Temperatures effects speed of chemical reactions.

For a given reaction the position of equilibrium changes with temperature and with other conditions of reaction,such as the initial concentrations of the reactants.Equilibrium constant is affected by temperature.

Speed of reaction approximately doubles for every 10ºC rise.

In reversible reactions, temperature effects time to reach equilibrium and the point of equilibrium.

A + B -> C + D + energy term

Many reactions effecting water quality are biochemical and center around microbial activity.Most reactions occur at low temperatures in presence of enzymes wich in turn are temperature sensitive. Most are in the mesophylic classification and thrive on temperature range of 10 to 40ºC.Maximum activity occurs between 30 and 37ºC and then falls off.

Taste and odor problems may be induced by temperature that accelerates chemical or biochemical action, particularly when oxygen is depleted.

Substances wich may accumulate include H2S, SO2,CH4,SOX,iron compounds, carbonates, sulfates and phenols.

Tastes and odors are more pronounced in warm water because of decreased solubility.

When temperatures of receiving waters rise the action of microorganisms cause BOD to be satisfied in shorter distances from discharge of biodegradable organic material.

Increased temperature has mixed effects on specific chemical reactions.

Desinfection action is increased, coagulant dosages are contradictory, increase slime and algae, taste and odor are increased.

Click here to go back.