Source of Bicarbonate
The Bicarbonate (HCO3) ion is the principal alkaline constituent in almost all water supplies. Alkalinity in drinking water supplies seldom exceeds 300 mg/i. Bicarbonate alkalinity is introduced into the water by CO2 dissolving carbonate-containing minerals. Alkalinity control is important in boiler feed water, cooling tower water, and in the beverage industry. Alkalinity neutralizes the acidity in fruit flavors; and in the textile industry, it interferes with acid dying. Alkalinity is known as a "buffer".
Treatment of Bicarbonate
In the pH range of 5.0 to 8.0 there is a balance between excess CO2 and bicarbonate ions. Removing the free CO2 through aeration can reduce the bicarbonate alkalinity. Feeding acid to lower the pH can also reduce the alkalinity. At pH 5.0 there is only CO2 and 0 alkalinity. A strong base anion exchanger will also remove alkalinity.