Airhead Composting ToiletThe Airhead Composting Toilet works simply. By separating liquids from solids, the volume of solid human matter is significantly reduced. Air Heads approximate five gallon capacity means that up to a seasons worth of weekend use may be held. (Based on solid matter volume for two persons use twice every weekend for five months: 80 uses). A liveaboard couple can expect 60 uses (one month) before theyll have to empty the solids tank. Much like a