vfeu water quality control in sts-95 sts-95 space shuttle mission, an aquatic animal research facility, vestibular function experiment unit (vfeu), was flown to perform neurobiological experiment with marine fish, oyster toadfish. for this purpose, we have developed a sea water purification system using highly active nitrifying bacteria at low temperature. with this system, the water quality in the vfeu was maintained in sufficient condition to keep the toadfish in healthy state for 9 days of the mission. this report summarizes ...199911542797
water quality management for low temperature marine fishes in space.vestibular function experiment unit (vfeu), one of the spacelab facility flown in neurolab mission (sts-90) in april, 1998, was to support neurophysiological research using a marine fish, opsanus tau (oyster toadfish). the functions of the vfeu were primarily a quality management of environmental water during the mission at 14 degrees c and for acquiring physiological signals from implanted micro-electrodes in the otolith nerves as well as the spatial acceleration of the fish. a key element of t ...199911542798
r&d of long-term life support system by using electrochemically activated biofilm reactor of aquatic animals for space examinations.we have developed the long-term life support system that enables the experiment of aquatic animals breeding for 90 days or more for the future experiments in orbit. in order to enable long-term breeding of wide aquatic animals, it is necessary to remove nitrate produced by biological nitrification. then, we examined a denitrification method to use an electrochemical reaction of biofilm-electrode reactor. in this research, we have not kept the aquatic animals actually but imitated breeding of fiv ...199911542801
ammonia-oxidizing bacteria: a model for molecular microbial ecology.the eutrophication of many ecosystems in recent decades has led to an increased interest in the ecology of nitrogen transformation. chemolitho-autotrophic ammonia-oxidizing bacteria are responsible for the rate-limiting step of nitrification in a wide variety of environments, making them important in the global cycling of nitrogen. these organisms are unique in their ability to use the conversion of ammonia to nitrite as their sole energy source. because of the importance of this functional grou ...200111544365
potential nitrification rate as a tool for screening toxicity in metal-contaminated soils.a potential nitrification rate test (pnr) was used to identify metal toxicity in field-contaminated soils. the test was applied to metal salt-spiked soils, to 27 uncontaminated soils, and to 15 soils that are contaminated by former metal smelting activities. four agricultural soils (ph 4.5-6.6) were spiked with various rates of cdcl2 (0-200 mg cd/kg dry wt) or zncl2 (0-3,000 mg cd/kg dry wt) and were equilibrated more than nine months prior to testing. the soil zn ec50s of the pnr were between 1 ...200111699771
ammonia- and nitrite-oxidizing bacterial communities in a pilot-scale chloraminated drinking water distribution system.nitrification in drinking water distribution systems is a common operational problem for many utilities that use chloramines for secondary disinfection. the diversity of ammonia-oxidizing bacteria (aob) and nitrite-oxidizing bacteria (nob) in the distribution systems of a pilot-scale chloraminated drinking water treatment system was characterized using terminal restriction fragment length polymorphism (t-rflp) analysis and 16s rrna gene (ribosomal dna [rdna]) cloning and sequencing. for ammonia ...200211772611
fatty acid profiles of nitrite-oxidizing bacteria reflect their phylogenetic heterogeneity.the fatty acid profiles of all described species of the nitrite-oxidizing genera nitrobacter, nitrococcus, nitrospina and nitrospira were analyzed. the four genera had distinct profiles, which can be used for the differentiation and allocation of new isolates to these genera. the genus nitrobacter is characterized by vaccenic acid as the main compound with up to 92% of the fatty acids and the absence of hydroxy fatty acids. the genus nitrococcus showed cis-9-hexadecenoic acid, hexadecanoic acid ...200111822673
the aquatic budding bacterium blastobacter denitrificans is a nitrogen-fixing symbiont of aeschynomene indica.blastobacter spp. are freshwater bacteria that form rosette structures by cellular attachment to a common base. comparative analyses of ribosomal 16s rrna gene and internally transcribed spacer region sequences indicated that b. denitrificans is a member of the alpha-subdivision of proteobacteria. among the alpha-proteobacteria, b. denitrificans was related to a cluster of genera, including rhodopseudomonas palustris, afipia felis, nitrobacter hamburgensis, and bradyrhizobium spp. although the p ...200211872460
water purification system by using the biofilter for long-term experiment equipment with aquatic animals for the space station.we have developed a water purification system that enables long-term experiment with aquatic animals for 90 days or more on the space station. we designed the system that combined a biofilter for ammonia removal (nitrification) with another for nitrate removal (denitrification). the experiment with goldfish was for 90 days with an aquatic animals' examination device. the equipment consists of a fish tank, a filter module, pumps, and an artificial lung for gas exchange. the goldfish were kept in ...199811876203
the canon system (completely autotrophic nitrogen-removal over nitrite) under ammonium limitation: interaction and competition between three groups of bacteria.the canon system (completely autotrophic nitrogen removal over nitrite) can potentially remove ammonium from wastewater in a single, oxygen-limited treatment step. the usefulness of canon as an industrial process will be determined by the ability of the system to recover from major disturbances in feed composition. the canon process relies on the stable interaction between only two bacterial populations: nitrosomonas-like aerobic and planctomycete-like anaerobic ammonium oxidising bacteria. the ...200111876366
immunological detection of nitrospira-like bacteria in various soils.chemolithotrophic nitrite oxidizers were enriched from five different soils including freshwater marsh, permafrost, garden, agricultural, and desert soils and monitored during the cultivation procedure. immunoblot analysis was used to identify the nitrite oxidizing organisms with monoclonal antibodies, which recognize the key enzyme of nitrite oxidation in a genus-specific reaction [bartosch et al. (1999) appl environ microbiol 65:4126-4133]. the morphological characteristics of the enriched nit ...200211984626
isolation and characterization of cbbl and cbbs genes encoding form i ribulose-1,5-bisphosphate carboxylase/oxygenase large and small subunits in nitrosomonas sp. strain eni-11.the cbbl and cbbs genes encoding form i ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) large and small subunits in the ammonia-oxidizing bacterium nitrosomonas sp. strain eni-11 were cloned and sequenced. the deduced gene products, cbbl and cbbs, had 93 and 87% identity with thiobacillus intermedius cbbl and nitrobacter winogradskyi cbbs, respectively. expression of cbbl and cbbs in escherichia coli led to the detection of rubisco activity in the presence of 0.1 mm isopropyl-beta-d-th ...200212005060
intestinal urea metabolism: could the bacteria involved in nitrogen cycle lead to reutilization of intestinal urea nitrogen in uremic rabbits?we aimed to evaluate the effect of bacteria involved in the nitrogen cycle on the reutilization of intestinal urea nitrogen in uremic rabbits. new zealand white rabbits were made uremic via bilateral nephrectomy. study and control rabbits were given live and heat-inactivated bacteria through their jejunostomies. after they were injected with 99mtc biurea intravenously, serial serum and stool levels of labeled nitrogen were assessed by instant thin-layer chromatography, and the change in the labe ...200212026184
high mortality in zebrafish (danio rerio).a group of 100 adult zebrafish were housed in a new system at a stocking density of 20 fish per tank. four weeks after arrival, 15 fish presented with petechial hemorrhages and ulceration on the surfaces of the skin. samples of the fish were collected for histopathology, fungal culture, and bacterial culture and sensitivity. water samples were analyzed for ph, ammonia, nitrite, and submitted for bacterial and fungal culture. histologically, the epidermis had multiple areas of ulceration and mono ...199912086431
tfda-like genes in 2,4-dichlorophenoxyacetic acid-degrading bacteria belonging to the bradyrhizobium-agromonas-nitrobacter-afipia cluster in alpha-proteobacteria.the 2,4-dichlorophenoxyacetate (2,4-d)/alpha-ketoglutarate dioxygenase gene (tfda) homolog designated tfdaalpha was cloned and characterized from 2,4-d-degrading bacterial strain rd5-c2. this japanese upland soil isolate belongs to the bradyrhizobium-agromonas-nitrobacter-afipia cluster in the alpha subdivision of the class proteobacteria on the basis of its 16s ribosomal dna sequence. sequence analysis showed 56 to 60% identity of tfdaalpha to representative tfda genes. a male-tfdaalpha fusion ...200212089027
use of natural zeolite to enhance nitrification in enhance nitrification, natural zeolite and activated carbon were tested as a media in a biofilter to treat wastewater containing relatively high concentrations of tkn. using those media, the adsorption isotherms for ammonium ion were compared; the k values for natural zeolite and activated carbon were found to be 0.5117 and 0.0006, respectively. in comparison of the performance of the two media, two identical, lab-scale biofilters were then operated for 4 months. the effect of nh3-n loading r ...200212164639
in situ characterization of nitrifiers in an activated sludge plant: detection of nitrobacter spp.the purpose of this work was to investigate microbial ecology of nitrifiers at the genus level in a typical full-scale activated sludge plant.200212174041
go or no go for gel entrapped nitrifiers? a belgian case the coming years, as stricter environmental requirements are imposed, many european union wastewater treatment plants (wwtp) need to be expanded and/or upgraded. this requires considerable investments. optimising the renovation recourses can lead to significant savings. the use of entrapped nitrifying bacteria for upgrading of wwtp towards nutrient removal may be benificial. long term pilot tests were performed to evaluate a so-called pellet reactor. differences in performance and microbiolog ...200212216669
melissa: a loop of interconnected bioreactors to develop life support in space.the development of a loop of interconnected continuous bioreactors, aimed to provide life support in space, is reported. the complete loop concept consists of four bioreactors and one higher plant compartment. for its realization the continuous and controlled operation of the bioreactors is characterized, up to the pilot scale level, first for each individual reactor, second for the interconnected reactor operation. the results obtained with the two more advanced bioreactors in the micro ecologi ...200212385718
diversity of nitrifying bacteria in full-scale chloraminated distribution systems.chloramination for secondary disinfection of drinking water often promotes the growth of nitrifying bacteria in the distribution system due to the ammonia introduced by chloramine formation and decay. this study involved the application of molecular biology techniques to explore the types of ammonia-oxidizing bacteria (aob) and nitrite-oxidizing bacteria (nob) present in several full-scale chloraminated systems. the results of aob community characterization indicated the ubiquitous detection of ...200312465801
[vfeu water quality control in sts-95 aquatic animal experiment]. 199912533005
canon and anammox in a gas-lift reactor.anoxic ammonium oxidation (anammox) and completely autotrophic nitrogen removal over nitrite (canon) are new and promising microbial processes to remove ammonia from wastewaters characterized by a low content of organic materials. these two processes were investigated on their feasibility and performance in a gas-lift reactor. the anammox as well as the canon process could be maintained easily in a gas-lift reactor, and very high n-conversion rates were achieved. an n-removal rate of 8.9 kg n (m ...200312586414
use of polyclonal antibodies to detect and quantify the nor protein of nitrite oxidizers in complex the approaches or models which aim to understand and/or predict how the functioning of ecosystems may be affected by perturbations or disturbances, little attention is generally given to microorganisms. even when they are taken into account as indicators, variables which are poorly informative about the changes in the microbial functioning (microbial biomass or diversity or total number of microorganisms) are often used. to be able to estimate, in complex environments, the quantity of enzymes ...200312609727
biological treatment process of air loaded with an ammonia and hydrogen sulfide mixture.the physico-chemical characteristics of granulated sludge lead us to develop its use as a packing material in air biofiltration. then, the aim of this study is to investigate the potential of unit systems packed with this support in terms of ammonia and hydrogen sulfide emissions treatment. two laboratory scale pilot biofilters were used. a volumetric load of 680 g h2s m(-3) empty bed day(-1) and 85 g nh3 m(-3) empty bed day(-1) was applied for eight weeks to a unit called bgsn (column packed wi ...200312656240
susceptibility of ammonia-oxidizing bacteria to nitrification inhibitors.activity of nitrification inhibitors to several typical ammonia-oxidizing bacteria isolated recently, i. e. nitrosococcus, nitrosolobus, nitrosomonas, nitrosospira and nitrosovibrio species was assayed using 2-amino-4-methyl-trichloromethyl-1,3,5-triazine (mast), 2-amino-4-tribromomethyl-6-trichloromethyl-1,3,5-triazine (br-mast), 2-chloro-6-trichloromethylpyridine (nitrapyrin) and others, and compared to confirm the adequate control of ammonia-oxidizing bacteria by the inhibitors. the order of ...200312710742
structure and activity of multiple nitrifying bacterial populations co-existing in a biofilm.a biofilm from a nitrifying pilot-scale sequencing batch reactor was investigated for effects of varying process conditions on its microscale activity and structure. microsensor measurements of oxygen, substrates and products of nitrification were applied under incubation at different ammonium and oxygen concentrations which reflected various situations during a treatment cycle. a high net n loss was observed under high ammonium (ha) concentrations in contrast to low ones. additionally, results ...200312713462
changing concepts in the systematics of bacterial nitrogen-fixing legume of february 2003, bacteria that form nitrogen-fixing symbiotic associations with legumes have been confirmed in 44 species of 12 genera. phylogenies of these taxa containing legume symbionts based on the comparative analysis of 16s rdna sequences show that they are not clustered in one lineage but are distributed in the classes alphaproteobacteria and betaproteobacteria, and dispersed over the following nine monophyletic groups, being intermingled with other taxa that do not contain legume sy ...200312949698
minimum phosphate and magnesium requirements of nitrifying bacteria. 195213013339
[the relation of oxidized nitrogen to the reduced carbon in nitrobacter]. 195413171874
[on nitrite oxidation by nitrobacter winogradskyi]. 195413229327
[physiology and biochemistry of nitrifying micro-organisms]. 195613321534
[nitrite oxidation by nitrobacter vinogradskii buch. and its relation to weather factors]. 195613340834
ferrobacillus ferrooxidans: a chemosynthetic autotrophic bacterium. 195613376518
the biochemistry of the nitrifying organisms. v. nitrite oxidation by nitrobacter. 195713403908
[problem of nitrite oxidation with supplementary co2 assimilation in nitrobacter winogradskii buch]. 195713522131
cytochromes of nitrobacter. 195813590096
cell-free nitrification by nitrobacter. 195813598710
[agents initiating the second phase of nitrification. ii. effect of heavy metals on nitrification]. 195813622243
[organism inducing the second phase of nitrification. iii. morphology of the organism inducing the second phase of nitrification]. 195813632414
nitrite oxidation by nitrobacter in the presence of certain nitrophenols. 196013689460
the biochemistry of the nitrifying organisms. 6. the effect of oxygen concentration on nitrite oxidation in the presence of different inorganic ions. 196013689461
the biochemistry of the nitrifying organisms. 7. the phosphate compounds of nitrobacter and the uptake of orthophosphate by the organism. 196013689462
[the assimilation of carbon dioxide by nitrobacter winogradskyi]. 196113755762
[photoinactivation of nitrobacter winogradskyi buch]. 196113773574
on the excitant of the 2nd phase of nitrification. iv. dehydrogenase activity of the washed suspension of nitrobacter winogradsky buch 196013788009
nutrition and physiology of nitrobacter agilis. 196013792492
the isolation and culture of the nitrifying organisms. part i. nitrobacter. 196013828576
[on the effect of hydrocyanic acid on chemical synthesis]. 196113830946
[research on chemical synthesis]. 196113830947
the morphology of nitrobacter winogradskyi. 195913847099
[the gross equation of carbon dioxide-assimilation of nitrobacter winogradskyi buch]. 195913849711
use of electron paramagnetic resonance spectroscopy in investigations of functional metal components in micro-organisms. 196213938326
kinetics of nitrite oxidation by nitrobacter winogradskyi. 196214013807
[on the mechanism of chemosynthesis]. 196214037073
[on the mechanism of chemosynthesis. on the "residual respiration" of chemoautotrophic nitrobacter winogradskyi]. 196314042164
[bacterial associations and biological alterations of limestone monuments]. 196314048726
adenosine triphosphate-dependent reduction of nicotinamide adenine dinucleotide by ferro-cytochrome c in chemoautotrophic bacteria. 196314087009
[on the reduction of diphosphopyridine nucleotide in chemo-synthesis]. 196314087312
[the behavior of nitrobacter winogradskyi buch. towards increased co2 partial pressure]. 196414134892
[apropos of nitrate reductases of a denitrifying bacterium]. 196414205501
on the assimilation of energy from inorganic sources in autotrophic forms of life. 196414224403
the biochemistry of the nitrifying organisms. 8. the effects of oxygen tension, nitrite concentration, and cyanate concentration on nitrite oxidation by nitrobacter. 196414228219
[the behavior of nitrifying bacteria towards dissolved oxygen]. 196414245150
molybdenum as a micronutrient for nitrobacter.finstein, m. s. (university of california, davis), and c. c. delwiche. molybdenum as a micronutrient for nitrobacter. j. bacteriol. 89:123-128. 1965.-the requirement of nitrobacter for molybdenum was investigated by use of a medium purified by chemical means, as well as by depletion by the prior growth of this autotrophic bacterium. during 5 days of growth, added molybdenum induced an approximately 11-fold increase in both nitrite utilization and cell-mass development. in short-term studies, max ...196514255651
characterization of a nitrate reductase from the chemoautotroph nitrobacter agilis. 196514284757
determination of kinetic constants for nitrifying bacteria in mixed culture, with the aid of an electronic computer. 196514287204
structure of nitrosocystis oceanus and comparison with nitrosomonas and nitrobacter.murray, r. g. e. (university of western ontario, london, ont., canada), and s. w. watson. structure of nitrosocystis oceanus and comparison with nitrosomonas and nitrobacter. j. bacteriol. 89:1594-1609. 1965.-nitrosocystis oceanus has distinctive features: the cell wall (overall thickness, 250 a) has an inner triplet structure and a dense enveloping layer; between these lie the "cell-wall organelles" (two or more per cell; plaques about 0.5 mu in diameter and 0.1 mu thick) of unknown function an ...196514293026
[studies on the respiration of nitrobacter winogradskyi buch]. 196514304663
the effect of 2-chloro, 6-(trichloromethyl) pyridine on the chemoautotrophic metabolism of nitrifying bacteria. ii. nitrite oxidation by nitrobacter. 196514315632
[studies on the influence of temperature on nitrification in the elbe estuary]. 196414320216
poly-beta-hydroxybutyric acid in nitrobacter. 196514323606
continuous flow method in soil microbiology. v. nitrification. 196514332135
[comparative studies on the effect of visible light on nitrosomonas europaea and nitrobacter winogradskyi]. 196514347921
the effect of chlorate on the rate of nitrite oxidation by nitrobacter. 195414351163
the use of cyanate and chlorate in studies on the relation between the nitrite oxidation and the reduction of a cytochrome system in nitrobacter. 195414351219
kinetics of the nitrite oxidation by nitrobacter winogradskyi. 196014414502
bacterial destruction of sodium nitrite in open cooling water systems. 195914418926
[the inactivation of the oxidation capacity of nitrobacter winogradskyi buch]. 195914444497
formate odixation by cell-free preparations from nitrobacter agilis. 196214468824
the effect of 2,3,6-trichlorophenylacetic and 2,2-dichloropropionic acids on nitrite oxidation.the effects of two herbicides, 2,3,6-trichlorophenylacetic acid, sodium salt, and 2,2-dichloropropionic acid, sodium salt, on nitrite-oxidizing bacteria were studied by the soil perfusion technique. the time of application of 2,3,6-trichlorophenylacetic acid affected its toxicity to the nitrifier. when it was present in the environment as the nitrifier started growth, it was more toxic than if the organisms were allowed to nitrify actively before they were subjected to the herbicide. the herbici ...196214471731
growth rates of nitrifying chemoautotrophs in soil. 196214476222
dynamic response of nitrifying activated sludge batch culture to increased chloride concentration.dynamic response of nitrifying activated sludge batch cultures to increased chloride concentration was studied in this paper, which focused upon the changes in the specific nitrification rate (snr) and nitrifier population when the chloride level was gradually or stepwise increased to 30,000 mg cl l-1. the dominant species of ammonia-oxidizers and nitriteoxidizers in the population were examined by fluorescent in situ hybridization technique with 16s rrna-targeted oligonucleotide probes. it was ...200314509699
molecular analysis of microbial communities in nitrification and denitrification reactors treating high ammonia leachate.molecular analysis of microbial populations in two bench-scale nitrification and denitrification reactors fed with high ammonia landfill leachate was conducted in this study by using dgge, cloning, and fish techniques in addition to classical efficiency control parameters. nitrification tank was operated with a computer-controlled alkalinity dosing system to supply the alkalinity intermittently as consumed on the basis of on-line ph monitoring. by keeping the ph at 7.0 with this system, 99% nitr ...200314524656
nitrification and nitrifying bacteria in the lower seine river and estuary (france).the achères wastewater treatment plant, located just downstream of paris, discharges its effluents into the lower seine river. the effluents contain large numbers of heterotrophic bacteria, organic matter, and ammonium and are a source of nitrifying bacteria. as a result, degradation of organic matter by heterotrophic bacteria and subsequent oxygen depletion occur immediately downstream of the effluent outlet, whereas nitrifying bacteria apparently need to build up a significant biomass before a ...200314660353
an analysis of nitrification during the aerobic digestion of secondary sludges.investigations were undertaken to study the occurrence and progress of nitrification during aerobic digestion of activated sludge in a wide range of initial concentrations of total solids (1000 to 80 000 mg litre(-1), initial ph range of 4.5 to 10.4 and digestion temperature range of 5 degrees to 60 degrees c. batch aerobic digestion studies on activated sludge grown on wastewater (enriched with organic solids from human excretal material) indicate that almost complete elimination of the 'biodeg ...198915092439
nitrite accumulation followed by denitrification using sequencing batch reactor.biological ammonia-nitrogen removal utilizes two distinct processes, nitrification and denitrification. in nitrification, ammonia oxidizes to nitrite then to nitrate. in this study, elimination of nitrite oxidation to nitrate step was attempted in order to directly remove nitrite to nitrogen gas by denitrification. for this study the supernatant from an anaerobic digester was used as an ammonia source and a sequencing batch reactor (sbr) was employed. emphasis was given to the evaluation of the ...200415137406
effects of seawater salinity on nitrite accumulation in short-range nitrification to nitrite as end product.the effect of seawater salinity on nitrite accumulation in short-range nitrification to nitrite as the end product was studied by using a sbr. experimental results indicated that the growth of nitrobacteria was inhibited and very high levels of nitrite accumulation at different salinities were achieved under the conditions of 25-28 degrees c, ph 7.5-8.0, and the influent ammonia nitrogen of 40-70 mg/l when seawater flow used to flush toilet was less than 35% (salinity 12393 mg/l, cl- 6778 mg/l) ...200415137648
influence of chemical oxygen demand/total kjeldahl nitrogen ratio and sludge age on nitrification of nitrogenous wastewater.four laboratory-scale biological nitrification units (influent total kjeldahl nitrogen [tkn] = 1002 to 1062 mg/l) were operated at chemical oxygen demand (cod)/tkn ratios of approximately 0.5, 1.0,15, and 2.0 and at three different sludge ages of 30, 20, and 10 days to study the influence of cod/tkn, sludge age, cod loading, and tkn loading on nitrification and nitrifiers. percent nitrification was found to increase with decreases in cod/tkn and increases in sludge age. the average nitrifier con ...200415168847
dynamics of a pasture soil microbial community after deposition of cattle urine amended with [13c]urea.within grazed pastures, urine patches are hot spots of nitrogen turnover, since dietary n surpluses are excreted mainly as urea in the urine. this short-term experiment investigated 13c uptake in microbial lipids after simulated deposition of cattle urine at 10.0 and 17.1 g of urea c m(-2). confined field plots without or with cattle urine amendment were sampled after 4 and 14 days, and soil from 0- to 5-cm and 10- to 20-cm depths was analyzed for content and composition of phospholipid fatty ac ...200415528493
treatment of nitrogen and phosphorus in highly concentrated effluent in sbr and sbbr processes.various sludge treatment processes produced supernatant with high ammonia concentration from 500 to 2,000 mgn/l and generally high phosphate concentration. conversion of ammonia into nitrite via partial nitrification has proven to be an economic way, reducing oxygen and external cod requirements during the nitrification/denitrification process. two processes with biomass retention are studied simultaneously: the sequencing batch reactor (sbr) and the sequencing batch biofilm reactor (sbbr). at a ...200415537016
diversity of green-like and red-like ribulose-1,5-bisphosphate carboxylase/oxygenase large-subunit genes (cbbl) in differently managed agricultural soils.a pcr-based approach was developed to detect ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) form i large-subunit genes (cbbl) as a functional marker of autotrophic bacteria that fix carbon dioxide via the calvin-benson-bassham cycle. we constructed two different primer sets, targeting the green-like and red-like phylogenetic groups of cbbl genes. the diversity of these cbbl genes was analyzed by the use of three differently managed agricultural soils from a long-term field experiment. ...200515640185
influence of long-term diesel fuel pollution on nitrite-oxidising activity and population size of nitrobacter spp in soil.previous investigations have shown that ammonia oxidation is not inhibited by diesel fuel in a soil with a long history of contamination contrary to a non-contaminated soil. as a consequence, ammonia oxidation does not constitute a limited step in nitrification process (appl. environ. microbiol. 65 (1999) 4008). moreover, this type of soil also has had the opportunity to develop an abundant microbial population able to metabolise the diesel hydrocarbons. whether the properties of soil with a lon ...200415646378
modeling microbial-mediated reduction in batch reactors.the governing equations that depict microbially-mediated reduction of heavy metals in the subsurface include a system of coupled nonlinear partial differential equations (pde's) that describe physical (transport), chemical (sorption), and microbial (reduction/oxidation) processes. the existence of nonlinear reaction terms makes numerical simulations more challenging; however, with the advent of time-splitting solution algorithms, nonlinear reaction terms can be isolated from the convective-dispe ...200515833496
[nitrification and denitrification in the integrated vertical flow constructed wetlands].nitrification and denitrification in the different layers of the integrated vertical flow constructed wetlands (ivcw) are studied. the results show the constants rate of nitrification and denitrification in the strata of ivcw were 0.01 - 6.35microg x (gxd)-1 and 3.37 - 4.19microg x (gxd)-1 respectively. the most probable number (mpn) method are employed to determine the number and distribution of nitrifying and denitrifying bacteria in the strata of the system. the results show that the numbers ...200515859407
[stability of shortcut nitrification-denitrification].the effects of temperature and aeration time on the stability of shortcut nitrification-denitrification are studied specially in some experiments are carried on a sequencing batch reactor (sbr) fed with soybean wastewater. results show that shortcut nitrification-denitrification achieved by controlling temperature was not stable until the temperature was more than 28 degrees c. in addition, for the first time strong effect of excess aeration on shortcut nitrification-denitrification is observed. ...200515859410
effect of temperature and free ammonia on nitrification and nitrite accumulation in landfill leachate and analysis of its nitrifying bacterial community by fish.the cause of seasonal failure of a nitrifying municipal landfill leachate treatment plant utilizing a fixed biofilm was investigated by wastewater analyses and batch respirometric tests at every treatment stage. nitrification of the leachate treatment plant was severely affected by the seasonal temperature variation. high free ammonia (nh3-n) inhibited not only nitrite oxidizing bacteria (nob) but also ammonia oxidizing bacteria (aob). in addition, high ph also increased free ammonia concentrati ...200615927463
simulation modeling for nitrogen removal and experimental estimation of mass fractions of microbial groups in single-sludge system.nitrification-denitrification in a single-sludge nitrogen removal system (ssnrs; with a sufficient carbon source for denitrification) was performed. with an increase in the mixed liquor recycle ratio (r(m)) from 1 to 2, the total nitrogen (tn) removal efficiency at a lower volumetric loading rate (vlr=0.21 nh(4)(+)-n m(-3) d(-1)) increased, but the tn removal efficiency at a higher vlr (0.35 kg nh(4)(+)-n m(-3) d(-1)) decreased. a kinetic model that accounts for the mass fractions of nitrosomona ...200615936800
[potential of nitrification and denitrification in water purification system with hydroponic bio-filter method].the potential of nitrification and denitrification of sediment and the density of ammonium-oxidizing bacteria and nitrite-oxidizing bacteria in sediment in water quality purifying system with hydroponic bio-filter method (hbfm) were measured. the variation of nitrification and denitrification potential of the sediment along the stream way was quantitatively studied. the results show that among the sediments from front, middle and retral part of the stream way, the sediment from middle part reach ...200516004307
dna microarray detection of nitrifying bacterial 16s rrna in wastewater treatment plant samples.a small scale dna microarray containing a set of oligonucleotide probes targeting the 16s rrnas of several groups of nitrifying bacteria was developed for the monitoring of wastewater treatment plant samples. the microarray was tested using reference rrnas from pure cultures of nitrifying bacteria. characterization of samples collected from an industrial wastewater treatment facility demonstrated that nitrifying bacteria could be detected directly by microarray hybridization without the need for ...200516009395
[operation performance of membrane nitrification bioreactor for ammonia-containing wastewater].the operation performance of membrane nitrification bioreactor to treat ammonia-containing wastewater as well as the capabilities of separation and filtration of polypropylene membrane modules were tested. the removal efficiency of ammonia was kept higher than 95% when the hydraulic retention time was set at 1 day, the influent concentration was increased up to 80 mmol (nh4+ -n) x l(-1) and the volume loading rate was increased up to 1.12 kg (nh4+ -n) x m(-3) x d(-1). the biomass in the reactor ...200516013490
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