Why alkalinity as caco3

The determination of the equivalent concentration of acidity in terms of CaC03 is a bit tricky. Calcium carbonate does not react with an 0H- which ought to determine the amount of acidity that CaC03 contains, if it does.

But since no reaction can ever occur, CaC03 does not have any acidity; it has alkalinity, instead, as shown by the reaction in Equation If CaC03 does not have any acidity, why then express acidity in terms of calcium carbonate? This is one of the biggest blunders in the environmental engineering literature, and it ought to be a big mistake; however, right or not, things can always be made arbitrary and then rationalized—this is what is done and used in practice.

Arbitrarily, Equation Where there is an excess of positive epm, the remaining negative epm usually is assumed to be nitrate. To calculate dissolved solids, convert the various constituents from ppm to epm and total the various cations positively charged ions and anions negative ions.

The cations should equal the anions. If not, add either sodium plus or nitrate minus ions to balance the columns. Convert each component ionic epm to ppm and total to obtain ppm dissolved solids.

For example, to convert ppm calcium as CaCO 3 to epm Table divide by 50 the equivalent weight of calcium carbonate and obtain 3. To convert 96 ppm sulfate as SO 4 2- to epm, divide by 48 the equivalent weight of sulfate and obtain 2.

After balancing the cations and anions by adding sodium, convert to ionic ppm by multiplying the epm by the particular ionic equivalent of weight. For example, to convert 3. To obtain the ppm dissolved solids, total the ppm of the individual ions.

Positively charged ions are called "cations" e. Table 2 is a list of chemicals commonly used in water treatment processes, giving their chemical formula, formula weight and factor to convert to equivalent weight as CaCO3.

As an example of how to apply these ideas, let's look at a typical water supply: the Waranga Channel at Rochester, Victoria Table 3. From this analysis we can conclude:. Search this site. Tank Specs. However, they are very separate measurements, and have very different importance. Fish and other aquatic life require a pH range of 6. Higher alkalinity levels in surface water will buffer acid rain and other acid wastes, preventing pH changes that are harmful to aquatic life.

Alkalinity is also in important considering the treatment of wastewater and drinking water because it influences cleaning processes such as anaerobic digestion. Water may also be unsuitable for use in irrigation if the alkalinity level in the water is higher than the natural level of alkalinity in the soil. Two important and interrelated water-related conditions are acidity and alkalinity.

The variables used are the volume of acid B used in the titration, the concentration of the acid C a , the volume of water in the sample V s and a correction factor CF , if necessary. Alkalinity determines how water resists changes in pH, in particular resistance to becoming acidic. Higher alkalinity means higher resistance to changes in pH. Changes in pH can be devastating to the ecosystem. Many plants and aquatic animals require a very narrow pH range to survive. Even less pH-sensitive animals suffer if changes in pH impact the food chain.

In addition to the natural ecosystem, alkalinity impacts wastewater systems and suitability of water for irrigation. Alkalinity, also referred to as water hardness, impacts home water systems by building mineral deposits in pipes and pans as well as increasing the amount of soap people use by inhibiting lather.

Alkalinity measures the amount of calcium, magnesium and other acid-moderating ions. Alkalinity may be reported in terms of calcium carbonate, CaCO 3. Alkalinity is usually measured and reported in terms of parts per million ppm or grains per gallon. The recommended method for determining alkalinity uses inflection point titration IPT with sulfuric acid solution.

Even when using commercially available 0.