Bricks made of butts

Researchers from RMIT University have shown how fired-clay bricks made with cigarette butts can save energy and help solve a global littering problem. Their results have been published in Waste Management.

“The disposal and littering of cigarette butts (CBs) is a serious environmental problem,” the study authors wrote. “Trillions of cigarettes are produced every year worldwide, resulting in millions of tonnes of toxic waste being dumped into the environment in the form of cigarette butts.”

As CBs have poor biodegradability, it can take many years for them to break down. Meanwhile, heavy metals such as arsenic, chromium, nickel and cadmium trapped in the filters leach into soil and waterways.

Now, Dr Abbas Mohajerani and his team at RMIT have demonstrated that bricks with as little as 1% cigarette butt content can cut brick production costs and save the environment. The study represents something of a dream project for Dr Mohajerani, who has wished for many years to find sustainable and practical methods for solving the problem of CB pollution.

“In Australia alone, people smoke about 25 to 30 billion filtered cigarettes a year and, of these, about 7 billion are littered,” Dr Mohajerani said. “This research shows that if just 2.5% of the world’s annual brick production incorporated 1% cigarette butts, we could completely offset annual worldwide cigarette production.”

Dr Mohajerani’s team discovered that adding butts can cut the energy needed to fire bricks by up to 58%. During firing, heavy metals and other pollutants in CBs are trapped and immobilised in the bricks, reducing problems caused by leaching.

Fired-clay bricks incorporated with CBs were lighter with better insulation properties, meaning reduced household heating and cooling costs. Furthermore, bricks incorporated with 1% CBs maintained properties very similar to those of normal bricks.

“Incorporating butts into bricks can effectively solve a global litter problem as recycled cigarette butts can be placed in bricks without any fear of leaching or contamination,” Dr Mohajerani said.

“They are also cheaper to produce in terms of energy requirements and, as more butts are incorporated, the energy cost decreases further.”

Image caption: Dr Abbas Mohajerani.