Many people don't realise that they might have driven over the bottles they put in their recycling bins, some as often as twice a day.
How so? Their empties have been reused to help to make the roads we drive on.
Crushed glass sourced from kerbside recycling collections has been turned into sand to build Victorian roads, including the recent Tullamarine Freeway widening from Bulla Road to Power Street.
And two new plants will now divert the equivalent of 1 billion of glass bottles that cannot be recycled from landfill every year.
Construction company Alex Fraser Group opened a $20 million glass and asphalt recycling operation at Laverton North in Melbourne's west on Friday.
The hi-tech recycling plants, funded in part by state government body Sustainability Victoria's research and development grants and assisted with research by Swinburne University and VicRoads, make use of dirty or contaminated glass containers and shards collected in kerbside recycling.
The shards that are too small to be sorted, or are contaminated with plastic or metal lids or other materials – and therefore can't be reused to make new glass products – would otherwise be stockpiled or go to landfill.
The new glass plant can produce up to 800 tonnes of construction sand a day – the equivalent of four million bottles.
Illustration: Matt Golding.Credit: .
After the lids and other foreign materials are sorted and sifted via conveyor belts, the glass goes into a big blue crusher. It comes out the other end, and into a truck-trailer, as sand.
The sand can then be used in aggregates and asphalt in road building and other construction projects.
The recycling process not only benefits the environment through reducing rubbish sent to landfill. It also provides a ready resource for the many construction projects now in train around Victoria.
And it massively reduces the amount of trips it takes to truck sand from quarries that are often 100 kilometres from the city, and transport it to work sites.
Alex Fraser Group managing director Peter Murphy said the recycling revolution in Victoria's civil construction industry was far advanced compared with other states and countries.
That was in part because VicRoads had the foresight as far back as 1993 to produce the specifications required to build roads out of recycled materials.
The Alex Fraser Group's recycling plants crush glass into sand used to make asphalt.
His company specialises in recycling of construction and demolition materials, and has been recycling glass for years, but its new plants step up that capacity.
"I think what lots of people don’t realise is that the glass that goes into your wheelie bin can be used to resurface your street," Mr Murphy said.
He estimates that every 150,000 tonnes of sand produced from glass equates to about 5000 truckloads that would have been transported up to 100 kilometres from a quarry to a work site.
It's cost-effective and helps create more of a precious resource for which there is unprecedented demand due to the state government's huge building program.
And it helps curtail the huge stockpiles of recyclables since China imposed strict restrictions a year ago, followed by other Asian countries since, stopping us from exporting our problem.
"We’ve got some innovative people and for us we really saw it as a metropolitan problem, in that glass was being stockpiled and didn’t have an end use," Mr Murphy said.
"And the other challenge is that there’s a resource shortage, and both of those issues are front and centre now.
"We’ve heard lots about the recycling crisis and we had the Treasurer and the Planning Minister talk last year about the cost of 'Victoria’s big build' skyrocketing.
The new crusher in Laverton North turns glass back into sand.
"So we just saw an opportunity to get in on that. There’s two problems that we can solve if we’ve got ... a good network of sites within the city and some people who were prepared to have a crack at it."
Now the sand created in the Laverton North glass crusher will be transported 100 metres to the company's new asphalt recycling plant, which also uses recycled bricks and concrete.
Matt Genever, the director of resource recovery at Sustainability Victoria, said the plants would be the linchpin of glass recycling in Victoria and were among a number of such projects funded by the agency.
Glass was just one component of the projects it had funded, Mr Genever said.
The asphalt recycling plant.
Others include using plastic to make low-impact concrete, and even railway sleepers for the Metro Tunnel.
More than $2.5 million was awarded to 20 projects in 2018. Applications for the second round, of matched funding of between $50,000 to $200,000 for each project, closed on Friday.