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Biofilm Community Dynamics in Bench-Scale Annular Reactors Simulating Arrestment of Chloraminated Drinking Water Nitrification
Citation:
Gomez-Alvarez, V., K. A. Schrantz, J. G. Pressman, AND D. G. Wahman. Biofilm Community Dynamics in Bench-Scale Annular Reactors Simulating Arrestment of Chloraminated Drinking Water Nitrification. ENVIRONMENTAL SCIENCE & TECHNOLOGY. ACS Publications, Washington, DC, 48(10):5448-5457, (2014).
Impact/Purpose:
This study provided a novel insight into the temporal dynamics of biofilm microbial communities when simultaneously increasing NH2Cl concentrations and Cl2:N mass ratios. These results may have implications on the use of models based on the integration of microbial ecology.
Description:
Annular reactors (ARs) were used to study biofilm community succession and provide an ecological insight during nitrification arrestment through simultaneously increasing monochloramine (NH2Cl) and chlorine to nitrogen mass ratios, resulting in four operational periods (I to IV). Analysis of 16S rRNA-encoding gene sequence reads (454-pyrosequencing) examined viable and total biofilm communities and found total samples provided a representation of the underlying viable community. Bacterial community structure showed dynamic changes corresponding with AR operational parameters. Period I (complete nitrification and no NH2Cl residual) was dominated by Bradyrhizobium (38%), while environmental Legionella-like phylotypes peaked (19%) during Period II (complete nitrification and minimal NH2Cl residual). Nitrospira moscoviensis, a nitrite-oxidizing bacteria was detected in early periods (2%) but decreased to <0.02% in later periods, corresponding to nitrite accumulation. Methylobacterium (19%) and members of the Nitrosomonadaceae (42%) dominated Period III (complete ammonia and partial nitrite oxidation and low NH2Cl residual). An increase in the relative abundance of haloacetic acid-degrading bacteria Afipia (<2% to 42%) occurred during Period IV (minimal nitrification and moderate to high NH2Cl residual). Microbial community and operational data analysis provided no evidence of taxa-time relationship, but rapid community transitions indicated that the system had experienced ecological regime shifts to alternative stable states.
