Prelims Level
Mains Level
Prelims Syllabus : Mains Syllabus :

The Power Generated in degradation Can be used to Sustain the Process:

  • Microbial fuel cells (MFCs) are fast emerging as an option for several specific requirements.
  • The principle of using the MFC to degrade wastewater is simple. A carefully selected cohort of bacteria is made to act on the textile wastewater placed in the fuel cell.
  • These bacteria are isolated from the very wastewater they are meant to degrade. They feed on the organic material in the water and break it down under anaerobic (without oxygen) conditions, releasing electrons in the process. The electrons are collected at the anode which results in a current in the circuit. Because the bacteria form a biofilm on the anode, the electrons are collected easily by it.
  • “After a period, when the thickness of the biofilm exceeds a limit, it will automatically detach and bring back the thickness to optimal level. A nanotech filter is required to improve this process. “This is like a ‘trickling filter’ – where after thickness exceeds a limit, and it is difficult to sustain that thickness, the excess tears off. When it falls off, it shouldn’t get mixed up with the water. That’s where the nanotechnology filter will come in, to remove the bacteria and get clean water.
  • The bacteria take turns to act on the wastewater and purify it: There are many species of bacteria. If a dye is present in the water, it is broken to a simpler form by one species; this, in turn, is acted on by another species and so on. “It has a cascading effect.
  • Using MFC to process wastewater was an idea that the two used in the Carbon zero challenge, a competition hosted by IIT Madras when they were students there. They used the funding obtained through the event to develop the 200 litre prototype within the few months they were given. “We spoke to some people [in the textile industries] at Tiruppur, and they said that if it is cheaper and more energy efficient than current technologies, we will use it.
  • While now, with the prototype, they can generate power of around 1 watt per square-metre, they aim to get to about 5 watts per square-metre. This power can be used to sustain the process. However, scaling up has challenges. The size of the chamber and its geometry and design remain to be worked out. All the power produced must be captured so that it is not wasted. “For that, we will work with some electrical engineers.
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