Purified Water
<p ><b>Purified water</b> is water that is mechanically filtered or processed to be cleaned for consumption. <a href="http://en.wikipedia.org/wiki/Distilled_water" title="Distilled water" >Distilled water</a> and <b>deionized (DI) water</b>have been the most common forms of purified water, but water can also be purified by other processes including <a href="http://en.wikipedia.org/wiki/Reverse_osmosis" title="Reverse osmosis" >reverse osmosis</a>, <a href="http://en.wikipedia.org/wiki/Carbon_filtration" title="Carbon filtration" class="mw-redirect" >carbon filtration</a>, <a href="http://en.wikipedia.org/wiki/Microfiltration" title="Microfiltration" >microfiltration</a>, <a href="http://en.wikipedia.org/wiki/Ultrafiltration" title="Ultrafiltration" >ultrafiltration</a>, <a href="http://en.wikipedia.org/wiki/Ultraviolet" title="Ultraviolet" >ultraviolet</a> <a href="http://en.wikipedia.org/wiki/Oxidation" title="Oxidation" class="mw-redirect" >oxidation</a>, or<a href="http://en.wikipedia.org/wiki/Electrodialysis" title="Electrodialysis" >electrodialysis</a>. In recent decades, a combination of the above processes have come into use to produce water of such high purity that its trace contaminants are measured in parts per billion (ppb) or parts per trillion (ppt). Purified water has many uses, largely in science and engineering laboratories and industries, and is produced in a range of purities. Purified water in colloquial English can also refer to water which has been treated ("rendered potable") to neutralize, but not necessarily remove contaminants considered harmful to humans or animals.</p>
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Distilled water is produced by a process of distillation and has an<a href="http://en.wikipedia.org/wiki/Conductivity(electrolytic)" title="Conductivity (electrolytic)" >electrical conductivity</a> of not more than 10 µ<a href="http://en.wikipedia.org/wiki/Siemens(unit)" title="Siemens (unit)" >S</a>/cm and total dissolved solids of less than 10 mg/litre.<sup id="cite_ref-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Deionized_water#cite_note-0" >[1]</a></sup> Distillation involves <a href="http://en.wikipedia.org/wiki/Boiling" title="Boiling" >boiling</a> the water and then condensing the <a href="http://en.wikipedia.org/wiki/Vapour" title="Vapour" class="mw-redirect" >vapour</a> into a clean container, leaving solid contaminants behind. Distillation produces very pure water. A white or yellowish mineral scale is left in the distillation apparatus, which requires regular cleaning.</p>
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Distillation alone does not guarantee the absence of bacteria in drinking water unless containers are also sterilized. For many applications, cheaper alternatives such as deionized water are used in place of distilled water.</p>