Perturbed conditions favored electron competition for sulfate in cathode biofilms of bioelectrochemical systems: heterogeneous structure of biofilms, microbial community structure, and functional genes

In a multi-fluid interaction actural environment (eg perturbed caused by wastewater flow.), the efficacy of bioelectrochemical systems (BESs) for treating sulfate wastewater containing heavy metals has been greatly affected. However, few studies have been reported to analyze the mechanisms of multifactor competition from changes in biofilm structure induced by perturbed conditions. In this study, a BES under perturbed conditions was constructed for the treatment of copper-containing sulfate wastewater. The results indicated that the perturbed condition was more favorable for sulfate to compete for electrons in BES, owing to thinner biofilm, better microbial activity, more the relative abundance of sulfate-reducing bacteria. And having more functional genes for extracellular electron transfer and sulfate reduction improving sulfate reduction by 5.7% and copper removal by 28.75% of BES. This study reveals the electron competition in BES treatment of copper-containing sulfate wastewater under perturbed conditions, which provides a new insight for the enhancement of the biological sulfate reduction system.