Incineration of municipal sold waste works fine, as long as the waste has been correctly recycled at the source. Impurities can harm both the environment and the incinerator. Chlorine, for example, can corrode the incinerator walls as well as producing nasty poisons.
[English translation]. Finnish version: click here.
It is important that recycling at the source is done well. However, since it is a human activity, it is never done well. The question is how badly it is done. Many people do not care. And even for those who do care, the reality is so complicated that mistakes will happen.
PVC plastics are a good concrete example. One needs to remember that it is OK to incinerate plastic bottles, but not plastic dividers, binders, or inflatable toys. One needs to figure this out from small nearly identical icons which, to be honest, mean absolutely nothing unless one has cracked the code and has a good memory.
(The top row can be incinerated. The bottom row cannot).
This being the case, we know there will be some PVC in the incinerator waste. How much? Where does it come from? Does quality control get rid of it? How much improvement is possible, if the recycling is done better at the source — basically, in peoples’ kitchens?
There are other similar substances. Problems are caused by waste which a) is harmful when incinerated and b) can easily get put in the wrong trash bin. Aluminum (for example the covers of yogurt cups) is another potential substance which should be recycled rather than burned, and it can cause problems in the furnace.
Is the amounts so small that this is completely irrelevant? Perhaps. Hard to say without studying more. Has it been researched? Yes. Several studies on the trash contents have been done in Finland alone.
However, I have not (yet) found research that would answer this exact question. Scientifically, it is incomprehensibly boring: does a typical person wash the caps of his yogurt containers and put them in the metal-recycling bin, and does he not? The physicist in me could not care less.
Yet it might well be worth researching, both for the environment and for the operation of the incinerators.
If mistakes turn out to be common, it would imply that the usability of recycling needs to be improved. Instead of seven identical triangles, would it make more sense to have large colorful icons which say exactly what should be done with the material? Usability is an artform of its own, so I do not know.
More blogs on the subject (Finnish only): here.
“Fast1” ideas have 15 minutes or less of thought behind them. They should be treated accordingly. Errors are possible, even probable.