Metro Vancouver now has approval to landfill bottom ash from its Burnaby garbage incinerator that had been set aside after some loads failed pollution tests.
Starting last spring, testing began to show some samples of bottom ash contained more than twice the allowed level of leachable cadmium for landfill disposal. Those loads were kept under tarps instead of being dumped at the Vancouver Landfill in Delta, as usual.
Metro solid waste general manager Paul Henderson said extensive additional testing found there were tiny bits of cadmium-containing material – mostly from incinerated rechargeable batteries – randomly distributed through the ash loads in what he calls a "chocolate chip phenomenon."
With the provincial environment ministry's approval, Metro staff used statistical analysis to conclude that the ash loads as a whole were within regulatory limits.
"In all cases, when you took enough samples and did statistical analysis of the samples, the material was determined to be non-hazardous," Henderson said.
The waste-to-energy plant generates about five truckloads a day of bottom ash, or 50,000 tonnes per year.
Henderson said cadmium content in garbage is generally from rechargeable batteries, as well as electronic devices and toys containing rechargeable batteries.
"Those are all easily recyclable materials," he said, adding Metro is planning more public education to get residents to return the products for recycling instead of throwing them in the trash.
Henderson said Metro is also convinced the incinerator's fly ash, which the Cache Creek landfill refuses to accept after some failed tests in 2012, is also non-hazardous.
But since there's no other viable destination in B.C., Metro expects to soon sign a new three-year contract to send the fly ash to an out-of-province special waste landfill.
That ash has so far been trucked to a landfill near Hinton, Alberta.
A consultant named by the province is still expected to make recommendations on what to do with the fly ash brought to Cache Creek in 2012.