The natural annual period of effective treatment at a contaminated site in the Arctic is 2-3 months, and 1-2 months in coastal Antarctica. In sub-polar regions, the treatment season varies up to 6 months. Generally, cold weather and freezing and frozen ground conditions dictate the treatment season and efficacy. However, engineered remediation can enhance conditions within the contaminant zone and extend the treatment season by a couple of months. Location may limit treatment options as a function of cost and manpower needs; restricted site access limits treatment options.
It is important to understand that no one treatment method is necessarily applicable to all cold regions. For example, soil vapor extraction coupled with air sparging is a viable in situ treatment strategy for a petroleum-contaminated site in the sub-Arctic, but it is not practical in the Arctic. Therefore, essential considerations for cold-climate environmental remediation are:
• A good understanding of (cold) temperature effects on physical and biological processes that occur in petroleum-contaminated soil
• A feasibility study of treatment alternatives
• Local (preferably site-specific) weather conditions
• Logistical requirements
• Thorough site characterization, and
• A treatability study (field trial is preferable).
The first two considerations aid decision makers with evaluating cost, (treatment) time, and risk. The middle two relate to treatment limitations, and influence site monitoring and treatment duration. The last two considerations aid the environmental practitioner with remediation design. A feasibility study evaluates treatment methods (Tables 19.1-19.4) for practicality, whereas a treatability study is then used to assess the efficacy of the chosen method under site-specific conditions. When biological treatment is relied upon, we opine that a treatability study is essential to effective treatment. Snape et al. (2008b) provide detailed discussions about the various treatability studies that are performed for bioremediation and landfarm-ing projects.
The list of twelve soil remediation technologies identified in Fig. 19.1 represent those treatments that are routinely used in cold regions with success, or occasionally used with favorable results. These methods are identified and discussed in the following sections. Tables 19.1 and 19.2 summarize the methods as broadly divided between ex situ and in situ remediation techniques. Other remediation methods not discussed herein are either intuitively not applicable, have not been used, or may have been attempted but were unsuccessful in meeting cleanup standards.
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