Aerobic versus Anaerobic
Simply put, an aerobic environment is characterized by the presence of oxygen while an anaerobic environment is characterized by the absence of oxygen.

Anaerobic environments

Anaerobic environments are said to be exempt of free oxygen. However, it is important to understand that even in the absence of free oxygen, so-called atomic oxygen can be found.

Atomic oxygen represents the oxygen atom that can be linked to other atoms when there is a polyatomic molecule. We can think of nitrate (NO3), carbon dioxide (CO2) or manganese (Mg2+).

The anaerobic environments are varied, we can mention different types of soil, some sludge, the intestines of some animals and hydrothermal sources located at the bottom of the sea or oceans.

  • It should be noted that these oxygen-deprived environments are not without life. However, the life forms found there are generally resistant, unicellular, and very small organisms. We generally find tardigrades.


Aerobic Environments

In contrast, aerobic environments are characterized by the presence of oxygen. In these environments, we can find free oxygen, dissolved oxygen, or atomic oxygen.

These are the environments that are preferred by the different forms of life since the presence of oxygen is essential to plants, animals, and most other living organisms.

Aerobic environments are found almost everywhere on earth, in the atmosphere, in the soil and even in water. Moreover, the oxidation of various materials as well as corrosion is generally possible only in aerobic environments.

What is the Valence in Water Chemistry?
Although we specialize in water treatment, some fundamental concepts of chemistry are important to us. Among these, the valence of atoms is of key importance in many ways.