alkalinity determination measurement

Determination of Alkalinity
Determination of Alkalinity

Determination of Alkalinity

The alkalinity of a water is its capacity to neutralize acids. The alkalinity of natural waters results from the weak acid salts in it. Bicarbonates come first. Bicarbonates are the most basic form of alkalinity. These are formed in the waters by the activity of carbon dioxide on the substances that show the nature of the base in the soil. Apart from bicarbonates, other weak acid salts such as silicates, borates and phosphates are present in small amounts in natural waters.

Natural waters can sometimes contain significant amounts of carbonate and hydroxide alkalinity. This situation is very common especially in the surface waters produced by algae. Algae absorb the free or ionized carbon dioxide present in the water and raise the pH of the water. Boiler waters may also contain carbonate and hydroxide alkalinity.

Briefly, the alkalinity of the water consists mainly of weak acid salts and strong bases. Alkalinity of water is a commonly used feature in water treatment plants. Waters with high alkalinity are generally unpleasant and not harmful to human health. In natural waters, the following three basic substances form the alkalinity of water: hydroxides, carbonates and bicarbonates.

Alkalinity measurements are also carried out by authorized laboratories within the scope of water and wastewater measurements, and phenolphthalein and methylorange indicators are mainly used for alkalinity determination. If it contains water, hydroxide or carbonate, it gives pink color with phenolphthalein indicator and if it is acid, it becomes colorless. Methylorange indicator turns yellow when one of the three alkalinity is present in the water and turns red if acid is present.

The normal carbonate alkalinity may be in combination with bicarbonate or hydroxide or one of its alkalinity, but the hydroxide and bicarbonate alkalinity do not coexist.

Alkalinity measurements are frequently used by environmental engineers in the following studies:

  • Chemical coagulation of drinking and wastewater
  • Calculation of the required amount of chemicals in the softening process of water with lime and soda / lime methods
  • Corrosion control studies
  • To evaluate the buffering capacity of wastewater

Laboratories operate in accordance with the TS EN ISO / IEC 17025 standard.