Kao to implement diaper carbonization recycling system across Japan

16 Feb 2023 --- Kao Corporation and Kyoto University have successfully completed the verification testing of the Used Disposable Diaper Carbonization Recycling System that has been ongoing since 2021. They aim to establish the technology this year – a system that converts diapers into carbon material – with the goal of implementing it publicly by 2025.

The R&D is being done in collaboration with Saito City, Japan.

More than two million metric tons of used disposable diapers are discarded as trash each year in Japan, most of which are incinerated and comprise between 4 to 6% of burnable trash.

To encourage decarbonization, Kao reports its internal rise in the carbon price to ¥18,500 (US$136) per metric ton of carbon dioxide. As part of strengthening its ESG governance structure, Kao describes changes to the company’s biodiversity policy and creating new ESG steering committees.

Disposing of the waste material
The research project aims to reduce the environmental impact via carbon dioxide emission reductions by developing carbonization equipment for used disposable diapers, converting the carbonized disposable diapers to carbon material and recycling it efficiently.

The moisture retained in the diaper material often degrades incinerator combustion efficiency. The use of disposable diapers for adults has increased with the aging of the population – over 15% of Japanese are over 75, according to the countries’ Ministry of Internal Affairs and Communications. The volume of waste is expected to increase and have an even greater impact on the environment.More than two million metric tons of used disposable diapers are discarded as trash annually in Japan alone.

Not wasting an opportunity
The project will ensure efficient carbonization from relatively low-energy inputs through low-temperature reactions.

Carbonization sterilizes and deodorizes, which will resolve hygiene problems caused by processing the used diapers and reduce weight and volume hence decreasing the frequency with which this waste is collected.

When used disposable diapers are incinerated, they generate CO2 emissions. However, when carbonization is performed, the carbon is fixed in carbon material, making it possible to reduce the amount of carbon emissions.

In related news, Kimberly-Clark, manufacturer of Huggies nappies, partnered with Australian companies to introduce a local nappy recycling trial, aimed at curbing the high rates of pollution caused by diaper disposal at landfill.

Edited by Inga de Jong

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