I think this falls in the category of oddities rather than serious proposals, but if there's a push to rethink indoor plumbing and the treatment of human wastes, there may be more room for change than we usually assume.
consider that since at least 135,000 urine-diversion toilets are in use in Sweden and that a Swiss aquatic institute did a six-year study of urine separation that found in its favor. In Sweden, some of the collected urine — which contains 80 percent of the nutrients in excrement — is given to farmers, with little objection. “If they can use urine and it’s cheap, they’ll use it,” said Petter Jenssen, a professor at the Agricultural University of Norway.
A friend’s grandmother remembers the man coming round for the buckets 60 years ago in Yorkshire, which were then sold to the tanning industry. The flush toilet ended that, and no one — my friend’s nan included — wants outside privies again. “Any innovation in the toilet that increases owner responsibility is probably seen as downwardly mobile,” said Carol Steinfeld, of New Bedford, Mass., who imports NoMix toilets into the United States.