CaCOekvivalenttia

CaCOekvivalenttia, often abbreviated as CaCO3eq, is a unit used to express the total alkalinity of a water sample in terms of the mass of calcium carbonate (CaCO3) that would produce the same alkalinity. Alkalinity itself is a measure of the capacity of water to neutralize acids. It is primarily contributed by the presence of dissolved bicarbonate (HCO3-), carbonate (CO32-), and hydroxide (OH-) ions.

The term "equivalent" signifies that the measurement is standardized to a common reference compound. Calcium carbonate is chosen because it is a naturally abundant mineral and its ions (Ca2+ and CO32-) are common contributors to alkalinity in many natural waters. By expressing alkalinity as CaCO3eq, different water samples can be more easily compared, regardless of the specific combination of ions contributing to their alkalinity.

This unit is widely used in water quality monitoring, environmental science, and various industrial processes where controlling water chemistry is important. For instance, in wastewater treatment, alkalinity is crucial for biological nutrient removal processes. In boiler systems, understanding alkalinity helps prevent scale formation and corrosion. The concentration is typically expressed in milligrams per liter (mg/L) of CaCO3eq. A higher CaCO3eq value indicates a greater capacity of the water to resist changes in pH due to acid addition.