کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
584705 1453183 2007 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Application of multiphase transport models to field remediation by air sparging and soil vapor extraction
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی بهداشت و امنیت شیمی
پیش نمایش صفحه اول مقاله
Application of multiphase transport models to field remediation by air sparging and soil vapor extraction
چکیده انگلیسی
The design and operation of air sparging and soil vapor extraction (AS/SVE) remediation systems remains in large an art due to the absence of reliable physically based models that can utilize the limited available field data. In this paper, a numerical model developed for the design and operation of air sparging and soil vapor extractions systems was used to simulate two field case studies. The first-order mass transfer kinetics were incorporated into the model to account for contaminant mass transfer between the water and air (stripping), NAPL and water (dissolution), NAPL and air (volatilization), and water and soil (sorption/desorption), the model also accounted for soil heterogeneity. Benzene, toluene, ethyl benzene and xylenes (BTEX) were the contaminants of concern in both case studies. In the second case study, the model was used to evaluate the effect of pulsed sparging on the removal rate of BTEX compounds. The pulsed sparging operation was approximated assuming uniform contaminant redistribution at the beginning of the shut-off period. The close comparison between the observed and simulated contaminant concentration in the aqueous phase showed that the approximation of the pulsed sparging operation yielded reasonable prediction of the removal process. Field heterogeneity was simulated using Monte Carlo analysis. The model predicted about 80-85% of the contaminant mass was removed by air-water mass transfer, which was similar to the average removal obtained by Monte Carlo analysis. The analysis of the removal/rebound cycles demonstrated that removal rate was controlled by the organic-aqueous distribution coefficient Koc. Due to the lack of site-specific data, the aerobic first-order biodegradation coefficients (kbio) were obtained from a literature survey, therefore, uncertainty analysis of the kbio was conducted to evaluate the contribution of the aerobic biodegradation to total contaminant removal. Results of both case studies showed that biodegradation played a major role in the remediation of the contaminated sites.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Hazardous Materials - Volume 143, Issues 1–2, 8 May 2007, Pages 156-170
نویسندگان
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