What is the main objective of secondary wastewater treatment?

The main objective of secondary wastewater treatment is to remove organic material from wastewater. This phase of treatment typically follows primary treatment, which mainly focuses on the physical separation of solids from the liquid waste. In secondary treatment, biological processes are employed, utilizing microorganisms to break down organic pollutants present in the wastewater. This step is crucial for reducing the biochemical oxygen demand (BOD) and suspended solids in the water, leading to a significant improvement in water quality before it is either discharged into the environment or subjected to further treatment.

While removing heavy metals, disinfecting water, and separating solids from liquids are important processes in wastewater treatment, they primarily relate to different phases or types of wastewater management. For example, removing heavy metals often occurs in advanced treatment processes or specialized facilities; disinfection typically happens later, often in tertiary treatment, and separating solids from liquids is the main function of primary treatment. Therefore, the primary focus of secondary treatment is clearly on degrading and removing organic materials from wastewater.