being applied, and the thinking that underlies good decision making related to contaminated sites. Papers will be provided on:
• Keynote address Presenter to be advised: Setting the scene: commentary on the international approaches and new developments in remediation strategy.
• Dr Peter Nadebaum (CRC CARE, ALGA, GHD, SuRF ANZ): Identifying the most appropriate remediation strategy: An outline of a structured approach to assessing the problem and deciding what strategy should be adopted, including taking into account regulatory requirements and necessary endpoints, the risk perception of the various stakeholders, the town planning interface and development options, the concepts of risk-based land management, the role of institutional controls, how to facilitate development when multiple sites are involved and the role of an auditor, the concepts of sustainable remediation, and how to achieve closure and an end to the remediation process.
• Dr John Hunt and Mr Ian Brookman (ALGA, Thiess Services, SuRF ANZ): Designing a remediation system – your Solution is only as good as the Problem definition: defining the remediation problem and the necessary endpoints, a contractor’s perspective and data requirements, interpreting assessment data, evaluating remediation options, data requirements above and beyond data gathered in the contaminated site assessment phase, maximising the value of assessment using standard interpretation techniques and the potential of further field investigation and treatability studies to reduce outcome risk and uncertainty , the maturity and certainty of the technology, and how to evaluate the sustainability of various options and how this might affect the technology selection.
• Mr Ian Brookman and Dr John Hunt (ALGA, Thiess Services, SuRF ANZ): Managing risk and uncertainty when Implementing a remediation system: the contractor and land developer’s perspective and requirements, how to define risk and how risks and potential liabilities should be shared between the various stakeholders, how to understand and allow for uncertainty, and how to address the problem if the technology doesn’t work to the level expected and contracted.
• A further external presentation chosen from the submitted abstracts and / or a facilitated discussion.
abstract #4949 is the second for the proposed session
We have been in contact with Dominique Demendrial and Hans Slanders and understand that the special sessions may have been oversubscribed with several around the Sustainable Remediation theme. So we propose an alternative session on site assessment and remediation, titled CONTAMINATED SITE REMEDIATION – A REAL WORLD APPROACH. While it has some apparent similarities with other sessions which we understand are proposed and are being considered by the technical program committee, we believe the proposed session has important differences. It draws on a vigorous debate that is occurring in Australia – referring to the various approaches existing and being proposed internationally. In particular, the proposed session considers how one should move from site assessment to remediation, how decision making really occurs, and the gaps in information that exist in many cases (that are often not apparent to the specialists skilled in assessment, but which are important to the contractors who have to decide on and design the remediation system). While we encourage applying the concepts of Sustainable Remediation (which we understand may be the subject of another session), we believe it is only part of the picture and actual decision making is based on much more. This is the message of the proposed alternative session, and we would propose to outline the issues and provide a suggested approach:
• CONTAMINATED SITE REMEDIATION – A REAL WORLD APPROACH
• Keynote – Peter Nadebaum – on the need to improve the process of moving from assessment to remediation, remediation selection and design requires more than what assessment requires, review of international and Australian perspectives.
• Presentation 1 John Hunt – on defining the problem
• Presentation 2 Ian Brookman - on managing remediation risks
• Presentation 3 – Facilitated discussion
In the early days of soil remediation, the first reaction was to strive for full removal of contaminated soil. Since then much has changed, and soil policies all over the world have evolved. While this evolution has varied depending on the economic climate and political setting, in general the following stages of evolution can be recognised: Growing Awareness of the Problem – Complete Removal – Risk Based Land Management – Risk Informed and Sustainable Remediation (SURF-US/NICOLE/Common Forum). Some countries have since proceeded further, considering sustainable management and use of the subsurface, which is an extension to the concept of sustainable use of land at the earth’s surface. Within this broad process of evolution, approaches and decision making can differ, and making decisions at a project level can vary markedly from the national policy framework. This paper provides an overview of innovative remediation solutions that are being adopted, and how decisions can be made to determine what is the most practical and appropriate solution for a contaminated site.
“Risk Informed and Sustainable Remediation”
Since the CLARINET report of 2002 many countries are moving to “Sustainable Remediation” of soil, sediment and groundwater, seeking to maximise the overall benefit through a balanced, evidence-based and transparent decision-making process, taking into account environmental, social and economic benefits and impacts of remedial strategies and options. This implies widening the scope of decision making, recognising that stakeholder involvement is crucial in minimising project-specific uncertainties, and allowing stakeholders to provide their perspectives on the balance of benefits and impacts. As a general decision framework “sustainability” is of great importance, and the first part of this paper will provide a short overview around the globe as to what is developing.
Moving on to innovative approaches, there are two aspects: new technical strategies, concepts and methods for dealing with the contamination; and new ways of evaluating options and making decisions.
New concepts and strategies, including consideration of the use of the subsurface
In densely populated Netherlands (and increasingly in neighbouring countries), the scale and number of contaminated sites is well known and there is growing awareness that other solutions are needed to tackle areas where the contamination is common and widespread. The process of reaching an agreement with all stakeholders (site owners, municipalities, water boards etc.) is well documented and examples will be presented of strategies involving for example “biowashing machines in city centres”, and remedial plans for areas of 200 km2. Groundwater extraction or Aquifer Thermal Energy systems are no longer prohibited, and are now encouraged because they can have a beneficial effect on the contaminants. Green remediation strategies involving solar or wind power are also being adopted. The biggest gain, however, will often be achieved by agreeing on reasonable and flexible remediation targets and levels. But the question is: how do we do this?
Decision tools
There are many frameworks and guidelines for assessing and remediating contaminated sites. Nearly every country has its own methodology. Many tools are available for evaluating or comparing remediation options; these include for example sustainability tools, and CO2 calculators. Multi-criteria analyses are widely practised; these can seek to balance benefits and impacts, but making indicators measurable and comparable and giving due consideration to essential matters such as effectiveness of a technology and likely outcome is often a challenge. How does the global soil community perform? We present an example that illustrates the issues.
End Point strategies
More and more we come to realize that every remediation project and site must come to an end, and that there should be a focus on minimising after care and reducing the risk that additional remediation will be required at some time in the future. Realising this leads to other decisions, more robust solutions and perhaps initial higher investments, or further consideration of remedial targets, within the context of a sustainable approach. This strategy is illustrated with a real life case in Amersfoort. This involved renegotiation of the clean-up strategy and the replacing a bioscreen (that would need continuous operation) with a physical, vertical narrowing of a funnel.
Total cost of Ownership
Selecting the remediation strategy also involves balancing the investigation/preparation cost against the resulting remediation cost. Often investing more in the investigation phase can result in a reduced cost of remediation, and vice versa.
This presentation is part of a free session proposal titled: CONTAMINATED SITE REMEDIATION – PRACTICAL DECISION MAKING
Determining the most appropriate remediation strategy for a contaminated site is often the single most important issue that a site owner or regulator has to resolve. Regulatory agencies have particular objectives; these are generally framed in terms of reducing the concentration of contaminants to below certain threshold values, and in some jurisdictions the practicability of achieving this outcome is taken into account. There is also increasing consideration being given to the principles of sustainability, with the objective not only being fixed on protection of human health and the environment, but also considering the benefits and trade-offs with respect to environmental, social and economic factors.
Formulation of a National Remediation Framework is underway in Australia to guide the industry on how to determine the most appropriate remediation strategy. This work is being led by Australia’s peak ?assessment and remediation research centre CRC CARE. Formulating a Remediation Framework has prompted thinking about the decision process that should apply.
The author is involved in this work and is contributing to the preparation of various modules that will make up the Framework, and is working closely with various organisations including government, industry, the Australasian Land and Groundwater Association, SuRF ANZ, and CRC CARE. This paper presents a personal view on the issues that arise in developing guidance on determining the most appropriate remediation strategy, reflecting various of the views that are being canvassed. A structured approach to the problem is suggested, taking into account regulatory requirements and necessary endpoints, the risk perception of the various stakeholders, the town planning interface and development options, the concepts of risk-based land management, the role of institutional controls, how to facilitate development when multiple sites are involved, the role of independent review and certification, when and how to take into account the principles of sustainable remediation, and how to achieve closure and an end to the remediation process.
The approach outlined seeks to protect key environmental values, encourage a wise use of resources commensurate with the problem, consider the views of stakeholders, have a measure of what constitutes “serious” contamination and requires careful management, and how to facilitate the development of brownfields comprising many individual contaminated sites.
As remediation contractors we too often are presented with remediation tenders where the remediation problem is poorly defined, the remediation solution is poorly thought through and the associated level of technical and commercial risk and uncertainty is unacceptably high. This presentation will discuss how to get the most out of the assessment data when defining a remediation problem with reference to ex-situ and insitu solutions, selection of an appropriate remediation solution and additional information requirements minimise risk when implementing the solution.
Many clients are unaware that once a problem has been identified that requires active remediation; the assessment data are insufficient to define the problem and remediation solution with certainty to manage technical and commercial risks during remediation. The outcome is that many remediation projects run over time and over budget resulting in costly commercial litigation. The key to implementing a cost effective and timely remediation solution is to adequately define the remediation problem by interpreting the remediation data and collecting additional information required to support a remediation solution.
All remediation problems require information on the:
• The extent and composition of the contaminated matrix to be treated including principally soil and groundwater. For soil this should include maps showing the thickness and structure of the affected strata particularly fill and bedrock, and estimates of composition including waste, oversize, grainsize, moisture content and density
• The nature of the contaminants including the concentration and mass distributions of the contaminants of concern, other contaminants, species or properties relevant to the potential remediation methods such as total organic carbon, material with calorific value and alkalinity / acidity;;
• Solution specific treatability data such as oxidant demand for oxidation methods, biological activity, nutrient status and inhibitors for bioremediation methods, leachability and compressive strength for stabilisation / immobilisation methods and calorific value and sulphur, fluorine, chlorine and nitrogen balances for thermal methods.
The above points will be illustrated with examples from real life showing the importance of using common methods to interpret assessment data and the role of treatability data in assessing technical risk.