Premium
Geophysical and Hydrologic Monitoring of Air Sparging Flow Behavior: Comparison of Two Extreme Sites
Author(s) -
Lundegard Paul D.,
LaBrecque Doug J.
Publication year - 1998
Publication title -
remediation journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.762
H-Index - 27
eISSN - 1520-6831
pISSN - 1051-5658
DOI - 10.1002/rem.3440080306
Subject(s) - airflow , air sparging , sparging , borehole , geology , secondary air injection , principal component analysis , environmental science , hydrology (agriculture) , environmental remediation , geotechnical engineering , engineering , contamination , chemistry , mechanical engineering , ecology , artificial intelligence , computer science , biology , waste management
The distribution of air around injection wells is an important determinant of the effectiveness, design, and cost of air sparging remediation systems. High‐level air sparging field tests were conducted at two sites for the purpose of determining the pattern of airflow under widely different subsurface conditions. One site consisted of relatively homogeneous dune sand (Site A). The other consisted of highly heterogeneous glacial till (Site B). At both sites, cross‐borehole electrical resistance tomography (ERT) was used to image the principal region of airflow in the saturated zone. The response of conventional monitoring data was compared with the ERT results. At Site A, the principal region of airflow was approximately symmetric about the sparge well and only 2.4 m in radius. At Site B, the pattern of airflow was much more complex and had a major horizontal component. In both site studies, conventional monitoring data provided a much more ambiguous indication of the region of airflow in the saturated zone than did ERT. The investigations at these two sites demonstrate that, while the exact distribution of injected air is not readily discernible by conventional monitoring, the character of the airflow pattern can be recognized when appropriate physical response data are collected. Such response data can be used to evaluate site suitability for air sparging and to improve the system design and operation.