I've used one for so long now that I dislike using the "standard" water- and fertility-wasting version that Americans everywhere use. But it wasn't that long ago that I too found the idea, well, dirty. Bring up the subject among the uninitiated and before the dialogue goes very far at all you'd better be prepared to field wrinkled faces, upturned noses, and 5 year old arguments, like,
Yep, that's the standard logic. You do what?? Compost our wastes, yes, you heard me. And not just kitchen scraps, leaves, and livestock poo, either. Our own human wastes. Number 1 and number 2.
"You mean, kind of like a kitty litter box?"
Yeah, sort of, except that we don't scratch around in it once it's been used, it gets dumped the second it's full, and it doesn't stink to high heavens. Doesn't stink at all actually. And it's much cuter.
And here's the thing. It's dang near impossible for me to come up with one single easier change you could make in your life that would have a more positive impact on the planet's health (or the persistence of humanity).
Think about it. Fresh water is both a finite commodity on this planet - the only planet we'll ever live on, by the way - and the single most important resource in our lives, excepting perhaps oxygen. And how do we treat it with standard flush toilets? Like shit. Literally. It's like pulling down your pants and taking a dump on your mother. We take a gallon and a half of this most precious substance - drinking quality water - and flush it down the toilet every time we wish to rid our homes of a pint of piss. Piss that, I might add, is loaded with nitrogen, phosphorus, and trace minerals. Dilute it, at least 10:1, and you have an excellent liquid fertilizer (that also repels deer).
Ever heard of peak phosphorus? If not, it's time you did. See, industrial agriculture relies heavily on rock phosphate to fertilize our major food crops, and when you do anything on the scale that industrial agriculture does things, you need a pretty large amount of pretty high quality material to fit your production scheme. And, as with all finite resources on finite planets, both the quantity and, more importantly, the quality decline with use over time. Rock phosphate supplies have already peaked and are in decline. There is no debate raging over the subject. High quality rock phosphate supplies are on their way out for good. And get this: we also make herbicides out of the stuff! That's right, we take a major nutrient, vital for plant growth, whose supplies are in terminal decline, and warp and twist it into chemicals that KILL plants! Oh, sweet irony...
But wait, there's an upside, too. Peak phosphorus and declining rock phosphate quantity and quality only matter if you get your food from the industrial food supply that relies on it! It isn't a problem for all of us who grow our food organically, at home, and recycle all of our bodily wastes back into the soil. So you're all set, right? I thought so. There are a dozen ways to collect phosphorus from your surroundings, every day, and composting toilets are right up there at the top of the list. Easy peasy.
So now that you've started using a composting toilet, you're NOT wasting tens of thousands of gallons of drinking quality water every year, water that won't find its way back into your aquifer within your or your grandchildren's lifetime, nor are you flushing away vital nutrients, nutrients that are in increasingly short supply globally every year, in such a cavalier way, as if the nutrient fairy will just show up with a fresh supply when you run low.
And no, there is no danger from pathogens. Gut microbes like E. coli live in very specialized, temperature controlled environments, like, well, your gut, and compost piles are a very hostile place for them. They don't stand a chance in there. That objection you're waving your hand about right now is simply part of your cultural programming (the 5 year old part). Cultural programming that, I might add, is currently destroying humankind's ability to continue enjoying this fine little planet we call home. But don't worry about it too much, I'm sure another planet will show up when we need one. Or the Rapture. Or the Singularity. Or the...
Welcome to the composting toilet club...one day...when you grow up.