It was an idea born out of equal parts inspiration and despair. Indonesia, which is facing a steady rise in urban population and rising costs of building materials, has been falling further in the deficit of affordable living spaces. At the same time, urban population growth has led to an exponential increase in the use of non-recyclable waste products, including tons of disposable diapers.
Could dirty diapers help solve the housing crisis in a developing country by replacing some of the materials needed to build new structures?
Perhaps surprisingly, the answer is a conditional yes.
What happens is only the leading edge of emerging knowledge, and there are broad caveats about the limits of what is experienced. But there’s no need to wonder if old diapers can be used to help build a new home — and save them from a landfill in the process. It is already happening.
says Michael Liebke, a professor of civil and environmental engineering at Stanford University and an expert on sustainable building. “I’ve never seen this exact work before, and I think it’s exciting to see such new innovation in this area.”
As told in Scientific reportsA recent study found that disposable pads—clean, sterile, and shredded—can be a substitute for sand in varying proportions in the production of concrete and mortar. The team tested six different models of building materials with different ratios of diapers to see how much pressure they could take, so they knew how much sand they could substitute for the diapers and still safely fall within building codes.
The answers were enlightening. For the non-load-bearing walls of a home, up to 40% of the sand used in concrete can be substituted for shredded diapers; For columns and beams in a single story unit, the replacement rate was 27%. For a full 387-square-foot house constructed, approximately 8% of the sand in concrete and mortar can generally be replaced with diaper shreds—about 1.7 cubic meters of waste being reused instead of being thrown straight into a landfill. These are promising numbers in fact, limited only by the fact that compressive strength decreases as more diaper waste is added.
The approach is not entirely new. “A lot of materials have been used to substitute sand or gravel to eliminate waste and reduce cost,” says engineer John Straub of the University of Waterloo in Canada, but inserting diapers into concrete to build a typical house is. And there’s good reason to hope this is the start of a trend: Diapers like these are an absolute environmental nightmare.
Disposable diapers are made primarily of plastic and pulp, and contain large amounts of super absorbent polymer fibres, or SAPs. SAPs, networks of hydrophilic polymer chains, can absorb and retain liquids into gels Even under pressure– Exactly what is the value of adult diapers and incontinence products.
Experts say that diapers also have a life cycle of at least 500 years, which means that the first disposable diapers since when Most likely they are still buried in landfills, with centuries to pass before they decompose. on 20 billion used diapers All over the world they are heading to landfills every year, as they are slowly being released Harmful chemicals And Toxic microplastics in the environment.
Research idea any The way these diapers are reused is to be commended. But in a place like Indonesia, where material can contain up to 80% From the cost of building a home, figuring out a way to include them in the construction process is particularly attractive.
Siswante Zoraida, a civil engineer at Kitakyushu University and the study’s lead author, noted projections that indicate approximately 70% of all Indonesians will live in urban areas by 2025And according to expectations. However, the nation is facing a housing shortage that is increasing approx 300,000 units every year. Concrete, brick, wood, and ceramics are essential components of most housing construction, but they can carry real environmental impacts, including: Carbon emissions and environmental costs.
This, by the way, is a story of a very developing country, where rising birth rates put acute pressure to produce more housing more quickly. “We in North America don’t use concrete homes very much,” says Waterloo’s Straube, an expert on sustainable low-energy buildings. “High-rise buildings that are vulnerable to hurricanes, yes. But the environmental impact of building a house made of concrete is significant for a wood-frame house, so reducing the impact of concrete on the environment is viable.”
Zuraida and her team followed up on previous research dealing with “the use of SAP (in diapers) as concrete ingredients,” she told me. “These also encourage us to apply their findings on a large scale, which[was]to build actual dwellings using baby diapers as part of the building components.”
The team did the dirty work themselves, cleaning and disinfecting Zuraida’s family’s diapers, then ripping them up and letting them cure for 28 days. Although replacing diapers with sand could apply to any type of construction, the 387-square-foot structure was designed with low-cost housing standards in mind, Zoraida says, due to the demand for such housing in Indonesia.
In short, shredded diapers did what the evidence suggested they could do, effectively replacing a proportion of sand (a natural resource) in various mixtures. Zuraida says the next step is to scale up the model, but that will require stakeholder approval and funding that has yet to emerge.
As for the limitations of the idea, some are obvious. First, shredded diapers can replace certain fixed proportions of sand, and sand is only one component of concrete. Some environmentally conscious engineers prefer plans that avoid concrete more than others A substance widely used on land besides wateras far as possible.
“Don’t use concrete,” Straub says. “Changing nappies to be biodegradable. Using plastic components as fillers in concrete is better than nothing – but really, a little better, with minimal impact… Plastic is a high-impact material that should either be avoided or recycled at the very least, not “recycled.” “to a lower value is used.”
Replacing sand with shredded diapers, notes Stanford’s Lepech, “is about trying to manage the increasing amount of diaper waste generated. It is not, very much, about improving the sustainability of concrete materials, and it should not be put that way.”
Efforts to innovate admixture in concrete have been ongoing. Industrial wastes such as fly ash and blast furnace slag have sometimes replaced cement in concrete. “We also recycle the old concrete, crushing it and mixing the reclaimed gravel back into the concrete, which can work quite well,” says Lepech. It’s not clear, he adds, that replacing disposable nappies with sand would save any money — and it could be more expensive — and Zuraida’s study points to other limitations, such as the difficulty of collecting nappies from homes and completely sterilizing them.
Even diaper technology isn’t entirely new. More than 100,000 diapers have been used Recycled to help pave the way in Walespart of a pilot program designed to reduce the number of diapers going straight to landfills.
But the Indonesian effort is really trying to work on two issues simultaneously. The country’s housing shortage is real – “but building materials are limited,” notes the Scientific Reports study. Finding a way to recycle diapers as part of a concrete mix is one way to create a building material in part from already existing products.
“Our idea is not (ready) yet for prime time,” Zuraida says. “Research is still in its infancy.” Just as childhood around the world produced the massive environmental challenge of disposable diapers, this emerging research may begin to find more creative ways to address that challenge — and build a second story on top of it.
Carolyn Barber, MD. , an internationally published science and medicine writer and an emergency physician for 25 years. She is the author of the book Wild Medicine: What You Don’t Know May Kill YouCo-founder of the California Homeless Action Program wheels of change.
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