Which action best targets nutrient pollution at the source of wastewater?

• A. Upgrade wastewater treatment with tertiary nutrient removal
• B. Expand transit and EVs
• C. Deploy green infrastructure
• D. Promote conservation

Answer: (A)

The main idea is removing nutrients before wastewater is discharged. Nutrients like nitrogen and phosphorus come from households and industry and, if released, fuel algal blooms and oxygen depletion in receiving waters. Upgrading wastewater treatment to remove nutrients at the treatment stage adds specialized steps that target these compounds in the effluent. This includes processes that reduce nitrogen from the wastewater and methods that lower phosphorus levels, so the treated water released into rivers or lakes contains far fewer nutrients.

Other options address different pathways or broader practices but don’t directly remove nutrients from the wastewater itself. Expanding transit and EVs focuses on air pollution. Deploying green infrastructure helps manage nutrient loads from rainfall runoff, which is a nonpoint source issue, not the wastewater stream. Promoting conservation can decrease water use and wastewater volume, but it doesn’t guarantee nutrient removal. The most direct and effective way to target nutrient pollution at its source in wastewater is upgrading to tertiary nutrient removal.