科研之友
微信
新浪微博
Facebook
分享链接
摘要
A recent study assessing the state-of-the-practice of in situ thermal remediation technologies (e.g., electrical resistive heating [ERH], conductive heating, steam-based heating, in situ large-diameter auger soil mixing with steam/hot air injection, and radio-frequency heating) identified 182 applications in the 1988 to 2007 period and summarized the geologic settings in which these technologies were applied, chemicals treated, design parameters, and operating conditions. That study concluded that documentation for less than 8% of those applications contained sufficient data to assess the effect remediation had on groundwater quality. Consequently, post-treatment data were collected at five ERH sites, with emphasis on assessing reductions in dissolved groundwater concentrations and mass discharge (mass flux) to the aquifer. For each site, dissolved groundwater concentrations and hydraulic conductivities were determined across a vertical transect oriented perpendicular to groundwater flow and at the downgradient edge of the treatment zone. Dissolved concentration and mass discharge reductions ranged from about less than 10x to 100x, with post-treatment groundwater concentrations ranging from about 101 to 104 mu g/L and mass discharges ranging from about 101 to 102 kg/y. The primary factors differentiating sites with greater and lesser dissolved concentration and mass discharge reductions were the adequacy of pre-treatment source zone delineation, the extent to which the treatment zone encompassed the source zone, and the duration of treatment at the design operating temperature. The results suggest that ERH systems are capable of reducing groundwater concentrations to 10 to 100 mu g/L levels and lower in some settings, but only if the source zone is adequately delineated and fully encompassed by the treatment system, and the treatment system is operated for a sufficiently long period of time.
- 出版日期2012
