My boat needed a holding tank, and was about to install one when my wife saw the Airhead toilet. She loves the idea. Me not so much. I wanted a conventional system (holding tank) since I know what I'm in for.
I did some reading, and found this:
Joseph Jenkins, Inc. - The LOVEABLE LOO
Airhead and Nature's Head people say that if you keep the urine and most liquids out, you get no smell.
Well, I thought I'd try an experiment. I set up a 5 gallon bucket in the bathroom of my house to use. It was funny. We just remodeled the bathroom: new wide pine floor, new toilet & sinks curtains & paint..and now an orange bucket. Toilet was off-limits except to pee. I also got some coco husks bricks to mix. To start, I slightly hydrated about one gallon of the coco husks as the composting medium, then after every use, a cup gets added. We stir the bucket with a stick every few days. This was late winter, all windows closed all the time. I was kind of hoping the experiment would stink up the house so we could be done with it. I was surprised that there was no smell what so ever. Not kidding! I was expecting it to stink at first, and kept the bathroom door closed (no vent fan) to let the stink collect, but there was no smell. After you go, a cup of the husks and the smell disappears as quick as flushing the toilet. Smell would not be a reason to doubt this system. I must admit that it somehow seems "grosser"...not flushing it away and out. The stirring is a little gross too, no smell or anything, it doesn't even look gross, just the idea is unsettling.
We're going to try it on the boat. I've glassed over the two hull holes, and we'll see. We are still undecided as to which we get, the Airhead or the Nature's Head. At this point, if it were me I'd stick with the 5 gallon bucket but I've been told that females might appreciate the urine separating feature of the commercial units.