共查询到20条相似文献，搜索用时 15 毫秒
1.
2.
An Overview of In Situ Air Sparging 总被引：3，自引：0，他引：3
R.L. Johnson P.C. Johnson D.B. McWhorter R.E. Hinchee I. Goodman 《Ground Water Monitoring & Remediation》1993,13(4):127-135
In situ air sparging (IAS) is becoming a widely used technology for remediating sites contaminated by volatile organic materials such as petroleum hydrocarbons. Published data indicate that the injection of air into subsurface water saturated areas coupled with soil vapor extraction (SVE) can increase removal rates in comparison to SVE alone for cases where hydrocarbons are distributed within the water saturated zone. However, the technology is still in its infancy and has not been subject to adequate research, nor have adequate monitoring methods been employed or even developed. Consequently, most IAS applications are designed, operated, and monitored based upon the experience of the individual practitioner.
The use of in situ air sparging poses risks not generally associated with most practiced remedial technologies: air injection can enhance the undesirable off-site migration of vapors and ground water contamination plumes. Migration of previously immobile liquid hydrocarbons can also be induced. Thus, there is an added incentive to fully understand this technology prior to application.
This overview of the current state of the practice of air sparging is a review of available published literature, consultation with practitioners, a range of unpublished data reports, as well as theoretical considerations. Potential strengths and weaknesses of the technology are discussed and recommendations for future investigations are given. 相似文献
The use of in situ air sparging poses risks not generally associated with most practiced remedial technologies: air injection can enhance the undesirable off-site migration of vapors and ground water contamination plumes. Migration of previously immobile liquid hydrocarbons can also be induced. Thus, there is an added incentive to fully understand this technology prior to application.
This overview of the current state of the practice of air sparging is a review of available published literature, consultation with practitioners, a range of unpublished data reports, as well as theoretical considerations. Potential strengths and weaknesses of the technology are discussed and recommendations for future investigations are given. 相似文献
3.
Jennifer L. Triplett Kingston Paul R. Dahlen Paul C. Johnson 《Ground Water Monitoring & Remediation》2010,30(4):64-72
In situ thermal-based soil and aquifer remediation technologies (e.g., electrical resistance heating [ERH], conductive heating, and steam-based heating) have undergone rapid development and application in recent years. These thermal technologies offer the promise of more rapid and thorough treatment of nonaqueous phase liquid (NAPL) source zones; however, their field-scale application has not been well documented in the technical literature. A state-of-the-practice review of the application of these technologies was conducted in this study. Available documents from 182 applications were reviewed, which included 87 ERH, 46 steam-based heating, 26 conductive heating, and 23 other heating technology applications conducted between 1988 and 2007. Approximately 90% of the 182 applications were implemented after 1995 and about half since 2000. More specifically, this review identified the geologic settings in which these technologies were applied, chemicals treated, design parameters, operating conditions, and performance metrics. The results of this study are summarized in a table linking this information to five generalized geologic scenarios. Practitioners considering thermal technologies for their site can identify the geologic scenario that most closely resembles their site and then can quickly see which technologies have been applied in that setting, the designs employed, operating conditions, and the performance achieved. 相似文献
4.
5.
6.
7.
8.
9.
10.
Katharine P. North Douglas M. Mackay Julian S. Kayne Daniel Petersen Ehsan Rasa Laleh Rastegarzadeh Reef B. Holland Kate M. Scow 《Ground Water Monitoring & Remediation》2012,32(3):52-62
The potential for in situ biodegradation of tert‐butyl alcohol (TBA) by creation of aerobic conditions in the subsurface with recirculating well pairs was investigated in two field studies conducted at Vandenberg Air Force Base. In the first experiment, a single recirculating well pair with bromide tracer and oxygen amendment successfully delivered oxygen to the subsurface for 42 d. TBA concentrations were reduced from approximately 500 μg/L to below the detection limit within the treatment zone and the treated water was detected in a monitoring transect several meters downgradient. In the second experiment, a site‐calibrated model was used to design a double recirculating well pair with oxygen amendment, which successfully delivered oxygen to the subsurface for 291 d and also decreased TBA concentrations to below the detection limit. Methylibium petroleiphilum strain PM1, a known TBA‐degrading bacterium, was detectable at the study site but addition of oxygen had little impact on the already low baseline population densities, suggesting that there was not enough carbon within the groundwater plume to support significant new growth in the PM1 population. Given favorable hydrogeologic and geochemical conditions, the use of recirculating well pairs to introduce dissolved oxygen into the subsurface is a viable method to stimulate in situ biodegradation of TBA or other aerobically degradable aquifer contaminants. 相似文献
11.
12.
13.
14.
15.
Detailed site characterization data from the former electroplating shop at the U.S. Coast Guard Air Support Center, Elizabeth City, North Carolina, suggested that the elevated Cr(VI) in the capillary fringe area had contaminated the ground water at the site. Most of the mobile Cr(VI) is present in the capillary fringe zone of the aquifer under an oxidizing environment. Current literature suggests that the reduction of Cr(VI) to Cr(III) through in situ redox manipulation in the presence of a reductant is an innovative technique for remediating chromate-contaminated sediments and ground water. The objective of this study was to evaluate the effectiveness of sodium dithionite in creating a reductive environment to remediate Cr(VI) present in soil. Sodium dithionite, a strong reductant, was injected into a small area of the vadose zone where elevated Cr(VI) was identified. Several striking changes observed in the target zone during the post-injection monitoring periods include a significant decrease in Eh(SHE), as much as ∼700 mV, absence of dissolved oxygen for 48 weeks, and the increase of Fe(II) concentrations. Results indicated that the in situ remedial treatment of Cr(VI) in the capillary fringe area was effective and consequently the concentration of Cr(VI) in ground water dropped below the MCLG level. This research demonstrated the effectiveness of in situ abiotic remediation by reducing Cr(VI) concentrations, mobility, and toxicity in soils and ground water within a short period of time. Therefore, sodium dithionite would be a feasible and cost-effective option for a full-scale remedial approach for the contaminated site at the U.S. Coast Guard Facility. 相似文献
16.
17.
Modeling In Situ Iron Removal from Ground Water 总被引：2，自引：1，他引：1
18.
19.