Which process involves the conversion of ammonium to nitrate and requires oxygen?

The process that involves the conversion of ammonium to nitrate and requires oxygen is known as aerobic nitrification. During this biological process, ammonium ions (NH4+) are oxidized to nitrite (NO2-) by ammonium-oxidizing bacteria, and subsequently, nitrite is further oxidized to nitrate (NO3-) by nitrite-oxidizing bacteria. This conversion is integral to the nitrogen cycle in aquatic environments and wastewater treatment systems, as it allows for the removal of nitrogenous compounds that can contribute to water pollution if left untreated.

Aerobic conditions are essential for nitrification because the microorganisms involved rely on oxygen for their metabolic processes. Without sufficient oxygen, these bacteria cannot perform the oxidation reactions necessary for converting ammonium into nitrate. Understanding this process is crucial for effective wastewater treatment, as it helps mitigate the impacts of nitrogen compounds in effluent discharges.

Other processes mentioned, such as anoxic or anaerobic, do not involve oxygen and are not responsible for the conversion of ammonium to nitrate, making them unsuitable in this context. Oxidative is a broader term that doesn't specifically refer to the biological processes involved in nitrification.