What would cause them to be an environmental issue? As far as I know they can be built in a safe manner and there is plenty of space for them.
We need to reduce the amount of trash we produce, not hope for a miracle technology.
https://sf.curbed.com/2019/3/19/18273029/milpitas-odor-studi...
https://www.clf.org/blog/all-landfills-leak-and-our-health-a...