A flat microbial fuel cell for decentralized wastewater valorization: process performance and optimization potential

Abstract

A very compact flat microbial fuel cell (MFC), with 64 cm2 each for the anode surface and the cathode surface and 1 cm3 each for the anode and cathode chambers, was tested for wastewater treatment with simultaneous electricity production with the ultimate goal of implementing an autonomous service in decentralized wastewater treatment systems. The MFC was operated with municipal wastewater in sequencing batch reactor mode with re-circulation. Current densities up to 407 W/m3 and a carbon removal of 83% were obtained. Interruption in the operation slightly decreased power density, while the re-circulation ratio did not influence power generation. The anode biofilm presented high conductivity, activity and diversity. The denaturing gradient gel electrophoresis band-pattern of the DNA showed the presence of several ribotypes with different species of Shewanellaceae and Geobacteraceae families.

Resources recovery in the dairy industry: bioelectricity production using a continuous microbial fuel cell

“…The measured OCV was 562 mV during biofilm formation and 649 mV during continuous operation. These values are in the range of those reported in literature for similar setups (500e800 mV) (Peixoto et al, 2013;Logan, 2010). The polarization curves depicted in Fig.…”

“…The power density (P) is calculated as the product of current intensity and voltage divided by the projected surface area of the anode (Equation (3)). The polarization curve, describing the voltage and the power density as a function of the current density (Peixoto et al, 2013) was recorded using a series of resistances in the range of 71.1 kU to 50 U during biofilm formation and the stable phase of bioelectricity production along the continuous operation (Peixoto et al, 2013). The internal resistance of the MFC (R int ) was calculated from the slope of the polarization curve in the region dominated by Ohmic losses (Peixoto et al, 2013).…”

“…After sampling, the wastewater was deoxygenated with nitrogen gas and kept at 4 C until use (Peixoto et al, 2013). When necessary, wastewater was replaced to avoid organic carbon limitations on bioelectricity production.…”

“…One of those possibilities is the use of microbial fuel cells (MFCs) Martins et al, 2010). The MFC technology is based on the ability of some carbon-oxidizing microorganisms to transfer electrons directly to an anode in anaerobic conditions (Peixoto et al, 2013;. The standard design consists of an electrochemical cell with anodic and cathodic compartments separated by a proton exchange membrane.…”

Energy Balance Affected by Electrolyte Recirculation and Operating Modes in Microbial Fuel Cells

“…In addition to electrolyte recirculation, the SBR operation of the MFC was examined and compared with the continuous operation. Sequence batch reactor operation is used in wastewater treatment, but seldom adopted in MFC operation (Peixoto et al, 2013). In this test, the anolyte recirculation rate was 16% and the catholyte recirculation rate was 20%.…”