Thursday April 24, 2014





Stop burying fly ash with garbage

This is with reference to the contaminated fly ash at the Cache Creek landfill.

As you know, fly ash is what we have been getting from the Burnaby incinerator since 1998. Untreated fly ash is very toxic because of the high concentration of heavy metals such as lead, cadmium, etc.

If this fly ash is placed in a landfill untreated, any prolongued exposure to acidic moisture will cause the heavy metals in the ash to leach out. In Cache Creek it doesn’t (normally) rain much, so rain (which tends to be acidic) in itself may not be the greatest cause of heavy metal leaching.

To reduce the amount of potential metal leaching, the ash brought to Cache Creek is treated. The process involves mixing the ash with some calcine product (lime) and water, which makes the resulting sludge alkaline and it is this alkalinity that makes the heavy metals in the sludge relatively stable.

This sludge is (or was until recently) taken to Cache Creek and dumped in with the rest of the garbage. At this point, it was reasoned, the ash is pretty safe, since it is now very alkaline and the amount of rain that could wash away the alkaline effect was very limited.

Hence, the heavy metals would be stable and they would not leach into groundwater. Reasonable enough, it would seem.

The second part of this story, though, tends to be ignored. A couple of years ago, as you may also recall, a Ministry-commissioned report was very critical of the then practice of burying the ash sludge together with the regular garbage, so the practice was discontinued and the ash has since been disposed of in a monofill.

We now know that this monofill has serious problems and that the ash buried here shows heavy contamination.
The Ministry is obviously aware of this and appears to be doing something about it. Whether it’s going far enough is debatable. There is talk of removing a significant portion of the ash deposited in the monofill in the past couple of years but nothing is being said, though, about the thousands and thousands of tonnes of ash buried with the regular garbage in the Cache Creek landfill.

Sure, this ash is treated and sure, we don’t get (normally) a great amount of rain, so the de-alkalinization of the ash is very slow.

However, one thing that is usually, if not always, ignored is this — the ash comes in contact with regular garbage that contains a good deal of moisture and that this moisture is itself generally acidic.

This contact over time will have the inevitable effect of “washing out” the alkalinity. The end result will be the leaching of heavy metals into the groundwater.

Peter Montague, a well-known expert in such matters, reminds us that, “eventually the lime’s alkalinity will be entirely exhausted; then the rain will leach the toxic metals quickly. It’s only a matter of time, and nature has all the time in the world. The hazard from the metals in ash will not degrade with time — the hazard is eternal.”

Sure, Montague specifically refers to rainwater as having this effect, but I see no reason at all why the moisture in the garbage should not work in the same way.

If there is any lesson to be learned from this latest news it surely has to be this — the practice of burying this sort of toxic ash in Cache Creek has to end.

Incidentally, the Fraser Valley is critical of having waste-to-energy facilities in its own immediate environment, but it has shown little regard for our own wellbeing in wanting the Cache Creek operation to continue accepting the Metro Vancouver waste, including its own and including the toxic ash in question.

ERMES CULOS

Ashcroft





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