Which processes are involved in wastewater treatment?

The correct answer highlights the three main stages of wastewater treatment: primary, secondary, and tertiary treatment. Each stage serves a distinct purpose in reducing pollutants and improving water quality.

Primary treatment involves the physical separation of solids from the wastewater through processes such as sedimentation. This step reduces the load of suspended solids and organic matter, making the subsequent treatment processes more effective.

Secondary treatment primarily focuses on biological processes where microorganisms break down organic matter in the wastewater. This stage is essential for further reducing biochemical oxygen demand (BOD) and removing dissolved organic substances.

Tertiary treatment is the final stage that involves additional processes to improve the quality of treated wastewater before it is discharged or reused. Techniques used in this stage can include filtration, nutrient removal, and advanced disinfection methods, ensuring that the water meets regulatory standards for release or reuse.

This structured approach is critical for the effective treatment of wastewater, emphasizing the necessity of each stage in achieving high water quality and protecting public health and the environment.