KEY POINTS:
Auckland and Manukau city councils are being warned by Environment Minister David Benson-Pope not to sacrifice quality for cost efficiency in their plans to have householders dump all recyclable materials into single wheelie bins.
Sorting would then be done at a central depot.
A report has warned that such systems overseas had led to problems of contamination of materials, particularly paper, and increased volumes of glass not fit for use by glass manufacturers.
Mr Benson-Pope is urging the councils to "get serious about recycling" and not opt for the cheapest and easiest household collection systems.
The Glass Packaging Forum report indicated that a mixed wheelie bin collection reduced the value of materials collected compared with crate-based systems now used in Auckland and Manukau where materials were sorted at the kerb.
Mr Benson-Pope said he noted with some concern that Auckland and Manukau were moving to a single, big wheelie bin.
"While I'm sure this will encourage recycling and reduce litter, it will merely exacerbate commingling problems."
The minister said that while the mixed system might be cheaper for councils in the short term it ignored the downstream costs of degrading glass and sending otherwise recyclable material to landfill because it had been contaminated.
He intended to meet the councils next week to discuss their plans and had already written to all councils, and met Local Government New Zealand, to urge them to consider the wider implications of their decisions.
The report showed that mingling led to significant volumes of glass collected for recycling ended up in low-value end uses or as landfill.
It pointed to problems with glass breakage on the North Shore and Waitakere where collections were mixed, although the paper collection was still separate.
Bradley Nolan, waste minimisation manager for the North Shore City Council, said mingling was international best practice and already the council was collecting 10 per cent more glass than before.
He acknowledged glass breakage problems and conceded that the compaction in trucks was quite high.
However, Mr Nolan said the amount of high standard glass being sent to the O-I glass manufacturer in Penrose had not reduced by any significant amount although Onyx, the contracted recycling operator, was stockpiling broken glass that could not be used.
He insisted it would would not end up in a landfill and could be ground up for a number of other uses.
Carl Storm, general manager Onyx, said the stockpile of broken glass was due to a time lag from winning the contract to buying equipment.
He was confident the volumes could be controlled and eventually reduced.
Onyx had invested $500,000 into machinery that could take broken glass and grind it down so it could be sold back to quarries for uses such as builders' mix and roading material.
The Auckland and Manukau councils said they taken the issues surrounding breakage and contamination seriously and discussed the problems with interested groups to find compromises.
Ashley Chisholm, executive officer of Paper Forum, said the mingling was "not good" and paper that had been contaminated with broken glass was less attractive to purchasers.
Paper would "kill the machines" used at the country's only paper recycle mill in Auckland, Mr Chisholm said. "We are strong advocates of a separate collection."
Crates Binned
* Auckland City and Manukau households will be given a 240 litre wheelie bin to recycle paper, cardboard, tin and aluminium cans, glass bottles and plastic containers graded from 1 to 7.
* They will replace 45 litre crates and be collected fortnightly.
* About 250,000 of the green bins will be given out when the service starts in July next year. Householders will still put out 120 litre bins for other rubbish.
