Proof-of-Concept Study: Novel Microbially-Driven Fenton Reaction for In Situ Remediation of Groundwater Contaminated with 1,4-Dioxane, Tetrachloroethene (PCE) and Trichloroethene (TCE)
Final rept. 1 May 2013-15 Dec 2014
GEORGIA INST OF TECH ATLANTA SCHOOL OF BIOLOGY
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A microbially-driven Fenton reaction was designed to autocatalytically generate hydroxyl HO radicals that degrade 1,4-dioxane, TCE, and PCE. In comparison to conventional purely abiotic Fenton reactions, the microbially-driven Fenton reaction operates at circumneutral pH and does not require addition of exogenous H2O2 or UV irradiation to regenerate FeII. The 1,4-dioxane, TCE, and PCE degradation process was driven by the FeIII-reducing facultative anaerobe Shewanella oneidensis. S. oneidensis batch cultures were provided with lactate, FeIII, and either 1,4-dioxane, TCE or PCE and exposed to alternating aerobic and anaerobic conditions. During the aerobic phase, S. oneidensis reduced O2 to H2O2, while during the anaerobic phase, S. oneidensis reduced FeIII to FeII. During the aerobic-to-anaerobic transition period, the produced FeII and H2O2 interacted chemically via the Fenton reaction to form FeIII, OH- ion, and HO radicals which oxidatively degraded 1,4-dioxane, TCE, and PCE at potential source zone concentrations. Under optimal conditions, the microbially-driven Fenton reaction completely degraded 1,4-dioxane, TCE, and PCE in 53 h with optimal aerobic-anaerobic cycling frequencies of 3 h. Acetate and oxalate were detected as transient intermediates during the microbially-driven Fenton degradation of 1,4-dioxane, an indication that conventional and microbially-driven Fenton degradation processes may follow similar reaction pathways.
- Inorganic Chemistry
- Hydrology, Limnology and Potamology
- Water Pollution and Control