• Microbial fuel cells (MFCs) are fast emerging as an option for several specific requirements.
  • Now, a startup, JSP Enviro, aims to use this technology to process textile wastewater and additionally generate electricity that will render this exercise energy-efficient.
  • Now working at the Biotechnology Department of IIT Madras with a prototype of about 200 litre capacity, the team plans to increase it to 1,000 litre capacity by 2020.
  • Though we have developed the technology for processing wastewater from the textile industry, it can be used with any other industrial wastewater
  • The team is also working on the restoration of a lake attached to the Integral Coach factory at Villivakkam in Chennai.

What about the Principle?

  • 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
  • The team is working on a nanotech filter 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.
  • People [in the textile industries] at Tiruppur, said that if it is cheaper and more energy efficient than current technologies, they 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.