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Comment by SlowBro | Hacker News Reader

I wonder if within 1,000 years they don’t develop nano robots that actually mine our current trash for the minerals? We toss out gold, silver, rare earth metals, petroleum, every day... the trick is it’s so very hard right now to extract those minerals, but perhaps our current landfills and garbage patches will become the “gold mines” of the future. It would be super easy to reach — landfills have trash just feet below the surface. No dangerous digging.

Just thinking optimistically here. I personally do what I can now to keep the earth clean. No sense peeing in your own pool.

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Not using nanobots, but some municipal waste incineration plants are already recovering valuable metals. A more recent development is using dry discharge of bottom ash to recover >95% of all metals [1].

From 100 000 metric tons of clinker, ZAV Recycling AG in Hinwil (Switzerland) is extracting 60kg of gold, 1500kg of silver and 800 metric tons of copper each year.

[1] http://www.hz-inova.com/cms/wp-content/uploads/2016/03/04b_R...

For anyone who was wondering, that's about $2.5 million worth of gold alone at current prices.

And 5.2 mil in copper

When I lived in a crappier area of a city I noticed an interesting system: "scrappers" - poor, probably homeless, people who would dig through your trash looking for recyclables that they could sell.

So there was this totally organic system that had emerged which helped make sure the trash didn't contain things that still had value. Of course it wasn't perfect, not to mention that we really don't want people to have to do that. Interesting non the less.

Where I live people raid the recycling bins and collect all the cans.

Yes, they would also go through my recycling bin. That part may be a net negative, because I assume they take the most valuable stuff and leave the rest for the city, which has to cover the costs of picking up and processing most of the recycling.

Michigan has a 10 cent bottle/can deposit and it's very common for homeless people to go through trash looking for bottles and cans.

Before and after college football games it's common for people to go around asking for empties at the tailgate. They can make a pretty good amount of money on those days.

I watched a whole movie about garbage pickers in a Brazilian waste dump: http://www.imdb.com/title/tt1268204/

If you liked that there is another one about garbage pickers in Cairo called Garbage Dreams.

Important to note that you do not have to be homeless nor live in a crappy fit to enjoy scrapping.

I have a theory that buying landfills (especially older landfills from before the popularization of recycling) is a good very long term investment.

They are often in a terrible state here in New Zealand. No liner, on costal estuaries and all of a sudden a storm pulls a section into the sea. It’s depressing how perfectly set up they are to cause trouble.

Landfills don't compare well to even low quality ores. Extracting the materials in them may get cheap at some point (at which point they can be thoroughly cleaned up), it won't get cheaper than other sources.

This is a technical solution to a human problem. Even with extremely advanced technology (by today's standards), the garbage of today will still be separated into valuable materials (just, more than today) and garbage... and the garbage will still be dumped in the ocean (or wherever).

If you consider it from an atom and energy perspective, you only really need to worry about the atoms that are going to cause you problems no matter what you do, like mercury and the other heavy metals. Those are generally valuable, though (the fact that they are valuable is why they are in a landfill at all in the first place, because it had value at one time), so if there was a cost-effective mechanism to remove those things from a landfill for profit, what was left over would not necessarily be a problem anymore.

Garbage getting dumped somewhere is not intrinsically a problem, if the garbage is not as intrinsically harmful as our current garbage.

(This is also why radioactive waste is so difficult to get rid of; it isn't a chemical problem, it's a problem all the way down to the atoms. Were it a mere chemical problem we'd have solved it long ago.)

A fish with a polymer of "innocuous" organic atoms in the digestive tract is likely to disagree.

Removing more harmful materials would certainly be a benefit, but it wouldn't solve the large part of the problem (which, in the case of the patch, is plastics).

"A fish with a polymer of "innocuous" organic atoms in the digestive tract is likely to disagree."

First of all, since the topic was landfills, I have some questions as to how the fish managed to get plastic from a landfill stuck in them. Yeah, it's possible, but somebody screwed up along the way.

Second, that's the exact opposite of what I meant by thinking just from an atom and energy perspective. It's a small amount of energy to turn those organic atoms into something less harmful, and probably a net gain from a strictly chemical perspective (i.e., plastics tend to burn). We are intrinsically speaking from a much higher tech than we currently have here. The process of extracting out mercury and cadmium and such can be reasonably assumed to either process waste to something safe before putting it out into the ecosystem, or that they will place the plastics somewhere where they aren't going to affect anything when done. I don't think our hypothetical future landfill miners are going to be allowed to just tear open the landfills and start shooting whatever they decide they don't want with cannons into the surrounding countryside.

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