What type of processes primarily characterize tertiary treatment?

Tertiary treatment is primarily characterized by chemical processes that are designed to further purify wastewater beyond the capabilities of primary and secondary treatment. This stage of treatment aims to remove remaining contaminants, including nutrients like nitrogen and phosphorus, and pathogens, making the treated water suitable for potential reuse or safe discharge into the environment.

In this phase, various chemical additives and processes may be employed, such as coagulation, flocculation, disinfection (using chlorine or UV light), and advanced oxidation processes. These methods are effective in achieving a high level of purification, which is crucial for protecting aquatic ecosystems and public health, especially when the treated water is intended for irrigation, industrial use, or even as potable water in some advanced treatment systems.

While physical processes, such as filtration, and biological processes, such as additional aeration or microbial treatment, can play roles in tertiary treatment, the defining characteristic relies heavily on the introduction of specific chemicals to achieve desired water quality standards.