ABSTRACT

The Dow Chemical Company, Louisiana Division (Dow) manufacturing complex was constructed in Plaquemine, Louisiana in the late 1950s. Through past waste management practices and product spills, chlorinated organics and chloride contamination have entered the shallow ground water underlying several areas of the facility. Upon detection of impact, Dow implemented groundwater recovery and treatment in four areas of the facility and began a voluntary sitewide subsurface assessment.

The site-wide assessment has provided characterization of subsurface conditions at the facility as well as areal distribution and depth of groundwater contamination. A comprehensive database was prepared which incorporated the analyses of soil and ground water samples, geotechnical and electric logs, cone penetrometer test data, and electromagnetic survey data. This data base served as the basis for the development of a detailed 3-D relational model showing stratigraphy, lithology, and contaminant concentrations from which site ground water remediation strategies can be evaluated, prioritized, and implemented.

Data obtained during the site assessment along with an unsuccessful, full scale in-situ bioremediation project conducted at the site, and extensive reviews of potentially applicable remedial technologies determined the technology to be used in remediation of the site. Since treatment facilities were already a functional part of the operating facility, only the method of contaminant removal was in question. Due to low hydraulic conductivities and thin pervious zones in which the contaminants were found, directional drilling for the construction of horizontal wells provided the most advantageous mechanism for ground water recovery and hydraulic containment of the contaminated ground water.

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