We’ve had a Separett composting toilet for eleven years now, it’s great, have had zero problems. No need for a septic tank, no smells, very little plumbing. We have the urine piped into a container which gets diluted with water and emptied on compost heap at the moment but it could easily be fitted into existing waste water pipe system. It has a vent pipe through the wall. That’s it. A fan runs to dehydrate solids, and the fan ensures there’s no ‘privy smell’. It also keeps our bathroom dry, we don’t get condensation as it’s always quietly running. I would highly recommend it to anyone.