Seems like Northern Africa would be a pretty logical place for disposing waste. Lots of unused desert land very close to the sea for easy access by barge.
Barge access isn't the problem so much as deep-water port capacity is as most waste is transported via cargo container. It takes years to build up the infrastructure needed to handle the increased garbage and transport it to massive landfills, even if you've got cheap land for them. I'd expect that it'd stress existing African port capacity, even if we're only talking about a portion of the waste that was previously sent to China.
With luck, we'll see improvements in recycling technology and investment to compensate. In the meantime, the bulk of it's already going to landfills with all of the problems that entails.
Deserts aren't inhospitable. They're still ecosystems for animals that perhaps do not want their groundwater (perhaps) tainted by a landfill. Problems are already happening with pretty terrible materials that have been dumped,
Sort of historical note. Depending on how such a program is formed, you could inadvertently spawn e.g. Somali piracy out of illegal dumping. So while the idea could work, it could also be implemented in such a way to go horribly, horribly wrong.
