The future is increasingly shiny for used disposable diapers, suggests this November 5, 2020 press release from the Nippon Shokubai company of Fukuoka, Japan. It says:
“The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) [is] aiming to establish a guideline for the acceptance of used disposable diapers into the sewage system based on the New Sewerage Vision Acceleration Strategy. Recycling of used disposable diapers, the amount of which continues to increase, is thus expected to be promoted.”
(Thanks to Ryoma Komiyama for bringing this to our attention.)