It takes hundreds of years for disposable diapers to decompose in landfills – but this new machine can turn 220 pounds of dirty diapers into clean, raw materials in a single hour. Sz-Chwun John Hwang and a team of researchers at Taiwan’s Chung Hua University built the machine as a pilot plant – and they’re planning to build a larger facility that can recycle 10 tons of used diapers in just one day.

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Disposable diapers are convenient but problematic

Have you ever thought about the evolution of the diaper? You might be surprised to learn that the history of diapers goes back thousands of years, but disposable diapers have only been around since the 1960s. Diapers have evolved to be more effective and efficient. The disposable variety makes parents’ lives easier – they’re convenient, absorbent and gentle on babies’ skin. However, there is a huge downside to disposable diapers: the amount of waste generated from their use.

In the U.S., it is estimated that 20 billion disposable diapers end up in landfills each year, and pathogens from solid waste contained in those diapers find their way into the environment. It can take hundreds of years for diapers to degrade in a landfill, and they release methane and other toxic gases into the air. If soiled diapers don’t end up in landfills, some companies choose to incinerate them, leading to an estimated 3428 kg of CO2 emissions per day, based on 10 tons of diapers per day.

There is a need to reduce the amount of waste caused by disposable diapers, and companies and researchers are using technology to find innovative ways to recycle and reuse soiled diapers.

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Recycling disposable diapers

Recycling diapers and other absorbent hygiene products might sound like a no-brainer, but the process has its complications — including cost-effectiveness and complex engineering. As technology advances, science can overcome these obstacles and make recycling disposable diapers a viable solution for reducing the amount of waste in landfills and harmful chemicals in the environment.

Sz-Chwun John Hwang and his team have developed a diaper recycler that can make it easy for institutions — like long-term care facilities, day cares or hospitals — to give old diapers new life. The plan is simple: a specialized on-site washing machine sanitizes used diapers so they can be processed into reusable raw materials.

The staff loads the machine with diapers and washes them with a disinfectant to destroy any pathogens. After the diapers are cleaned, the different materials (plastic, fluff fibers and absorbent material) are separated using stratification. This method uses less water than an average toilet, and the used water can be recycled on-site or easily disposed in the facilities’ existing drainage systems. The estimated carbon emission from this process is 35.1 kg of CO2 per day, based on 10 tons of diapers per day.

rendering of the recycling machine

After they are cleaned and separated on-location, the materials are taken to a central recycling center. The separated layers are transformed into new materials, which can be made into a range of products: plastic bags or trash cans from the plastic; new diapers, cardboard boxes or paper products from the fluff fill; and absorbent pet pads, desiccant or polyacrylate fiber from the absorbent material.

In order for the product to be successful, the researchers had to make it user-friendly. If the process is too complicated or time-consuming, most people won’t bother with it. Hwang and his team designed the machines to make it easy for people to lift the diapers and load the machine.

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Diaper design must become more eco-friendly

Hwang and his team are working with facilities to find new and inventive ways to recycle disposable diapers, and some other businesses are following suit. However, Hwang’s method stands out in that it focuses on making it easier for caretakers to collect the used diapers.

Moving forward, diaper companies will need to partner with researchers to design the most effective and efficient diapers with a lower environmental impact. By finding innovative ways to reuse products and reducing the impact our waste has on the environment, we can help sustain our world for generations to come.

+ Chung Hua University

Images via Chung Hua University, Hermes Rivera and Flickr

rendering of the recycler shows stairs leading up to the top of the machine

diagram explains how the machine works