Background information

How to control de pH

The pH is the measure of free hydrogen activity in water or in more practical terms the measure of free acidity or free alkalinity of water, is expressed like as:

pH= -log[H⁺]

The pH is measured in a scale of 0-14, solutions with a pH lower than 7 are acids (orange juice and acid rain), and higher are bases (blood and soap). Bases are used to neutralize acids and acids are used to neutralize alkalis. Byproducts are normally salt (they could be soluble or not) and water.

                             

The task of any pH adjustment is to regulate the pH of the process stream into the acceptable discharge range. In the case of an acid neutralization, caustic (NaOH) is added to the pH in order to neutralize the solution.

There are two primary system designs for pH adjustment systems: continuous and batch.

Continuous system are very suitable for relatively high flows of slightly acidic or alkaline wastewaters (example: 2.0 < pH < 12.0).

For more demanding applications, such as those with changing flows those who are characterized by highly acidic or highly alkaline wastewater then a batch system is a more appropriate choice.