It's certainly a better option than putting it into a landfill, where the organic portion will turn into energy anyway, and the non-organic portion will do nothing but potentially pollute the groundwater.
Sounds like they do a pretty good job of controlling the emissions. My primary concern, and this is a fairly uneducated concern, but I always envisioned a (bleak) future where we had already mined all the precious and rare-earth metals and minerals and were forced to use our garbage dumps to re-claim those materials. Of course a good recycling program, would in theory, prevent this from ever being necessary, but in general, burning stuff to create energy feels sooo 20th century, we should really be using renewables and nuclear.
Well my primary concern was the garbage and pollution, such as the Great Pacific Garbage Patch. If we really found a way to cut our garbage down to 4%, that's pretty incredible ... of course if we start generating 25x more garbage to begin with then it will negate that.
Massive amounts of CO2 primarily. Also dioxins, but there are ways to combat that they may be be employed.
So where does this CO2 go? Do we need more trees to offset it, or what