What does the term 'adsorbed' refer to in wastewater treatment?

In wastewater treatment, the term 'adsorbed' specifically refers to substances that adhere to the outer surface of solid materials or particles. This process is crucial as it involves the attraction and bonding of molecules from the liquid phase onto the surfaces of solids, such as activated carbon or other adsorbent materials.

Adsorption plays a significant role in removing contaminants from wastewater because it allows for the effective trapping of pollutants, including organic compounds and heavy metals, onto the surface of adsorbents. This process is different from absorption, where a substance is taken up into the volume of another material.

Understanding this concept is essential for optimizing wastewater treatment methods, as it influences the choice of treatment technologies and materials used for effluent purification. The distinction between adsorption and other processes like filtration or evaporation clarifies how pollutants can be managed and removed from wastewater streams effectively.