A new approach to in situ sediment remediation based on air-cathode microbial fuel cells

Abstract

Purpose As an attempt to remove the back color and odor of the organic-rich sediment, a novel tubular air-cathode MFC (TAC-MFC) was constructed and employed for in situ sediment remediation. The biodegradation of organic matter in sediment was stimulated by providing anodic electrode as an electron acceptor. The TAC-MFC was more favorable for application than typical sediment-type MFCs, whose performances are strongly limited due to the drawbacks such as low oxygen availability of cathodes, big electrode spacing, and fouling of cathodes. Materials and methods The TAC-MFC was constructed with a cloth cathode assembly (CCA) structure that consisted of a conductive, catalytic, and waterproof layer to replace the cathode and ionic exchange membrane in a typical MFC. By simply inserting TAC-MFC into the sediment, a whole electrochemical biosystem was established for simultaneous organic matter oxidization and electricity generation. The MFC performance for power generation and sediment bioremediation were evaluated under various external loadings, in terms of power density and the sediment quality parameters including loss on ignition (LOI), readily oxidizable organic matter (ROOM), and acid volatile sulfide (AVS). Results and discussion The highest power density (107.1± 8.6 mW/m 2 ), coulombic efficiency (17.9%), and the lowest internal resistance (20 Ω) were obtained from the TAC-MFC that was loaded with an external resistance of 30 Ω.At the same time, LOI was decreased by about 33.1%, ROOM was decreased by about 36.0%, and AVS was decreased by about 94.9% in the sediment. Under closed circuit conditions, the oxidation and reduction potential value in the sediment increased from −162.5 to +245.7 mV, suggesting that an improved environment of sediment was achieved upon MFC treatment. Conclusions A higher power output was achieved in the proposed TAC-MFC compared with sediment-type MFCs reported in previous literature, indicating that the TAC-MFC with a CCA was a desirable configuration. From the analysis of sediment quality parameters, the proposed MFC was demonstrated to be a potential means for the sediment remediation coupled with electricity production.

Suitability of granular carbon as an anode material for sediment microbial fuel cells

“…However, taking also the use of plants and possible agricultural practices into account, this study has shown that granular materials can provide a good alternative. MFC-technology has been proposed as a means of alternative or enhanced soil or sediment remediation (Yuan et al 2010;Zhang et al 2010;Williams et al 2010). The idea behind this concept is to provide an extra electron donor or acceptor in the form of an electrode.…”

Effect of Operating Parameters on the Performance Evaluation of Benthic Microbial Fuel Cells Using Sediments from the Bay of Campeche, Mexico

“…This is because the soil is moderately eutrophic or hypereutrophic during this season, there being no further significant differences with respect to the distances between electrodes in the same seasons (Table 1) [9,30].…”

“…Some authors such as Reimers et al (2001) and Tender et al (2008) observed that the oxygen in the aqueous cathode is limited by the submerged electrode, generating a maximum power density of 10 and 16 mW/m 2 respectively [12,21]. Therefore, this performance has been limited mainly by the oxygen reduction reaction at the aqueous cathode due to the poor kinetics of the reaction at neutral pH, which is why some authors propose the use of aerated cathodes for BMFC, where the oxygen flow is 3.7 times higher than in an aqueous cathode [10,16,23,[28][29][30]. These air cathodes are composed of three layers: the first is the collector in which electrons are received from the anode through the external circuit, the second is the catalyst which promotes the reduction reaction at the cathode and the third layer is the diffuser, which allows the reaction, improving the conditions of evaporation and substrate consumption [18,31].…”

Potential of Electric Power Production from Microbial Fuel Cell (MFC) in Evapotranspiration Reactor for Leachate Treatment Using Alocasia macrorrhiza Plant and Eleusine indica Grass

“…MFC system utilization using waste residue at wetland forest as substrates that are oxidized by microbes, whereas in sediments it in eutrophication lake condition which generates maximum electricity was 294 mW/m 2 at the same time can remove of nitrate more than 90% [14,15]. MFC operated with continuous flow can remove of 50% COD from wastewater with the result of electrical energy was 464 mW/m 2 [16]. Constructed Wetlands (CW) to COD from textile waste when the system was combined with MFC.…”