Water Hardness Test Method

Water Hardness Test Method
Rana Sohel
Executive Engineer
Sunman Textile Mills Ltd. Chittagong
Cell: +8801912-420118
Email: rsohel07tex@gmail.com

The presence of Calcium, Magnesium salt i.e bi-carbonates, sulphates, Chloride in water is called causes of hardness of water. Such soluble salt are chloride, nitrites, sulphates and bicarbonate of these metal heavy metal like Fe and Al also can tribute in the hardness of water. The water which contains these salt is called hard water. Hard water caused many problems during wet processing. There are two types of hardness: Temporary hardness and permanent hardness.
Water hardness testing
Water hardness testing
Hardness Test Method:
There are few methods for measuring water hardness. In this article I have explained three methods of measuring hardness of water.

a. Ammonia- Ammonium Chloride Buffer Solution:
Dissolve 67 gms. Ammonium Chloride to 570 ml concentrated Ammonia and then make up the solution to one Litre by distilled water.

b. Erichrome Black – T Solution:
Dissolve 75 ml Tri-ethanolamine to 25 ml Ethanol and then add 0.5 gm Erichrome Black – T in 100 ml volumetric flask.

c. 0.01M EDTA standard solution:
Dissolve 3.722 gms EDTA(Ethylene Diamine Terra Acetic Acid) to one Litre distilled water.

Take 100 ml of Sample in a Beaker + 5 ml (NH4)Cl buffer solution + 1-2 drops of Black – T and Titrate it against EDTA (0.01M)

1 ml of 0.01 M EDTA = 1 mg.
Total Hardness= Volume of EDTA * 10 ppm.

100 ml Sample are taken. But for ppm sample will be 1 litre, so the result will be 10 times more. 
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Mazharul Islam Kiron is a textile consultant and researcher on online business promotion. He is working with one European textile machinery company as a country agent. He is also a contributor of Wikipedia.

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