ABSTRACT
This chapter focuses on findings from the research community in concert with experience gained at sites undergoing remediation. It provides an overview of the factors involved in in situ bioremediation, outlines the types of information required in the application of such systems, and explores the advantages and limitations of this technology. The chapter addresses processes which are currently being utilized or are in development of treating contaminated unsaturated subsurface soils in place. It explains subsurface soil refers to unsaturated soil within the vadose zone at depths greater than three feet below the land surface. The chapter also addresses specific environmental processes, factors, and data requirements for characterizing and evaluating the application of subsurface in situ bioremediation, and describes selected field-scale applications of recovery and delivery systems to enhance in situ subsurface soil bioremediation. Microbial communities in the subsurface are diverse and adaptable. Recovery and delivery technologies are those that facilitate transport of materials either out of or into the subsurface.
