What does the term "nutrient removal" refer to in wastewater treatment?

The term "nutrient removal" in wastewater treatment specifically focuses on the process of eliminating excess nitrogen and phosphorus from wastewater before it is discharged into the environment. These nutrients can lead to algal blooms and can cause significant ecological damage in receiving water bodies.

Effective nutrient removal is critical for protecting water quality, as excessive nitrogen and phosphorus can lead to eutrophication, which depletes oxygen in the water and harms aquatic life. Wastewater treatment processes often include stages specifically designed to reduce these nutrients through biological processes, such as denitrification for nitrogen and chemical precipitation for phosphorus.

The other choices mentioned do not directly capture the essence of nutrient removal. Eliminating solids from wastewater pertains to the physical separation of particulate matter, while increasing nutrient levels is counterproductive to the goal of combating nutrient pollution. Filtering out chemical pollutants refers to another aspect of wastewater treatment that focuses on reducing toxicity rather than addressing nutrient loading.