Can Biologically-activated Carbon be Used for Removal of 1,4-Dioxane and Other Trace Contaminants In an Indirect Potable Reuse System?

1,4-dioxane is commonly used as a solvent stabilizer for 1,1,1 trichloroethane and is readily soluble in water with a low Henry’s law constant. It is poorly removed by conventional air stripping and adsorption techniques and is generally thought to be resistant to biodegradation. Certain bacteria, such as Rhodococcus sp., Pseudonocardia sp. and Mycobacterium sp. have been shown to biodegrade 1,4-dioxane by monooxygenase enzymes in presence of co-substrates such as propane, butane and tetrahydrofuran (THF) (Vainberg et al. 2006; Mahendra et al. 2007). The goal of this project was to evaluate the feasibility of using biologically activated carbon (BAC) filtration used for indirect potable reuse biodegradation of 1,4-dioxane. 1,4-dioxane can be removed by hydroxyl radicals in an advanced oxidation (AOP) process, such as ozone hydrogen peroxide or UV peroxide (Stefan and Bolton, 1998). However, biodegradation in a BAC filter would be cost efficient and mitigate production of disinfection byproducts produced by the above AOPs.