Microbial Fuel Cells For Wastewater Treatment Research Articles

Potential of Electricity Generation and Wastewater Treatment of Organic Brewery Effluent Using Inoculated H-Type Microbial Fuel Cell

MFCs are bio-electrochemical devices that are capable of transforming chemical energy stored in waste organic matter into direct electrical energy through catalytic activity of microorganisms under anaerobic conditions. Bio-electrochemical systems, such as microbial fuel cells (MFCs), serve as greener alternatives to conventional fuel energy. In recent years, MFCs have drawn science community interest as a method for direct bioelectricity recovery from wastewater while simultaneously treating the wastewater. Moreover; they gain a competitive advantage over other water treatment technologies due to their unique features such as huge energy benefits, less environmental impact, good operating stability, and high economic efficiency. Reports reveal that MFCs are the subject of much interest to researchers, and the number of papers on MFCs in wastewater treatment is increasing. The ever-growing demand for green waste management and renewable sources of energy has enthused research efforts all over the world. This study, therefore, investigated the effect of process variables on the bio-electrical performance of H-type microbial fuel cells fueled with brewery wastewater and inoculated with distillery plant waste. From the experimental results, 1150mV maximum voltage output, 92.85%, 91.40%, 68.87%, and 70.10% removal efficiencies of COD, BOD, TN and TP respectively were obtained at 35ºC, pH 7, and 5 days. These results confirmed that brewery wastewater effectively treated would generate a considerable amount of direct bio-electricity. Results also revealed that the MFC provides an alternative insight into an effective treatment of wastewater that can simultaneously generate a direct bio-electricity in a sustainable and eco-friendly manner.

Mapping Research on Microbial Fuel Cells in Wastewater Treatment: A Co-Citation Analysis

Microbial fuel cells (MFCs) are promising technologies, aiming at treating different types of industrial and domestic wastewater. In recent years, more and more publications focusing on wastewater treatment have been published. Based on the retrieval of publications from Web of Science Core Collection database, the new emerging trends of microbial fuel cells in wastewater treatment was evaluated with a scientometric analysis method from 1995 to 2020. All publications downloaded from (WOS) were screened by inclusion criteria, and 2233 publications were obtained for further analysis. Document co-citation and burst detection of MFCs in wastewater treatment were analyzed and visualized by software of CiteSpace. Our study indicated that “Environmental Science” is the most popular discipline, while the journal of Bioresource Technology published the greatest quantity of articles in the field of MFCs applied wastewater treatment. China and the Chinese Academy of Science are the most productive country and institution, respectively. “Azo dye” has become the new research topic, which indicates the application area and the development of MFCs. The performance of MFCs for wastewater treatment has been widely discussed. The findings of this study may ameliorate the researcher in seizing the frontier of MFCs in wastewater treatment.

Effect of Corncob Derived Biochar on Microbial Electroremediation of Dye Wastewater and Bioenergy Generation

AbstractThis paper describes the potential of waste biomass derived biochar for improvement in the dye wastewater treatment in a microbial fuel cell (MFC). The complete MFC, an energy generating unit, was made with the waste products in order to demonstrate that low cost alternatives are available to replicate the positive results. Waste corncob derived biochar produced after acid modification has been evaluated as a supplement in an MFC for treatment of real dye wastewater (RDW). The two doses of sulfuric acid modified corncob biochar (SA‐MCB), (0.5 g and 1 g) and a blank (without any dose) were assessed for the effect on MFC performance. The maximum power density (49.92 W/m2), current density (0.28 A/m2), COD removal efficiency (88.39%), decolorization efficiency (81.6%) and TDS reduction (84.4%) were obtained with 0.5 g biochar dose. The Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed the structural changes occurring on the SA‐MCB after use in the MFC. The SEM analysis revealed the better biofilm formation due to SA‐MCB deposition. Power density with 0.5 g of SA‐MCB dose improved to more than 24 times in comparison to the system without any such dose. The UV spectrophotometer analysis confirmed the azo bond deformation during treatment. The overall results suggest that the use of SA‐MCB biochar as anode material and as a supplement in the MFC system may provide an effective anode‐biofilm in MFCs for wastewater treatment.

Characterising and control of ammonia emission in microbial fuel cells

The serious ammonia (NH3) emission of air-cathode microbial fuel cells (MFCs) was reported but how to control and mitigate the emission hasn’t been well studied. Considering the importance of the issue for the application of MFCs in wastewater treatment, this study focused on understanding the NH3 emission process in MFCs and investigating mitigation approaches. The study found that when feeding with dairy wastewater the typical flat-cathode MFCs can emit NH3 of more than 0.82 mg-N/L. The NH3 emission reduced with the grown of cathode biofilm and the decrease of ammonium concentration in the influent. Combined experimental and theoretical results showed that the current density rather than the total current was the determined factor for ammonia emission. The novel Cu-blended 3D cathode developed in this study significantly decreased the NH3 emission to 0.037 mg-N/L (or 0.068% of the total removed ammonium), which was 6.3% of that in the activated sludge wastewater treatment plants (WWTP). In addition, the good power performance and high pollutants removal (14.4 W/m3, 88.1%-COD and 92.8%-TN removal) were also obtained by the Cu-blended 3D cathodes. This study unveiled the ammonia emission process and proposed effective mitigation methods, which will promote the practical application of MFCs for ammonium-rich wastewater treatment.

Domestic wastewater treatment and energy harvesting by serpentine up-flow MFCs equipped with PVDF-based activated carbon air-cathodes and a low voltage booster

Microbial fuel cells (MFCs) exhibit high capital cost and low energy output, which are major issues of the expected practical application of MFCs in wastewater treatment. Here, we have developed serpentine up-flow MFCs equipped with polyvinylidene fluoride (PVDF)-based activated carbon (AC) air-cathode (MFC-PVDF/AC) and continuously operated for more than 6 months with real domestic wastewater as a substrate. The MFC-PVDF/ACs achieved average total COD removal rates (5.11 ± 0.94 kg tCOD/m3/d) and power densities (3.96 ± 3.01 W/m3) without major water leakage, which were even higher than those of MFCs equipped with Pt-based air-cathode (MFC-Pts). The MFC-PVDF/ACs also achieved high and stable suspended solid (SS) removal efficiency (>90%) at 1.5-h HRT without any clogging event during the entire operation period. Since the PVDF-based AC air-cathode is less expensive, more durable, and easy to manufacture, expensive Pt cathodes are not necessary for MFCs treating low strength domestic wastewater. Furthermore, we have developed a low voltage booster (LVB) to increase low output voltage of MFC-PVDF/ACs (i.e., <0.4 V). Connecting a single LVB with a single MFC-PVDF/AC increased the voltage from <0.4 V to 4.35–5.2 V without the voltage reversal, which was enough to turn on three LED bulbs for >12 days. Taken together, the MFC-PVDF/AC with a LVB circuit exhibits excellent and stable performance of domestic wastewater treatment and usable power generation, suggesting that it could be used as a cost- and energy-saving primary wastewater treatment system.

Greywater Treatment with Simultaneous Generation of Energy Using Low-Cost Microbial Fuel Cells

Microbial fuel cells (MFCs) are an emerging type of biological wastewater treatment units with simultaneous power generation. The present study demonstrates an effective treatment of greywater and generation of electricity in a double-chambered MFC. This MFC was fabricated using cost-effective and easily available materials replacing expensive materials like Nafion membranes, graphite electrodes, etc. Experimental results showed a maximum open circuit voltage of 0.64 ± 0.04 V and 114 ± 1.41 mA current during the study period. The results further indicate a maximum power generation of 24.50 mW along with 307.69 mW/m² of power density; 34.62 mA/m² of current density, 1.33 W/m³ of volumetric power density, 0.15 A/m³ of volumetric current density and a power yield of 0.40 mW /kg of COD removal. The chemical oxygen demand (COD) removal efficiency was 77.6 %. The use of low-cost and easily available raw materials has brought down the total manufacturing cost of MFCs used in this study to less than USD 4.0. However, the performance of the MFCs used in the current study is comparable with other sophisticated MFCs built with expensive raw materials reported in the literature. This cost-effective MFC used in the present study might be an effective replacement of expensive MFCs for wastewater treatment at scaled-up levels. DOI: http://dx.doi.org/10.5755/j01.erem.71.3.11482

Conversion of activated-sludge reactors to microbial fuel cells for wastewater treatment coupled to electricity generation

Wastewater can be treated in microbial fuel cells (MFCs) with the aid of microbes that oxidize organic compounds using anodes as electron acceptors. Previous studies have suggested the utility of cassette-electrode (CE) MFCs for wastewater treatment, in which rice paddy-field soil was used as the inoculum. The present study attempted to convert an activated-sludge (AS) reactor to CE-MFC and use aerobic sludge in the tank as the source of microbes. We used laboratory-scale (1L in capacity) reactors that were initially operated in an AS mode to treat synthetic wastewater, containing starch, yeast extract, peptone, plant oil, and detergents. After the organics removal became stable, the aeration was terminated, and CEs were inserted to initiate an MFC-mode operation. It was demonstrated that the MFC-mode operation treated the wastewater at similar efficiencies to those observed in the AS-mode operation with COD-removal efficiencies of 75-80%, maximum power densities of 150-200mWm(-2) and Coulombic efficiencies of 20-30%. These values were similar to those of CE-MFC inoculated with the soil. Anode microbial communities were analyzed by pyrotag sequencing of 16S rRNA gene PCR amplicons. Comparative analyses revealed that anode communities enriched from the aerobic sludge were largely different from those from the soil, suggesting that similar reactor performances can be supported by different community structures. The study demonstrates that it is possible to construct wastewater-treatment MFCs by inserting CEs into water-treatment tanks.

Gaseous pollutant treatment and electricity generation in microbial fuel cells (MFCs) utilising redox mediators

Microbial fuel cell (MFC) is an emerging technology for sustainable energy generation and waste treatment. This paper reviews the potential of a gaseous substrate when it is combined with a mediator in an MFC to generate electricity and to treat toxic gaseous pollutants. Most MFCs for waste water treatment often cannot use mediator to enhance the electron transfer from the microbe to the anode because of the difficulty in recovering the expensive and potentially toxic compound. Combining gas feeds with mediators is possible since the soluble mediator would remain in the anode chamber as the gas passes through the reactor. In addition, this type of MFC is possible to be integrated into an anaerobic biofiltration system (BF-MFC), where the biofilter removes the gaseous contaminant and produces the reduced mediator and the MFC produces the electricity and recycles the reoxidised mediator. This paper also talks about the past research on gaseous feed MFCs, and reviews the mechanism and strategies of electron transfer in MFC using redox mediator. The advantages, process parameters and challenges of BF-MFC are discussed. This knowledge is very much required in the design and scale up of BF-MFC. This paper will be useful for those who work in the area of gaseous pollutant treatment and electricity generation.

Implementation of Microbial Fuel Cells (MFCs)-Based Wastewater Treatment

This paper provides feasibility estimation for actual domestic wastewater treatment under assumptions of a flow of 10,000 m3/d (about 40,000 capita), when air cathode MFCs configurations were adopted. Temperature-phased (mesophilic-ambient) process configurations in which can achieve either better effluent quality (i.e. maximizing treatment) or high energy recoveries is schematized. The performance used in the mass balance analysis of the treatment process conducted here compared with typical values in conventional biological wastewater treatment. Various advantages of using MFCs for wastewater treatment, including energy saving, less sludge production (and perhaps the lack of a need for a secondary clarifier), and no need for sludge handling, etc., were also addressed.

MICROBIAL FUEL CELLS - AN OPTION FOR WASTEWATER TREATMENT

The Microbial Fuel Cell (MFC) is a promising technology for efficient wastewater treatment and recovering energy as direct electricity for onsite applications. For treatment of biodegradable organic matters in MFCs, removal efficiencies comparable with established treatment methods can be obtained. Even some of the bio-refractory compounds can be effectively removed in MFCs. Power densities higher than 2 W/m2 and volumetric power of 500 W/m3 are reported. However the power output varies drastically depending on the MFC configuration, substrate used, type of bacterial culture and operating conditions. The results presented so far demonstrated that electricity can be generated by exploiting microorganisms as biocatalysts, but both technical and biological optimizations are needed to maximize power output. The advantages of using MFCs for wastewater treatment, the organic matter removal efficiency and electricity generation reported recently for different MFC configurations are described in this paper. Factors affecting performance of the MFC are summarized. MFC scale-up issues and further development needs are emphasized. This information on factors affecting MFC performance and scale-up issues would be very useful tool for researchers for shifting this technology from lab-scale to pilot and full-scale applications for sustainable wastewater treatment.