What are the primary contaminants removed during tertiary treatment of wastewater?

Tertiary treatment of wastewater is the advanced stage of treatment that follows primary and secondary processes. The primary focus during this stage is to remove remaining impurities, particularly pathogens and residual contaminants that may still exist after earlier treatment phases.

Pathogens, which include harmful microorganisms such as bacteria, viruses, and protozoa, are typically targeted during tertiary treatment to ensure that the effluent is safe for discharge or reuse, especially in applications where water quality is critical, such as agricultural irrigation or human contact. Additionally, residual contaminants, which may comprise trace organic compounds, pharmaceuticals, and other pollutants not fully removed in previous treatment stages, are also addressed during this phase.

The significance of removing these contaminants is that it helps in protecting public health and the environment, ensuring that the treated water is safe and of high quality. Thus, the choice highlighting the removal of pathogens and residual contaminants is accurate in the context of what tertiary treatment aims to achieve.