title: Influence of free ammonia on completely autotrophic nitrogen removal over nitrite (CANON) process.
abstract: Free ammonia (FA) plays a significant role in the stable, long-term, completely autotrophic nitrogen removal over nitrite (CANON) system operation. The influence of FA on the CANON process in a sequencing batch biofilm reactor was explored. Under controlled FA concentrations of 5.0 mg L(-1) to 10.0 mg L(-1), nitrite-oxidizing bacteria (NOB) was inhibited and achieved partial nitrification, which was important for a successful and quick start-up of the CANON process from activated sludge. However, NOB was acclimated to the condition after the process start-up. Ammonia-oxidizing bacteria (AOB) and anaerobic ammonium-oxidizing bacteria (AnAOB) activities were unaffected when FA concentration was increased from 10 mg L(-1) to 17 mg L(-1), but NOB was completely inhibited only for a short time. The AOB and AnAOB activities were inhibited and the CANON system was deteriorated when FA concentration reached 30 mg L(-1) to 32.5 mg L(-1) at pH 8.5, whereas NOB activity was unaffected. Correlation analysis showed that FA concentration higher than 20 mg L(-1) resulted in the deterioration of the system.
authors.affiliation: Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment of MOE, Chongqing University, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Li
authors.forename: You-Peng
authors.initials: YP
authors.lastname: Chen
authors.forename: Chun
authors.initials: C
authors.lastname: Li
authors.forename: Jin-Song
authors.initials: JS
authors.lastname: Guo
authors.forename: Fang
authors.initials: F
authors.lastname: Fang
authors.forename: Xu
authors.initials: X
authors.lastname: Gao
mesh_terms: D000641:Ammonia / Q000494:pharmacology*; D052818:Autotrophic Processes; D001419:Bacteria / Q000187:drug effects* / Q000378:metabolism*; D018441:Biofilms; D019149:Bioreactors / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D009573:Nitrites / Q000378:metabolism*; D009584:Nitrogen / Q000302:isolation & purification* / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D013997:Time Factors
chemical_list: D009573:Nitrites; D000641:Ammonia; D009584:Nitrogen