The nitrification capacity of a nitrifying activated sludge which is not exposed to ammonium for several days is reduced by a significantly smaller amount if kept under anoxic and anaerobic rather than aerobic conditions, respectively. Since the enzyme system is not degraded as long as the micro-organisms are not in a starving state, this effect is probably due mainly to the anoxic and anaerobic biomass decay rate being smaller than the aerobic one. At 20°C the decay rate of nitrification activity reduces from about 0.2 to 0.03 d−1 from aerobic to anaerobic conditions, respectively. From these results it becomes clear that aeration has to be properly controlled to reduce biomass decay. Nitrate respiration is reduced by 35-40% as compared to aerobic heterotrophic respiration. This is probably due to the reduced anoxic decay rate of heterotrophic micro-organisms and only partly because of the reduced anoxic hydrolysis rate.
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Research Article|
January 01 1999
Reduction of biomass decay rate under anoxic and anaerobic conditions
Water Sci Technol (1999) 39 (1): 129–137.
Citation
H. Siegrist, I. Brunner, G. Koch, Linh Con Phan, Van Chieu Le; Reduction of biomass decay rate under anoxic and anaerobic conditions. Water Sci Technol 1 January 1999; 39 (1): 129–137. doi: https://doi.org/10.2166/wst.1999.0028
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