Impacts of Bioturbation From Tubificidae on the Electrochemical Performance and Microbial Community of Sediment Microbial Fuel Cells

Abstract

Sediment microbial fuel cells (SMFCs) have been examined extensively for bioremediation, but the impact of organisms that live in the sediment has not been previously investigated. In this study, the impacts from the bioturbation of Tubificidae on the electrochemical performance and microbial community of SMFCs were investigated using lake water and sediment. It was observed that Tubificidae were burrowing in the sediment and eventually dwelled on the anode of SMFCs. Although the voltage output of the SMFC in the presence of Tubificidae experienced a dramatic decline at the beginning of operation, it outperformed that of the SMFC in the absence of Tubificidae after operating for 30 days. The polarization curves of the SMFC anode and Shannon diversity index suggested that the anodic biofilm was devoured by Tubificidae. However, the cathode performance was improved due to more chemical oxygen demand (COD) and ammonia-nitrogen (NH3-N) released from the sediment. After 90 days of operation, a high loss on ignition (LOI) removal efficiency of 24.5 ± 3% was achieved by combining the anodic oxidation of SMFC and the ingestion of Tubificidae. This study shows that SMFCs can alleviate the impact of Tubificidae on pollutants transfer to overlying water and still remove organic matters from the sediment effectively.