In the USA, landfill space concerns are based on a hoax. Landfill space is a function of landfill development, and there’s no shortage of spaces to create landfills.
If you can burn it, there is no point in burring it. We're still taking a lot of stuff from underground and burn it for energy, why not burn the stuff we already have above ground?
You can used a closed system so that the waste is actually all captured. Or you can have a more continuous system that'll capture/scrub the output.