Are we talking about classic incinerators (simply burn stuff) or plasma arc (gasification)incinerators? With plasma arc gasifications the temperatures are so high (2,200 to 13,900 °C) that all the waste and any resulting toxic byproducts, the very molecules themselves, are broken down to individual atoms. There are no toxic compounds left.

All that remains at the end is ash that contains various metals and syngas that is produced in the process. Which can be used for generating electric power.

I hope plasma arc gasification becomes the standard for managing and disposing municipal solid waste. It really works. But you do need a certain scale (enough waste) for it to be effective.

https://en.wikipedia.org/wiki/Plasma_gasification

http://www.waste-management-world.com/articles/print/volume-...

> Are we talking about classic incinerators (simply burn stuff) or plasma arc (gasification)incinerators?

In 2015 "incinerator" means classic burners. Plasma gasification is practically unused: there are less that 10 plasma gasification facilities in the world.

Japan has a lot of low cost land.

According to the most recent land ministry survey conducted in 2013, there are 8.2 million vacant residences in Japan, 39 percent of which are designated as “abandoned,” meaning they are not for sale or rent. The portion of abandoned houses found in the previous survey, conducted in 2008, was 35 percent, and since 200,000 houses are demolished every year in Japan, the increase in the number is actually steeper than the percentage difference would indicate.

Japan is also weird in that they tend to tear down houses every 30 years and rebuild rather than resell them and renovate them keeping them up for hundreds of years like many other places in the world.