The present lab-scale research reveals the enrichment of anaerobic ammonium oxidation microorganism from methanogenic anaerobic granular sludge and the effect of inorganic carbon(sodium bicarbonate)on anaerobic ammoni...The present lab-scale research reveals the enrichment of anaerobic ammonium oxidation microorganism from methanogenic anaerobic granular sludge and the effect of inorganic carbon(sodium bicarbonate)on anaerobic ammonium oxidation.The enrichment of anammox bacteria was carried out in a 7.0-L sequencing batch reactor(SBR)and the effect of bicarbonate on anammox was conducted in a 3.0-L SBR.Research results,especially the biomass,showed first signs of anammox activity after 54 d cultivation with synthetic wastewater,when the pH was controlled between 7.5 and 8.3,the temperature was 35°C.The anammox activity increased as the influent bicarbonate concentration increased from 1.0to 1.5 g/L,and then,was inhibited as the bicarbonate concentration approached 2.0 g/L.However,the activity could be restored by the reduction of bicarbonate concentration to 1.0 g/L,as shown by rapid conversion of ammonium,and nitrite and nitrate production with normal stoichiometry.The optimization of the bicarbonate concentration in the reactor could increase the anammox rate up to 66.4 mgN/(L-d).展开更多
Objective To investigate the effect of chemical oxygen demand （COD） concentrations on the anaerobic ammonium oxidation （ANAMMOX）. Methods An Expanded Granular Sludge Bed （EGSB） reactor was used to cultivate the ...Objective To investigate the effect of chemical oxygen demand （COD） concentrations on the anaerobic ammonium oxidation （ANAMMOX）. Methods An Expanded Granular Sludge Bed （EGSB） reactor was used to cultivate the granular sludge and to perform the ANAMMOX reaction in the bench scale experiment. NH4^＋-N and NO2^--N were measured by using colorimetric method. NO3^＋-N was analyzed by using the UV spectrophotometric method. COD measurement was based on digestion with potassium dichromate in concentrated sulphuric acid. Results When the COD concentrations in the reactors were 0 mg/L, 200 mg/L, 350 mg/L, and 550 mg/L, respectively, the NH4^＋-N removal efficiency was 12.5%, 14.2%, 14.3%, and 23.7%; the removal amount of NO2-N was almost the same; the nitrate removal efficiency was 16.8%, 94.5%, 86.6%, and 84.2% and TN removal efficiency was 16.3%, 50.7%, 46.9%, and 50.4%, moreover, the COD removal efficiency was 85%, 65.7%, and 60%; the COD removal rate was 27.42, 61.88, and 97.8 mg COD/（h·L）. Conclusion COD concentrations have a significant influence on anaerobic ammonium oxidation by granular sludge.展开更多
The concept of anaerobic ammonium oxidation(ANAMMOX) is presently of great interest. The functional bacteria belonging to the Planctomycete phylum and their metabolism are investigated by microbiologists. Meanwhile,th...The concept of anaerobic ammonium oxidation(ANAMMOX) is presently of great interest. The functional bacteria belonging to the Planctomycete phylum and their metabolism are investigated by microbiologists. Meanwhile,the ANAMMOX is equally valuable in treatment of ammonium-rich wastewaters. Related processes including partial nitritation-ANAMMOX and completely autotrophic nitrogen removal over nitrite(CANON) have been developed,and lab-scale experiments proved that both processes were quite feasible in engineering with appropriate control. Successful full-scale practice in the Netherlands will ac-celerate application of the process in future. This review introduces the microbiology and more focuses on application of the ANAMMOX process.展开更多
The feasibility of the nitrous organic wastewater treated was studied in seven anaerobic sequencing batch reactors（ASBRs） （0^#-6^#） which had been run under stable anaerobic ammonium oxidation （Anammox）. By mean...The feasibility of the nitrous organic wastewater treated was studied in seven anaerobic sequencing batch reactors（ASBRs） （0^#-6^#） which had been run under stable anaerobic ammonium oxidation （Anammox）. By means of monitoring and data analysis of COD, NH4^#-N, NO2^--N, NO3^--N and pH, and of microbial test, the results revealed that the optimal Anammox performance was achieved from 2^# reactor in which COD/NH4^＋ -N was 1.65, Anammox bacteria and denitrification bacteria could coexist, and Anammox reaction and denitrification reaction could occur simultaneously in the reactors. The ratio of NH4^＋-N consumed ： NO2^- -N consumed ： NO3^- -N produced was 1：1.38：0.19 in 0^# reactor which was not added glucose in the wastewater. When different ratio of COD and NH4^＋-N was fed for the reactors, the ratio of NO2^- -N consumed： NH4^＋-N consumed was in the range of 1.51-2.29 and the ratio of NO;-N produced： NH4^＋ -N consumed in the range of 0 -0.05.展开更多
An ammonia-oxidizing strain of Penicillium sp., M25-22 which was isolated from chicken feces compost, was studied to make clear its characteristics of ammonium oxidation and provide references for its application in a...An ammonia-oxidizing strain of Penicillium sp., M25-22 which was isolated from chicken feces compost, was studied to make clear its characteristics of ammonium oxidation and provide references for its application in aerobic composting. In media containing （NH4）2SO4 at a concentration of 0.5 g 100 mL^-1, mycelium weight and utilization ratio of ammonium nitrogen increased markedly during the 1st 5 d, concentration of nitrate increased markedly from the 3rd to the 5th d and concentration of nitrite remained at a low level. The strain showed the ability to oxidize ammonium nitrogen growing in media containing glucose, sucrose, starch, or cellulose as the sole carbon source and to oxidize the negative trivalent nitrogen of ammonium sulfate, peptone, acetamide, urea, or L-aspartate. Slowly available carbon or nitrogen sources such as starch, cellulose, and peptone were beneficial to ammonium oxidation. In media containing sucrose as the sole carbon source and ammonium sulfate as the sole nitrogen source, nitrate formation was the most pronounced with sucrose present at a concentration of 12 g L^-1 and ammonium nitrogen present at a concentration of 2.438 mg mL% at the initial pH level of 7.5 and at 30℃.展开更多
In this study,nitrogen removal performance of the denitrifying ammonium oxidation(DAO)process was investigated when treating sulfamethoxazole(SMX)-laden secondary wastewater effluent.The influent SMX concentration sho...In this study,nitrogen removal performance of the denitrifying ammonium oxidation(DAO)process was investigated when treating sulfamethoxazole(SMX)-laden secondary wastewater effluent.The influent SMX concentration showed negligible effect on efficiencies for removal of nitrate and COD.However,the ammonium ions removal rate was moderately reduced,when the influent SMX concentration in wastewater reached 6 mg/L.Total nitrogen removal efficiency remained as high as 76.77%towards the day 158 at the end of experiment.Candidatus_Brocadia and Candidatus_Kuenenia were the functional anammox strains.The unclassified_f__Rhodobacteraceae sp.was predominant heterotrophic denitrifying strain in the studied reactor.The concentrations of soluble extracellular polymeric substances in sludge obviously increased from 16.76 mg/g VSS to 32.31 mg/g VSS,which might protect the nitrogen removal strains from high-concentration SMX.This result provides a theoretical and technical foundation for the application of denitrifying ammonium oxidation process in treating sulfamethoxazole-laden secondary wastewater effluent.展开更多
The short-and long-term effects of chlortetracycline（CTC） on the nitritation-anaerobic ammonium oxidation（anammox） process were evaluated. The half maximal inhibitory concentration of CTC in the batch tests of the...The short-and long-term effects of chlortetracycline（CTC） on the nitritation-anaerobic ammonium oxidation（anammox） process were evaluated. The half maximal inhibitory concentration of CTC in the batch tests of the nitritation-anammox process was 278.91 mg/L at an exposure time of 12 hr. The long-term effects of CTC on the process were examined in a continuous-flow nitritation-anammox reactor. Within 14 days, the nitrogen removal rate significantly decreased from 0.61 to 0.25 kg N/m^3/day with 60 mg/L CTC in the influent.The performance suppressed by CTC barely recovered, even after CTC was removed from the influent. Furthermore, the inhibition of CTC also reduced the relative abundance of ammonium oxidizing bacteria（AOB） and anaerobic ammonium oxidizing bacteria（An AOB）in the reactor, resulting in both a decreased amount of and an imbalance between AOB and An AOB. When fresh anammox sludge was reseeded into the nitritation-anammox reactor,the nitrogen removal rate recovered to 0.09 ± 0.03 kg N/m3/day.展开更多
Shortcut nitrification-denitrification,anaerobic ammonium oxidation(ANAMMOX),and methanogenesis have been successfully coupled in an Expanded Granular Sludge Bed-Biological Aerated Filter(EGSB-BAF)integrated system.As...Shortcut nitrification-denitrification,anaerobic ammonium oxidation(ANAMMOX),and methanogenesis have been successfully coupled in an Expanded Granular Sludge Bed-Biological Aerated Filter(EGSB-BAF)integrated system.As fed different synthetic wastewater with chemical oxygen demand(COD)of 300-1200 mg·L^(-1)and NH_(4)^(+)-N of 30-120 mg·L^(-1)at the outer recycle ratio of 200%,the influence of influent on ANAMMOX in the integrated system was investigated in this paper.The experimental results showed that higher COD concentration caused an increase in denitrification and methanogenesis but a decrease in ANAMMOX;however,when an influent with the low concentration of COD was used,the opposite changes could be observed.Higher influent NH_(4)^(+)-N concentration favored ANAMMOX when the COD concentration of influent was fixed.Therefore,low COD=NH_(4)^(+)-N ratio would decrease competition for nitrite between ANAMMOX and denitrification,which was favorable for reducing the negative effect of organic COD on ANAMMOX.The good performance of the integrated system indicated that the bacterial community of denitrification,ANAMMOX,and methanogenesis could be dynamically maintained in the sludge of EGSB reactor for a certain range of influent.展开更多
Red anaerobic ammonia oxidation (Anammox) granular sludge (AnGS) has been reported insuccessfully operating Anammox systems, and its color is associated with sludge activity.However, in long-term operating systems, An...Red anaerobic ammonia oxidation (Anammox) granular sludge (AnGS) has been reported insuccessfully operating Anammox systems, and its color is associated with sludge activity.However, in long-term operating systems, AnGS exhibits different sensory colors, physicalstructures, community structures, and denitrification performance, but the relationship betweenthem has not yet been elucidated.The AnGS of the Anammox system, which has beenin operation for more than a decade, can be divided into twomain categories: red and white.The specific Anammox activity (SAA) in conventional red AnGS increased continuously asthe particle size increased from <0.51 mm to 6.02 ± 0.84 mm. The SAA of white AnGS wereslightly lower than those of red AnGS with similarly-size granules but significantly higherthan AnGS with smaller red granules. Compared with red AnGS, the extracellular polymericsubstances of white AnGS were significantly reduced,mainly due to the higher intracellulariron content, resulting in lower heme c concentration. Thus, heme c may prove not to bean evaluative tool for measuring Anammox activity. Red and white AnGS, whether throughself-aggregation or adsorption by hydroxyl apatite and other carriers, will face the fate ofinternal voids during particle size growth. White AnGS exhibited amore complex microbialcommunity than red AnGS. Candidatus Brocadia was abundant in red AnGS and the abundanceincreased with increasing granule size. Candidatus Kuenenia and Candidatus Jetteniamade significant contributions to denitrification in white AnGS. This study provides a newperspective on particle selection for anammox engineering applications.展开更多
A GAC-sand dual media filter （GSF） was devised as an alternative solution for drinking water treatment plant to tackle the raw water polluted by ammonium in place of expensive ozone-GAC processes or bio-pretreatment...A GAC-sand dual media filter （GSF） was devised as an alternative solution for drinking water treatment plant to tackle the raw water polluted by ammonium in place of expensive ozone-GAC processes or bio-pretreatments. The ammonium removal pathways and microbial community in the GSFs were investigated. The concentrations of ammonium, nitrite and nitrate nitrogen were monitored along the filter. Total inorganic nitrogen （TIN） loss occurred during the filtration. For 1 mg ammonium removal, the TIN loss was as high as 0.35 mg, DO consumption was 3.06 mg, and alkalinity consumption was 5.55 rag. It was assumed that both nitrification and denitrification processes occur in the filters to fit the TIN loss and low DO consumption. During the filtration, nitritation, nitrification and nitritation-anaerobic ammonium oxidation processes probably occur, while traditional nitrification and denitrification and simultaneous nitrification and denitrification processes may occur. In the GSFs, Nitrosomonas and Nitrospira are likely to be involved in nitrification processes, while Novosphingobium, Comamonadaceae and Oxalobacteraceae may be involved in denitrification processes.展开更多
The anaerobic ammonium-oxidizing （ANAMMOX） bacteria were enriched from a sequencing batch biofilm reactor （SBBR）. A quantitative competitive polymerase chain reaction （QC-PCR） system was successfully developed t...The anaerobic ammonium-oxidizing （ANAMMOX） bacteria were enriched from a sequencing batch biofilm reactor （SBBR）. A quantitative competitive polymerase chain reaction （QC-PCR） system was successfully developed to detect and quantify ANAMMOX bacteria in environmental samples. For QC-PCR system, PCR primer sets targeting 16S ribosomal RNA genes of ANAMMOX bacteria were designed and used. The quantification range of this system was 4 orders of magnitude, from 10^3 to 10^6 copies per PCR, corresponding to the detection limit of 300 target copies per mL. A 312-bp internal standard was constructed, which showed very similar amplification efficiency with the target amxC fragment （349 bp） over 4 orders of magnitude （10^3-10^6）. The linear regressions were obtained with R^2 of 0.9824 for 10^3 copies, 0.9882 for 10^4 copies, 0.9857 for 10^5 copies and 0.9899 for 10^6 copies, respectively. Using this method, ANAMMOX bacteria were quantified in a shortcut nitrification/denitrification-anammox system which was set for piggery wastewater treatment.展开更多
The short-term effects of temperature and free ammonia (FA) on ammonium oxidization were investigated in this study by operating several batch tests with two different partial nitrification aggregates, formed as eithe...The short-term effects of temperature and free ammonia (FA) on ammonium oxidization were investigated in this study by operating several batch tests with two different partial nitrification aggregates, formed as either granules or flocs. The results showed that the rate of ammonium oxidation in both cultures increased significantly as temperature increased from 10 to 30 °C. The specific ammonium oxidation rate with the granules was 2-3 times higher than that with flocs at the same temperature. Nitrification at various FA concentrations and temperatures combination exhibited obvious inhibition in ammonium oxidation rate when FA was 90 mg·L 1 and tempera- ture dropped to 10 °C in the two systems. However, the increase in substrate oxidation rate of ammonia at 30 °C was observed. The results suggested that higher reaction temperature was helpful to reduce the toxicity of FA. Granules appeared to be more tolerant to FA attributed to the much fraction of ammonia oxidizing bacteria (AOB) and higher resistance to the transfer of ammonia into the bacterial aggregates, whereas in the floc system, the bacteria distributed throughout the entire aggregate. These results may contribute to the applicability of the nitrifying granules in wastewater treatment operated at high ammonium concentration.展开更多
A novel bromination of α,β-unsaturated carboxylic acids was developed via a decarboxylation by virtue of a direct anodic electro-oxidation.In this method,ammonium bromide was employed as a bromine source and the rea...A novel bromination of α,β-unsaturated carboxylic acids was developed via a decarboxylation by virtue of a direct anodic electro-oxidation.In this method,ammonium bromide was employed as a bromine source and the reaction features transition-metal-free,short time,and no additional supporting electrolyte.展开更多
6-Substituted 5,8-O-dimethyl-1,4-naphthoquinones（6-DMNQ）,the promising anticancer scaffolds,were selectively generated by oxidative demethylation of 2-substituted 1,4,5,8-tetramethoxynaphthalenes with CAN in EtOAc/H...6-Substituted 5,8-O-dimethyl-1,4-naphthoquinones（6-DMNQ）,the promising anticancer scaffolds,were selectively generated by oxidative demethylation of 2-substituted 1,4,5,8-tetramethoxynaphthalenes with CAN in EtOAc/H2O in comparatively high yields.An interesting finding was that apart from the reported electron-withdrawing effects of substituents on position 2 of naphthalene ring,regioselective synthesis of 6-DMNQ was largely dependent on the steric effects in CAN-mediated oxidation.The selective cytotoxicities of 6-DMNQ from the in vitro cell-based assays were exhibited between the cancer cells and normal cells.Moreover,most of sulfur-containing 6-DMNQ derivatives displayed better anticancer activities than the corresponding oxygen-containing ones,which could provide an available strategy for the design of 6-DMNQ derivatives as potential anticancer agents.展开更多
hhen ammonium sulfate-iron oxide is treated below 573 K, ammonium sulfate can spontaneously desperse on the surface of iron oxide. Simultaneously ammonium sulfate decomposes to some extent. During or after the dispers...hhen ammonium sulfate-iron oxide is treated below 573 K, ammonium sulfate can spontaneously desperse on the surface of iron oxide. Simultaneously ammonium sulfate decomposes to some extent. During or after the dispersion, sulfate ion can interact with Fe atom on the surface of iron oxide to form a sort of surface sulfato complex of Fe and thus is transformed from the isolated into the bidentately bound form. Above 573 K the sulfato complex of Fe will gradually decompose with a further increase in temperature.展开更多
Soil organic amendments(OAs)are used to replenish carbon(C)and nutrients in the soil to prevent its degradation and increase its fertility.While soil can be an important C sink,it can also release significant amounts ...Soil organic amendments(OAs)are used to replenish carbon(C)and nutrients in the soil to prevent its degradation and increase its fertility.While soil can be an important C sink,it can also release significant amounts of greenhouse gases(GHGs).Different OA pretreatment technologies indirectly affect soil aggregate formation and C stabilization even when the same initial substrate is used.However,little is known about the long-term effect of OA pretreatment on the soil C and nitrogen(N)associated with macroaggregates,which are known to disintegrate faster than microaggregates.In this study,we studied the effect of OA pretreatment on soil C and N in relation to aggregate formation and GHG emissions using five differently pretreated OAs from the same original OA,i.e.,composted,digested,and fermented OA,a 1:1 mix of the composted and fermented OAs,and the unpretreated original OA.We monitored the changes in a soil column experiment after 6 and 12 months of incubation.Our results indicated that OA pretreatment indirectly affected GHG emissions from soil.The composted and mixed OAs released less GHGs(i.e.,carbon dioxide,nitrous oxide,and methane)but had no positive impact on macroaggregates,while the digested OA induced long-lasting macroaggregation and occluded particulate organic matter formation,emitting intermediate levels of GHGs.The unpretreated OA exhibited the highest GHG emissions,similar to the fermented OA,albeit without benefiting macroaggregation.These demonstrated that OA pretreatment had a long-lasting indirect effect on soil C and N,influencing total GHG emissions,nitrous oxide formation mechanisms,and soil macroaggregate formation.展开更多
Dissolved oxygen(DO)concentration is regarded as one of the crucial factors to influence partial nitrification process.However,achieving and keeping stable partial nitrification under different DO concentrations were ...Dissolved oxygen(DO)concentration is regarded as one of the crucial factors to influence partial nitrification process.However,achieving and keeping stable partial nitrification under different DO concentrations were widely reported.The mechanism of DO concentration influencing partial nitrification is still unclear.Therefore,in this study two same sequencing batch reactors(SBRs)cultivated same seeding sludge were built up with realtime control strategy.Different DO concentrations were controlled in SBRs to explore the effect of DO concentration on the long-term stability of partial nitrification process at room temperature.It was discovered that ammonium oxidation rate(AOR)was inhibited when DO concentration decreased from 2.5 to 0.5 mg/L.The abundance of Nitrospira increased from 1011.5 to 1013.7 copies/g DNA,and its relative percentage increased from 0.056%to 3.2%during 190 operational cycles,causing partial nitrification gradually turning into complete nitrification process.However,when DO was 2.5 mg/L the abundance of Nitrospira was stable and AOB was always kept at 1010.7 copies/g DNA.High AOR was maintained,and stable partial nitrification process was kept.Ammonia oxidizing bacteria(AOB)activity was significantly higher than nitrite oxidizing bacteria(NOB)activity at DO of 2.5 mg/L,which was crucial to maintain excellent nitrite accumulation performance.展开更多
Ferrous and manganese ions, as essential elements, significantly affect the synthesis of Haem-C, which participates in the energy metabolism and proliferation of anammox bacteria. In this study, two identical sequenci...Ferrous and manganese ions, as essential elements, significantly affect the synthesis of Haem-C, which participates in the energy metabolism and proliferation of anammox bacteria. In this study, two identical sequencing batch biofilm reactors were used to investigate the effects of ferrous and manganese ions on nitrogen removal efficiency and the potential of metal ions serving as electron donor/acceptors in the anammox process. Fluorescence in situ hybridization analysis was applied to investigate the microbial growth. Results showed that the nitrogen removal increased at high concentrations of Fe2＋ and Mn2＋ and the maximum removal efficiency was nearly 95% at Fe2＋ 0.08 mmol/L and Mn2＋ 0.05 mmol/L, which is nearly 15% and 8% higher than at the lowest Fe2＋ and Mn2＋ concentrations （0.04 and 0.0125 mmol/L）. The stabilities of the anammox reactor and the anammox bacterial growth were also enhanced with the elevated Fe2＋ and Mn2＋ concentrations. The Fe2＋ and Mn2＋were consumed by anammox bacteria along with the removal of ammonia and nitrite. Stoichiometry analysis showed Fe2＋ could serve as an electron donor for NO3-N in the anammox process. Nitrate could be reduced with Fe2＋ serving as the electron donor in the anammox system, which causes the value of NO^-N/NH4-N to decrease with the increasing of N-removal efficiency.展开更多
Ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),and anaerobic ammonia-oxidation(anammox)bacteria are very important contributors to nitrogen cycling in natural environments.Functional gene abundances of...Ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),and anaerobic ammonia-oxidation(anammox)bacteria are very important contributors to nitrogen cycling in natural environments.Functional gene abundances of these microbes were believed to be well relevant to N-cycling in groundwater systems,especially in the Pearl River Delta(PRD)groundwater with unique high intrinsic ammonia concentrations.In this research,20 sediment samples from two in the PRD were collected for porewater chemistry analysis and quantification of N-cycling related genes,including archaeal and bacterial amoA gene and anammox 16S ribosomal Ribonucleic Acid(rRNA)gene.Quantitative Polymerase Chain Reaction(qPCR)results showed that gene abundances of AOA,AOB,and anammox bacteria ranged from 3.13×10^(5)to 3.21×10^(7),1.83×10^(4)to 2.74×10^(6),and 9.27×10^(4)to 8.96×10^(6)copies/g in the sediment of the groundwater system,respectively.Anammox bacteria and AOA dominated in aquitards and aquifers,respectively,meanwhile,the aquitard-aquifer interfaces were demonstrated as ammonium-oxidizing hotspots in the aspect of gene numbers.Gene abundances of nitrifiers were analyzed with geochemistry profiles.Correlations between gene numbers and environmental variables indicated that the gene abundances were impacted by hydrogeological conditions,and microbial-derived ammonium loss was dominated by AOA in the northwest PRD and by anammox bacteria in the southeast PRD.展开更多
Marine aquaculture in semi-enclosed bays can significantly influence nutrient cycling in coastal ecosystems.However,the impact of marine aquaculture on the dynamics of dissimilatory nitrate reduction processes(DNRPs)a...Marine aquaculture in semi-enclosed bays can significantly influence nutrient cycling in coastal ecosystems.However,the impact of marine aquaculture on the dynamics of dissimilatory nitrate reduction processes(DNRPs)and the fate of reactive nitrogen remain poorly understood.In this study,the rates of DNRPs and the abundances of related functional genes were investigated in aquaculture and non-aquaculture areas.The results showed that marine aquaculture significantly increased the denitrification(DNF)and dissimilatory nitrate reduction to ammonium(DNRA)rates and decreased the rate of anaerobic ammonium oxidation(ANA),as compared with non-aquaculture sites.DNF was the dominant pathway contributing to the total nitrate reduction,and its contribution to the total nitrate reduction significantly increased from 66.72%at non-aquaculture sites to 78.50%at aquaculture sites.Marine aquaculture can significantly affect the physicochemical characteristics of sediment and the abundances of related functional genes,leading to variations in the nitrate reduction rates.Although nitrate removal rates increased in the marine aquaculture area,ammonification rates and the nitrogen retention index in the aquaculture areas were 2.19 and 1.24 times,respectively,higher than those at non-aquaculture sites.Net reactive nitrogen retention exceeded nitrogen removal in the aquaculture area,and the retained reactive nitrogen could diffuse with the tidal current to the entire bay,thereby aggravating N pollution in the entire study area.These results show that marine aquaculture is the dominant source of nitrogen pollution in semi-enclosed bays.This study can provide insights into nitrogen pollution control in semi-enclosed bays with well-developed marine aquaculture.展开更多
文摘The present lab-scale research reveals the enrichment of anaerobic ammonium oxidation microorganism from methanogenic anaerobic granular sludge and the effect of inorganic carbon(sodium bicarbonate)on anaerobic ammonium oxidation.The enrichment of anammox bacteria was carried out in a 7.0-L sequencing batch reactor(SBR)and the effect of bicarbonate on anammox was conducted in a 3.0-L SBR.Research results,especially the biomass,showed first signs of anammox activity after 54 d cultivation with synthetic wastewater,when the pH was controlled between 7.5 and 8.3,the temperature was 35°C.The anammox activity increased as the influent bicarbonate concentration increased from 1.0to 1.5 g/L,and then,was inhibited as the bicarbonate concentration approached 2.0 g/L.However,the activity could be restored by the reduction of bicarbonate concentration to 1.0 g/L,as shown by rapid conversion of ammonium,and nitrite and nitrate production with normal stoichiometry.The optimization of the bicarbonate concentration in the reactor could increase the anammox rate up to 66.4 mgN/(L-d).
基金The work was supported by the National Natural Science Foundation of China (Grant No. 59978020).
文摘Objective To investigate the effect of chemical oxygen demand （COD） concentrations on the anaerobic ammonium oxidation （ANAMMOX）. Methods An Expanded Granular Sludge Bed （EGSB） reactor was used to cultivate the granular sludge and to perform the ANAMMOX reaction in the bench scale experiment. NH4^＋-N and NO2^--N were measured by using colorimetric method. NO3^＋-N was analyzed by using the UV spectrophotometric method. COD measurement was based on digestion with potassium dichromate in concentrated sulphuric acid. Results When the COD concentrations in the reactors were 0 mg/L, 200 mg/L, 350 mg/L, and 550 mg/L, respectively, the NH4^＋-N removal efficiency was 12.5%, 14.2%, 14.3%, and 23.7%; the removal amount of NO2-N was almost the same; the nitrate removal efficiency was 16.8%, 94.5%, 86.6%, and 84.2% and TN removal efficiency was 16.3%, 50.7%, 46.9%, and 50.4%, moreover, the COD removal efficiency was 85%, 65.7%, and 60%; the COD removal rate was 27.42, 61.88, and 97.8 mg COD/（h·L）. Conclusion COD concentrations have a significant influence on anaerobic ammonium oxidation by granular sludge.
基金Project supported by the National Hi-Tech Research and Develop-ment Program (863) of China (No. 2006AA06Z332)the Scienceand Technology Foundation for Key Project of Zhejiang Province (No2003C13005), China
文摘The concept of anaerobic ammonium oxidation(ANAMMOX) is presently of great interest. The functional bacteria belonging to the Planctomycete phylum and their metabolism are investigated by microbiologists. Meanwhile,the ANAMMOX is equally valuable in treatment of ammonium-rich wastewaters. Related processes including partial nitritation-ANAMMOX and completely autotrophic nitrogen removal over nitrite(CANON) have been developed,and lab-scale experiments proved that both processes were quite feasible in engineering with appropriate control. Successful full-scale practice in the Netherlands will ac-celerate application of the process in future. This review introduces the microbiology and more focuses on application of the ANAMMOX process.
文摘The feasibility of the nitrous organic wastewater treated was studied in seven anaerobic sequencing batch reactors（ASBRs） （0^#-6^#） which had been run under stable anaerobic ammonium oxidation （Anammox）. By means of monitoring and data analysis of COD, NH4^#-N, NO2^--N, NO3^--N and pH, and of microbial test, the results revealed that the optimal Anammox performance was achieved from 2^# reactor in which COD/NH4^＋ -N was 1.65, Anammox bacteria and denitrification bacteria could coexist, and Anammox reaction and denitrification reaction could occur simultaneously in the reactors. The ratio of NH4^＋-N consumed ： NO2^- -N consumed ： NO3^- -N produced was 1：1.38：0.19 in 0^# reactor which was not added glucose in the wastewater. When different ratio of COD and NH4^＋-N was fed for the reactors, the ratio of NO2^- -N consumed： NH4^＋-N consumed was in the range of 1.51-2.29 and the ratio of NO;-N produced： NH4^＋ -N consumed in the range of 0 -0.05.
基金study was supported by the National Natural Science Foundation of China (NSFC-30371054)
文摘An ammonia-oxidizing strain of Penicillium sp., M25-22 which was isolated from chicken feces compost, was studied to make clear its characteristics of ammonium oxidation and provide references for its application in aerobic composting. In media containing （NH4）2SO4 at a concentration of 0.5 g 100 mL^-1, mycelium weight and utilization ratio of ammonium nitrogen increased markedly during the 1st 5 d, concentration of nitrate increased markedly from the 3rd to the 5th d and concentration of nitrite remained at a low level. The strain showed the ability to oxidize ammonium nitrogen growing in media containing glucose, sucrose, starch, or cellulose as the sole carbon source and to oxidize the negative trivalent nitrogen of ammonium sulfate, peptone, acetamide, urea, or L-aspartate. Slowly available carbon or nitrogen sources such as starch, cellulose, and peptone were beneficial to ammonium oxidation. In media containing sucrose as the sole carbon source and ammonium sulfate as the sole nitrogen source, nitrate formation was the most pronounced with sucrose present at a concentration of 12 g L^-1 and ammonium nitrogen present at a concentration of 2.438 mg mL% at the initial pH level of 7.5 and at 30℃.
基金This research was supported by the Natural Science Foundation of Shandong Province(ZR2019MEE038)the Fundamental Research Funds for the Central Universities(19CX02038A).
文摘In this study,nitrogen removal performance of the denitrifying ammonium oxidation(DAO)process was investigated when treating sulfamethoxazole(SMX)-laden secondary wastewater effluent.The influent SMX concentration showed negligible effect on efficiencies for removal of nitrate and COD.However,the ammonium ions removal rate was moderately reduced,when the influent SMX concentration in wastewater reached 6 mg/L.Total nitrogen removal efficiency remained as high as 76.77%towards the day 158 at the end of experiment.Candidatus_Brocadia and Candidatus_Kuenenia were the functional anammox strains.The unclassified_f__Rhodobacteraceae sp.was predominant heterotrophic denitrifying strain in the studied reactor.The concentrations of soluble extracellular polymeric substances in sludge obviously increased from 16.76 mg/g VSS to 32.31 mg/g VSS,which might protect the nitrogen removal strains from high-concentration SMX.This result provides a theoretical and technical foundation for the application of denitrifying ammonium oxidation process in treating sulfamethoxazole-laden secondary wastewater effluent.
基金supported by the National Natural Science Foundation of China (No. 51578043)the Basic research funds (No. C16JB00480)
文摘The short-and long-term effects of chlortetracycline（CTC） on the nitritation-anaerobic ammonium oxidation（anammox） process were evaluated. The half maximal inhibitory concentration of CTC in the batch tests of the nitritation-anammox process was 278.91 mg/L at an exposure time of 12 hr. The long-term effects of CTC on the process were examined in a continuous-flow nitritation-anammox reactor. Within 14 days, the nitrogen removal rate significantly decreased from 0.61 to 0.25 kg N/m^3/day with 60 mg/L CTC in the influent.The performance suppressed by CTC barely recovered, even after CTC was removed from the influent. Furthermore, the inhibition of CTC also reduced the relative abundance of ammonium oxidizing bacteria（AOB） and anaerobic ammonium oxidizing bacteria（An AOB）in the reactor, resulting in both a decreased amount of and an imbalance between AOB and An AOB. When fresh anammox sludge was reseeded into the nitritation-anammox reactor,the nitrogen removal rate recovered to 0.09 ± 0.03 kg N/m3/day.
基金This research was supported by the Natural Science Foundation of China(Grant No.50378094).
文摘Shortcut nitrification-denitrification,anaerobic ammonium oxidation(ANAMMOX),and methanogenesis have been successfully coupled in an Expanded Granular Sludge Bed-Biological Aerated Filter(EGSB-BAF)integrated system.As fed different synthetic wastewater with chemical oxygen demand(COD)of 300-1200 mg·L^(-1)and NH_(4)^(+)-N of 30-120 mg·L^(-1)at the outer recycle ratio of 200%,the influence of influent on ANAMMOX in the integrated system was investigated in this paper.The experimental results showed that higher COD concentration caused an increase in denitrification and methanogenesis but a decrease in ANAMMOX;however,when an influent with the low concentration of COD was used,the opposite changes could be observed.Higher influent NH_(4)^(+)-N concentration favored ANAMMOX when the COD concentration of influent was fixed.Therefore,low COD=NH_(4)^(+)-N ratio would decrease competition for nitrite between ANAMMOX and denitrification,which was favorable for reducing the negative effect of organic COD on ANAMMOX.The good performance of the integrated system indicated that the bacterial community of denitrification,ANAMMOX,and methanogenesis could be dynamically maintained in the sludge of EGSB reactor for a certain range of influent.
基金supported by the National Key Research and Development Programme of China(No.2023YFC3206903)the Natural Science Foundation of China(No.51938010)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX23_1717).
文摘Red anaerobic ammonia oxidation (Anammox) granular sludge (AnGS) has been reported insuccessfully operating Anammox systems, and its color is associated with sludge activity.However, in long-term operating systems, AnGS exhibits different sensory colors, physicalstructures, community structures, and denitrification performance, but the relationship betweenthem has not yet been elucidated.The AnGS of the Anammox system, which has beenin operation for more than a decade, can be divided into twomain categories: red and white.The specific Anammox activity (SAA) in conventional red AnGS increased continuously asthe particle size increased from <0.51 mm to 6.02 ± 0.84 mm. The SAA of white AnGS wereslightly lower than those of red AnGS with similarly-size granules but significantly higherthan AnGS with smaller red granules. Compared with red AnGS, the extracellular polymericsubstances of white AnGS were significantly reduced,mainly due to the higher intracellulariron content, resulting in lower heme c concentration. Thus, heme c may prove not to bean evaluative tool for measuring Anammox activity. Red and white AnGS, whether throughself-aggregation or adsorption by hydroxyl apatite and other carriers, will face the fate ofinternal voids during particle size growth. White AnGS exhibited amore complex microbialcommunity than red AnGS. Candidatus Brocadia was abundant in red AnGS and the abundanceincreased with increasing granule size. Candidatus Kuenenia and Candidatus Jetteniamade significant contributions to denitrification in white AnGS. This study provides a newperspective on particle selection for anammox engineering applications.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment(No. 2009ZX07423-003)
文摘A GAC-sand dual media filter （GSF） was devised as an alternative solution for drinking water treatment plant to tackle the raw water polluted by ammonium in place of expensive ozone-GAC processes or bio-pretreatments. The ammonium removal pathways and microbial community in the GSFs were investigated. The concentrations of ammonium, nitrite and nitrate nitrogen were monitored along the filter. Total inorganic nitrogen （TIN） loss occurred during the filtration. For 1 mg ammonium removal, the TIN loss was as high as 0.35 mg, DO consumption was 3.06 mg, and alkalinity consumption was 5.55 rag. It was assumed that both nitrification and denitrification processes occur in the filters to fit the TIN loss and low DO consumption. During the filtration, nitritation, nitrification and nitritation-anaerobic ammonium oxidation processes probably occur, while traditional nitrification and denitrification and simultaneous nitrification and denitrification processes may occur. In the GSFs, Nitrosomonas and Nitrospira are likely to be involved in nitrification processes, while Novosphingobium, Comamonadaceae and Oxalobacteraceae may be involved in denitrification processes.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (No.KZCX3-SW-442, KSCX2-YW-G-008)
文摘The anaerobic ammonium-oxidizing （ANAMMOX） bacteria were enriched from a sequencing batch biofilm reactor （SBBR）. A quantitative competitive polymerase chain reaction （QC-PCR） system was successfully developed to detect and quantify ANAMMOX bacteria in environmental samples. For QC-PCR system, PCR primer sets targeting 16S ribosomal RNA genes of ANAMMOX bacteria were designed and used. The quantification range of this system was 4 orders of magnitude, from 10^3 to 10^6 copies per PCR, corresponding to the detection limit of 300 target copies per mL. A 312-bp internal standard was constructed, which showed very similar amplification efficiency with the target amxC fragment （349 bp） over 4 orders of magnitude （10^3-10^6）. The linear regressions were obtained with R^2 of 0.9824 for 10^3 copies, 0.9882 for 10^4 copies, 0.9857 for 10^5 copies and 0.9899 for 10^6 copies, respectively. Using this method, ANAMMOX bacteria were quantified in a shortcut nitrification/denitrification-anammox system which was set for piggery wastewater treatment.
基金Supported by the Project of Scientific Research Base and Scientific Innovation Platform of Beijing Municipal Education CommissionNational Key Science and Technology Special Projects
文摘The short-term effects of temperature and free ammonia (FA) on ammonium oxidization were investigated in this study by operating several batch tests with two different partial nitrification aggregates, formed as either granules or flocs. The results showed that the rate of ammonium oxidation in both cultures increased significantly as temperature increased from 10 to 30 °C. The specific ammonium oxidation rate with the granules was 2-3 times higher than that with flocs at the same temperature. Nitrification at various FA concentrations and temperatures combination exhibited obvious inhibition in ammonium oxidation rate when FA was 90 mg·L 1 and tempera- ture dropped to 10 °C in the two systems. However, the increase in substrate oxidation rate of ammonia at 30 °C was observed. The results suggested that higher reaction temperature was helpful to reduce the toxicity of FA. Granules appeared to be more tolerant to FA attributed to the much fraction of ammonia oxidizing bacteria (AOB) and higher resistance to the transfer of ammonia into the bacterial aggregates, whereas in the floc system, the bacteria distributed throughout the entire aggregate. These results may contribute to the applicability of the nitrifying granules in wastewater treatment operated at high ammonium concentration.
基金the National Nature Science Foundation of China(Nos.21472177,21672200,21432009,J1310010)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB20000000)
文摘A novel bromination of α,β-unsaturated carboxylic acids was developed via a decarboxylation by virtue of a direct anodic electro-oxidation.In this method,ammonium bromide was employed as a bromine source and the reaction features transition-metal-free,short time,and no additional supporting electrolyte.
基金supported by National Natural Science Foundation of China(No.81373274)Ph.D.Programs Foundation of Ministry of Education China(No.20120073110068)Shanghai Biomedical Supporting Funding(No.15431900600)
文摘6-Substituted 5,8-O-dimethyl-1,4-naphthoquinones（6-DMNQ）,the promising anticancer scaffolds,were selectively generated by oxidative demethylation of 2-substituted 1,4,5,8-tetramethoxynaphthalenes with CAN in EtOAc/H2O in comparatively high yields.An interesting finding was that apart from the reported electron-withdrawing effects of substituents on position 2 of naphthalene ring,regioselective synthesis of 6-DMNQ was largely dependent on the steric effects in CAN-mediated oxidation.The selective cytotoxicities of 6-DMNQ from the in vitro cell-based assays were exhibited between the cancer cells and normal cells.Moreover,most of sulfur-containing 6-DMNQ derivatives displayed better anticancer activities than the corresponding oxygen-containing ones,which could provide an available strategy for the design of 6-DMNQ derivatives as potential anticancer agents.
文摘hhen ammonium sulfate-iron oxide is treated below 573 K, ammonium sulfate can spontaneously desperse on the surface of iron oxide. Simultaneously ammonium sulfate decomposes to some extent. During or after the dispersion, sulfate ion can interact with Fe atom on the surface of iron oxide to form a sort of surface sulfato complex of Fe and thus is transformed from the isolated into the bidentately bound form. Above 573 K the sulfato complex of Fe will gradually decompose with a further increase in temperature.
基金funded by the Dutch Ministry of Economic Affairs and Climate Policy,the European Union Regional Development Fund,the City of Leeuwarden,the Province of Fryslân,the Northern Netherlands Provinces and The Netherlands Organization for Scientific Research.Wetsus also coordinates the WaterSEED project,which received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement(No.665874)。
文摘Soil organic amendments(OAs)are used to replenish carbon(C)and nutrients in the soil to prevent its degradation and increase its fertility.While soil can be an important C sink,it can also release significant amounts of greenhouse gases(GHGs).Different OA pretreatment technologies indirectly affect soil aggregate formation and C stabilization even when the same initial substrate is used.However,little is known about the long-term effect of OA pretreatment on the soil C and nitrogen(N)associated with macroaggregates,which are known to disintegrate faster than microaggregates.In this study,we studied the effect of OA pretreatment on soil C and N in relation to aggregate formation and GHG emissions using five differently pretreated OAs from the same original OA,i.e.,composted,digested,and fermented OA,a 1:1 mix of the composted and fermented OAs,and the unpretreated original OA.We monitored the changes in a soil column experiment after 6 and 12 months of incubation.Our results indicated that OA pretreatment indirectly affected GHG emissions from soil.The composted and mixed OAs released less GHGs(i.e.,carbon dioxide,nitrous oxide,and methane)but had no positive impact on macroaggregates,while the digested OA induced long-lasting macroaggregation and occluded particulate organic matter formation,emitting intermediate levels of GHGs.The unpretreated OA exhibited the highest GHG emissions,similar to the fermented OA,albeit without benefiting macroaggregation.These demonstrated that OA pretreatment had a long-lasting indirect effect on soil C and N,influencing total GHG emissions,nitrous oxide formation mechanisms,and soil macroaggregate formation.
基金supported by the National Natural Science Foundation of China(No.51878011)
文摘Dissolved oxygen(DO)concentration is regarded as one of the crucial factors to influence partial nitrification process.However,achieving and keeping stable partial nitrification under different DO concentrations were widely reported.The mechanism of DO concentration influencing partial nitrification is still unclear.Therefore,in this study two same sequencing batch reactors(SBRs)cultivated same seeding sludge were built up with realtime control strategy.Different DO concentrations were controlled in SBRs to explore the effect of DO concentration on the long-term stability of partial nitrification process at room temperature.It was discovered that ammonium oxidation rate(AOR)was inhibited when DO concentration decreased from 2.5 to 0.5 mg/L.The abundance of Nitrospira increased from 1011.5 to 1013.7 copies/g DNA,and its relative percentage increased from 0.056%to 3.2%during 190 operational cycles,causing partial nitrification gradually turning into complete nitrification process.However,when DO was 2.5 mg/L the abundance of Nitrospira was stable and AOB was always kept at 1010.7 copies/g DNA.High AOR was maintained,and stable partial nitrification process was kept.Ammonia oxidizing bacteria(AOB)activity was significantly higher than nitrite oxidizing bacteria(NOB)activity at DO of 2.5 mg/L,which was crucial to maintain excellent nitrite accumulation performance.
基金supported by the National Natural Science Foundation of China(No.21177033)
文摘Ferrous and manganese ions, as essential elements, significantly affect the synthesis of Haem-C, which participates in the energy metabolism and proliferation of anammox bacteria. In this study, two identical sequencing batch biofilm reactors were used to investigate the effects of ferrous and manganese ions on nitrogen removal efficiency and the potential of metal ions serving as electron donor/acceptors in the anammox process. Fluorescence in situ hybridization analysis was applied to investigate the microbial growth. Results showed that the nitrogen removal increased at high concentrations of Fe2＋ and Mn2＋ and the maximum removal efficiency was nearly 95% at Fe2＋ 0.08 mmol/L and Mn2＋ 0.05 mmol/L, which is nearly 15% and 8% higher than at the lowest Fe2＋ and Mn2＋ concentrations （0.04 and 0.0125 mmol/L）. The stabilities of the anammox reactor and the anammox bacterial growth were also enhanced with the elevated Fe2＋ and Mn2＋ concentrations. The Fe2＋ and Mn2＋were consumed by anammox bacteria along with the removal of ammonia and nitrite. Stoichiometry analysis showed Fe2＋ could serve as an electron donor for NO3-N in the anammox process. Nitrate could be reduced with Fe2＋ serving as the electron donor in the anammox system, which causes the value of NO^-N/NH4-N to decrease with the increasing of N-removal efficiency.
基金This study was financially supported by the General Research Fund of the Research Grants Council,the Hong Kong Special Administrative Region,China(HKU 702612P and HKU 703010P).
文摘Ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),and anaerobic ammonia-oxidation(anammox)bacteria are very important contributors to nitrogen cycling in natural environments.Functional gene abundances of these microbes were believed to be well relevant to N-cycling in groundwater systems,especially in the Pearl River Delta(PRD)groundwater with unique high intrinsic ammonia concentrations.In this research,20 sediment samples from two in the PRD were collected for porewater chemistry analysis and quantification of N-cycling related genes,including archaeal and bacterial amoA gene and anammox 16S ribosomal Ribonucleic Acid(rRNA)gene.Quantitative Polymerase Chain Reaction(qPCR)results showed that gene abundances of AOA,AOB,and anammox bacteria ranged from 3.13×10^(5)to 3.21×10^(7),1.83×10^(4)to 2.74×10^(6),and 9.27×10^(4)to 8.96×10^(6)copies/g in the sediment of the groundwater system,respectively.Anammox bacteria and AOA dominated in aquitards and aquifers,respectively,meanwhile,the aquitard-aquifer interfaces were demonstrated as ammonium-oxidizing hotspots in the aspect of gene numbers.Gene abundances of nitrifiers were analyzed with geochemistry profiles.Correlations between gene numbers and environmental variables indicated that the gene abundances were impacted by hydrogeological conditions,and microbial-derived ammonium loss was dominated by AOA in the northwest PRD and by anammox bacteria in the southeast PRD.
基金supported by the National Natural Science Foundations of China(Nos.41730646,41761144062,91851111,41671007,41501524 and 41971105)the Chinese National Key Programs for Fundamental Research and Development(Nos.2016YFE0133700,and 2016YFA0600904)。
文摘Marine aquaculture in semi-enclosed bays can significantly influence nutrient cycling in coastal ecosystems.However,the impact of marine aquaculture on the dynamics of dissimilatory nitrate reduction processes(DNRPs)and the fate of reactive nitrogen remain poorly understood.In this study,the rates of DNRPs and the abundances of related functional genes were investigated in aquaculture and non-aquaculture areas.The results showed that marine aquaculture significantly increased the denitrification(DNF)and dissimilatory nitrate reduction to ammonium(DNRA)rates and decreased the rate of anaerobic ammonium oxidation(ANA),as compared with non-aquaculture sites.DNF was the dominant pathway contributing to the total nitrate reduction,and its contribution to the total nitrate reduction significantly increased from 66.72%at non-aquaculture sites to 78.50%at aquaculture sites.Marine aquaculture can significantly affect the physicochemical characteristics of sediment and the abundances of related functional genes,leading to variations in the nitrate reduction rates.Although nitrate removal rates increased in the marine aquaculture area,ammonification rates and the nitrogen retention index in the aquaculture areas were 2.19 and 1.24 times,respectively,higher than those at non-aquaculture sites.Net reactive nitrogen retention exceeded nitrogen removal in the aquaculture area,and the retained reactive nitrogen could diffuse with the tidal current to the entire bay,thereby aggravating N pollution in the entire study area.These results show that marine aquaculture is the dominant source of nitrogen pollution in semi-enclosed bays.This study can provide insights into nitrogen pollution control in semi-enclosed bays with well-developed marine aquaculture.
