Clean-Up Alternatives for 1,4-Dioxane in Groundwater

The cyclic ether 1,4-dioxane, widely used as a stabilizer in chlorinated organic solvents, also has a myriad of other uses. This compound is poorly retarded in groundwater flow systems, and difficult to remove. Further, 1,4-dioxane is not readily biodegraded. Chemical oxidation has been employed successfully in aboveground systems, but there have been limited in-situ demonstrations. Potential health risks from exposure to this compound are now typically assessed by regulators assuming that this chemical is a human carcinogen; coupled with this situation have been advancements in analytical techniques such that low micrograms per liter (μg/L) measurement in water is possible. Five alternatives were developed and evaluated by an engineering feasibility study (FS) for remediation of a plume of 1,4-dioxane in groundwater beneath an industrial facility. Although there are no current or foreseeable future groundwater receptors, regulators insisted that a future off-site residential exposure scenario be considered in the risk assessment for this site. General response actions for groundwater are no action, institutional controls, monitoring, containment, in-situ treatment, and ex-situ treatment. Technologies and process options to accomplish these response actions were identified and screened for effectiveness, ease of implementation, and relative cost. Five (5) alternatives emerged from the work for this groundwater containing 1,4-dioxane. Alternatives were evaluated against eight (8) evaluation criteria and then against one another to select a course of action.