Out here, waste is wealth

With pollution getting out of hand in cities like Bengaluru, it was only a matter of time before entrepreneurs found some use for it.

Building bricks from sewage sludge

Students of CMR Institute of Technology have come up with the idea of cement-free concrete-bricks made from the sludge found in lakes.

Using a new geopolymer technology that is environment-friendly, they have created three products and applied for patents.

"Our patent applications are for ornamental bricks, sewage sludge bricks and cement-less structural element paver blocks. These are made using geopolymer technology, which reduces the cost by almost 50%, while increasing the strength by one-and-a-half times over normal blocks," says Mohsin Ali Khan, a student.

The team comprises Mohsin, Gautham, Dr Phani Kumar Pullela, Prof Karthik N M and Prof Srinivas Reddy and Sharath Kumara Devraju. "Two other classmates of ours, Vinay and Parvez, are also part of the project," says Mohsin.

Dr Phani Kumar, who mentored the team, holds seven US patents. A PhD in chemistry, he is helping the students with their patent applications.

The idea of using sewage sludge serves two purposes, Mohsin says. "Blocks made from sewage are transportable. The bricks can also be broken on the site by farmers for use as agricultural fertiliser," he explains.

Mohsin and Gautham have now set up a company called CO3 Structural Systems. "We want no single individual to own the patent. We are continuing the research and plan to set up a factory soon," Mohsin says.

Drinking water from thin air

Uravu Labs is working on turning water vapour into drinking water. "The idea came up in 2013 when we were working on a college project at NIT, Calicut. Two of us continued with the idea even after that," says Swapnil Shrivastav, founder CEO.

They started working on the prototyping in 2016, and a six-member team came up with a model.

"Hydroscopic material absorbs water vapour at night. During the day, we use solar collectors to heat the material. This then releases the vapour and we condense it by passing it through condenser tubes," he explains.

Uravu has made it to the finals of the Water Abundance Xprize competition, and is the only Indian startup in the race to win $1.75 million. It is also one of five finalists from 98 global contenders.

"To get the prize, we have to make a 2,000 litre-a-day version which works on 100 percent renewable energy. Our current capacity is 15-20 litres. Also, the cost should be less than Rs 1.2 a litre," he says.

Shrivastav sees huge potential in the technology. "There are many places where government water supply mechanisms do not work. Then there are places with ground water that is unfit for drinking," he says.

The technology can work in all such areas. "The amount of water vapour in the air is very high. if you quantify it, it is almost ten times what we have in our rivers," he says.

Printer ink from vehicle smoke

Graviky Labs in Bengaluru has created a novel technology that captures air pollution and repurposes it as ink.

The company is a MIT Media Lab spin-off, co-founded by MIT Media Lab alumnus Anirudh Sharma, Nikhil Kaushik and Nitesh Kadyan.

"At Graviky Labs, we fuse disciplines, technologies, and design thinking," says Anirudh. "We are applying high technology and design thinking to environmental issues."

Air-Ink is the first ink made from air pollution.

The company's proprietary technology 'Kaalink' is used to capture soot emitted from vehicles via a contraption retrofitted to the exhaust pipes.

This contraption can be customised to fit cars, bikes, trucks, even generators. The soot gathered is then detoxified to create purified carbon pigment. This is then used to make different types of inks and paints.

So far, they have met 600 orders via a kickstarter campaign, and are soon launching a retail webstore.

The ink is popular among artists in London, Berlin and Hong Kong but the cost is a deterrent in India. A 10 ml pen costs about Rs 2,200.