How to determine alkalinity of water sample

Alkalinity is primarily a way of measuring the capacity of water to neutralize acids (ability to maintain a relatively constant pH). The possibility to maintain constant pH is due to the hydroxides, carbonates and bicarbonates ions present in water. The ability of natural water to act as a buffer is controlled in part by the amount of calcium and carbonate ions in solution.

Water may have a low alkalinity rating but a relatively high pH or vice versa, so alkalinity alone is not of major importance as a measure of water quality.

Here’s how to determine Alkalinity and constituents in water sample using methyl orange indicator.

Alkalinity is not considered detrimental to humans but is generally associated with high pH values, hardness and excess dissolved solids. High alkalinity may also have a distinctly flat, unpleasant taste.

As per the provisional code, alkalinity should not exceed 200 mg/L for potable water. For fresh water, alkalinity ranges between 20-100 mg/L.