That's my question as well. Perhaps the environmentalists don't want them to have traditional sewer systems. Perhaps the future of civilization in these leftists' minds is to return to the dark ages.
Problem is... I some places the ground is all solid rock so a septic tank leach system will not percolate and drain or keep up with the amount of water being dumped into it. Water is another problem, where water is limited normal toilets can use quite a bit of water.
What he is talking about are called Vermicomposting toilets. They are quite common when the circumstances are like above and folks live in remote locations and usually use red worms. they work fine and what comes out is safe for fertilizer.