Auckland mayors weigh up organic waste collection

Rubbish collections could be just fortnightly if organic waste was dealt with separately.

Auckland's mayors are investigating a scheme to take food and garden scraps from every home in the region and turn them into fertiliser.

Manukau City Mayor Len Brown is leading a working group backed by all of the Auckland councils looking at the possibility of an organic waste collection similar to one that has just started in Christchurch.

Manukau City Council waste manager Patricia Facenfield is in Christchurch today watching the city's new composting facility in action.

A "three bins" system to collect garden and kitchen scraps from Auckland homes will be presented to the new Super City mayor once elected.

A $20 million composting facility began running in Christchurch last month and will take up to 65,000 tonnes of organic waste each year, turning it into fertiliser for crops and gardens.

Food and garden scraps - which make up about half the waste of an average household - give off methane, a greenhouse gas, when they are left to break down in landfills.

Rob Fenwick, whose company Living Earth built and operates the Christchurch plant, said composting produced much less greenhouse gas than landfills because there was enough oxygen for the food to break down naturally. "If you try and do it without [air] it just putrefies," he said.

Christchurch City Council's Tim Scott said composting food waste gave off a small amount of CO2 but most of it stayed in the compost.

In Christchurch, householders put their waste out in three bins: rubbish, recycling and organic waste.

Homeowners pay for the collection through their rates.

Mr Scott said he could not tell how much the compost had added to collection costs because Christchurch had switched from user-pays rubbish collection at the time it was introduced.

Ms Facenfield said the working group was considering whether kerbs would be too crowded if homeowners had to put three bins out at once. It was possible rubbish would only need to be collected fortnightly once kitchen and garden scraps were removed.

Len Brown said diverting scraps to a composting plant could save Manukau 200,000 tonnes of waste that would otherwise go to landfill each year.The Auckland region could save more than one million tonnes of waste, he said.

As well as reducing waste to landfill, composting returned nutrients to soil that would otherwise be wasted.

Mr Brown said any new facility would have to capture smells so they were not released into the air.

Ms Facenfield, who has been working on the proposal for Manukau, said a report into the pros and cons of regional kerbside compost collection should be ready by August.

The results had been very positive so far, she said.

It was likely the working group would get all the information ready for a decision by the new Super City council, said Ms Facenfield.

Living Earth won the right to open a $5 million composting plant on Manukau City's Puketutu Island in December.