The purpose of this paper is to introduce a procedure for remedial investigations and for beginning cleanup more quickly than by traditional approaches. Simultaneous Testing, Exploration, Remedial Design, and Installation (STERDI) speeds the early and mid-phases of the remediation process, eliminates some traditional repetitive steps, and thereby results in lower project costs. The procedure involves the installation of in-ground components of an appropriate remedial system during the same exploration program that delineates the contaminant distribution. The method is built upon two capabilities: (1) planning for the multiple possible contaminant distributions, and (2) conducting “real-time” quantitative chemical analyses of soils during explorations in the vicinity of a release.
To implement STERDI, one has to recognize the various contaminant distributions which may have resulted from the release, prior to conducting subsurface explorations. Several spill “conceptual models” are developed, based on knowledge of the contaminant's geochemical behavior and on local geological characteristics. For each model, a “presumptive remedial design” (involving borehole-installed equipment) is prepared. An exploration program, incorporating in-field chemical analysis, is planned with sequencing which would allow early identification of which set of modeled conditions actually occurs. Once actual conditions are identified, the exploratory boreholes are completed by immediately installing remediation system components, guided by the in-field chemical testing results, according to the presumptive design which was developed for that model prior to the fieldwork.
At a gasoline release, the contaminant distribution was discovered and the in-ground portions of a vapor extraction system, including monitoring wells, were installed, all in a single three-day field effort. At a tetrachloroethylene spill, contamination was found through the unsaturated zone, and within the upper 20 ft (6.1 m) of the 50-ft-deep (15 m) overburden aquifer; a bubbler was installed in an exploratory borehole for remediation, accurately placed just beneath the contaminated interval, all in a two-day effort.