Having a water access cottage in the north woods makes one an expert on alternative toilets. We have tried many of them and recount our experiences herein.
We started with an Incinolet- one drops a sort of Melita coffee cone into it to catch everything, and then you press a pedal which drops it all into the combustion chamber and incinerates to ash (sort of) in 40 minutes and sounds like you have a 747 in your cottage. Smoke. Flames. Kilowatt-hours galore. A strange smell lingering around the cottage on still days. This hot seat put our kids off potty training for a year.
Wanting a more home-like experience, we bought a Sun-mar Centrex composting toilet with a china bowl and a flush mechanism. It all goes into a big composting cylinder where you add peat moss every week. We churn it, let it bake, follow instructions carefully and yet seem to be constantly removing not compost but a soggy mixture of peat moss and poop. Furthermore there is "excess fluid" that does not evaporate and has to be dealt with by constructing a whole other Class II septic system. Not having this, we got closed down by the local toilet police.
UPDATE Sun-mar advises that I was not using the proper mix of sawdust and peat moss, and that the Building Code issues regarding the excess fluid have been resolved. I suspect that my problems with the unit are more my fault than that of the centrex system.
Getting desperate, we designed a funky A -frame outhouse for the heavy lifting
and bought a waterless self-contained Envirolet composter for nights and visiting moms, which works fairly well but is not without problems, including aesthetic issues of looking down and realizing that you are inches away from something down there, and if you do not operate the levers at the right time you have some extra cleaning to do. It works but it is not quite there yet.
Imagine our delight when we recently discovered the swedish Mulltoa composting toilet. Lifting the lid fires up the fans; sitting on the toilet seat opens the trap doors; putting the lid back down activates the churning motors. It does everything automatically and anticipates your every move and movement. We want one now.