Horizontal carbon fiber brush amendment and maximum radius of influence prediction: A novel soil bioelectrochemical system for extending the range of petroleum hydrocarbons degradation

Soil bioelectrochemical system (SBES) has the potential to be applied to soil contaminated by total petroleum hydrocarbon (TPH), whereas the long-distance performance of vertical SBESs is not ideal due to the mass transfer limitation in soil matrix. In this study, a novel configuration of SBES was constructed with carbon fiber brushes as horizontal anodes, thus promoting TPH degradation and expanding the radius of influence (ROI) through a horizontal electronic pathway. The results showed that the removal rate of TPH was 46.4%–49.0% after 80 days in SBESs with carbon fiber brush, which was 113.8%–125.8% and 373.5%–400.0% higher than that of closed-circuit control and open-circuit control, respectively. The maximum ROI was over 135 cm in SBESs with carbon fiber brush, which was a 1.5 fold approximately increase than that of vertical SBES. In addition, the former cost was 1.97 $/g TPH, which was only one-fifth of the latter. These findings demonstrated that the horizontal carbon fiber brush amendment promoted the performance of TPH degradation far from SBES electrodes, which provided not only (i) a systematic approach focusing on ROI prediction in the application of SBES engineering, but also (ii) a novel configuration to improve TPH degradation in a green and economical way.