https://geonika.agis.uniba.sk/tsenz/index.php?action=history&feed=atom&title=Hard_water 2026-04-08T14:51:11Z História úprav pre túto stránku na wiki MediaWiki 1.31.1 https://geonika.agis.uniba.sk/tsenz/index.php?title=Hard_water&diff=294&oldid=prev 2014-08-07T13:14:26Z

<p>Importing text file</p> <p><b>Nová stránka</b></p><div>:Slovak term: [[Slovenský termín]]<br /> # Generally, water that requires considerable amounts of soap to produce a foam or lather and that also procudes scal in hot water pipes, heaters, boilers and other units in which the temperature of water is increased materially (Symons et al, 2000).<br /> # &lt;del&gt;See hardness, total.&lt;/del&gt;<br /> <br /> ==Explanation==<br /> Hardness in water is caused by dissolved calcium and, to a lesser extent, magnesium. It is<br /> expressed as the equivalent quantity of calcium carbonate. Hardness above about 200<br /> mg/litre can result in scale deposition, particularly on heating. No health-based guideline<br /> value is proposed for hardness (WHO 2004).<br /> <br /> ==Example==<br /> With respect to hardness, waters have been classified as follows: 0-25 milligrams per litre<br /> as calcium carbonate (CaCO3) as very soft; 25-75 milligrams per litre as calcium carbonate<br /> (CaCO3) as soft; 75-150 milligrams per litre as calcium carbonate (CaCO3) as moderately<br /> hard; 150-300 milligrams per litre as calcium carbonate (CaCO3) as hard; and 300<br /> milligrams per litre as calcium carbonate (CaCO3) and up as very hard (Symons et al,<br /> 2000).<br /> <br /> ==References==<br /> * WHO (2004) [http://www.who.int/water_sanitation_health/dwq/gdwq3rev/en/index.html Guidelines for Drinking-water Quality]<br /> * Symons, JM, Bradley LC and Cleveland TC (2000). The drinking water dictionary. American Water Works Association.<br /> <br /> ==Links==<br /> * [http://apps.who.int/thelexicon/ WHO — The Health and Environment Lexicon]<br /> <br /> [[Category:EN]]</div>

Vrut