The Influence Of Alkalinity On Natural Waters And Wastewaters

846 Words Mar 16th, 2016 4 Pages
Alkalinity is a measure of the ability of a water to resist changes in pH. Alkalinity in water is due to the presence of weak acid systems that consume by hydrogen ion produced by other reactions, allowing chemical or biological activities to take place within a water without changing the pH (1). In this way the alkalinity protects aquatic life.
The measured value may vary considerably with the end-point pH used. Alkalinity is a measure of an aggregate property of water and can be interpreted in terms of specific substances only when the chemical composition of the sample is known (2).
Alkalinity is an important parameter in various applications and treatments of natural waters and wastewaters. The amount of alkalinity is taken into consideration on the coagulation process where high alkalinity values make pH adjustment for optimum coagulation more difficult (1). In coagulation, when the alkalinity naturally present in water is insufficient, calcium hydroxide and sodium carbonate can be added to supply alkalinity to react with the coagulant(6).
Alkalinity (carbonate and bicarbonate) affects corrosion rates of some metals. A published document (5) refers that some metals solubility is increased at low pH as well as high alkalinity.
The alkalinity of most surface waters is principally a function of carbonate, bicarbonate, and hydroxide content, it is taken as an indication of the concentration of these constituents. The measured values also may include contributions from…

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