I'm a bit skeptical of any business method that does not depend on the special nature of the ocean, as I say in the book:

"It's very important to be honest about the advantages and limitations of doing business on board a floting platform. We've seen numerous proposals for ideas to make money on floating cities that are obviously not going to work, because they don't leverage any of the comparative advantages. There are lots of people out there who want to make money, and there is no easy way or magic recipe to do so. By moving a business to the ocean, you are cutting it off from resources and customers, making everything more expensive and more difficult. To be able to compete with the possibiltiy of doing the same thing on land, there has to be a damn good reason why the ocean is a better place.

After a fair bit of thought, we've only come up with two unique features of seasteading which provide its competitive edge. The first is the freedom offered by sovereignty and the second is the unique ability of seasteads to provide some of the comfort and stability of land in remote marine locations. Hence any business must center around one of these features."

Put another way: if it was easy to turn trash into money, I'm pretty sure that existing refuse companies would be doing it.

While I suspect the costs of such a generator are way too high for original seasteaders to afford (I stand to be corrected on that one), a promising approach to handling trash is to convert it into energy and building blocks. There are several companies working on plasma based trash disposal units. The idea is to feed it trash (the latest generators can handle almost anything with no prior preparation) and it converts it into energy and a small amount of residual material that can be used as building blocks for all kinds of things. It actually produces more energy than it consumes as long as it is fed trash. I believe the technology to be in its infancy and still quite expensive, but it's already competitive with hauling the trash from NYC to nearby landfills. I suspect trash will be costly on a seastead and sea going vessels (and more so permanent structures) should be among the first to benefit from this technology which doesn't even require much room.