Which pollutant category includes nitrogen and phosphorus?

• A. Conventional
• B. Toxic
• C. Nonconventional
• D. Primary

Answer: (C)

Nitrogen and phosphorus are nutrients that, when they enter a water body, can drive excessive algae growth and deplete oxygen. They’re categorized as nonconventional pollutants because they’re nutrients rather than the traditional set used for basic treatment design. Conventional pollutants include things like BOD, total suspended solids, and pH, while toxic pollutants are hazardous substances. Primary treatment focuses on solids removal, not on nutrients. So nitrogen and phosphorus fit best under the nonconventional category.