Options for expressing concentrations of inorganic componds

Why do we need different forms of expressing the concentrations of the same substances?

Frequently, when discussing the concentration of specific substances in water, you may encounter unconventional concentration expressions, such as nitrite nitrogen or phosphate phosphorus. It's crucial to emphasize that the nitrogen content in nitrates doesn't directly equate to the concentration of nitrates. In this article, we will delve into why this distinction is necessary and how to convert between different forms of concentration expressions.

Additionally, a similar method of expressing concentration can prove valuable when you need to determine the proportion of a specific compound within the overall content of an element. For instance, calculating the proportion of nitrate nitrogen within the total nitrogen content.

In certain scenarios, such as in biological wastewater treatment, the content of a particular element in the water holds significance, while its chemical form may not. In such instances, it's common practice to convert the concentrations of specific substances into the desired element. These conversions are most frequently employed when assessing the concentrations of nitrogen-based compounds, phosphorus-based compounds, and heavy metals. Each conversion case involves a unique conversion factor. For example:

• From ammonium to ammonium nitrogen: 0.78
• From nitrite to nitrite nitrogen: 0.304
• From nitrates to nitrate nitrogen: 0.226

To determine phosphorus concentrations:

• From orthophosphates and polyphosphates to phosphorus: 0.326.