RMIT University researchers have developed a plan to implement cigarette butt recycling into bricks at mass scale to save energy and reduce the amount of toxic waste dumped into the environment.
More than 6 trillion cigarettes are produced each year around the world, resulting in 1.2 million tonnes of toxic waste in the environment.
Previous research has found fired-clay bricks with 1 per cent cigarette butt content are as strong as normal bricks while using 10 per cent less energy to produce.
Analysis showed if just 2.5 per cent of global annual brick production incorporated 1 per cent cigarette butts, it 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.
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“Firing butts into bricks is a reliable and practical way to deal with this terrible environmental problem, while at the same time cutting brickmaking 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.”
The plan, published in a special issue of the journal Materials, shows 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 brickmaking materials.
Requirements for maintaining health and safety are also detailed, with analysis showing how risks can be mitigated for both industrial brickmaking and handmade bricks.
The new study also details for the first time 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 brickmaking process.
It can take many years for cigarette butts to break down, while heavy metals like arsenic, chromium, nickel and cadmium trapped in the filters can leach into soil and waterways.
During firing these metals and pollutants are trapped and immobilised in the bricks.
Bricks made with cigarette butts are also lighter and can 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 7 billion butts littered.