The serious answer is that even if you could create a black hole in your garbage disposal, you can’t eliminate the mass. You just eliminate the volume. Humans produce billions of tons a year in trash. All you would be doing is concentrating that mass in a single point. Which would then promptly drop through the floor and settle in the Earth’s core.
The main reason we don’t dump garbage into the Marianas Trench is the same as the reason we don’t just dump it in the center of Antarctica; there is no reason to.
We have lots and lots and LOTS of room to put our garbage. The world’s not going to end up as a WALL-E covered garbage mess. You could put all the garbage we ever make into a big hole in the Northwest Territories, well away from anything it could pollute that anyone would care about, and have enough room in the hole for all the garbage human beings will make for the next thousand years.
The issue with garbage disposal is cost. Cities usually dump garbage nearby simply because that’s what’s cheap. Sailing it out, sealing it. and dumping it into the Marianas Trench would be expensive, which is why it’s not done.
Yup, transportation of garbage half-way around the world would be prohibitively expensive, and that shit floats. It’s not going to sink to the bottom and stay there.
True before the advent of plastic, probably; glass and paper and wood and metals and animal bones generally aren’t much to worry about. Not true now, though. Plastic nurdles, for instance, are being consumed near the bottom of our food chain and moving their way up. And do you know how long plastic takes to biodegrade? Neither does anyone else.
I thought the way to extract energy from a micro black hole was to dump stuff into it, let the matter be accelerated to tremendous speeds as it circles in the accretion disc, and then, POW! Tremendous amounts of X-Rays and Gamma rays, that, presumably, would then heat the crap out of some heat-transfer medium a safe distance from the black hole and go on to make steam and spin turbines, etc.
And even if the nuclear waste did get subducted down, it would eventually melt and come back to the surface via lava in volcanic island arcs. That’s right: radioactive volcanoes!
I haven’t any idea what, specifically, you say is “Not true,” but the simple fact is that there is far, far more room to put our garbage that we could ever possibly use, even if plastic never biodegrades for the rest of eternity.
Yes, that would be one way to implement getting energy from the gravitational potential energy. I’m not an engineer, though (and the relevant branch of engineering probably doesn’t even exist yet), so I can’t say whether that’s the most practical way of doing it.