Tertiary treatment of wastewater is primarily a ___________ process.

Tertiary treatment of wastewater is primarily a chemical process, which enhances the quality of treated wastewater before it is discharged or reused. This stage is designed to remove specific contaminants and pollutants that were not sufficiently addressed in the primary and secondary treatment phases.

Chemical processes in tertiary treatment can include advanced filtration methods, chemical coagulation, flocculation, and the use of chlorination or advanced oxidation processes to eliminate pathogens and reduce nutrient concentrations like nitrogen and phosphorus. These methods effectively target residual contaminants, ensuring that the treated water meets higher quality standards for various purposes, including irrigation, industrial use, or even potable reuse in some cases.

While physical and biological processes may play roles in earlier treatment stages, tertiary treatment focuses on achieving specific chemical reactions to ensure the water's safety and usability post-treatment.