Tech: More plastic to stay in NZ

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 the Auckland Council’s Visy recycling facility, means up to 35 per cent less plastic will need to be shipped overseas for recycling.

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 6 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 to 7 and all have unique characteristics and levels of recyclability.

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, nongovernmental organisations have raised major concerns that plastic was simply being burned or dumped along already-polluted waterways, as these countries were already inundated in plastic waste.

Auckland Council general manager waste solutions Parul Sood said 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 nearinfrared 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.