These water-closets use a quarter of the water to flush waste away, by ejecting the body of water with a sealed ejection of air, as far as I understand it.
I wonder if anyone has considered the amount of water required to transport solids along a soil pipe... Would the reduced water flow lead to a build up of solids...?
Apparently a good number of companies, such as McDonalds are replacing toilets with these newer inventions. There appears to be no blockage with solids, but I can agree that I might be concerned on that count too.