And the world may make a beaten path to your door
A REPORT published last year by Water UK, an industry body, said that more than 90% of sewer-pipe blockages in Britain were caused by “non-flushable wipes”. Accumulations of these can clog up pumps. Worse, when they are gathered together by the adhesive power of kitchen grease, they can form giant “fatbergs” that choke the passage of effluent.
Some of the wipes in question were for cleaning surfaces or removing cosmetics. Most of those that could be identified, though, were for wiping babies’ bottoms. And probably not only those of babies. As people grow richer, they can afford more comfortable means of personal hygiene, so many adult nether regions are probably being tended to in this way as well.
Ordinary toilet paper is not a problem for sewers. It disintegrates rapidly, after being flushed, into the fibres from which it is made. Wet-wipes are different. To keep them intact while damp, before and during use, their fibres are held together by resins. But these resins also hold them together after use, meaning they do not disintegrate. Deng Chao and his colleagues at Donghua University, in Shanghai, therefore wondered if it might be possible to make resin-free wipes. And, as they report in Royal Society Open Science, they think they have managed to do so.
Instead of using resin to hold the fibres together, Dr Deng and his colleague have been experimenting with a technique called hydroentanglement. This involves bombarding the web of fibres destined to become a wipe with jets of water. The jiggling thus induced shifts the fibres around in a process that is, in effect, the opposite of combing. As with uncombed hair, the result is strongly knitted together—so strongly that in Dr Deng’s experiments the effect was as good as with a conventional wipe. Those experiments also showed, though, that unlike a conventional, resin-bound wipe, the hydroentangled version disintegrated in the same way as toilet paper does when it was put into water and agitated.
Hydroentanglement is, as a bonus, an established industrial process, employed to make fabrics without weaving. (The result is known as spunlace.) Adapting it to make wet-wipes should not, therefore, be that difficult. And if it can be so adapted, then the days of the fatberg should be numbered—meaning that one of the most vital, if hidden, parts of any society’s infrastructure, its drains, can run free.