What is the primary purpose of aeration tanks in wastewater treatment?

The primary purpose of aeration tanks in wastewater treatment is to promote the growth of microorganisms that decompose organic matter. In these tanks, air is introduced into the wastewater, which serves a dual function: it provides the oxygen necessary for aerobic bacteria to thrive and it helps to mix the wastewater, ensuring that the microorganisms come into contact with the organic substances they need to break down.

The aeration process encourages the development of a biologically active population that metabolizes organic pollutants, converting them into more benign substances, such as carbon dioxide and water. This biological treatment is essential for reducing biochemical oxygen demand (BOD) in the wastewater before it undergoes further treatment or is discharged into the environment. Hence, aeration tanks play a crucial role in the biological treatment stage of wastewater processing, enabling efficient degradation of contaminants.