- Ammonia Oxidizing Bacteria (AOB) - these organisms convert ammonia (NH3) into nitrite (NO2)
- Nitrite Oxidizing Bacteria (NOB) - organisms converting nitrite (NO2) into nitrate (NO3)
- Denitrifying Organisms - many species can use nitrate (fewer nitrite) under anoxic conditions
- Anammox - or Anaerobic Ammonia Oxidation is biochemical pathway that has NO2 + NH4 --> N2 (gas) + H2O. This is an anaerobic process that requires a long MCRT & low F/M conditions. Often a fixed film with anammox cultures is required for significant development.
- Comammox - abbreviation for Complete Ammonia Oxidation - some organisms such as Nitrospira have the ability to completely convert ammonia into nitrate. Instead of two distinct microbial populations, Comammox have a single population completely removing problem nitrogen forms.
- Feammox - (the latest identified reactions) - iron reducing organisms work at lower pH without oxygen. Ammonia oxidation with concurrent Iron III reduction produces energy for this class of organisms. Research is still in the early phase regarding these organisms and their potential in waste treatment.
We sure love to use acronyms in environmental science and wastewater treatment. I have had full discussions with people mistaking "the nitrifiers" for "denitrifiers" when speaking - think about how close the words sound in normal speech. So, I thought a list of terms would help get everyone on the same page.
Erik Rumbaugh has been involved in biological waste treatment for over 20 years. He has worked with industrial and municipal wastewater facilities to ensure optimal performance of their treatment systems. He is a founder of Aster Bio (www.asterbio.com) specializing in biological waste treatment.
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