How to deliver drinking water chlorine-free

February 26, 2016, Ecole Polytechnique Federale de Lausanne
Drinking water: how to deliver it chlorine-free?

Chlorinated tap water is the norm around the world, but the experiences of several European countries is that it doesn't have to be. The benefits of foregoing chlorine include better-tasting and, potentially, healthier water.

If you have spent time in southern Europe or overseas, you are probably familiar with the taste of chlorinated tap water. Distributing tap water with residual chlorine is a century-old strategy used to protect populations by preventing the proliferation of waterborne pathogens. But is it necessary? In a commentary published in the journal Science, researcher Urs von Gunten from EPFL and his colleagues at Eawag provide evidence from Europe showing that chlorine could be forgone if other protective barriers are in place.

Three factors determine the quality of tap water: the quality of its source, of its treatment, and of its distribution network. Decades of experience in the Netherlands, Germany, Austria, and Switzerland have shown that, when none of these three elements are compromised, the number of waterborne-disease outbreaks are low, even lower than in countries that add to their water supply in order to compensate for poorly maintained networks, insufficient water treatment, or contaminated water sources.

But the researchers point out that distributing the water without added chlorine comes at a cost. It requires protecting groundwater sources, properly controlled water treatment, and regular maintenance of the water . But where chlorine can be foregone, the benefits go beyond improving the taste of . When disinfectants, like , react with natural organic matter that is always present in drinking , this can lead to the formation of disinfection by-products, some of which are potential carcinogens.

Explore further: Cooking with chloraminated water and salt could create toxic molecules

More information: F. Rosario-Ortiz et al. How do you like your tap water?, Science (2016). DOI: 10.1126/science.aaf0953

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vlaaing peerd
4 / 5 (2) Feb 26, 2016
Lucky to live in NL, not many people realise what a luxury it is to have tapwater that is both tastier and mineral-richer than actual spa/evian mineral water.

We use both ground- and surface water, the latter requiring a more extensive filtering process. Ground water can be cleaned by a process called cascaded oxygen filtering which is the best quality water.

Surface water is indeed more troublesome, especially because our rivers (Rhine/Maasdelta), flow through an enormous industrial area on the German border, where industrial giants like BASF have little concerns about illegally dumping chemical waste into the rivers.

So only clean flows get stored in reservoirs and preprocessed with ozone and UV light treatment (which replaces the need for fluoride after it was forbidden in 1973) and sinks into the ground over a period of 3~4 months, after this it gets the same treatment as groundwater and though it's just as clean, the calcium level is higher making it less tasty.
ab3a
5 / 5 (1) Feb 26, 2016
This is lovely, if the infrastructure is clean enough to support it and the filtration is tight enough to keep it from getting dirty. But in many cases, it isn't. Problems with cryptosporidium are commonplace.

The other problem with ozonation is that it doesn't stay in solution nearly as long as chlorine does. In many cities, the water can remain in the distribution system for several days before it reaches the tap. Chlorine at reasonable levels can help to keep that water sanitary.

Another point: We know that high doses of trihalomethanes (THM), a byproduct of chlorination, are probably not good for anyone, but we don't know the lower limits of what THM exposure should be. Saying that we shouldn't have any THM is unrealistic in today's distribution systems with ages measured in many decades, if not centuries.

If you want to rip up and replace the pipeline infrastructure, I'd be happy to entertain the idea. But it probably isn't necessary.
rrrander
not rated yet Feb 27, 2016
More crank ideas. Much like anti-vaccination types. Ban chlorine, die of cholera and other water-borne diseases. Ban fluoride, go back to the days when people lost all their teeth by 30.

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