I've been steadily working towards trash collecting robots for several years now, ever since hearing about the Great Pacific Garbage Patch. After the initial shock wore off I thought to myself, "hey, free resources."<p>The initial challenge was finding a secure OS to run on the robots so they wouldn't be suborned into a (physical) botnet. That proved challenging, as the only way you can trust your system is to prove it correct from the metal up. In order to be able to trust the proof you have to be able to understand symbolic logic. It turns out there's a simple notation that makes this easy[1] and which makes for a simple SAT solver. Combined with a logical-paradigm reasoning engine (i.e. Prolog or miniKanren or Coq, etc... There are a few to choose from these days) you can describe and compile e.g. a trustworthy OS and application code for a swarm robot distributed over the ocean. (I'm <i>just</i> at that point now. It's been slow going, I lead a chaotic life.)<p>In the meantime the NN/ML renaissance hit and now a lot of what would have been hairy problems are already solved. I had thought to have some sort of volunteer "Mechanical Turk" network of humans to help sort the trash, but very effective sorting machines have become available in just the last few years.<p>There are (at least) two major method of recycling plastic: Thermal depolymerization[2] which uses heat and pressure to turn it back into a kind of oil-like slurry; and Molten Salt Oxidation[3] which oxidizes (burns) molecules (not just plastic) within a red-hot bath of molten salt. This latter process can handle pretty much anything, it's used to dispose of munitions including chemical weapons. It's also exothermic, you can get power out. It also makes a good atomic reactor.<p>There's another option that could be called "divide and conquer". What makes something a piece of "trash" rather than a building material? Uniformity of shape and material. Consider the "timbrel vault"[4]. The basic idea is to subdivide a piece of trash until it's more-or-less "pure" (glass, paper, plastic, whatever), record the shapes of the individual pieces, and then assemble them (by machine) into larger structures and glue them together. Because you would have precise control over the fine structure of the composite material output you could build non-linear structures (i.e. that bend or compress in one direction but are stiff in others, etc.) or reinforce weaker or more brittle materials with stronger bits.<p>All this to say: "waste" is another word for "resource". Change your perspective and you change your level of wealth. And it's getting exponentially cheaper and easier to apply automated intelligence to rearrange the "waste" into useful forms! From this POV, China has done US a favor.<p>[1] "Laws of Form" G. Spencer-Brown. Cf. "Markable Mark" G. Burnett-Stuart.<p>[2] <a href="https://en.wikipedia.org/wiki/Thermal_depolymerization" rel="nofollow">https://en.wikipedia.org/wiki/Thermal_depolymerization</a><p>[3] <a href="http://moltensalt.org/references/static/home.earthlink.net/bhoglund/whatsMoltenSal.html" rel="nofollow">http://moltensalt.org/references/static/home.earthlink.net/b...</a><p>[4] <a href="http://www.lowtechmagazine.com/2008/11/tiles-vaults.html" rel="nofollow">http://www.lowtechmagazine.com/2008/11/tiles-vaults.html</a>