Eli5 why we don’t move trash like we move human solid waste.
Poop floats and breaks up in the water. Trash doesn’t do that. Some of it may float, a lot of it won’t. Some of it will break up, a lot of it won’t. Also people produce a small amount of biological waste compared with the mountains of trash.
To take your idea a step further, it wouldn’t be impossible to have like industrial shredders turn paper and cardboard and plastic into tiny bits and then transport them in tubes of running water. Would the infrastructure and the operation be any net value added compared to our current system? I don’t have the right info to make an assessment. My gut kinda says no.
They do that for some organic waste in places where they have garbage disposal (a blender in the sink to throw trash in the sink) which is common in the US.
However, for big trash that’s not convenient. Also, there are a lot trash you shouldn’t put in the garbage disposal because it has contaminant that sewer facility aren’t meant to dispose off. It’s mostly for small food waste.
It was be big, incredibly complicated, and absurdly expensive.
Human solid waste can still be moved relatively easy by just running water. Trash has so many other variables in it that it’d get jammed/clogged up basically right away. Plus, the pipes would have to be *huge*.