What a waste

The building sector's "skip-it" mentality is a threat to NZ's sustainability goals. But an Auckland trial shows the problem can be sorted.

- DIANA CLEMENT

Every day in New Zealand, 17,000 tonnes of construction and demolition waste is dumped into landfills. That's up to twice the tonnage the general public produces as household waste, according to the Building Research Association of New Zealand (Branz).

While politicians and the public wring their hands about plastic drinking straws, single-use bags and fruit labels, Branz says the construction and demolition (C&D) sector is one of the largest waste producers in New Zealand.

It's a hidden problem, says Mark Roberts, senior waste planning specialist at Auckland Council. About 90% of it could be diverted from landfills for reuse or recycling, but isn't.

"It's created on building sites that are fenced off," says Roberts. "It goes into high-sided skip bins, so you can't see what's in there. And then it's transported to a landfill."

With little incentive to do otherwise, builders and contractors choose the cheapest skip provider. Inside that skip will be rubble, wood, plastic, metal, plasterboard, insulation, packaging and a range of materials. "If they're lucky, [the skips] might go to somewhere like Green Gorilla or Waste Management, where it's sorted," says Roberts. "The general public don't go to those places. That's why the public zeroes in on things like straws and plastic bags and coffee cups."

INTERNATIONAL LAGGARD

New Zealand's scorecard on C&D waste is poor compared with many other developed nations. Waka Kotahi NZ Transport Agency estimated in 2019 that 3.5 million tonnes of C&D waste is generated every year. Data for the diversion of waste is of low accuracy but is estimated at 17% nationwide, according to the Ministry for the Environment. That compares with 87% of C&D waste recycled as a matter of course in Denmark.