More glass recycled but it's bound for the crushers

A mountain of glass at a recycling plant in Onehunga. Photo / Glenn Jeffrey

Less than half of the glass put out for recycling comes back to the shelves as new bottles, as increasing amounts are sent instead to be crushed.

Figures released by the Glass Packaging Forum show extra glass from increasingly enthusiastic recycling efforts since 2004 is being mopped up by crushers, which turn it into aggregate for building and roads, filtration systems and agricultural materials.

The industry has beaten a voluntary goal of recycling 55 per cent of glass by the middle of this year.

But while New Zealanders are recycling 64 per cent of glass, less of it is being turned into new bottles.

Using old glass for new bottles is considered better for the environment than using raw materials, because it uses less energy and fewer natural resources.

Glass Packaging Forum general manager John Webber said the industry started using glass for aggregate in 2005, when there was not enough demand for recycled glass to keep up with recycling rates. "The public being as enthusiastic as it was, they were still recycling ... [so] we started to look at alternative uses."

Since then the amount of glass turned into new containers had plateaued.

In 2004, nearly all glass sent for recycling was turned into new glass containers.

Now, more than half of it was crushed.

An Auckland smelter glass furnace that container-maker Owens-Illinois is building late next year should increase the amount of glass used for containers, but it was too early to say by how much, said Mr Webber.

He said the co-mingled recycling schemes adopted by Auckland and other councils - where paper, plastic and glass are put in a single wheelie bin - had not helped.

Mr Webber said a proportion of the glass collected from households in wheelie bins arrived at recycling facilities in too poor a condition to be used for new containers.

But Auckland city development committee chairman Aaron Bhatnagar said switching to the scheme had sparked a "dramatic" increase in recycling of paper, plastics, metals and glass.

Aggregate was still a sustainable use for glass and "beat the hell out of" digging up new land for quarries, he said.

He acknowledged that co-mingling might produce more glass that was suitable for aggregate, and therefore less valuable to the industry.

But he said there was an overall benefit from a big reduction of waste to landfill. "I think everyone would agree that that is the ultimate goal."

The new Auckland furnace will boost the country's capacity to smelt glass from about 80,000 tonnes to about 155,000 tonnes a year.

Owens-Illinois and recycling company Visy are also building an optical sorting plant to try to increase the rate of glass recovery.

The latest recycling rates, which mark the end of a five-year voluntary agreement under the Packaging Accord, did not include 13,000 tonnes of glass that is stockpiled at Visy's Onehunga plant awaiting processing. If that were counted the rate would have been 69 per cent.

* Turning it around

2004: 50 per cent of glass recycled.
90-95 per cent of that made into new glass containers.

2009: 64 per cent of glass recycled.
Less than 50 per made into new glass containers.