Nathan VanderKlippe
Northern News Services

Yellowknife (Mar 22/02) - When city councillors and residents debate the possibility of incinerating Yellowknife's garbage, one of the questions that will inevitably arise is, "what impact will this have on the environment?"

Supporters of the technology cite the direction taken by the German government, which has mandated that all waste be either incinerated or diverted from landfills by 2005.

Germany is often cited as having the most strict policies on the environment in the world. For some, that is evidence enough that incinerators are environmentally-friendly.

But what exactly are possible environmental issues?

Incinerators produce two types of waste: ash and gas. The burning process releases a number of substances, which can appear in both waste products. Some of the more harmful include dioxins and furans, heavy metals, sulphur dioxide, hydrogen chloride and nitrogen oxides.

Of those, dioxins and furans are typically considered the worst. Created when smaller molecules recombine into larger molecules -- usually involving extreme heat -- dioxins and furans are extremely carcinogenic.

But in the 1,100-degree Celsius heat of the German incinerators, the bonds of dioxins and furans are broken apart.

"Most organics will just break up (and) form water vapour and carbon dioxides," said University of Toronto chemistry professor James Makoto Toguri. But, he warned, they can recombine when they are cooled if special precautions are not taken.

That frightens some environmental activists, who say waste should be composted or recycled rather than incinerated.

Emission concerns

Christopher Pickles is a Queen's University professor in Kingston, Ont. who studies gases.

He said he thinks solid waste incinerators are a good idea, because they eliminate "the problems of landfills, and you can recover energy from the waste," he said.

"The only problem is you have to make sure the off-gas is not emitting any nasty things."

Pickles said two devices can be used to clean up off-gases: a baghouse (which works like a huge vacuum cleaner) and an electrostatic precipitator, which removes charged particles from the air.

The resulting ash is filtered, but can still contain heavy metals. To render it inert, the ash can be used in roadbuilding (as it is in Germany) or turned into glass to render it inert.

Thomas Jahrfeld works with DETEC, one of the German companies eyeing the Yellowknife waste stream. He said that until a scientific analysis is done of the Yellowknife waste stream, "you can't make precise information now" on possible environmental hazards.

Experience elsewhere

However, other Canadian waste incinerators operate below Canadian limits.

Wainwright, Alta., is home to a municipal solid waste incinerator that burns about 10,000 tonnes a year.

Actual incinerator output levels in each category -- which included heavy metals and hydrogen chloride -- were significantly below Canadian standards. But Jim Sparling, who works in the environmental protection division of RWED, said that even though air emission values from the Alberta incinerator look promising, recycling should always take priority.

"It raises a lot of complex question that would need to be reviewed," he said, "questions about the volumes of waste needed to make it economical and what other plans we have in terms of waste diversion that make sense for other environmental reasons."

In the U.S., incinerators haven't been the boon they promised. James Thompson is president of Chartwell Information, a California market research firm for the solid waste management industry.

He said that while recycling options for incinerator ash do exist -- and are legal in the U.S. -- a nation-wide survey found that 95 per cent of ash is landfilled.