Cigarette butts added to construction material could lower energy use

Over six trillion cigarettes are produced each year globally, resulting in 1.2 million tonnes of toxic waste dumped into the environment.

RMIT University researchers have previously shown fired-clay bricks with 1 per cent recycled cigarette butt content are as strong as normal bricks and use less energy to produce.

Their analysis showed if just 2.5 per cent of global annual brick production incorporated 1 per cent cigarette butts, this would offset total cigarette production each year.

Lead researcher Associate Professor Abbas Mohajerani said cigarette butts were saturated with toxic chemicals, including over 60 known to cause cancer.

“Firing butts into bricks is a reliable and practical way to deal with this terrible environmental problem, while at the same time cutting brick-making production costs,” Mohajerani said.

“We need to do far more to stop cigarette butts from polluting our streets, rivers and oceans, and prevent them leaching harmful toxins into our environment.

“Our ultimate goal is a world free of cigarette butt pollution: our industry implementation plan outlines the practical steps needed to bring this vision to reality.”

They have also developed a plan on how cigarette butts can be collected and recycled on an industrial scale.

Different incorporation methods are outlined – using whole butts, pre-shredded butts, or a pre-mix where the butts have already been incorporated into other brick-making materials.

The new study also details the types of harmful bacteria found on cigarette butts, analyses how heavy metals can leach from them into the environment, and examines the energy value of butts in the brick-making process.

By analysing the butts’ energy value, the team in the School of Engineering at RMIT, Australia, showed the incorporation of 1 per cent cigarette butt content would reduce the energy required to fire bricks by 10 per cent.

“It takes up to 30 hours to heat and fire bricks, so this is a significant financial saving,” Mohajerani said.

It can take many years for cigarette butts to break down, while heavy metals like arsenic, chromium, nickel and cadmium trapped in the filters leach into soil and waterways.

During firing, however, these metals and pollutants are trapped and immobilised in the bricks.

Bricks made with cigarette butts are also lighter and provide better insulation – meaning reduced household heating and cooling costs.

About 25 to 30 billion filtered cigarettes are smoked in Australia each year, with about seven billion butts littered.

Mohajerani has also developed technology for incorporating butts into asphalt concrete and said the technical solutions would need to be backed up by more stringent laws and harsher littering penalties.

“Local authorities would also need to provide more specialised bins for cigarette butts, to both prevent littering and enable smooth collection for the brick-making process,” he said.

“My dream is a dedicated brick-making recycling facility in every country, that can recycle butts and solve this pollution problem for good.”