What chemicals are used to increase both pH and alkalinity in water?

The use of lime and soda ash effectively increases both pH and alkalinity in water. Lime, or calcium hydroxide, has the ability to raise the pH level due to its calcium content and it also contributes to the overall alkalinity by providing a source of hydroxide ions. This increase in hydroxide ions helps neutralize acids present in the water, thus stabilizing the pH and enhancing alkalinity.

Soda ash, also known as sodium carbonate, likewise raises pH and contributes to alkalinity. It works by introducing carbonate ions into the water, which play a crucial role in buffering against pH changes. By using these two chemicals together, operators can efficiently manage water chemistry to ensure it is within desired parameters for both drinking water standards and operational efficiency in treatment processes.

The other options do not serve this dual purpose effectively. For instance, sodium sulfate and ammonium sulfate primarily affect salinity and do not significantly impact pH or alkalinity. Calcium carbonate can increase alkalinity but does not raise pH as effectively as lime. Chlorine and ozone are primarily used for disinfection purposes and do not have a role in altering pH or alkalinity levels.