Bio-GAC flow-through column systems and drums for the simultaneous removal of 1,4-dioxane and CVOCs mixtures
1,4-Dioxane is a probable human carcinogen, and industrial solvent stabilizer, and common groundwater chemical found co-occurring with chlorinated volatile organic compounds (CVOCs). Both classes of chemicals have proven challenging to sustainably remove from groundwater. This study examined the effectiveness of granular activated carbon bioaugmented with Pseudonocardia dioxanivorans CB1190 (bioGAC) at removing 1,4-dioxane and CVOCs simultaneously. This sorption-biodegradation synergistic treatment was investigated in bench-scale flow-through column reactors as well as in pilot-scale drums. The reactors consisted of fixed beds with 1.5% w/w GAC and 98.5% w/w sand homogenously distributed. Results demonstrate a 50% to 800% increase in 1,4-dioxane removal compared to non-bioaugmented controls. Hydraulic retention time (HRT), sufficient nutrient amendments, and consistent dissolved oxygen supply were identified as crucial parameters to sustain 1,4-dioxane degradation and mitigate desorption events to extend operational longevity of aerobic bioGAC systems. This research supports consideration of bioGAC systems to treat solvent impacted water resources.