Microbial fuel cells under extreme salinity: performance and microbial analysis

Abstract

Environmental context The treatment of extremely saline, high-strength wastewaters while producing electricity represents a great opportunity to mitigate environmental effects and recover resources associated with wastes from shale oil and gas production. This paper demonstrates that extreme halophilic microbes can produce electricity at salinity up to 3- to 7-fold higher than sea water. Abstract Many industries generate hypersaline wastewaters with high organic strength, which represent a major challenge for pollution control and resource recovery. This study assesses the potential for microbial fuel cells (MFCs) to treat such wastewaters and generate electricity under extreme salinity. A power density of up to 71mWm–2 (318mWm–3) with a Coulombic efficiency of 42% was obtained with 100gL–1 NaCl, and the capability of MFCs to generate electricity in the presence of up to 250gL–1 NaCl was demonstrated for the first time. Pyrosequencing analysis of the microbial community colonising the anode showed the predominance of a single genus, Halanaerobium (85.7%), which has been found in late flowback fluids and is widely distributed in shale formations and oil reservoirs. Overall, this work encourages further research to assess the feasibility of MFCs to treat hypersaline wastewaters generated by the oil and gas industry.

Key findings

• ▸Extreme halophilic microbes can produce electricity at high salinity
• ▸MFCs can treat hypersaline wastewaters and generate electricity
• ▸Halanaerobium genus predominates in the anode microbial community

Keywords

Identifiers

DOI

10.1071/en13243

Journal

Environmental Chemistry

Year

2014