What type of microorganisms are primarily involved in the nitrification process?

The nitrification process primarily involves nitrifying bacteria, which are specialized microorganisms responsible for the two-step conversion of ammonia to nitrate. This process is essential in wastewater treatment and occurs in aerobic conditions.

In the first step, ammonia-oxidizing bacteria, such as species from the genera Nitrosomonas and Nitrosococcus, convert ammonia (NH₃) into nitrite (NO₂⁻). Following this, nitrite-oxidizing bacteria, such as those from the genera Nitrobacter and Nitrospira, further convert nitrite into nitrate (NO₃⁻). Both of these conversions are critical in the nitrogen cycle and help remove ammonia from wastewater, which can be toxic to aquatic life when present in high concentrations.

The other types of microorganisms do not play a primary role in nitrification. While pathogenic bacteria can be present in wastewater, they are not involved in the nitrification process. Sludge bacteria typically refer to a broader group of microorganisms that may include various species engaged in different metabolic processes, but they do not specifically facilitate nitrification. Denitrifying bacteria, on the other hand, are involved in the conversion of nitrate to nitrogen gas, a process that occurs after nitrification and is essential for the removal of nitrogen but is