Which statement best describes how ammonia is measured in wastewater and what rising ammonia indicates?

Which statement best describes how ammonia is measured in wastewater and what rising ammonia indicates?

• A. Measured as NO3- with standard titration; rising ammonia indicates better nitrification
• B. Measured as NH3 only using pH meter; rising indicates reduced ammonia load
• C. Measured as NH3/NH4+ using colorimetric or ion-selective methods; rising ammonia indicates insufficient nitrification or excessive ammonia load
• D. Measured as total nitrogen; rising indicates increased nitrification

Answer: (C)