Which is why we need rail guns. Compress the waste into slugs, maybe mixed with some ferrous material to make it magnetic, and then sling that shit on a one-way trip to the Sun. If engineered properly, it would be extremely unlikely to disintegrate in atmosphere. (The ideal launch site would somewhere like the Moon...far lower velocity required, no atmospheric friction, etc.) But then you have to get it to the Moon.
Okay, so we need a space elevator and rail guns....
Actually, I had a thought about that. With electrical applications, we use "ground" as the base voltage of the Earth. We call it "Zero", but it's not really zero. It has some value, it's just relative to everything else it might as well be zero. The voltage potential of the planet *should* be increasing over time due to electrical storms and generated electricity that we sink into it. I'm pretty sure it's confirmed that the moon was once a part of Earth. That means that the Earth has a greater potential relative to the moon. If we had a space elevator connecting the two, I'm pretty sure electricity would actually flow to the moon (or someone who knows more than me can figure out a way to have it flow from the moon to the Earth). Yes, the distance is extremely long, so resistance of whatever conductor we're using will be huge, but I'm sure the part that remains in space could utilize super-conductors that are more easily kept cool enough to function as such, which would help with the resistance. I'm also pretty sure the voltage difference would be high enough that electricity would flow anyway.
So we have flowing current between a planet and a planetoid. Store the power into something, ship it back (Or figure out how to radio-wave electricity like Tesla and just broadcast to Earth).
Then again I'm going off of a pretty limited understanding of the physics involved.
About water power: hydroelectric dams are a terrible, terrible idea.
There are experimental wave generators though, and they could be used without flooding places.
Also, since I apparently forgot to mention it before: thorium based nuclear power plants.
Since the middle part didn't sound sarcastic, I'd really like to know what's so bad about hydroelectric. Pretty clean, helps to not flood developed areas, etc. TVA (Tennessee Valley Authority) manages a LOT of electricity for eastern USA, and hydroelectric is their big thing.