Introduction
Introduction to Microbial Biotechnology for Wastewater Treatment
Hi everybody, I am Raheem, and I will present to you microbial biotechnology for wastewater treatment. As an example, I chose microbial fuel cells.
Rationale
Why Microbial Fuel Cells?
So why did I choose this example? Because microbial fuel cells are a recent technology, and they are not used a lot in industrial applications. As you know, the global population will be 9.7 billion by 2050. This huge growth in the human population is correlated with a higher increase in energy consumption, especially fossil fuels. Therefore, it is essential to reduce our dependence on fossil fuels in the current global energy demand.
Need for Sustainable Energy
Innovative Energy Sources
Innovative energy sources that are eco-friendly and can be used sustainably are needed. The values stored inside waste have led to comprehensive research methods, not only to treat waste but also to extract energy and value-added products from it, by using microbial fuel cells. The generation of energy using microbial fuel cells is a promising and sustainable technology that is becoming more efficient.
How Microbial Fuel Cells Work
Mechanism of Microbial Fuel Cells
How does this microbial fuel cell work? As you see, a microbial fuel cell is a bio-electrochemical system employing the metabolic activity of microorganisms to oxidize organic and inorganic matter and generate electricity. These microorganisms are capable of extracellular electron transfer by breaking down a wide range of simple and complex organic matter. The electrons generated from this degradation are transferred to the anode, which acts as an electron acceptor, and flow to the cathode through an external circuit.
Electron Transfer Mechanisms
Electron Transfer Pathways
The mechanisms involved in electron transfer to the anode are shown in this schema.
Indirect Transfer via Mediators: It's an indirect transfer via a mediator for fermentation products.
Direct Transfer via Cytochrome C: It's a direct transfer via cytochrome C proteins.
Direct Transfer via Conductive Pili or Nanowires: It's a direct transfer via conductive pili or nanowires.
A large number of exoelectrogenic bacterial strains have the capacity to transfer electrons to the electrode. For example, I have a lot of bacteria, and the most studied are Geobacter and Shewanella, as they are more efficient in waste degradation and energy generation.
Configurations of Microbial Fuel Cells
Different Configurations
Now, let's see the configuration of microbial fuel cells. There are many configurations: one component, two components with proton exchange membranes, without membranes, with air cathodes, and without air cathodes.
Standard Microbial Fuel Cell: A schematic of a normal microbial fuel cell with an air cathode.
Microbial Electrolysis Cell
Microbial Desalination Cell: Good for desalination of saltwater.
Microbial Electrosynthesis Cell: Synthesis or production of multi-carbon compounds, depending on the power source or the electricity generated.
Importance of the Anode
Role of the Anode
As you see, a lot of bacteria are attached to this anode. The anode is an essential constituent of microbial fuel cells and plays one of the greatest roles in increasing power density. Anodes are key determining factors that influence microorganism adhesion and electron transfer.
Characteristics of a Good Anode
Here is an example of low-cost materials. As you see, they are made from carbon. In general, a good anode should be:
Biocompatible
Highly conductive
High physical and chemical stability
High specific surface area
High porosity
Non-fouling properties for microbial adhesion and biofilm formation.
Applications of Microbial Fuel Cells
Substrates and Pollutant Removal
As we see, microbial fuel cells can use a wide range of substrates, ranging from simple organic molecules to complex waste.
Heavy Metal Removal: Removal of heavy metals from wastewater, including chromium, cobalt, and cadmium, with the most common method being the reduction of hexavalent chromium to trivalent chromium.
Wastewater Treatment: Wastewater treatments like olive mill wastewater (high concentration of polyphenolic compounds), diesel wastewater (phenolic compounds), brewery wastewater, and Congo Red from the textile industry.
Efficiency and Power Output
Power Output of Microbial Fuel Cells
Here, we see the average power output of a range of fuel technologies, including both traditional energy sources and renewable energy alternatives. The average efficiency of microbial fuel cells ranges from zero to forty-eight percent, and the average power output ranges from 0.1 to 1 megawatts. This comparison shows that microbial fuel cells are a good candidate for energy generation.
Scaling Up
Scaling Up Microbial Fuel Cells
Here, we see the scaling up of microbial fuel cells, from laboratory scale to industrial scale. These are types of microbial fuel cells, and we see an example of scaling up for plant wastewater treatment.
Benthic Microbial Fuel Cell: An image created by Prof. Tender's group.
Applications: Examples from Prof. Tender's group, including the application of microbial fuel cells for energy generation, where they tried to charge a mobile phone using wastewater.
Innovative Projects
PEE POWER Project
Here, we see a startup by students at the University of the West of England. They tried to use wastewater from the bathroom to generate electricity. The project is named PEE POWER.
Conclusion
Conclusion and Future Prospects
In conclusion, microbial fuel cells are a promising technology for reducing environmental pollution and generating electricity. Thank you for your attention.
){kind=link}
0 Comments