Refers to the process or system of treating and disposing of sewage and wastewater.
Sewage disposal is not adequately carried out in this area.
The aging of sewage disposal facilities has become a problem.
下水処理 (sewage treatment) focuses on the purification process, while 下水処分 emphasizes the disposal aspect, including final discharge or elimination.
排水処理 (wastewater treatment) is a broader term covering industrial and domestic wastewater, whereas 下水処分 specifically refers to sewage disposal.
Compound of 下水 (sewage) and 処分 (disposal). The exact historical derivation is uncertain, but the term follows standard Sino-Japanese word formation patterns.