Microbial fuel cell fed by Barnett Shale produced water: Power production by hypersaline autochthonous bacteria and coupling to a desalination unit

Hydraulic fracturing for oil and gas production can generate large volumes of highly saline produced waters that pose a significant disposal challenge and a potential opportunity for reuse. Here, we report on a microbial fuel cell (MFC) fed with produced water (Barnett Shale), which produced power (47 mW/m2) and accomplished a COD removal efficiency of 68% (influent COD 10,520 ± 1340 mg/L). Bacterial population analysis showed two autochthonous halophilic species colonizing the anode, H. praevalens and M. hydrocarbonoclasticus. In addition, we demonstrated that hypersaline MFCs (100 g/L NaCl) can produce electricity to power a capacitive deionization (CDI) device for desalination, with a salt adsorption capacity of up to 40 mg of salt per g of carbon electrode. This is the first report of a MFC operating with hypersaline produced water, and illustrates the potential to couple MFCs with CDI to enable desalination and reuse of hypersaline wastewaters.