In my opinion the main source of smell from human wastes comes from urine. Segregating the urine greatly reduces the volume of waste and makes everything easier to handle.

The urine can be held in a sealed container and applied to the garden or fields. Don't get it on the plant directly and either dilute it or apply after a rain to prevent burning. Urine is also a source of nitrates and ammonia for those who want to go the whole self-sufficiency route.

Excluding the vast majority of urine makes the need for an absorption medium much less important. Sawdust, kitty litter, shredded newspaper will all work but one of the keys to success is to make sure that the materials don't mat. You need air to flow over and through the pile. If it does the existing bacteria will process the waste in a manner that, in the end, it does not smell bad. You end up with compost that smells like fresh earth. Ventilation may be as simple as extending a pipe up. The bacteria produce a fair amount of heat and this causes the air that has gone through the pile to rise. With intake air volume controlled and exhaust air exiting well above where people are the smell is usually quite acceptable.

Of course the natural tendency is to seal these wastes into closed containers. The feeling is these sorts of materials are best kept contained and as far away and as inaccessible as possible. Problem is that when sealed away and deprived of oxygen the bacteria produce the sorts of chemical byproducts that are associated with the worse florid funk that sewage can produce. The sorts of mind-bending pong that cause grown men to flee.

The lesson is that if you let your crap breath your crap will let you breath. Fair enough trade in my book.