Sediment Microbial Fuel Cells Research Articles

Oil-contaminated sediment amended with chitin enhances power production by minimizing the sediment microbial fuel cell internal resistance

• Unamended river sediment generates 5 mW m −2 on unmodified C-cathode. • Oxygen reduction reaction was improved on MnO 2 /C surface. • Amended sediment with chitin generates 178 mW m −2 on modified MnO 2 /C-cathode. • Electroactive, degrader bacteria were identified on anode surface. Biodegradation of oil-contaminated sediments (OCS) in sediment microbial fuel cells (SMFC) is limited by several factors such as adapted microorganisms to degrade OCS, low conductivity and organic matter content, sluggish cathodic O 2 reduction reaction (ORR), among others. The use of a birnessite/Carbon Fabric (CF) cathode improves the O 2 reduction in SMFC. Oil-contaminated sediments amended with chitin (commercial analytical grade (CC) and dried natural shrimp shells (NC)) allows faster anaerobic biodegradation in the anolyte by the indigenous bacteria coming in the initial OCS, without further growth media. The SMFC containing the unmodified OCS produces a maximum power output of 5 mW m −2 in contrast to 62 mW m −2 and 178 mW m −2 of that SMFC containing CC and NC, respectively. High-power output of SMFC is the result of minimizing internal resistance by combining the following key factors: a) saturated air 0.8 M Na 2 SO 4 catholyte at pH 2, b) the use of a birnessite/CF-cathode, and c) the presence of bacterial groups enriched on the anode biofilm as Deltaproteobacteria and Bacteroidetes , additional to other groups such as Aminocenantia depending on the source of chitin. The pH of the catholyte strongly modifies the power production of SMFC; a detailed discussion is included in this paper.

3-Aminopropyltriethoxysilane Complexation with Iron Ion Modified Anode in Marine Sediment Microbial Fuel Cells with Enhanced Electrochemical Performance

Anode modification plays a key role in higher power output in marine sediment microbial fuel cells (MSMFCs). A low-molecular organosilicon compound (3-aminopropyltriethoxysilane) was grafted onto the surface of carbon felt using chemical method and a composite modified anode was prepared through organic ligands coordination Fe3+ for better electro-chemical performance. Results show that the biofilm resistance of the composite modified anode (2707 δ) is 1.3 times greater than that of the unmodified anode (2100 Ω), and its biofilm capacitance also increases by 2.2 times, indicating that the composite modification promotes the growth and attachment of electroactive bacteria on the anode. Its specific capacitance (887.8 F m−2) is 3.7 times higher than that of unmodified anode, generating a maximum current density of 1.5 Am−2. In their Tafel curves, the composite modified anodic exchange current density (5.25×10−6 A cm−2) is 5.8 times bigger than that of unmodified anode, which suggests that the electrochemical activity of redox, anti-polarization ability and electron transfer kinetic activity are significantly enhanced. The marine sediment microbial fuel cell with the composite modified anode generates the higher power densities than the blank (203.8 mWm−2 versus 45.07 mWm−2), and its current also increases by 4.4 times. The free amino groups on the anode surface expands a creative idea that the modified anode ligates the natural Fe(III) ion in sea water in the MSMFCs for its higher power output.

Enhanced Power Extraction with Sediment Microbial Fuel Cells by Anode Alternation

Sediment microbial fuel cells (SMFCs) are energy harvesting devices where the anode is buried inside marine sediment, while the cathode stays in an aerobic environment on the surface of the water. To apply this SCMFC as a power source, it is crucial to have an efficient power management system, leading to development of an effective energy harvesting technique suitable for such biological devices. In this work, we demonstrate an effective method to improve power extraction with SMFCs based on anodes alternation. We have altered the setup of a traditional SMFC to include two anodes working with the same cathode. This setup is compared with a traditional setup (control) and a setup that undergoes intermittent energy harvesting, establishing the improvement of energy collection using the anodes alternation technique. Control SMFC produced an average power density of 6.3 mW/m2 and SMFC operating intermittently produced 8.1 mW/m2. On the other hand, SMFC operating using the anodes alternation technique produced an average power density of 23.5 mW/m2. These results indicate the utility of the proposed anodes alternation method over both the control and intermittent energy harvesting techniques. The Anode Alternation can also be viewed as an advancement of the intermittent energy harvesting method.

The influence of organic pollutant load and external resistance on the performance of a solid phase microbial fuel cell fed orange peel wastes

AbstractThe degradation of organic matter in marine sediments could be taken advantage of to produce electricity by using a sediment microbial fuel cell (SMFC) inspired system. A single solid phase microbial fuel cell (SPMFC) in which orange peel wastes were supplemented as a carbon source mixed to marine sediments produced a power of 0.33 mW and a voltage of 0.7 V. By stacking multiple SPMFCs powers of 2.08 mW were generated for a voltage of 4.6 V. The use of dewatered sludge to inoculate the marine sediment improved the SPMFCs' performance. The removal of organic matter in the SPMFC system under closed circuit conditions was very interesting, removal rates were 19%–40% from readily oxidizable organic matter,15 to 35% for loss on ignition and 22%–55% for total organic carbon, indicating the possibility of using these systems to treat solid organic wastes and produce electricity at the same time.

Novel method to immobilize phosphate in lakes using sediment microbial fuel cells

Phosphate pollution in lakes poses an intractable remediation challenge. Accumulated stocks of phosphorus in sediments cause high concentrations in the overlying water despite elimination of external sources. We propose to use sediment microbial fuel cells (SMFCs) for lake remediation by sediment phosphorus immobilization. The hypothesis is that SMFCs can increase sediment redox potential at the top layer, and that such changes will allow the sediment to retain phosphorus as immobile species. This study placed an emphasis on scalability, practicality, and use of low-cost materials. Stainless steel net was selected as electrode material, and modifications were tested: (i) chronoamperometric operation with anode poised at +399 mV (versus standard hydrogen potential); (ii) injection of graphite slurry; and (iii) coating with nickel-carbon matrix. Stainless steel electrodes were implemented in laboratory microcosms (1.3 L) and at field scale in a eutrophic freshwater lake. All tests were carried out in untreated sediment and water from Lake Søllerød, Denmark. Phosphate immobilization was shown at lab scale, with 85% decrease in overlying water using steel electrodes. At field scale maximum phosphate decrease of 94% was achieved in the water body above a 16 m2 stainless steel SMFC electrode. Results are promising and warrant further study, including remediation trials at full scale. Added benefits include degradation of sediment organic matter and pollutants, inhibition of methane and sulfide emission and production of electricity.

On-line monitoring of minor oil spills in natural waters using sediment microbial fuel cell sensors equipped with vertical floating cathodes

Oil spills near natural water bodies pose considerable threats to aquatic ecosystem and drinking water system. Various detection techniques have been developed to identify the oil pollution in natural waters. These techniques mainly focus on large and major oil spills involving significant changes in environmental characteristics. However, monitoring of minor oil spills (from seepage and dripping) in waters remains a bottleneck, allowing inconspicuous and persistent oil contamination. To overcome this drawback, a sediment microbial fuel cell (SMFC) sensor equipped with a vertical floating cathode is developed for on-line and in-situ monitoring of minor oil spills in natural waters. The vertical floating cathode was intended for recognizing oil on water surface. Oil on the cathode will trigger current drop. Two kinds of natural sediments were adopted in two sensors (SMFC1 from a lake and SMFC2 from an urban stream) for comparison. Both showed linear relationship between net steady-state current decrease and oil dose (30.78 and 27.29 μA/mL of sensitivity, respectively). The current change process was fitted well to a pseudo-first order kinetic equation. A one-point/two-point dynamic identification methods were derived from the kinetic equation. Therefore, the detection time was shortened from 10 h to 10/30 min. The triggered current decrease was mainly attributed to the increase in internal resistance related to charge and mass transfer. Despite the power loss after oil contamination, results implied SMFC sensor could still achieve self-sustainability. This study shows that the SMFC sensor with vertical floating cathodes is applicable to monitoring the unnoticeable minor oil pollutions in natural waters.

The Bioelectricity Generation from Wastewater Treatment Plant Sludge using Sediment Microbial Fuel Cells (SMFCs) with Zinc-Carbon Electrode and Copper-Carbon Electrode

The primary source of electrical energy supply is fossil-based fuels. The continuous utilization of fossil-based fuel energy has negative impacts, not only harmful to the environment but also the depletion of natural resources. Generating renewable energy from waste is favorable because it can achieve both the new resources energy and the treatment of waste. Wastewater treatment plant (WWTP) generate sludge daily as a by-product of the wastewater treatment process. Sludge from WWTP has high organic and generous microorganism contents, so it is suitable for bioelectricity generation. The study investigated the bioelectricity generated from WWTP sludge with metal-based electrode and the operating conditions during power generation. The change of operating parameters such as pH, Electric Conductivity (EC), and salinity affect power generation in the bioelectricity process. The study was carried out in membrane-less single-cell sediment microbial fuel cells with Margasari, Balikpapan WWTP sludge. The zinc-carbon and the copper-carbon were used in this research. The carbon organic, pH, salinity and EC of WWTP sludge were 41.89%; 7.34; 400 mg/L, and 8907 μS/cm, respectively. The result found that The SMFC with zinc-carbon and copper-carbon electrodes produced the maximum power density of 3777 mW/m2 and 341 mW/m2, respectively. The decline of pH, TDS, salinity, and EC were found following the decrease of bioelectricity generation.

Suppression of phosphorus release from eutrophic lake sediments by sediment microbial fuel cells

ABSTRACT Sediment microbial fuel cells (SMFCs) have served as an alternative technique to suppress phosphorus release from lake sediments to water bodies and thus mitigate eutrophication. However, the phosphorus regulation mechanism remains unclear. The purpose of this research was to understand the electrochemical influence of an SMFC on the phosphorus concentration in interstitial water. In this study, a lab-scale SMFC was applied to acetate-spiked sediments (ace+) and unspiked sediments (sed) with closed-circuit (CC)/open-circuit (OC) columns, and the circuitry was switched to investigate the relationship between electron transfer and phosphorus concentration. The dissolved total phosphorus (DTP) concentration in the sediment interstitial water in CC columns significantly decreased to below 0.1 mg/L, whereas the DTP in OC columns remained high for nine weeks. After switching the circuit, the DTP in OC→CC columns dropped but that in CC→OC columns increased within one week. At the end of the experimental period, the DTP concentrations in CC/sed, CC/ace+, OC/sed, and OC/ace+ columns were 0.10 ± 0.02, 0.03 ± 0.00, 0.82 ± 0.01, and 1.66 ± 0.12 mg/L, respectively. The respective estimated anode capacitances of those columns were 2.05 ± 0.49, 5.15 ± 0.14, 0.72 ± 0.19, and 0.71 ± 0.12 nF. We concluded that the phosphorus may have been electrochemically attracted and retained on the anode in the sediment because the adsorbed DTP contents and the increased anode capacitances were strongly correlated. Thus, SMFCs can be used for suppressing phosphorus release from eutrophic lake sediments.

Simultaneous PAHs degradation, odour mitigation and energy harvesting by sediment microbial fuel cell coupled with nitrate-induced biostimulation

The study investigates a bioremediation process of polycyclic aromatic hydrocarbons (PAHs) removal and odour mitigation combined with energy harvesting. Sediment microbial fuel cells (SMFCs) were constructed with the addition of nitrate in the sediment to simultaneously remove acid-volatile sulphide (AVS) and PAHs. With the combined nitrate-SMFC treatment, over 90% of the AVS was removed from the sediment in 6 weeks of the SMFC operation and a maximum of 94% of AVS removal efficiency was reached at Week 10. The highest removal efficiencies of phenanthrene, pyrene, and benzo[a]pyrene was 93%, 80%, and 69%, respectively. The maximum voltage attained for the combined nitrate-SMFC treatment was 341 mV. Illumina HiSeq sequencing revealed that the autotrophic denitrifiers Thiobacillus are the dominant genus. In electricity generation, both sulphide-oxidation and PAH-oxidation are the possible pathways. Besides, the addition of nitrate stimulated the growth of Pseudomonas which is responsible for the electricity generation and direct biodegradation of the PAHs, indicating a synergistic effect. The developed bioremediation process demonstrated the potential in the in-situ bioremediation process utilizing SMFC combined with nitrate-induced bioremediation.

Sediment Microbial Fuel Cell Power Boosted by Natural Chitin Degradation and Oxygen Reduction Electrocatalysts

AbstractAn economic and simple sediment microbial fuel cell (SMFC) design is evaluated to improve the recovery of energy from a river sediment, in terms of power density output (maximum power pick) normalized to the cathode surface. The organic matter content in the sediment is boosted by adding abundant, natural, and waste biomass (chitin) near the anode surface. The sluggish kinetics in the two‐electron reduction reaction of O2 at the C‐cathode is replaced with an efficient four‐electron reduction reaction at the MnO2/C cathode. Five SMFCs composed of a common carbon fabric (CF) cathode and different unmodified anode materials, such as reticulate vitreous carbon (RVC: 10, 30, and 60 pore per inch, ppi), CF and commercial stainless‐steel (SS) mesh, are evaluated. The catholyte conductivity improved with Na2SO4. The results show that the power density output increased a 100‐fold when an MnO2/CF‐cathode is used with Na2SO4 catholyte and the anolyte contained chitin. A microbial analysis of the SMFC sediment is performed. The bacterial groups identified, mainly Aminicenantia and Deltaproteobacteria, offer metabolic capacities to participate in the degradation of organic matter in the presence of chitin. Therefore, bacterial groups enriched in the anode biofilm produce electrical energy.

Remediation of Mariculture Sediment by Sediment Microbial Fuel Cell

To investigate the removal effect of pollutants in mariculture sediment by sediment microbial fuel cell (SMFC) and its power generation capacity, the effects of external resistance, cathode pH and cathode dissolved oxygen concentration (DO) on the SMFC system were investigated. The results showed that the optimal parameters for SMFC were as follows: external resistance = 1500 Ω, pH = 8.5 and DO = 5 mg·L-1. In these situations, the power generation performance and organic degradation effect were both the best. The maximum output voltages were 585, 606, and 587 mV, respectively; the removal rates of COD in sediment were 75.51%, 84.21% and 86.63%, respectively; and the removal rates of ammonia nitrogen in sediment were 80.34%, 98.91% and 90.24%, respectively. The SMFC system had a certain degradation ability to pollutants such as COD and ammonia nitrogen in the sediment of the marine aquaculture areas, which had a broad application prospect.

Recent Advances in Sediment Microbial Fuel Cells

Sediment microbial fuel cell is a kind of microbial fuel cell with anode and cathode respectively placed in sediment and water, which can be used in the fields of power supply of low-power equipment and in-situ remediation of river and lake sediments. This paper introduced the related research, and summarized the principle, influencing factors, microbial community, and application.

Ferric iron stimulation in marine SMFCs: Impact on the microbial structure evolution in contaminated sediments with low and high molecular weight PAHs

The impact of ferric iron stimulation on the evolution of microbial structure in marine sediment microbial fuel cells (SMFCs), operated for the bioremediation of a complex mixture of low and high molecular weight PAHs (naphthalene, fluorene, pyrene and benzo(a)pyrene), was assessed. Microbial evolution profiles showed high relative abundances of exoelectrogenic iron-reducing bacteria throughout the biodegradation, namely Geoalkalibacter, under ferric iron stimulation and anode reducing conditions, irrespective of sulfate reducing bacteria (SRB) inhibition. Highest PAHs removal was measured in the absence of anode reduction, under Fe stimulation and SRB inhibition, reaching 40.85% for benzo(a)pyrene, the most persistent PAH used in this study. Results suggest that amendment of contaminated sediment with ferric iron could constitute a better bioremediation strategy than using SMFCs. This becomes significant when considering the well-established and dominant indigenous SRB population in marine sediments that usually limits the performance of the anode as a terminal electron acceptor in marine SMFCs.

Microbial fuel cell improves restoration of Hydrilla verticillata in an algae-rich sediment microcosm system

Settled algae may be used as nutrient for macrophyte establishment, but also can induce marked macrophyte decline during deep anaerobic decomposition. Sediment microbial fuel cells (SMFCs) may promote the utilization of algae-derived nutrients and relieve bio-toxicity from settled algae to submerged macrophytes, thus facilitating plant production. To test these hypotheses, a 62-day comparative study was designed and conducted in microcosms with the following six treatments: control (open-circuit SMFC), plant (open-circuit SMFC with plants), algae (open-circuit SMFC with algae), algae-plant (open-circuit SMFC with algae and plants), algae-SMFC (closed-circuit SMFC with algae), and algae-plant-SMFC (closed-circuit SMFC with algae and plants). The results showed that the presence of Hydrilla verticillata improved the power generation of SMFCs when algae were used as substrates during the whole operation. The decomposition of sedimented algae experienced two periods since the injection. During the slight decomposition period (14–38 day), the algal retention in sediments was enhanced by H. verticillata as a nutrient source. Nitrogen (N) assimilation in plant shoots was facilitated under electrogenesis due to a simultaneous increase of algae-derived dissolved inorganic carbon (DIC) and ammonium (NH4+) in the water column. At the end of the 38th day, the biomass of H. verticillata were increased by 21.4% and 52.3%, respectively, in the algae-plant and algae-plant-SMFC, compared with that in plant treatment. Obvious NH4+-stress was exerted on H. verticillata during the following intense algal decomposition period (38–62 day). Compared with shoots, roots of H. verticillata were more sensitive to the biotoxicity of algae-derived NH4+. The electrogenetic process diverted the degradation pathway from acetoclastic methanogenesis to electrogenesis via redox cycle, resulting in delayed algal decomposition in algae-SMFC treatment. In addition, electrogenesis enhanced the removal of algae-derived N. As a result, NH4+ toxicity to plant roots was effectively alleviated, and sedimented algae served as a stable nutrient source for plant development. Stable transfer rate of algae-derived N from sediments to plant roots was observed, while the assimilation rate of algae-derived N from water column to plant shoots showed a constant increase in the algae-plant-SMFC treatment. Electrogenesis enhanced N-fixing capacity belonged to rhizosphere of H. verticillata, evidenced by greater enrichment of some plant growth-promoting rhizobacteria (PGPRs), including Bradyrhizobium, Mycobacterium, Paenibacillus, Mesorhizobium, and Roseomonas in the algae-plant-SMFC treatment. At the end of the experiment, marked increases in the production of H. verticillata in algae-plant-SMFC were observed, with 90.1% and 32.8%, respectively, when compared with algae-plant and plant treatments (p < 0.05). SMFC application could be used as a strategy to promote the growth of submerged macrophytes in algae-rich sediments.

Scale Up of a Marine Sediment Microbial Fuel Cells Stack with a Floating Aerated Cathode Using a Circuit Storage Energy from Ultra-Low Power

In this study, it was proposed to design, build, analyze and evaluate a stack of 9 Sediment Microbial Fuel Cells (SMFC) with a depth in the sediment of 10 cm and separation between anode and cathode of 100 cm, using floating cathodes aerated with saturated oxygen, sediments and seawater were collected from the Campeche bay (Mexico). Maximum power density and current density were 101.28 mW/m2 and 899.51 mA/m2 respectively, and organic matter removal was 9.25%, obtaining aromatic structures. Using a circuit storage energy from ultra-low power. Our findings revealed that the implementations of SMFC stack proposal could be a candidate for real scale.

Scale-up and control the voltage of sediment microbial fuel cell for charging a cell phone

In this research, a power management system (PMS) has been developed to charge a cell phone battery based on sediment microbial fuel cells (SMFCs). The single SMFC produces a voltage of 1.16 V, which is too low for practical application. The voltage is increased by connecting several SMFCs in series or parallel, but the voltage reversal occurs when it is directly connected to the load. To prevent the voltage reversal, the super capacitor is first charged by the five different stack SMFCs and the charged super capacitor is used to provide the input power to a PMS. This PMS increases and regulates the input voltage of stack SMFCs up to 5.02 V for charging a cell phone battery. The charging and discharging times of the super capacitors have been investigated with five different stack SMFCs. In all five stack SMFCs, only module-5 provides power to PMS for long periods (13 min). Further, the cell phone battery is continuously charged using the two parallel-connected stack SMFCs similar to the module-5. The battery has been fully charged in 26 h using 72 SMFCs. The charged battery is used to perform for three purposes; voice calling, music playing and LED strip lighting. This study is informative for the application of SMFC in an off-grid location.

Bioelectricity generation and remediation of contaminated intertidal zone of Yamaguchi Bay, Japan

This study explores the use of sediment microbial fuel cells (SMFCs) to generate a safe, stable, and efficient supply of bioelectricity to sensors and simultaneously improve sediment quality. Supplying energy to geoenvironmental monitoring sensors remains a challenge as traditional batteries and solar cells are limited by the need to recharge and the erratic weather condition, respectively. Four different sediments from the Yamaguchi bay located in south part of the Honshu island, Japan were experimented on. The acid volatile sulfide (AVS) was the main source of contamination in the intertidal zone and was, hence, used as an indicator for possible bioremediation. Various factors have been studied for its effect on voltage generation. Voltage generation was dependent on the microbes in and grain size distribution of the sediment. It was found that voltage values showed almost twice when two anodes were used instead of a single anode. As the temperature reached optimum temperature of the enzymes of the Geobacteria, the increased activity lead to higher voltage. SMFC was effective in reducing the AVS value of the sediment. SMFCs in the field exhibited greater voltage generation compared to SMFCs of the same size in the laboratory. A positive correlation between voltage generation and AVS reduction was demonstrated.

The oil removal and the characteristics of changes in the composition of bacteria based on the oily sludge bioelectrochemical system

Microbial fuel cell (MFC) technology is a simple way to accelerate the treatment of the oily sludge which is a major problem affecting the quality of oil fields and surrounding environment while generating electricity. To investigate the oil removal and the characteristics of changes in the composition of bacteria, sediment microbial fuel cells (SMFCs) supplemented with oily sludge was constructed. The results showed that the degradation efficiency of total petroleum hydrocarbon (TPH) of SMFC treatment was 10.1 times higher than the common anaerobic degradation. In addition, the degradation rate of n-alkanes followed the order of high carbon number > low carbon number > medium carbon number. The odd–even alkane predominance (OEP) increased, indicating that a high contribution of even alkanes whose degradation predominates. The OUT number, Shannon index, AEC index, and Chao1 index of the sludge treated with SMFC (YN2) are greater than those of the original sludge (YN1), showing that the microbial diversity of sludge increased after SMFC treatment. After SMFC treatment the relative abundance of Chloroflexi, Bacteroidia and Pseudomonadales which are essential for the degradation of the organic matter and electricity production increased significantly in YN2. These results will play a crucial role in improving the performance of oily sludge MFC.

Enhanced power generation from algal biomass using multi‐anode membrane‐less sediment microbial fuel cell

In this study, a multi-anode sediment microbial fuel cell (SMFC) was used to investigate the electricity generation capacity of mixed-culture algae biomass. A multi-anode reactor configuration was used, which had tin-coated copper mesh (TCCM) anode and platinum-coated titanium mesh cathode. The SMFC produced a high-power density of 2965 mW/m2, which is the highest power density reported in SMFC studies so far. The microscopic observations and gene profiling analysis confirmed that the biocompatibility of TCCM favors the bacterial adhesion and enrichment of electroactive bacterial groups (Gammaproteobacteria, Deltaproteobacteria, and Alphaproteobacteria). Our findings indicated that algae biomass could be used as an appropriate feedstock in SMFC to significantly improve electricity generation.

Statement of Retraction

This article refers to:Simultaneous bioelectricity generation and remediation of sulfide-contaminated tidal flat through sediment microbial fuel cell (SMFC)