ABSTRACT
During its natural circulation through the atmosphere, the surface and underground water takes part in a variety of chemical, physical, and biological reactions. Various contaminants of natural water might be unfavorable with a view to its use. When it is used as drinking water, the most important requirement to be fulfilled is that water must not contain components detrimental for health. Water acceptable regarding health aspects contain components at concentrations that are sufficient to cause troublesome effects. In many ground- and surface waters, the nitrate levels have increased due to the extensive use of fertilizers in agriculture. Nitrate and sulphate ions can be removed by anion exchange for chloride ions. To increase the efficiency of the regeneration, a conventional lime dealkalization can be carried out prior to the application of the strong-acid exchanger.
