Natural Water Treatment (Lake & River Liming)

Acid rain is the result of air pollution caused by gases such as sulfur dioxide and nitrous oxides from industrial activities, such as the combustion of coal in power stations. Polluted air containing sulfur dioxide and nitrogen oxide gases results in acid rain, which has a negative effect on the pH value of open waters causing them to become acidic and develop a low pH level. This can consequently kill fish and other organisms such as aquatic plants.

Eutrophication is caused by agricultural and industrial runoff, pollution from septic systems and sewers, and other human-related activities which increase the flow of both inorganic nutrients and organic substances into ecosystems. Eutrophication decreases the quality of rivers, lakes and estuaries for recreation, fishing, hunting and aesthetic enjoyment. Eutrophication darkens the water and causes algal bloom, odor and the disappearance of fish from the area. Health problems can occur where eutrophic conditions interfere with drinking water treatment.

The environmental problems described above can be solved by spreading calcium carbonate on the water surface to increase the pH of the water. This procedure limits the eutrophication of water and adjusts the pH level (buffering the pH). Omya’s dedicated calcium carbonate products decrease the excess nutrients (phosphate, nitrate) in the water by adding calcium ions, which subsequently increases the quality and clarity of the water.


Omya deposits are near important markets to guarantee efficient, long-term supply of high-quality calcium carbonates.