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When water has been purified with ozone, are the resulting gases toxic? Is it safe to breath them?
Question Date: 2019-08-30
Answer 1:

Ozone water purification is the most used purification system around the world, mostly because it is so effective in combating many kinds of water contaminants, including dissolved metals, bacteria, viruses, and protozoans. Ozone has the chemical formula O3, meaning there are three oxygen atoms bound together. This is a very unstable molecule, and it wants to break into a single oxygen and O2 . The O2 is fine for us --it is the air we breathe. The single oxygen by itself is very reactive, and is what makes ozone both so potent against contaminants and so dangerous to use. This reactive oxygen oxidizes many molecules, meaning it can "steal" electrons from the molecules. In the case of metals, like iron, sulfur, and manganese, the oxidation process makes the metals insoluble in water. The metals precipitate out and can be filtered out of the water.

In the case of organic molecules and pathogens like bacteria or viruses, the lone oxygen reacts strongly with the molecules or cells and changes their structure. The oxygen in this case will pull off either electrons or entire atoms from the cells or molecules. In a water treatment system, ozone is bubbled through water so that many oxidation reactions can happen quickly. Likely, one organic molecule, bacterial cell, or viral cell will react many times with different lone oxygen atoms. The oxygen pulls off many atoms from the large molecules, and the gaseous byproducts tend to be oxygen, nitrogen, and carbon (the ingredients of many organic molecules), which won't harm humans. Ozone can be used in the same way to treat harmful airborne products, such as cigarette smoke, to decompose the carcinogens into inert compounds. The majority of the byproducts from ozone treatment are water and oxygen. Nitrogen and carbon dioxide are also generated from the oxidation reactions. In very small quantities, there are evaporated organic compounds from the water that were only partially treated, such as acids or other chemicals. These compounds are so dilute, though, that they pose no danger to a person standing right over the treated water. The gaseous products would be similar in composition to the air you breathe regularly.

Translation into Spanish:

La purificacion de agua mediante Ozono es el sistema mas utilizado en el mundo, principalmente porque es muy efectivo para combatir diversos tipos de contaminantes en agua incluyendo varios metales, bacterias viruses y protozoarios. El Ozono tiene la formula quimica O3, lo cual significa que hay tres atomos de oxigeno amarrados entre si. Se trata de una molecula muy inestable, la cual tiende a romperse en un oxigeno y una molecula de O2 . La molecula de O2 no tiene problema para nosotros los seres humanos --es parte del aire que respiramos. El oxigeno solo es muy reactivo, lo cual hace del ozono un elemento muy potente contra contaminantes y muy peligroso de usar. Este oxigeno reactivo oxida a muchas moleculas, lo cual quiere decir que les puede "robar" electrones. En el caso de los metales, como el hierro, el sulfuro, y el manganeso, el proceso de oxidacion hace que los metales sean insolubles en agua. Los metales se precipitan y pueden filtrarse para retirarse del agua.

En el caso de moleculas organicas y patogenos como las bacterias y los viruses, el oxigeno solo reacciona de manera muy fuerte con las moleculas o celulas y les cambia su estructura. En estos casos el oxigeno jala y saca, tanto electrones como atomos enteros de las celulas o moleculas. En un sistema de tratamiento de agus, el ozono se introduce en burbujas a traves del agua de manera que suceden muchas reacciones de oxidacion de manera muy rapida. Probablemente las moleculas organicas, o las celulas bacteriales, o las celulas virales, van a reaccionar muchas veces con los diferentes atomos individuales de oxigeno que encontraran en el agua. Este oxigeno va a jalar muchos atomos de las moleculas grandes y, los productos gaseosos resultantes van a ser oxigeno, nitrogeno, y carbon (ingredientes que constituyen muchas moleculas organicas), los cuales no son perjudiciales para los humanos. El ozono tambien puede utilizarse de esta manera para tratar productos perjudiciales en el aire, tales como el humo del cigarro, para descomponer los carcinogenos en compuestos inertes. La mayoria de los productos resultantes del tratamiento de agua con ozono, son el agua y el oxigeno. Tambien el nitrogeno y el bioxido de carbono son generados durante las reacciones de oxidacion. Tambien se evaporan del agua parcialmente tratada compuestos organicos en cantidades pequenyas, tales como acidos y otros quimicos. Sin embargo, estos compuestos estan tan diluidos que no presentan peligro alguno para las personas que se encuentran cerca del agua en tratamiento. Los productos gaseosos seran similares en composicion al aire que respiramos regularmente.

Answer 2:

The reason that ozone is used to purify water is that it is an unstable and reactive compound, and easily gives up one of its three oxygens to oxidize contaminants in water. When this oxidation reaction occurs, the ozone (O3) becomes oxygen gas (O2). The contaminants can be organic, such as bacteria or viruses, or inorganic, such as iron or manganese. Any living contaminants are killed by oxidation, and your body can easily dispose of them without harm. For the metals, the oxidized product, or metal oxides, are insoluble in water and can easily be filtered out. Any other potentially harmful oxidized byproducts can be removed with different types of filters.

The resulting gases from ozonation are primarily oxygen gas, with possible trace amounts of ozone remaining. Since ozone is harmful to your body, commercial ozonation plants usually treat the output gas from the purification process to protect the plant workers. Once any excess ozone has been removed from the output gas, it should be a breath of fresh air!

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