Fish Fertilize Trees
By Maya C. Lemaire
2018
2018
Designing a sustainable future: THe potential of microbial fuel cells
Sustainability. There is much talk on this subject, with the rising consequences of the deteriorating environment on humanity and our world. For over a century, much of our electricity has been generated by burning fossil fuels with little regard to its long-term implications. However, it is a well-known fact that it is time to turn to renewables to protect our world. Multiple alternatives have been developed to combat the threatening consequences of these methods, and one of the newest technological advancements we have turned to are ‘Microbial Fuel Cells’.
Over the summer holidays, I had the pleasure of interning at RISC (Research and Innovation for Sustainability Centre) to collaborate on a project with a team from ‘Plant-e’, a Dutch Microbial Fuel Cell Company. During the course of one month, I assisted them with data collection, analysis, and had the opportunity to present my findings to Dr. Chairat Treesubsuntorn, a university professor at King Mongkut's University of Technology . Not only was it was extremely enriching to learn about the scientific context, it was inspiring to work alongside innovators and it was amazing to feel like my creative ideas and suggestions were heard and implemented and played a part in this amazing project.
This project was done in conjunction with DTGO, a Thai organization dedicated to making the private sector an ethical force for sustainable development. The group was founded on the conviction that its undertakings must benefit ‘the people at large, the society we live in, [their] organization, and all other stakeholders[1]’. One of the residential projects they are currently working on is ‘The Forestias’ in Bangna, focused on placing the communities in a natural environment as ‘integral elements of the ecosystem[2]’. As part of their ‘Sustainnovation’ ideology, they decided to work with an external company to implement a new technology in their campus, turning to microbial fuel cells as one of the energy sources for the residence.
How Do Plant-assisted Microbial Fuel Cells work?
Microbial fuel cells are bio-electrochemical devices that harness the power of respiring microbes to convert organic substrates directly into electrical energy:
1. After photosynthesis, plants produce organic material – some is utilized in the leaves etc., but the remaining parts are excreted via the roots into the soil as rhizodeposits (acetate, carbohydrates etc.)
2. Mutualistic bacteria breakdown this organic material, releasing electrons and protons as part of the electron transport chain
3. Usually oxygen is the final electron acceptor, but when anaerobic conditions are simulated and an anode is placed in the system, the electrons flow to the pole instead
4. Electrons flow from the anode into the wires and potential difference is induced. With the assistance of a resistor board, the voltage can be increased for utilization
5. Electrons are transported to the cathode and react with oxygen and protons, forming water. This is an important step in the purification of wastewater.
Benefits
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Allows for multi-land use – it does not detract from nature reserves, e.g. in addition to food production, a rice field will have the added value of decentralized electricity production
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It is CO2 negative – plants consume more than they emit
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Aesthetically beneficial – the greenery from the fuel cell contributes to an increased aesthetic value
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Reduction of methane emissions
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Potential for Wastewater treatment
Disadvantages
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Degradation of electrodes
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Low power output
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High maintenance
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High cost
This is a possible implementation for the ‘FORESTIAS’ project – ‘plant-generated street lights’
References
[1] DTGO Corporation. 2019. About us | DTGO. [ONLINE] Available at: https://www.dtgo.com/about. [Accessed 04 September 2019].
[2] Home - The Forestias. 2019. Home - The Forestias. [ONLINE] Available at: https://www.theforestias.com/. [Accessed 04 September 2019].
[3] Plant-e. 2019. Information and technology - Plant-e. [ONLINE] Available at: https://www.plant-e.com/en/informatie/. [Accessed 04 September 2019]
Written by Varisa (Fern) Tantivess
Grad 20 student at Bangkok Patana School