In situ air sparging (IAS) is a technology commonly used for treatment of submerged source zones and dissolved groundwater plumes. The acceptance of IAS by regulatory agencies, environmental consultants, and industry is remarkable considering the degree of skepticism initially surrounding the technology in the early 1990s. Much has been learned and reported in the literature since that time, but it appears that practice has changed little. In particular, conventional pilot testing, design, and operation practices reflect a lack of appreciation of the complex phenomena governing IAS performance and the unforgiving nature of this technology. Many systems are poorly monitored and likely to be inefficient or ineffective. Key lessons-learned since the early 1990s are reviewed and their implications for practice are discussed here. Of particular importance are issues related to: (a) the understanding of air flow distributions and the effects of geology and injection flowrate, (b) the need to characterize air flow distributions at the pilot- and field-scale, (c) how changes in operating conditions (e.g., pulsing) can affect performance improvements and reduce equipment costs, and (d) how conventional monitoring approaches are incapable of assessing if systems are performing as designed.
ASJC Scopus subject areas
- General Environmental Science