Egg-shaped Sludge Digestion Tanks in Yokohama

These tanks exist in Yokohama Hokubu Sludge Treatment Center.

 

I found an article about the center at Kajima corporation web page (written in Japanese). According to the article, the tanks hold sludge to turn organic matter into methane gas. The shape enables effective stirring. The page has a nice photo of the tanks illuminated for sightseeing ships during Yokohama Expo held in 1989.

 

Done