Nitrifying microbial community analysis of nitrite accumulating biofilm reactor by fluorescence in situ hybridization

Abstract

Biological nitrogen removal via nitrite pathway in wastewater treatment is very important especially in the cost of aeration and as an electron donor for denitrification. Wastewater nitrification and nitrite accumulations were carried out in a biofllm reactor. The biofilm reactor showed almost complete nitrification and most of the oxidized ammonium was present as nitrite at the ammonium load of 1.2 kg N/m3/d. Nitrite accumulation was achieved by the selective inhibition of nitrite oxidizers by free ammonia and oxygen limitation. Nitrite oxidation activity was recovered as soon as the inhibition factor was removed. Fluorescence in situ hybridization studies of the nitrite accumulating biofilm system have shown that genus Nitrosomonas which is specifically hybridized with probe NSM156 was the dominant nitrifying bacteria while Nitrospira was less abundant than those of normal nitrification systems. Further FISH analysis showed that the combinations of Nitrosomonas and Nitrospira cells were identified as important populations of nitrifying bacteria in an autotrophic nitrifying biofilm system.

Detection of nitrifiers and evaluation of partial nitrification for wastewater treatment: A review

“…The threshold FNA inhibition levels on a 50% reduction in AOB activity were in the range of 0.42-1.72 mg N L À1 , while lower concentrations of 0.011-0.07 mg N L À1 would start to inhibit NOB and 0.026-0.22 mg N L À1 could completely inhibit NOB . FA and FNA inhibitions on NOB were reversible (Han et al, 2003), and other factors (e.g. control strategies, SRT, substrate concentrations) should be synthetically considered when FA or FNA was used as the control parameter for partial nitrification.…”

Biological nitrogen removal with nitrification and denitrification via nitrite pathway

“…Free ammonia has only an inhibition effect on NOB, but does not kill them. After a period of cultivation, NOB will recover activity (Beccari et al 1983;Han et al 2003). It is necessary to synthetically consider other factors to achieve stable partial nitrification when only by regulating free-ammonia concentration (Fdz-Polanco et al 1994;SurmaczGorska et al 1997).…”

Nitrite accumulation characteristics of high strength ammonia wastewater in an autotrophic nitrifying biofilm reactor

“…5 The tendency of nitrite oxidizers to form an aggregate within the nitrifying biofilm may account for the reduced wash-out effect of nitrite oxidizers in biofilm systems. 18 …”