Squat toilets are common in Asia, where squatting is seen as the natural position from which to relieve your bowels. Medical experts do say that position is healthier to do so.
What modern stuff do we want added on?
Bidet. That one's been a hit more than a miss, so let's include that.
There's
a technique that's been used for urinals, which is to seal the pooled water (ie. water-air interface) with an oil layer, which blocks odors from rising out. So alongside the bidet, we'd have some kind of oil-dripper thing to apply that oil layer after the flush. Could be some kind of scented oil layer.
For the flusher, we'd want the photo-electric eye, so that it will flush automatically in a hands-free way. That's a feature on many modern toilets.
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Alternatively, there are also incinerator toilets, which don't use water and are convenient for off-grid living. Haven't seen any version of those that's a Squat Toilet. Might be harder to empty the ashes out of a squat toilet, though - unless your'e squatting on a raised platform.
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We'd want no-slip-grip handlebars around the toilet on either side, just to help stabilize yourself, and for people who might have a little trouble getting in or out of the squatting position.
Maybe even a Squat Toilet can still have a toilet seat -- it's just that this seat would be designed to support your butt while in the squatting position. Not quite sure what that would look like, but it might be useful to have it -- otherwise how will women still be able to complain that we left the seat up?
Maybe there'd have to be a separate urinal in the bathroom just for men to urinate in, because I'd think that a squat toilet would be harder to aim into while standing, and standing seems to be the most natural way for men to urinate.