The world population is estimated to reach 9.5 billion by 2050. Given that the majority of our current energy is generated from fossil fuels, it poses significant challenges when it comes to providing sufficient sustainable electricity while mitigating climate change.
An idea that has gained traction in recent years is called electricity being generated using bacteria in devices Microbial fuel cell (MFC). These fuel cells rely on the ability of some naturally occurring microorganisms to exchange electrons to create electricity, the ability to “breathe” metals. This process can be fueled using substances called substrates, which include organic materials found in waste materials.
At this time microbial fuel cells are capable of generating electrical devices, such as calculators, small fans, and LEDs – in our lab we operated lights on a mini Christmas tree using “simulated wastewater”. But if technology is to be enhanced, it is a huge promise.
how do they work
MFCs use a system of anode and cathode – electrodes that pass one on or off. Common MFC systems have an anode chamber and a cathode chamber separated by a membrane. Bacteria grow at the anode and transform the substrates into carbon dioxide, protons and electrons.
The electrons that are generated are then transferred to the cathode chamber via an external circuit, while protons pass through the membrane. In the cathode chamber, a reaction between protons and electrons uses oxygen and forms water. And as long as the substrates are continuously converted, electrons will flow – which is electric.
Generating electricity through MFC has several advantages: systems can be installed anywhere; They make less “mud” than traditional methods of wastewater treatment Activated sludge system; They can be small-scale, yet a modular design can be used to construct large systems; They have a high tolerance to salinity, and can function at room temperature.
MFC has the potential to revolutionize power generation in the future by the availability of a wide range of renewable substrates that can be used to generate electricity. Such substrates include urine, organic matter in the waste material, substances contained in the soil (released from the root) by living plants, inorganic wastes such as sulfides, and even Gaseous pollutants.
1. The power of urine
Biodegradable substances in waste materials such as feces and urine can be converted into electricity. It was demonstrated in a microbial fuel cell latrine in Ghana, which suggested Toilets could be a potential powerhouse in the future. The latrine, which had been in operation for two years, was able to generate 268 NW / m² of electricity, enough to power an LED light inside the latrine, while removing nitrogen from the urine and composting the feces.
In places with no grid electricity or for refugee camps, the use of waste in toilets to produce electricity can be truly revolutionary.
2. Plant MFCs
Another renewable and permanent substrate that MFCs can use to generate electricity is called root exudate Plant MFCs. When plants grow they produce carbohydrates such as glucose, some of which are released into the root system. Microorganisms near the roots turn carbohydrates into protons, electrons, and carbon dioxide.
In a plant MFC, the protons are transferred through a membrane and recombinant with oxygen to complete the circuit of electron transfer. By connecting a load to the circuitry, the power generated can be harnessed.
Plant MFCs can revolutionize power generation in isolated communities that have no access to the grid. In towns, roads can be lit using trees.
3. Microbial Desalination Cells
There is another variety of microbial fuel cells Microbial desalination cells. These devices use bacteria to produce electricity, for example from wastewater, while simultaneously desalinating water. The desalination water is pumped into a chamber between the anode and cathode chambers of the MFC which uses the membranes of negatively (ion) and positively charged ions.
When bacteria in the anode chamber consume wastewater, protons are released. These protons cannot pass through the ionian membrane, so the negative ions move from the brine to the anode chamber. The cathode protons are consumed, so positively charged ions move from the saltwater into the cathode chamber, neutralizing the water in the middle chamber. The ions released in the anode and cathode chambers help improve the efficiency of power generation.
Conventional water desalination is currently very energy-intensive and therefore expensive. A process that achieves mass desalination while producing (not consuming) electricity will be revolutionary.
4. Improvement in natural gas yield
Anaerobic digestion – where microorganisms are used to break down biodegradable or waste material without the need for oxygen – are used to recover energy from wastewater that is mostly methane – the main component of natural gas. But this process is usually inefficient.
Research suggests The microbial groups used within these digests share electrons – dubbed electron transfer at the intersection – opening up the possibility that they can use positive energy to affect their metabolism.
By supplying a small voltage to anaerobic digesters – a process Electromethogenesis – Methane yield (and therefore the power that can be obtained from combined heat and power plants) can be significantly improved.
While microbial fuel cells are capable of generating electricity to power small devices, researchers are investigating ways to scale reactors to see how much electricity they can produce and to understand how external electron transfer works. Does. Some start-up companies such as Robbery And Plant-e Microbial fuel cells are being commercialized. In the future, microbial fuel cells may be used to generate electricity in regenerative life support systems during long-term manned space missions. It’s early days, but the technology promises a lot.