The primary benefits from a waste to energy plant are that it reduces the size of municipal landfills and energy can also be generated. Only the electricity portion of energy generated is assured for use; the resultant waste heat is typically not viable.
Building and operating such a plant does, however, create a number of problematic issues that must be addressed. Some of these issues, such as the increased truck traffic, odour and vermin infestations can be resolved by locating the plant away from populated centres. Other issues such as the significant amounts of dioxins, furans, and heavy metals (lead, cadmium, copper & zinc) which pose serious health hazards are extremely difficult, if not impossible, to deal with. In fact, the concentration of dioxins and furans from such a plant exceed those from a coal-fired power plant. Thus, the air quality in the area adjacent to, and downstream from, the waste-to-energy plant becomes a major health concern.
Aside from health concerns, there is another major concern relating to the fly ash and bottom ash generated by the plant. This amounts up to 25% of the waste processed, depending on whether the waste is properly sorted prior to processing. Of this, fly ash represents up to 20% of the total by weight. Given the fly ash contains heavy metals, as well as dioxins and furans, disposal at a conventional municipal landfill could become problematic. As for the bottom ash, which should be tested for toxicity prior to disposal, its disposal could also become problematic. Even if it is found to be non-toxic, it could very quickly, overwhelm the capacity of the existing municipal landfill because of the large amounts of solid waste the plant wants to import.
Having worked on energy-from-waste plants such as the 750 tons/day plant in Winnipeg, Manitoba (now closed due to air emissions concerns) serious consideration should be given to the aforementioned issues before proceeding further on the path to a waste to energy plant.
V. Donato, P.Eng. (Ontario)
Editor’s note: this letter is the writer’s opinion and contains information that has not been verified; nor did the writer provide The Journal with his sources.