What is the significance of ammonia nitrogen in wastewater?

Ammonia nitrogen is a critical parameter in wastewater treatment and environmental monitoring due to its potential toxicity to aquatic life. High concentrations of ammonia, particularly in the form of ammonium ions (NH4+), can disrupt the physiological processes of aquatic organisms, leading to harmful effects such as decreased growth rates, impaired reproduction, and in severe cases, mortality.

Aquatic organisms, especially fish, are sensitive to ammonia levels, and the toxicity increases with rising pH and temperature. Furthermore, the presence of ammonia can indicate the level of organic pollution, as higher ammonia concentrations typically arise from the decomposition of organic matter. Therefore, monitoring ammonia nitrogen levels is essential for assessing water quality and ensuring the safety of aquatic ecosystems.

In contrast, the other options do not accurately reflect the significance of ammonia nitrogen in wastewater. For instance, ammonia does not promote bacterial growth in a beneficial sense, and it is certainly not harmless to aquatic life. High levels of ammonia are typically a sign of pollution rather than an indication of low organic contamination.