- 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.
