Photos and Videos of Microbial Fuel Cells (MFCs), microbial electrolysis cells (MECs), microbial desalination cells (MDCs), and microbial reverse electrodialysis cells (MRCs) being developed or used in the Logan lab. Clicking on the photo should show a larger, higher resolution photo.
Click here for a downloadable video of a MFC that runs a small fan

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This is our most frequently used reactor, which holds 28-ml and is usually operated in fed-batch mode. We have used this system to examine a variety of factors that affect power generation, such as electrode spacing, solution chemistry, electrode materials, substrates and pure vs mixed cultures. This reactor has a graphite fiber brush anode. For the original paper of a cube reactor with a brush anode, Logan et al., Environ. Sci. Technol. (2007). For a comparison of cube reactors with brushes or flat anodes, see the review paper by Yang et al., Energy & Environ Sci. (2017).
This is also a well researched cube-type reactor, but this one has a flat anode (carbon paper) and a flat cathode. See publication by Liu & Logan, Environ. Sci. Technol. (2004), where we studied the performance in the presence and absence of a cation exchange membrane on the cathode.
As reactors were increased in size, we added more brushes. These 3 MFCs all have the same chamber size, but they are filled with 3, 5, or 8 brushes. This study was reported by Lanas and Logan (2013, Journal of Power Sources). The smaller brushes work better if there is high COD and they are placed close to the cathode. However, we later learned that the system was unstable when used with a low-strength wastewater like domestic wastewater, see the paper by Stager et al (2017, Bioelectrochem.). We now recommend using 2.5 cm diameter brushes, and keep them as close to the cathode (but do not let them touch).
This was the first multi-chamber MFC, consisting of 2 anode arrays and a central cathode chamber, each with a cathode facing a single anode. This is different from a “cassette” MFC, where the anodes and cathodes for a separate and complete chamber. Here the anode array is separate from the 2-sided cathode chamber. The main focus of this study was to look at different spacers in the cathode chamber, so that the cathode can have air flow but the two cathodes do not bend in under the water pressure. See the study by He et al. (2016, Environ. Science Water Res. Technol.).
This is a larger, 6 liter MFC with multiple chambers, having 6 separate electrical circuits. The anodes on the ends (circuits 1 and 6) face only a single cathode, but the inner anode arrays each face 2 cathodes, which increases power production relative to each anode. This reactor was tested in a variety of operational conditions under continuous flow using primary clarifier effluent (alternating direction of flow, fixed direction of flow, parallel or serial flow through the chambers). You can read more in He et al. (2016, Water Research).
This is an 80 liter MFC modules consisting of 22 brushes across the surface of a multi-panel cathode (made by VITO). This cathode was tested using domestic wastewater. See the papers by Rossi et al. (2019, Water Research) on the basic performance in batch mode, and Rossi et al. (2019, Journal of Power Sources) on flow across the brushes. This design is being used in a pilot test for a 300 L reactor.
This is a microbial reverse electrodialysis fuel cell (MRC) that combines an MFC with a reverse electrodialysis (RED) stack to capture additional energy from salinity gradients. When a high salt and low salt solutions are placed into alternating anion and cation exchange membrane pairs in the RED stack, the MFC works better and additional voltage is produced by the RED stack. This allows the combined MRC to produce a higher voltage and power density than that possible by either the MFC or RED stack alone. The salt solutions can be natural (freshwater and seawater) or regenerable solutions using waste heat (such as ammonium bicarbonate). You can read about the MRC in our paper by Cusick et al. (2012, Science).
This is a small (5 mL) microbial electrolysis cell (MEC). It is very inexpensive and can be made for only about $1.50 each. They can be autoclaved, and one power source can run thousands of reactors. Read more about how to make them in Call & Logan (2011, Biosen. Bioelec.). You can also see a study using this reactor in results using them in Call & Logan (2011, Appl. Environ. Microbiol.). Want to make one? Visit our YouTube page to see how these are made and used (3 videos).
This is a cube reactor, modified to collect gas produced in the reactor by drilling a hole in the top, and placing the gas collection tube there. Note the reference electrode placed through one of the ports used to empty the reactor. Our first MEC was a two-bottle reactor, similar to those shown below for MFCs. This reactor has high performance due to the use of a single chamber, although hydrogen gas can be converted to methane, resulting in a mix of hydrogen and methane. You can see the first paper using this cube reactor by Call and Logan (2008, Environ. Sci. Technol.) although we have used this design in many studies since then.
A membrane can be added in between two cube reactors to form a 2-chamber MEC that keeps the hydrogen gas that is produced at the cathode, separated by the membrane from the microorganisms in the anode chamber. Note the gas bag that is used to collect the hydrogen gas from the cathode chamber. There are several studies using this design, but see for example the impact of a saline catholyte on performance by Nam and Logan (2011, Int. J. Hydrogen Energy).
   Cube reactors are efficient for fed-batch tests, but in order to test the reactor under continuous flow conditions we designed this reactor to allow for fluid recirculation over the anodes, with separate catholyte recirculation over the cathodes. The flow over the cathodes helps to strip away the hydrogen gas that is produced, allowing for improved current densities. The impact of catholyte recirculation was examined by Kim et al. (2017, Int. J. Hydrogen Energy).
This is a larger, 2.5 liter MEC that has brush anodes and stainless steel cathodes. This reactor is meant to be operated in continuous flow conditions. The design is effective in achieving a good packing of electrodes, but the use of the single chamber design results in a lot of hydrogen gas loss to methane. This configuration is described in Rader and Logan (2010, Int. J. Hydrogen Energy).
This is the largest bioelectrochemical system we ever built. It was 1000 liters, and it was a microbial electrolysis cell (MEC) that was used to treat winery wastewater. The system is no longer running, but you can read about it in Cusick et al. (2011, Applied Microbiology Biotechnology). The hydrogen gas that was produced was converted to methane as the system was a single chamber MEC.
This is a conventional two-chamber microbial fuel cell. In this setup, both chambers are gas sparged: one with nitrogen gas to maintain anaerobic conditions in the chamber where the bacteria grow (anode); the other with air to provide oxygen in solution (cathode). These two-chamber systems do not produce much power due to high internal resistance caused by the small tube connecting the chambers. Flat electrodes are used in both chambers. The anode is plain carbon paper, with all connections sealed using epoxy. The cathode has a Pt catalyst on it. There is a Nafion membrane clamped between the side arms.
This is another two-chamber reactor with circular felt anode electrodes. Note that the side arms have a larger diameter, which allows for better ion motion between the electrodes, and therefore it is possible to produce more current and overall power than the bottle reactors in the figures above and below this one. For the impact of side-arm diameter and electrode sizes on power, see the paper by Oh & Logan (2006, Appl. Microbiol. Biotechnol). Unlike that earlier study, these reactors also have a reference electrode in each chamber, which is highly recommended.
This is a two-chamber reactor modified to have a crimp top on the reactor top and a crimp top side access port. The brush anode is suspended in the solution, and a large Pt-coated carbon paper is used for the cathode. The small opening in the top of the reactor can limit electrode sizes.
Same as the above two-chamber types of MFCs with small side arms, except the anode chamber is filled with a strong wastewater solution (animal wastewater).
This is an array of two-chamber MECs that were used to evaluate cathodic production of methane. In these systems a graphite fiber brush anode is used for water splitting, while the cathodes were all flat carbon paper coated with different materials in order to study the impact of cathode material on methane production and microbial communities. The archaea on the cathode were different when a good hydrogen evolution catalyst was used, such as Pt, than it was in all other cases with a poor hydrogen catalyst. See the two papers by Siegert et al. (2014, H2 production rates; 2015, community analysis; both in ACS Sus. Chem. Engin.)
This is a single chamber MFC that uses a very large brush anode and a flat cathode. This reactor is red due to the growth of Rhodopseudomonas palustris DX-1. Power is very much limited by the cathode surface area, but it is a nice easy design that can be made out of glass, plastic or just about any material. See Logan et al., Environ. Sci. Technol. (2007) for performance data of this glass bottle system with mixed cultures. The pure culture study with R. palustris DX-1 was originally published by Xing et al. (2008). However, the culture was lost when frozen and we have not been able to recover it. In addition, we no longer see our reactors turn red like this one.
This is the a cube reactor with a brush anode, but this one has a pure culture of Rhodopseudomonas palustris DX-1, which gives it the red color. See the above notes about the loss of this pure culture. See Xing et al. (2008, Environ. Sci. Technol.)
Tsinghua University and Penn State developed a new type of bioelectrochemical system called a microbial desalination cell (MDC). This reactor contained two membranes, and three chambers, with the water in the middle chamber desalinated when current is generated by bacteria. The paper can be found on the publications page (see Cao et. al. (2009, Environ. Sci. Technol.) Note that ferricyanide was used for the catholyte, which makes that aspect of the reactor impractical as the ferricyanide use is not sustainable.
This microbial desalination cell (MDC) uses an air cathode and catholyte in the right chamber. We now refer to an MFC that uses an air cathode as an MFDC (microbial fuel cell, desalination cell). You can read more about this in the paper paper by Mehanna et al. (2010, Energy & Environmental Science).
A microbial desalination cell (MDC) can also be made to produce hydrogen gas, by adding voltage as done in a microbial electrolysis cell (MEC), and by using ion exchange membranes. We can this a microbial electrolysis desalination cell (MEDC). See the paper by Mehanna et al. (2010, Environmental Science & Technology). We originally used flat electrodes for these tests.

This is a microbial desalination cell (MDC) with a stack of ion exchange membranes. The efficiency of the desalination is greatly improved compared to the 3-chamber (single pair of ion exchange membrane) systems shown below. To read more, see Kim and Logan (2011, Proc. National Academy of Engineering). 


This is the MDC shown with multiple MDCs in series.
Extracting energy at higher voltages from MFCs can be challenging. We developed a capacitor circuit system that efficiently increases the voltages produced by MFCs. You can read about it in Kim et al. (Kim et al. (2011, Energy & Environmental Science), or visit our YouTube page.
In order to scale up MFCs, we need to provide more surface area for the cathode. This is a reactor we tested using tubular cathodes made of ultrafiltration membranes that were coated on the inside with catalyst and a carbon conductive paint and a Pt catalyst. See the publication by  Zuo et al. (2007, Environ. Sci. Technol.).
This flat plate microbial fuel cell, that operates in continuous flow mode, has a proton exchange membrane sandwiched between two carbon paper electrodes. Channels are drilled to that the flow follows a serpentine path through the system. See paper by Min and Logan (2004, Environ. Sci. Technol.).
This is the original single chamber microbial fuel cell (SCMFC) described in our very first paper on air-cathode MFCs. Here is the SCMFC is empty– note the central cathode tube running down the center.  See the paper by Liu and Logan (2004, Environ. Sci. Technol.). The small graphite rods do not provide much area for the biofilm, and there is only a single cathode running down the center. This reactor looks really cool, but it didn’t produce a lot of power. Still, it showed for the first time how wastewater could be treated using an MFC.
Same as the SCMFC shown above, but here it is filled with wastewater.
A data logging multimeter is used to monitor voltage in the circuit containing a resistor. From the voltage and resistor information, we can calculate total power output by the system


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