The search for a Canterbury landfill site is continuing, following the loss of a site near Darfield.

It will cost $20 million to $30 million to establish a new site, which is needed because most Canterbury landfills, including Christchurch City Council's Burwood site, must close within a few years.

Canterbury councils have agreed that the issue is a cross-boundary one not a district one. So 10 councils are working together on waste management and waste minimisation and Transwaste Canterbury Ltd has the job to develop a modern, well-managed, environmentally secure landfill. Transwaste says waste management and minimisation is not someone else's problem but something everyone needs to be concerned about.

About 263,000 tonnes of solid waste is generated in Canterbury every year after recycling, composting and waste minimisation. That's enough to fill the WestpacTrust Centre arena about three-and-a-half times a year.

Already 20 old-style dumps have been closed around the region and another 30 are still open. Two big landfills - Burwood and the Redruth Landfill in Timaru - are still operating. While Canterbury is doing well by international standards in reducing its waste, with around one- third of waste diverted from landfills by recycling, composting and other methods, more needs to be done.

A landfill is seen as the preferred option on grounds of costs and availability of suitable land.

Calls have been made for an incinerator to be built, but there would still be a need for a landfill to get rid of the ash, which is toxic.

Incinerators have been used overseas, mostly because of the scarcity of land and its cost. Air emissions are generally controlled by the use of gas scrubbers and ash filters, which reduce toxic gasses and particulate. The ash contains high levels of heavy metals and has to be disposed of in a landfill or ash monofill.

Transwaste says the cost of an incinerator for Canterbury could be 10 times the capital cost of a landfill and could cost up to four times as much to operate. The estimated cost of an incinerator is more than $200 million; $60 million for emission control. Incineration would conflict with New Zealand's clean, green image. Modern landfills are flexible and nothing like the dumps of old, many of which were poorly designed and were in valleys and riverbeds - allowing toxic materials to leak into the ground.

While a modern dump might still be a hole in the ground, it is well designed and managed, with gas and leachate collection systems.

Today landfills have a liner system, a final cover, a leachate collection system, a stormwater management and a gas collection systems, and comprehensive daily management procedures.

See also: No Time To Waste website