An Overview of In Situ Air Sparging

TLDR

In situ air sparging is a growing technology for remediating VOC‑contaminated sites, yet it remains under‑researched, lacks standardized monitoring, and poses risks such as off‑site vapor migration and groundwater plume mobilization. The paper aims to deepen understanding of IAS before its application. The authors review published literature, practitioner insights, unpublished reports, and theory to assess IAS practice. Air injection combined with SVE improves removal rates for hydrocarbons in saturated zones, and the review highlights strengths, weaknesses, and future research directions.

Abstract

Abstract 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the practice of air sparging is a review of available published literature, consultation with practitioners, a range of unpublished data reports, as well as theoretical considerations.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.