Each year six trillion cigarettes are smoked by 20 per cent of the world.

Now an Australian scientist has come up with a world-first method of turning millions of tonnes of cigarette butt waste into bricks.

Not only does his process get rid of the pollution, it makes better bricks.

Dr Abbas Mohajerani from RMIT University hopes his discovery means one day cigarette butts will become valuable, and brick manufacturers will pay to have them collected, in the same way that used rubber tyres or glass bottles have become valuable for other industries.

"We are faced with billions of tonnes of cigarette buts on this planet," he told Hack. "There are tonnes and tonnes of cigarette butts everywhere in waterways and beaches."

The butts are discarded in drains or dumped in landfill, where the heavy metals including arsenic seep into the soil and pollute waterways. More than a million tonnes of butts are discarded every year.

Cigarette pollution is a worsening global problem.

Though consumption is falling in Australia (we smoke about 30 billion, of which 7 billion end up as litter), the global figure is on the rise.

The main reason for the increase: China. It smokes more than 38 per cent of the world's cigarettes.

It also makes a lot of bricks.

To put global consumption in perspective, enough cigarettes were consumed in 2009 for each man, woman and child in the world to have smoked an average of 865 cigarettes that year.

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Whatsapp Global cigarette consumption.

How it works

Dr Mohajerani and his team found that adding a tiny amount of cigarette butts to the clay mix halved the energy needed to fire bricks, and also improved their insulation properties.

Only a very small proportion of the brick is cigarette butts - about 1 per cent. But because we produce so many bricks per year, even if only 2.5 per cent of the world's annual brick production incorporated 1 per cent cigarette butts, there would be no cigarette butt pollution.

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Whatsapp Cross-sectional view of bricks with (a) 0% (b) 2.5% (c) 5% and (d) 10% cigarette butts.

"Some day in the future there will be no such thing as waste," Dr Mohajerani said.

"These waste materials are source of energy source of other materials for construction.

"No waste will be wasted."

What's the catch?

Dr Mohajerani says there is no danger of heavy metals leaching from the bricks. The firing process turns some of the toxic elements into new chemicals, and the remainder are locked and immobilised within the solid brick structure.

"One per cent is nothing," Dr Mohajerani said.

"If we have any problem with normal bricks then we have no concern for bricks with one per cent cigarette butts."

The catch will be collecting enough cigarette butts to use in industrial-scale brick production.

Dr Mohajerani says he hasn't had any interest from brick manufacturers yet, although it's only early days - his research was published this month.

"But maybe now we are getting to that time they will need our expertise," he said.

"Potentially there will be regulation on the carbon footprint of a brick, and then they will need to use recycled materials."



"When a system is set up for brick manufacturers, you'll see savings of 10 per cent or 20 per cent energy. And then demand will go up.

He says at that point cigarette butts will command a price.

"I think it will happen in the future that cigarette butts become a valuable source of energy."