A septic tank is a key component of the septic system, a small-scale sewage treatment

Sewage treatment

Sewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater and household sewage, both runoff and domestic. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants...

 system common in areas with no connection to main sewage pipes provided by local governments or private corporations. (Other components, typically mandated and/or restricted by local governments, optionally include pumps, alarms, sand filter

Sand filter

Sand filters are used for water purification. There are three main types;# rapid sand filters# upflow sand filters# slow sand filtersAll three methods are used extensively in the water industry throughout the world...

s, and clarified liquid effluent disposal means such as a septic drain field

Septic drain field

Septic drain fields, also called leach fields or leach drains are used to remove contaminants and impurities from the liquid that emerges from the septic tank. A septic tank, the septic drain field, and the associated piping compose a complete septic system. The septic drain field is effective for...

, ponds, natural stone fiber filter plants or peat moss

Sphagnum

Sphagnum is a genus of between 151 and 350 species of mosses commonly called peat moss, due to its prevalence in peat bogs and mires. A distinction is made between sphagnum moss, the live moss growing on top of a peat bog on one hand, and sphagnum peat moss or sphagnum peat on the other, the...

 beds.) Septic systems are a type of On-Site Sewage Facility (OSSF

OSSF

On Site Sewage Facilities are wastewater systems designed to treat and dispose of effluent on the same property that produces the wastewater....

).