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What Ozone Does


Chlorine's out, ozone's in as purifier of water

Of all the deadly technologies developed during World War 1, none was more gruesome, none more cruel than poisonous chlorine gas.

One strong whiff and a soldier would start coughing blood. the tortured hacking could go on for days. Inevitably, the gas would kill - hundreds of thousands of young men. In farmhouses and hospitals throughout Europe, people watched. And when the War To End All Wars was done, they gagged at the thought of disinfecting their drinking water with chlorine.

Not so across the Atlantic. In America hundreds of water systems began disinfecting their water with chlorine in the 1920's and '30s. To this day it is a commonplace chemical that we drink everyday, rub from our eyes after staying too long in the pool and used to kill bugs in the water as a matter of course. Soon, however, this will change.

American technology has finally confirmed what the Europeans suspected all along: Adding chlorine to drinking water is NOT a healthy practice.

When chlorine combines with the byproducts of rotting leaves, a family of chemicals called trihalomethanes. or THMs, are formed. THMs are carcinogenic. One study by the Presidents Council on Environmental Quality found that people drinking chlorinated water had a 13 percent to 93 percent greater chance of developing rectal cancer and a 53 percent greater chance of getting colon cancer than people who drank untreated (non-chlorinated) water.

For years, no one knew that people were getting small doses of THMs every time they brushed their teeth or made lemonade. It wasn't until the mid-1970s that the Environmental Protection Agencies water quality lab in Cincinnati first isolated THMs in drinking water. Before that, "We didn't worry about these cancer-causing chemicals because we didn't know they were there," said Pete Rogers, chief of the California Department of Health Services' drinking water branch.

"We didn't know how to measure them, and we really didn't know what the long term effects (of drinking them) were." All that is much clearer now. At the current maximum contaminant level of 100 parts of THM per billion parts of water, the EPA estimates that one additional cancer will strike among 100,000 people who drink two liters of water a day for 70 years. The EPA takes fewer risks with other drinking water contaminants.

For example, its recommended level for the industrial solvent trichloroethene, or TCE, is five times stricter when measured by the number of projected cancer deaths. The reason the EPA went easy on THMs: If the standard had been any tougher, water agencies wouldn't have been able to meet it unless they stopped chlorinating. And there was no alternative. Not in this country, not in 1979, when the standard was set.

As it was, the water industry balked at having to meet even the lenient 100 parts per billion standard for THMs. The first reaction by the American Waterworks Association, an industry group, was to file a suit to block the standards implementation. Too hard to meet, that association claimed, especially for agencies that get a lot of their water from rivers and streams, which are heavily laced with THMs chemical "precursors."....

Next year, however, the EPA says it's really going to get tough. It plans to lower the maximum allowable level of THMs to between 50 and 10 parts per billion. Again, water agencies are balking. This time, however, they also are scrambling to find another method of disinfecting water. One possibility that has been used for years in Europe: OZONE.

The gas, which smells like watermelons, disinfects as well as chlorine does. It is more expensive. Europeans pay much more for their water than Americans. But, unlike chlorine, ozone disappears into the air within 24 hours, leaving behind NO toxic residuals.....

"The fact of the matter is that our analysis of drinking water is incomplete," said William Glaze, a professor at UCLA's School of Public Health who specializes in water treatment.... For more than a year Glaze has been focusing his microscope on water samples from the city of Los Angeles' new filtration plant in Sylmar.

The 2-year-old, $106 million plant is the largest in the world that disinfects with ozone. So far, Glaze says he has found nothing alarming in the product of the plant he calls "one of the best in the world." There, where the Los Angeles Aqueduct dumps its relatively pure runoff from the Owens Valley, man-made lightning bolts pass through thousands of glass tubes in the plants huge ozone generators. Inside the tubes, the electricity converts liquid oxygen into ozone.

The gas is then piped over to holding tanks the size of small auditoriums. The tanks are filled with water and the ozone is allowed to percolate through it....From Egypt, Japan and Monroe, Michigan, water managers have come to observe.

bulletBy Emilia Asdari, Herald Examiner Staff Writer, Los Angeles Herald Examiner, Dec. 11-18 1988

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