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Every day, more than 141 billion liters of water are used solely to flush toilets. With millions of global citizens experiencing water scarcity, what if that amount could be reduced by 50%?
The possibility may exist through research conducted at Penn State, released today (Nov. 18) in Nature Sustainability.
"Our team has developed a robust bio-inspired, liquid, sludge- and bacteria-repellent coating that can essentially make a toilet self-cleaning," said Tak-Sing Wong, Wormley Early Career Professor of Engineering and associate professor of mechanical engineering and biomedical engineering.
In the Wong Laboratory for Nature Inspired Engineering, housed within the Department of Mechanical Engineering and the Materials Research Institute, researchers have developed a method that dramatically reduces the amount of water needed to flush a conventional toilet, which usually requires 6 liters.
Co-developed by Jing Wang, a doctoral graduate from Wong's lab, the liquid-entrenched smooth surface (LESS) coating is a two-step spray that, among other applications, can be applied to a ceramic toilet bowl. The first spray, created from molecularly grafted polymers, is the initial step in building an extremely smooth and liquid-repellent foundation.
"When it dries, the first spray grows molecules that look like little hairs, with a diameter of about 1,000,000 times thinner than a human's," Wang said.
While this first application creates an extremely smooth surface as is, the second spray infuses a thin layer of lubricant around those nanoscopic "hairs" to create a super-slippery surface.
Jing Wang, Lin Wang, Nan Sun, Ross Tierney, Hui Li, Margo Corsetti, Leon Williams, Pak Kin Wong, Tak-Sing Wong. Viscoelastic solid-repellent coatings for extreme water saving and global sanitation. Nature Sustainability, 2019; DOI: 10.1038/s41893-019-0421-0
(Score: 0) by Anonymous Coward on Wednesday November 20 2019, @09:50PM
As an aside, I do wonder where this 141 billion number comes from, but let's accept it.
The answer to the question posed by the article is "bugger all", because toilet flushing is such an irrelevant fraction of overall water usage, even if we ignore the fact that many municipal water systems include water treatment facilities that return most of the water used by toilets back to the source. So going by water withdrawals, the United States alone uses about ten times that amount per day [usgs.gov] (~1200 billion liters per day), and globally it is about 100 times that amount per day [worldometers.info] (~11000 billion liters per day). (note that these water stats are around 5 years old now and I suspect they are due for a refresh in the near future).
So that gives us a pretty good estimate of the impact: toilet use represent about 1% of global water withdrawals and reducing that usage by half means a reduction in global water withdrawals by about one half of one percent. This is going to do exactly bugger all to help with any water shortage problems.
Surely it is possible to write an article about cool toilet tech without wrapping it in save the planet nonsense.