permanent hardness


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permanent hardness

n
(Chemistry) chem hardness of water that cannot be removed by boiling as it results mainly from the presence of calcium and magnesium chlorides and sulphates
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
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Sulphate in water caused noticeable taste at a concentration above 250 ppm and contributed to the corrosion of water distribution system and permanent hardness. Water containing high sulphate level also caused laxative effect (Khan et al., 2005).
QUANTITATIVE ASSESSMENT OF WATER SAMPLES FROM DIFFERENT SOURCES OF DISTRICT ATTOCK AND ITS IMPACT ON AGRICULTURE
Permanent hardness is determined by titrating the boiled water instead of hard water and the same procedure of total hardness is followed.
Experimental study on the carwash water removal of oil and grease using zeolite and activated charcoal
Carbonates and bicarbonates are source of ordinary hardness of water while chlorides and sulfates cause permanent hardness. Ordinary hardness can be removed just by boiling the water and then filtration to remove suspended particles, while permanent hardness cannot be removed unless proper treatment is given.
Synthesis of New Congo Red Derivative Dyes and their Application as Hardness Reduction in Hard Water

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