The presence of nitrite in wastewater raises the demand for what chemical?

The presence of nitrite in wastewater raises the demand for chlorine as it is a common disinfectant used in wastewater treatment. Chlorine is effective in oxidizing nitrite to nitrate, which is a less toxic form of nitrogen in the treatment process. In the context of wastewater treatment, chlorine not only serves as a disinfectant but also helps in facilitating the biological processes involved in nitrogen removal.

When nitrite is present in elevated concentrations, it indicates inadequate nitrification, which can be harmful to aquatic life if released into receiving waters. By applying chlorine, operators can help to mitigate this issue, ensuring that the nitrite levels are reduced and that the water meets regulatory standards before it is released or reused.

Other chemicals listed do not specifically target nitrite removal as effectively as chlorine does. Sodium hydroxide is primarily used for pH adjustment, ammonia would contribute to nitrogen levels, and calcium carbonate is used for alkalinity but does not have the same oxidizing effect required in this situation.