Editing Autonomous building (section)

====Waste====
Sewage handling is essential for public health. Many diseases are transmitted by poorly functioning sewage systems.

The standard system is a tiled leach field combined with a [[septic tank]]. The basic idea is to provide a small system with primary [[sewage treatment]]. Sludge settles to the bottom of the septic tank, is partially reduced by [[anaerobic digestion]], and fluid is dispersed in the leach field. The leach field is usually under a yard growing grass. Septic tanks can operate entirely by gravity, and if well managed, are reasonably safe.

Septic tanks have to be pumped periodically by a [[Cesspool emptier|vacuum truck]] to eliminate non reducing solids. Failure to pump a septic tank can cause overflow that damages the leach field, and contaminates ground water. Septic tanks may also require some lifestyle changes, such as not using garbage disposals, minimizing fluids flushed into the tank, and minimizing non-digestible solids flushed into the tank. For example, septic safe toilet paper is recommended. However, septic tanks remain popular because they permit standard plumbing fixtures, and require few or no lifestyle sacrifices.

Composting or [[packaging toilet]]s make it economical and sanitary to throw away sewage as part of the normal garbage collection service. They also reduce water use by half, and eliminate the difficulty and expense of septic tanks. However, they require the local landfill to use sanitary practices.

Incinerator systems are quite practical. The ashes are biologically safe, and less than 1/10 the volume of the original waste, but like all incinerator waste, are usually classified as hazardous waste.

Traditional methods of sewage handling include [[pit toilet]]s, [[latrine]]s, and [[outhouse]]s. These can be safe, inexpensive and practical. They are still used in many regions.