Development of a Carbonization System for Used Paper Diapers

Recycling Technology

More than two million tons of used paper diapers are disposed of annually, mainly by incineration, and it is said that they account for four to six percent of burnable waste. Used paper diapers have absorbed large amounts of water, which reduces the combustion efficiency of incinerators.
In the future, the amount of waste is expected to increase as the usage of paper diapers for adults increases with the aging of society. Although society looks to us to establish effective recycling technologies, the reality is that there are many challenges to overcome in doing so.

We face two major hurdles in recycling used paper diapers.

  1. Since used paper diapers contain excretions, they are two to four times heavier than before they were used and become bulky when stored, collected, and transported. For this reason, they must be collected frequently to reduce the generation of bad odors and maintain hygiene.
  2. To recycle used paper diapers, it is necessary to separate the component materials according to type. Since used paper dippers consist of pulp and different types of plastic, this is technically difficult to accomplish.

In response to these problems, Kao worked on the development of new carbonization equipment which is based on existing diaper disposal equipment already used in nursing homes and other facilities and carbonization equipment for food waste. We then installed carbonization equipment in a childcare facility in Saijo City, Ehime Prefecture in November 2021, and have started demonstration tests for the equipment.
We are also promoting research with the aim of converting used paper diapers carbonized by the carbonization equipment to water-retention agents or soil improvers or to promote plant growth or treat sewage, or recycling them into electronic materials or other materials through advanced technologies.

Three photographs are shown. The left one shows the newly developed carbonization equipment. The center photograph shows a person putting used paper diapers into the equipment, and the one on the right shows carbonized used paper diapers.

Investigation into collecting carbon more efficiently with lower energy consumption and resource utilization

Sanitary Products

Sanitary Products

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