Tokyo Metropolitan Government
Official Video Channel

③第一沈殿池（英語：英語音声） 3. Primary Sedimentation Tank

２～３時間かけて下水を流し、下水に含まれる沈みやすい汚れを沈殿させます。

Suspended solids in the wastewater settles to the bottom as wastewater slowly flows through the tank for 2 to 3 hours.