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India: from soot to ink

Harald Franzen
September 28, 2018

Diesel generators are often dirty devices. But what if you could turn the soot they puff out into something useful? A young group of engineers in Delhi did just that. And ships are next.

People walk through the courtyard of Jama Masjid in heavy smog in the old quarters of New Delhi
Image: Getty Images/AFP/S. Hussain

There are times when the air pollution in Delhi is so bad, you can barely see the hand in front of your face. In fact, the Indian megacity has some of the worst air quality in the world.

Arpit Dhupar knows that only too well. He grew up in Delhi and developed breathing problems at a young age. Now 25 and a mechanical engineer, he has taken on the fight against pollution by tackling diesel generators.

Read more: Delhi is choking on its smog

Such generators are among the biggest polluters in Delhi, as well as many other Indian cities. They're often used for backup during power outages — a common occurrence in the city of almost 17 million.

"The problem with diesel engines is that they emit a lot of smoke from unburned diesel or soot, which is very harmful to people's health," Dhupar told DW. "That's because it consists of very, very fine particles that cannot be filtered by your nose or your lungs and go directly into the bloodstream."

Arpit Dhupar, cofounder of Chakr Innovation, an engineering startup from Delhi
Growing up in Delhi, Dhupar suffered the ill-effects of air pollution, so he decided to tackle the problemImage: Chakr Innovation

Ink from soot

There are devices that filter out the particles. But the question is what to do with them after. They are often burned but the inventors at Dhupar's Chakr Innovation had a different idea.

"In India, we have a lot of outside vendors that sell sugar cane juice and they use small diesel engines to run their crushers," said Dhupar.

One day, he noticed how the exhaust from one of the vendors' machines was turning the wall behind it black. "I began thinking, why not do that intentionally? Why not capture all the pollution and paint the walls with it?"

Together with some fellow engineering students, he took the idea to his college professors and other academics and all of them told him, if that were possible, someone would have done it already.

Dhupar was undeterred.

"You know, there is a saying: 'The fool did not know it was impossible so he did it anyway," he quipped. "We had nothing to lose, so we tried it anyway."

Diesel particle filter invented by Chakr Innovation,installed on a Delhi roof
Chakr Innovation found an new way to filter polluting particles from diesel generators and turn them into ink Image: Chakr Innovation

And it worked. After many ups and downs, the company developed a device that filters soot out of diesel exhaust with very little "back pressure" and traps it in a liquid. The back pressure innovation is "very very important," Dhupar said.

"These engines are very very sensitive to resistance in the flow of the exhaust gases, something known as back pressure, and we've been able to achieve very good capturing efficiency at very low back pressure. That was unheard of in the industry before," according to the young inventor.

That the soot is trapped in a liquid has its own advantages. There is no risk of the particles becoming airborne again. At the same time, it's a small step from there to painting walls.

No ink shortage in the world

After the soot-filled solution undergoes a few processes and harmful substances are removed, it's primarily a question of what kind of ink the customer wants.

"All you have to do is add the right amount and right type of something known as a binder," Dhupar explained.

Then you can print anything from t-shirts and coffee mugs to greeting cards or product packaging.

"Our largest client in terms of buying ink is Dell Computers," said Dhupar. "They use it to print the cardboard boxes for their laptops."

But just as Dell's main business is not printing cardboard boxes, Chakr Innovation's goal was never to become an ink manufacturer.

"The problem that we're trying to solve is not that there is a shortage of ink in the world, the problem is that there is lots of pollution," explained Dhupar.

Building filtering systems to keep that pollution from escaping into the atmosphere is where Chakr Innovation sees its core business.

Read more: Bosch announces 'breakthrough' in diesel technology

So far, the company is still small, having sold only 50 of its devices. But the start-up has already formed alliances with some powerful corporations including IndianOil and German engineering and electronics company Bosch. They have also won several awards for their work including, most recently, the UNEP Young Champions of the Earth award.

Bottles of ink on a table
Turning the particles into ink means they can't be released into the environment Image: Chakr Innovation

Next port of call: Ships

But even as the company is growing its client base, the inventors have already set their sights on a similar but different problem, namely emissions from large ships.

Cruise liners and large container ships are notorious for burning much dirtier fuels than cars and generators. Sulfur oxides, or SOx, are a particularly big problem with the large diesel engines powering these massive vessels.

"We have developed a technology that's an extension of our current technology and can work on marine engines as well. With it, we could reduce SOx-emissions by 90 percent," said Dhupar, adding that they're looking for maritime companies to try the technology in the field.  

Read more: Are electric vessels the wave of the future in shipping?

SOx filters do already exist but current systems consume a lot of energy themselves. 

"Currently, what they do is spray water into the chamber to clear out the SOx from the air. It's called wet scrubbing. But that consumes a lot of power," Dhupar explained. "What we're building would require much less energy, so it would be much cheaper to run."