What is the main goal of tertiary treatment in sewage treatment?

The primary aim of tertiary treatment in sewage treatment is to polish the effluent by removing remaining impurities that could affect the quality of the water before it is discharged or reused. This final stage of treatment typically involves advanced filtration processes, biological treatment, and chemical treatments to remove specific pollutants such as nutrients (like nitrogen and phosphorus), pathogens, and other contaminants that may not have been fully removed during primary and secondary treatments.

By ensuring that the treated water meets the strict environmental standards, tertiary treatment plays a crucial role in protecting water quality and public health. It can also allow for the water to be reused for various applications, making it a vital step in sustainable water management practices. The focus on polishing the effluent distinguishes tertiary treatment from earlier stages, which are geared more towards removing larger solids or general organic matter.