The amount of Auckland's plastic heading to landfill and heading overseas for recycling will be slashed thanks to an upgrade at the city's recycling sorting facility.
The new optical sorting equipment, installed in Auckland Council's Visy recycling facility, means up to 35 per cent less plastic will need to be shipped overseas for recycling.
In a rare tour, Visy, a multinational recycling company, opened its doors to journalists on Thursday to get a peek into how the city's recycling is done.
About 600 tonnes of recyclable materials are collected from across the city each day.
Annually, about 135,000 tonnes are collected from households, with plastic making up about six per cent, by weight.
The largest component is paper and cardboard at 40 per cent, glass 39 per cent, and aluminium and steel 3 per cent.
The materials all start unsorted on a conveyor belt where obviously unrecyclable items are removed by hand. These have included everything from nappies, to garden waste, to even dead animals.
They then move through a labyrinth of conveyor belts and sorting machines, which remove further contaminants and break each material down into specific components.
About 12 per cent is contaminated - which includes general waste and things like dirty plastic - and goes straight to landfill.
Another issue, though, was in the different types of plastics, which number 1 through 7 and all have unique characteristics and levels of recyclability.
Pre-Covid, the vast majority of New Zealand's plastic was sent overseas for recycling, often in bales made up of different types.
Exports reached a peak in 2016 with just shy of 50,000 tonnes shipped overseas, before China closed its doors over environmental concerns and exports dropped to just over 30,000 tonnes in 2018.
Overseas exports picked up again last year with new markets found in Malaysia and Indonesia, however non-governmental organisations have raised major concerns plastic was simply being burned or dumped along already-polluted waterways, as these countries were already inundated in plastic waste.
New Zealand's previous largest overseas market was Indonesia, which received over 12,000 tonnes of our waste in 2018 - doubling from 2017.
But Covid-19 saw overseas markets close, and a drop in oil prices made producing products from virgin plastic much cheaper than recycling.
Auckland Council General Manager Waste Solutions Parul Sood said this all meant over the past few months some plastics were having to go to landfill in Auckland as there was no market for them.
However the new optical sorting machine, which used light and near-infrared technology to differentiate plastics and an air jet to put them in the correct stream, would ensure that 99 per cent of the 7700 tonnes of recyclable plastic coming through each year could be recycled.
It also meant more could be done onshore.
Previously only about 6.5 per cent of Auckland's plastics were recycled in New Zealand.
But with the new sorting technology, up to 35 per cent could be recycled here, with local plastic recycler Astron Sustainability - which supported the upgrade - now expecting to receive approximately 2200 tonnes of plastic number 2 and 5 as a result.
Previously, plastic number 2 was going to overseas markets, and plastic number 5 has gone to landfill since June.
This material could now be used for a range of products, from flowerpots to culvert pipes.
Around 40 per cent of clear plastic number 1 is recycled by Flight Plastics in New Zealand.
Fonterra financially supported the new sorter, which Director of Global Sustainability Carolyn Mortland said reflected the fact the company produced over 50 million plastic milk bottles each year.
"Kiwis love milk, and now they can know that those bottles are being recycled here in New Zealand."
The company recently launched a milk bottle made from sugar cane resin, which was still recyclable, rather than petroleum.
Other companies have taken it further and produced their bottles from recycled plastics, which Mortland said was a technology the company was also looking into.
Auckland Councillor Richard Hills, chair of the Environment and Climate Change Committee, said while the new sorting technology was "exciting", the key was to continue to reduce plastic use in the first place.
"It is definitely a big eye-opener seeing all that machinery constantly going, and that is just one day of Auckland's waste.
"Building the capacity for over a third of our plastics to stay in New Zealand is a
great milestone that can reduce our emissions.
"In addition to improving our recycling, we continue to encourage people to avoid single use plastics wherever possible because it's better for our environment to refuse and reuse rather than relying on recycling alone.
"Less plastic in our recycling means that more of it can stay within New Zealand instead of needing an overseas market."
Rigid mixed plastics 3, 4, 6, and 7 containers - which are less than one per cent of Auckland's plastic - will continue to be sent to landfill because there is no viable market in the world at present.
"Manufacturers are strongly encouraged to stop using these hard to recycle plastic
materials for grocery items," Hills said.
However Visy would continue to search for solutions for these plastics so Auckland households could continue to put them in recycling bins while they worked to find a solution.