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Ground Water

Title:		Effect of Temporal Changes in Air Injection Rate on Air Sparging Performance Groundwater Remediation
Author(s):		Ben Neriah A; Paster A;
Address:		"Environmental Hydrology Laboratory, School of Mechanical Engineering, Tel Aviv University, Tel Aviv, Israel"
Journal Title:		Ground Water
Year:		2016
Volume:		20160422
Issue:		6
Page Number:		851 - 860
DOI:		10.1111/gwat.12428
ISSN/ISBN:		1745-6584 (Electronic) 0017-467X (Linking)
Abstract:		"Air sparging (AS) is a commonly applied method for treating groundwater contaminated with volatile organic compounds (VOCs). When using a constant injection of air (continuous mode), a decline in remediation efficiency is often observed, resulting from insufficient mixing of contaminants at the pore scale. It is well known that turning the injection on and off (pulsed mode) may lead to a better remediation performance. In this article, we investigate groundwater mixing and contaminant removal efficiency in different injection modes (i.e., continuous and pulsed), and compare them to those achieved in a third mode, which we denote as 'rate changing.' In this mode, injection is always on, and its rate is varying with time by abrupt changes. For the purpose of this investigation, we conducted two separate sets of experiments in a laboratory tank. In the first set of experiments, we used dye plume tracing to characterize the mixing induced by AS. In the second set of experiments, we contaminated the tank with a VOC and compared the remediation efficiency between the different injection modes. As expected, we observed that time-variable injection modes led to enhanced mixing and contaminant removal. The decrease in contaminant concentrations during the experiment was found to be double for the 'rate changing' and 'pulsed' modes compared to the continuous mode, with a slightly preferable performance for the 'rate changing' mode. These results highlight the critical role that mixing plays in AS, and support the need for further investigation of the proposed 'rate changing' injection mode"
Keywords:		"Air Environmental Restoration and Remediation *Groundwater Volatile Organic Compounds *Water Pollutants, Chemical;"
Notes:		"MedlineBen Neriah, Asaf Paster, Amir eng 2016/04/23 Ground Water. 2016 Nov; 54(6):851-860. doi: 10.1111/gwat.12428. Epub 2016 Apr 22"