1,4-Dioxane-contaminated groundwater remediation in the anode chamber of a microbial fuel cell

A two-chambered microbial fuel cell (MFC) was used for the first time for the remediation of an emerging contaminant-1,4-dioxane in its anode chamber. Groundwater historically detected 1,4-dioxane contamination was sampled from a Superfund site. Comparative study was carried out between metabolic (i.e., 1,4-dioxane as sole carbon source) and cometabolic (i.e., 1,4-dioxane and methanol as carbon sources) anodic degradations. It was found that cometabolic degradation increased 1,4-dioxane removal by 10%-52% after 7 days and increased maximum power production of the MFC by 18% to 88.9 mW/m³ . Oxalic acid was detected as a main metabolic degradation product. Beside oxalic acid, acetic acid and isopropanol were also detected as main products for cometabolic degradation. The presence of a biofilm for 1,4-dioxane anodic degradation was observed by a scanning electron microscopy. Phyla of Bacteroidetes, Firmicutes, and Proteobacteria, as well as a variety of species, were identified for the first time-especially Rikenella sp. and Solitalea canadensis, whose relative abundances were the highest of 18.8% and 24.0% for metabolic and cometabolic degradation, respectively. This study provided an innovative and sustainable approach for 1,4-dioxane anodic biodegradation, which would be potentially utilized for remediation of groundwater contaminated by 1,4-dioxane. PRACTITIONER POINTS: Groundwater contaminated with 1,4-dioxane was remediated in the anode chamber of a two-chambered microbial fuel cell. Cometabolic pathway increased 1,4-dioxane removal and power production of the MFC compared to metabolic pathway. The presence of a biofilm for 1,4-dioxane anodic degradation was observed, and oxalic acid was a main degradation product. This study would be potentially utilized for 1,4-dioxane-contaminated groundwater remediation with simultaneous energy production. External voltage supply for bioelectrochemical remediation of groundwater would potentially be reduced when treating chlorinated hydrocarbons co-occurred with 1,4-dioxane.