From disposable diaper to source for raw materials

Disposable diapers are convenient for the parents, but because of their composite structure, recycling them is complicated. However, a team of researchers at Taiwan’s Chung Hua University has built a machine that can turn 100 kilograms (220 pounds) of dirty diapers into clean, raw materials in one hour.

Most dirty diapers end up on the landfill, where they leak methane and other toxic gases into the environment. Some companies incinerate them, leading to an estimated release of 3,500 kilograms of CO2 per day.

Disposable diapers commonly consist of plastic, fluff fibres and absorbent materials, which are hard to separate and do not biodegrade.

The pilot plant the researchers built is able to recycle 100 kilograms of diapers per hour. The dirty diapers are washed and disinfected to destroy any pathogens. After that, the different materials are separated using stratification. The plastic, PE, floats on top and can be scooped off, while the polyacrylate and fluff fibres are sieved out.

The machine could be used in places that use a lot of diapers, for instance hospitals. The researchers say that the method uses less water than an average toilet, and the water can be recycled on-site, or disposed in the facilities’ existing drainage systems. The estimated carbon emission is about 35 kilograms (77 pounds) based on 9 tonnes (10 US tons) of diapers per day, significantly less than when the diapers are burned.

The separated materials are taken to a central recycling centre, where they can be turned into new materials, from plastic bags to new diapers.

Photos: Chung Hua University (via Inhabitat) / Harmid