1,4-Dioxane Contamination and Remediation Overview
1,4-Dioxane is a synthetic chemical that was primarily used as a stabilizer for 1,1,1-trichloroethane and is therefore often found at with chlorinated solvent contamination. It has a also been used as an alternative to tetrahydrofuran in some manufacturing processes.
Due to the physical properties (low sorption and high solubility), 1,4-dioxane in groundwater often travels much farther than other chlorinated solvents.
Applicable Remediation Technologies for 1,4-Dioxane
Air Sparging: Poor to Good – While the vapor pressure is greater than 1 mm Hg, air sparging can be ineffective due to the high solubility and low Henry’s constant of 1,4-dioxane. The key for air sparging to work is a significantly longer sparging residence time than compounds commonly treated with this technology.
SVE: Poor – While the vapor pressure is greater than 1 mm Hg, SVE is ineffective due to the high solubility of 1,4-dioxane. For SVE to be effective, the soils need to to be dry.
Thermal: Good– Thermal processes can be used to increase the Henry’s constant for 1,4-dioxane, making it partition more readily into the vapor phase.
Pump and Treat: Good – Pump and treat is usually not an effective source remedy for groundwater remediation, when there is significant non-aqueous mass present (absorbed to soil or non-aqueous phase liquids). As 1,4-dioxane is found primarily in the aqueous phase, this is one of the few compounds where pump and treat could be effective as a source reduction technology.
Aerobic: Good – Has been shown to degrade via a cometabolic pathway, which often requires the presence of oxygen and a simple hydrocarbon (like propane), or directly through biodegradation. Degradation can be inhibited by chlorinated ethenes or occurs very slowly. Therefore not practical at all sites.
Anaerobic: Poor – Has not been shown to be effective.
Activated Carbon: Poor – 1,4-Dioxane can adsorb to activated carbon in small quantities, making this method potentially cost prohibitive.
Synthetic Resins: Excellent – Synthetic resins can be used to collect various contaminants from liquids, vapor or atmospheric streams and be reused indefinitely. Potentially significant upfront capital costs.
Molecular weight (g/mole): 88.107
Solubility (mg/L): Completely Miscible
Vapor pressure (mm Hg): 38.09
Henry’s Coefficient (unitless): 0.7236304
Organic Carbon Partitioning Coefficient (cm3/g): 94.94
