Electricity production and bacterial communities of microbial fuel cell supplied with oily sludge

Oily sludge is a major problem affecting the quality of oil fields and surrounding environment. Microbial fuel cell (MFC) technology is a simple way to treat the oily sludge while generating electricity. To investigate the electrochemical properties of such MFC and the characteristics of bacteria attached to anode, a single-chamber MFC supplemented with oily sludge was constructed. The electrochemical results showed that the oily sludge is suitable for MFC operation, with a maximum output voltage of 299.13 mV and a maximum output power (P-max) of 2,255.52 mW/m(2). The cyclic voltammetry curve of MFC anode displayed an "S" shape, whereas the main peaks were at 0 and 0.1 V, indicating a strong redox reaction on the anode carbon felt. The limiting current was 0.08 A/cm(2). The scanning electron microscopy (SEM) of the bacteria on the anode surface showed that most of bacteria displayed a rod-shaped morphology, whereas the biological metagenomic classification sequencing showed that the predominant electricity-producing bacteria were Proteiniciclasticum (15.83%) from Firmicutes and Pseudomonas (11.9%) from Gammaproteobacteria. MFC can effectively utilize the oily sludge to generate electricity at the same time, which provides a theoretical basis for the research of MFCs' pollution control and electricity production.