Formatted Title
Thermal Remediation: Is it Worth the Price?
Background/Objectives
Over the past 25 or so years, in situ thermal remediation (ISTR) has become a widely accepted and proven technology for quickly and effectively remediating subsurface contaminant source zones, including those contaminated with dense non-aqueous phase liquids (DNAPL) and light non-aqueous phase liquids (LNAPL) hydrocarbon contamination. But many consultants, site owners and potentially responsible parties (PRPs) still hold the perception that ISTR is too expensive. So, is ISTR really too expensive? While it can be expensive to implement an ISTR project in terms of short-term capital outlay, due consideration should be given to the benefits of reliable, certain and proven treatment effectiveness and short remediation time frames. With these factors in mind, it is more appropriate to ask: Is ISTR worth the price? Guidance from USEPA recommends the use of life-cycle cost (LCC) evaluation during feasibility studies and in the final remedy selection process (EPA, 2000), to ensure that costs for competing remedial alternatives are compared on a consistent basis. Careful and realistic analysis of the LCC for an ISTR remedy versus other source zone treatment technologies will often demonstrate that ISTR presents a lower LCC and better overall value, albeit, often requiring a larger initial capital outlay.
Approach/Activities
ISTR is not inexpensive in many cases, with costs often ranging from just under $100 to over $300 per cubic yard, depending on the size and configuration of the site, chemicals targeted, treatment goals and other factors. However, ISTR has been proven to achieve very low post-treatment concentrations in timeframes on the order of 1 to 2 years from start of construction to post-treatment demobilization. Except for excavation and in situ stabilization (ISS), many other remediation technologies require significantly more time, and/or do not achieve the same level of treatment with a high degree of certainty, thereby delaying a site’s return to beneficial reuse and increasing the remedy’s LCC. Industry literature, and experience from over 20 years of ISTR implementation, have demonstrated the cost-effectiveness and technical successes of ISTR remedies. This paper will review some of the significant factors that can influence unit costs ($ per cubic yard) and total cost of an ISTR project, including treatment area definition, hydrogeologic conditions, contaminant mass, site infrastructure, cleanup goals, and other site-specific factors. In addition, examples will be provided of some items that owners and consultants may wish to consider to control or reduce the cost of an ISTR project, including high-resolution site characterization (HRSC) to tighten ISTR treatment zone delineation, utility supply bulk purchase agreements, task responsibility division, contract terms and risk-sharing strategies.
Results/Lessons Learned
ISTR is not the right fit for every site. Very small, shallow, or readily excavated sites, or large dilute plumes, are usually better suited to application of other remediation technologies. However, ISTR has been demonstrated to be capable of remediating high concentration contaminant source zones, including DNAPL and bedrock contamination, to achieve stringent goals reliably and safely, in about one year from start to finish. Despite the often inaccurate perception that ISTR is too expensive, it can often be the least costly solution for many highly contaminated sites when life cycle costs and the duration and limitations of competing technologies are accurately evaluated. In addition to the economic cost savings, there is also a notable environmental benefit of rapidly and effectively remediating the subsurface environment with ISTR. In brief, ISTR may not always be cheap, but for many sites the short time frame and certainty in meeting site goals it is worth the price.