High levels of nitrifying bacteria in intermittently aerated reactors treating high ammonia wastewater

Mota, César R.; Ridenoure, Jennifer A.; Ji, Cheng; Reyes, Francis L. de los

doi:10.1016/j.femsec.2005.05.001

Cited by 33 publications

(15 citation statements)

References 40 publications

(66 reference statements)

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“…Since pure cultures of Nitrospira were not available, in vitro-transcribed 16S rRNA was used as reference rRNA in membrane hybridizations as previously described (30).…”

Section: Methodsmentioning

confidence: 99%

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Effects of Aeration Cycles on Nitrifying Bacterial Populations and Nitrogen Removal in Intermittently Aerated Reactors

Mota¹,

Head

Ridenoure

et al. 2005

Appl Environ Microbiol

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The effects of the lengths of aeration and nonaeration periods on nitrogen removal and the nitrifying bacterial community structure were assessed in intermittently aerated (IA) reactors treating digested swine wastewater. Five IA reactors were operated in parallel with different aeration-to-nonaeration time ratios (ANA). Populations of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) were monitored using 16S rRNA slot blot hybridizations. AOB species diversity was assessed using amoA gene denaturant gradient gel electrophoresis. Nitrosomonas and Nitrosococcus mobilis were the dominant AOB and Nitrospira spp. were the dominant NOB in all reactors, although Nitrosospira and Nitrobacter were also detected at lower levels. Reactors operated with the shortest aeration time (30 min) showed the highest Nitrosospira rRNA levels, and reactors operated with the longest anoxic periods (3 and 4 h) showed the lowest levels of Nitrobacter, compared to the other reactors. Nitrosomonas sp. strain Nm107 was detected in all reactors, regardless of the reactor's performance. Close relatives of Nitrosomonas europaea, Nitrosomonas sp. strain ENI-11, and Nitrosospira multiformis were occasionally detected in all reactors. Biomass fractions of AOB and effluent ammonia concentrations were not significantly different among the reactors. NOB were more sensitive than AOB to long nonaeration periods, as nitrite accumulation and lower total NOB rRNA levels were observed for an ANA of 1 h:4 h. The reactor with the longest nonaeration time of 4 h performed partial nitrification, followed by denitrification via nitrite, whereas the other reactors removed nitrogen through traditional nitrification and denitrification via nitrate. Superior ammonia removal efficiencies were not associated with levels of specific AOB species or with higher AOB species diversity.There is increasing interest in biological nitrogen removal technologies that use low levels of oxygen to achieve partial nitrification, the oxidation of ammonia to nitrite by ammonia-oxidizing bacteria (AOB), and subsequent denitrification via nitrite, the reduction of nitrite to dinitrogen gas by heterotrophic denitrifiers. Alkalinity and oxygen demands are lower for partial nitrification, and organic substrate requirements are lower for denitrification via nitrite, than the traditional nitrification/denitrification process, resulting in substantial operational savings (2). Partial nitrification relies on the selection of AOB over nitrite-oxidizing bacteria (NOB), which allows the accumulation of nitrite. Sustained nitrite accumulation can be accomplished by controlling solids retention time, temperature, free ammonia and hydroxylamine concentrations, or dissolved oxygen (DO) conditions (2,12,15,19,23,42).The key to efficient and robust biological wastewater treatment relies on knowing the microorganisms involved and how they respond to different operating conditions (41). Several microbial diversity studies of activated sludge and biofilms based on 16S rRNA gene libr...

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“…Since pure cultures of Nitrospira were not available, in vitro-transcribed 16S rRNA was used as reference rRNA in membrane hybridizations as previously described (30).…”

Section: Methodsmentioning

confidence: 99%

“…Intermittently aerated reactors have been successfully used for nitrogen removal from digested swine manure by achieving complete nitrification during aerated periods, followed by denitrification during nonaerated periods (9,30). Digested swine manure usually contains high ammonia concentrations and a low carbon/ nitrogen ratio.…”

mentioning

confidence: 99%

Effects of Aeration Cycles on Nitrifying Bacterial Populations and Nitrogen Removal in Intermittently Aerated Reactors

Mota¹,

Head

Ridenoure

et al. 2005

Appl Environ Microbiol

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“…Higher average levels of AOB and NOB were reported for heterotrophic activated sludge process (ASP)-based treatment of piggery wastewater [12] in comparison to other types of wastewater, both rich and low in N. The combined NOB levels (73-81% of total bacterial rRNA) were as high as AOB (72-89% of total bacterial rRNA) in many samples. This was not observed in our work since their presence was always low.…”

Section: Influence Of Do On the N-speciesmentioning

confidence: 85%

“…Nitrite-oxidizing bacteria (NOB) were extensively studied in terms of their inhibition or elimination to avoid nitrification-denitrification [6][7][8][9][10], while ammoniaoxidizing bacteria (AOB) underlying the nitritation process were also investigated [11][12][13][14]. Denitrifiers in general received a considerable attention as a part of the process of denitrification, although their role in the denitritation process was not elucidated.…”

Section: Introductionmentioning

confidence: 99%

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N-removal performance and underlying bacterial taxa of upflow filter bioreactor system under different dissolved oxygen and internal recycle conditions

Laobusnanant

Lee

Anceno

et al. 2009

Bioprocess Biosyst Eng

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Biological N-removal treatment of piggery wastewater in the upflow anaerobic-anoxic-aerobic floating filter (UA(3)FF) bioreactor based on the concept of nitritation-denitritation was studied along with the changes in internal recycle ratio and dissolved oxygen concentration (DO). Consecutive changes in the recirculation ratio between the anoxic and aerobic reactors has resulted in abundance and composition shifts of N-cycling bacteria as well as other bacterial groups, reflecting different survival strategies across (bio/physico)chemical milieu. The DO concentration was optimized to achieve nitritation in the aerobic reactor and denitritation in the anoxic reactor. Optimal nitritation-denitritation (270 and 130 g NO(2) (-)-N produced or reduced/m(3) filter media/day) was obtained at DO of 1.0-1.5 mg/l, inter-reactor recirculation ratio of 1:1-2:1, HRT of 24 h, pH of 7.6 +/- 0.3, and temperature of 28 +/- 4 degrees C. Since only well known nitrifying and denitrifying taxa were found, nitritation-denitritation was likely carried out by these bacteria rather than the yet unidentified novel taxa. Archaeal nitrifiers recently discovered to be important in the global N-cycle were not detected.

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Population dynamics of ammonia-oxidizing bacteria in an aerated submerged biofilm reactor for micropolluted raw water pretreatment

Qin

Zhang

Ren

et al. 2008

Appl Microbiol Biotechnol

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Population dynamics of ammonia-oxidizing bacteria (AOB) in a full-scale aerated submerged biofilm reactor for micropolluted raw water pretreatment was investigated using molecular techniques for a period of 1 year. The ammonia monooxygenase (amoA) gene fragments were amplified from DNA and RNA extracts of biofilm samples. Denaturing gradient gel electrophoresis (DGGE) profile based on the amoA messenger RNA approach exhibited a more variable pattern of temporal dynamics of AOB communities than the DNA-derived approach during the study. Phylogenetic analysis of excised DGGE bands revealed three AOB groups affiliated with the Nitrosomonas oligotropha lineage, Nitrosomonas communis lineage, and an unknown Nitrosomonas group. The population size of betaproteobacterial AOB, quantified with 16S ribosomal RNA gene real-time polymerase chain reaction assay, ranged from 6.63 x 10(5) to 2.67 x 10(9) cells per gram of dry biofilm and corresponded to 0.23-1.8% of the total bacterial fraction. Quantitative results of amoA gene of the three specific AOB groups revealed changes in competitive dominance between AOB of the N. oligotropha lineage and N. communis lineage. Water temperature is shown to have major influence on AOB population size in the reactor by the statistic analysis, and a positive correlation between AOB cell numbers and ammonia removal efficiency is suggested (r = 0.628, P < 0.05).

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High levels of nitrifying bacteria in intermittently aerated reactors treating high ammonia wastewater

Cited by 33 publications

References 40 publications

Effects of Aeration Cycles on Nitrifying Bacterial Populations and Nitrogen Removal in Intermittently Aerated Reactors

Effects of Aeration Cycles on Nitrifying Bacterial Populations and Nitrogen Removal in Intermittently Aerated Reactors

N-removal performance and underlying bacterial taxa of upflow filter bioreactor system under different dissolved oxygen and internal recycle conditions

Population dynamics of ammonia-oxidizing bacteria in an aerated submerged biofilm reactor for micropolluted raw water pretreatment

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