Which process follows primary clarification in wastewater treatment?

In wastewater treatment, primary clarification is a critical first step where larger solids settle out of the wastewater. After this process, the next step typically involves aeration. During aeration, air is introduced into the water, promoting the growth of aerobic bacteria. These microorganisms play a vital role in breaking down dissolved organic matter that remains after primary clarification. This process is essential for reducing the biochemical oxygen demand (BOD) of the wastewater, which can be harmful to aquatic life if released untreated.

Aeration enhances the decomposition of organic material, helping to produce cleaner effluent that can further undergo additional treatment, such as secondary clarification or filtration, before eventual disinfection. Thus, the sequence of processes in wastewater treatment is designed to progressively remove contaminants, and aeration is specifically aligned as the next step following primary clarification due to its effectiveness in biological treatment.