pH

The pH-value says something about how acid a fluid is. The more acid, the lower the pH-value and the more akali, the higher the pH. The values vary from 1 to 14. The value of 7 is neutral, this is also the value of normal water.  

The ph has an influence on the material a filter is made from. A low pH is able to partly solve a plastic. To avoid this, you can neutralize the pH. This could be done by adding akali to the fluid. 

Polymers can be affected outside the values between 4-11. Some filters will be affected outside this range. This problem can be avoid by using other materials for the filters which wont be affected by akali or acids. The disadvantage of this solution is the higher costs. The best thing to do is to control the pH. 

The pH of water has influence on a lot of phases at the watertreatment. Examples are: coalgulation, chlorination and water softener. The pH also effects scaling and the scaling potential of sources. At the removal of iron with sandfiltration, the pH is also important. Iron can react with alkali. When this happens it's harder to remove the iron. 

The pH can be adapted by adding an acid or alkali to neutralize a solution. This could also be achieved by adding a buffer. This could be necessary when a stable pH is needed because a buffer can make a solutions pH more stable.   

The pH-value can be measured in a view ways. These are: colorindicators, pH-paper and pH-meters. The meters are mostly used. This is also the most reliable method. 

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