1. water-purification tank
2. septic tank
Wikipedia definition
3. Septic tankA septic tank is a key component of the septic system, a small-scale sewage treatment 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 filters, and clarified liquid effluent disposal means such as a septic drain field, ponds, natural stone fiber filter plants or peat moss beds.
Read “Septic tank” on English Wikipedia
Read “浄化槽” on Japanese Wikipedia
Read “Septic tank” on DBpedia


to talk about this word.