Which treatment process targets the removal of nutrients and heavy metals particularly in the tertiary stage?

The treatment process that specifically targets the removal of nutrients and heavy metals, particularly in the tertiary stage, is indeed the tertiary treatment. Tertiary treatment is the final stage of wastewater treatment where advanced processes are employed to enhance the quality of the effluent.

This stage typically includes methods such as filtration, chemical precipitation, and advanced oxidation processes. During tertiary treatment, processes such as biological nutrient removal (BNR) are implemented to efficiently eliminate nitrogen and phosphorus, which are nutrients that can contribute to water quality issues, including eutrophication in natural water bodies. Heavy metals, which can be toxic to aquatic life and humans, are also removed through specialized techniques such as ion exchange or adsorption.

In contrast, screening represents an initial process aimed at removing large solids from wastewater. Primary treatment involves physical separation methods to remove settleable solids and floatable materials, while secondary treatment primarily focuses on biologically breaking down organic matter and reducing biochemical oxygen demand (BOD). However, these earlier stages do not specifically target nutrients and heavy metals to the extent that tertiary treatment does, making tertiary treatment essential for achieving high water quality standards before the effluent is discharged or reused.