title: Acid-tolerant ammonia oxidizers allow for fast but unstable nitrification at low pH values
organism: Candidatus Nitrosacidococcus sp. I8
description: Ammonium oxidation and acidotolerant AOB growing under acidic conditions and high TN concentrations was investigated. Starting with activated sludge (AS) from a urine nitrification reactor, acidotolerant AOB were enriched with source-separated urine at a pH value of 5 and TN concentrations above 1000 mg N L-1. The predominant AOB specie was determined, and the effect of various environmental conditions on the acidotolerant AOB were tested. In particular, the long-term effect of pH values between 5 to 7 on the activity of acidotolerant AOB was investigated, which is important in cases where acidotolerant AOB should be avoided in the first place.