Which treatment method is commonly implemented in municipal sewage treatment plants to combat cultural eutrophication?

Cultural eutrophication is the excessive growth of algae in water bodies due to the over-enrichment of nutrients, primarily nitrogen and phosphorus, often from sources such as agricultural runoff, wastewater discharge, and other human activities. To combat this issue, tertiary treatment is specifically utilized in municipal sewage treatment plants.

Tertiary treatment involves advanced processes that go beyond basic sedimentation and biological degradation, focusing on the removal of remaining nutrients, particularly nitrogen and phosphorus, before the effluent is released into the environment. This stage often employs techniques such as chemical precipitation, biological nutrient removal, and filtration to ensure that nutrient levels are sufficiently low to prevent algal blooms and subsequent eutrophication in receiving waters.

While primary and secondary treatments focus on removing solids and organic matter, they do not adequately address the nutrient levels that contribute to cultural eutrophication. Disinfection primarily targets pathogens to ensure water safety, but it does not effectively reduce nutrient concentrations. Therefore, tertiary treatment is essential for the mitigation of cultural eutrophication and the protection of aquatic ecosystems by preventing the negative impacts associated with nutrient overloading.