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ABSTRACT: Anammox start-up can be limited by the availability of seeding biomass in some areas. Previous studies have listed suitable alternative seeding sludge for anammox start-up such as anaerobic digestion sludge and conventional activated sludge (CAS), the ecological reasons behind has long been ignored. In this study, the inherent ecological factors that trigger a prompt start-up of anammox were identified, focusing on the initial relative abundance and concentration of anammox bacteria. An external membrane bioreactor was utilized as an enriching tool due to its suitability of retaining cells. Results revealed that a high initial concentration of anammox bacteria benefitted the start-up, meanwhile an even community seeding sludge (Gini coefficient<0.25) gained a more than three-time higher anammox activity compared to the uneven one (Gini coefficient>0.5). The discovery reminds to select the seeding sludge that is ecologically appropriate rather than to only care for the type of sludge in general.
Bioresource technology 02/2013; 133C:475-481. · 4.25 Impact Factor
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ABSTRACT: In this study, the maximum laccase (Lac) activities by single white-rot fungus and combining white-rot fungi were investigated. The optimal combinations of white-rot fungi were obtained by comparing the maximum Lac activities and the time of achieving the maximum Lac activity. The results showed that the synergy of white-rot fungi Polyporellus picipes and Pleurotus ostreatus improved the secretion of the laccase, with the enzyme production of 50.45 U x mL(-1), as well as the combination of white-rot fungi Polyporellus picipes, Pleurotus ostreatus and Pseudotrametes gibbosa promoted the laccase production of 75.98 U x mL(-1). However, the combination of white-rot fungi Polyporellus picipes, Pleurotus ostreatus and Pycnoporus sanguineus generated antagonistic effect, with the enzyme production of 2.91 U x mL(-1). Both synergistic and antagonistic effects among the white-rot fungi results in different time for achieving the maximum Lac activity of white-rot fungi.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 01/2013; 34(1):271-6.
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ABSTRACT: The genetic diversity and distribution of ammonia-oxidizing Archaea (AOA) in nine seasonally frozen soils sampled around the city of Harbin, China, is analyzed based on archaeal amoA gene. Soil samples are divided into four groups by its properties: fertilized/unfertilized mesic (well-balanced supply of moisture) soils and fertilized/unfertilized hydric (abundant of moisture) soils. Clone libraries based on AOA amoA gene polymerase chain reaction products are constructed, and the phylogenetic analysis at 5 % cutoff level shows that AOA members mainly belong to the soil/sediment lineage which includes four clusters, and very few archaeal amoA gene sequences fall into the marine lineage. The four groups of soils have different archaeal amoA gene assemblage, and the available nitrogen and organic carbon are significantly correlated with diversity indexes. The result shows that long-term artificial amendment such as fertilization and agriculture cultivation has an important impact on AOA community shift in terrestrial environment. Moisture may drive the shape of different AOA communities by changing the aerobic environment into anaerobic. Soil composition is another noticeable factor effect AOA community, which can help the shape of a special AOA community with only two species.
Applied Microbiology and Biotechnology 10/2012; · 3.42 Impact Factor
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ABSTRACT: In this study, anammox bacteria were rapidly enriched in sequencing batch biofilm reactors (SBBRs) with different inoculations. The activated sludge taken from a sequencing batch reactor was used and inoculated to SBBR1, while SBBR2 was seeded with stored anaerobic sludge from an upflow anaerobic fixed bed (2-year stored at 5-15 °C). Nitrogen removal performance, anammox activity, biofilm characteristics and variation of the microbial community were evaluated. The maximum total nitrogen loading rate (NLR) of SBBR1 gradually reached to 1.62 kg N/(m(3)/day) with a removal efficiency higher than 88 % and the NLR of SBBR2 reached to 1.43 kg N/(m(3)/day) with a removal efficiency of 86 %. SBBR2 was more stable compared to SBBR1. These results, combined with molecular techniques such as scanning electron microscope, fluorescence in situ hybridization, and terminal restriction fragment length polymorphism, indicated that different genera of anammox bacteria became dominant. This research also demonstrates that SBBR is a promising bioreactor for starting up and enriching anammox bacteria.
Applied Microbiology and Biotechnology 09/2012; · 3.42 Impact Factor
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ABSTRACT: Under 5 m(COD)/m(N)/m(P) ratios, the shape, settle ability and organic removal performance of aerobic granules were investigated in 5 identical SBRs. The performance of aerobic granules bulking and its recovery methods were also analysed based on SVI30 value. The results indicated that when m(COD)/m(N)/m(P) was 100/5.8/1.2, the granules had integral and dense structures with the SVI30 of 15 - 30 mL x g(-1) and COD removal of above 90%. The system operated stably without any bulking. When m (COD)/m(N)/m(P) was 100/3/0.6 and 100/1.9/0.4, although the granules disintegration was observed, SVI30 was lower than 35 mLx g(-1) and the granules had no bulking, and high COD removal was keeping at above 85%. When m(COD)/m (N)/m(P) was 100/ 0.5/0.1 and 100/0/0, the SVI30 in both systems reached 150 mL x g(-1), and the granules was hard to settle due to sludge bulking in both systems. There is a significant difference of COD removal rate in two systems. The former COD removal rate stayed at 65% -80% in late experiment, while the latter COD removal was quite low during the early operation and finally reduced to about 10% until the system broke down. Aerobic granule bulking due to the lack of N and P could be recovered by adding sufficient nutrient to the systems. After 48 cycles' operation, granules settle ability and organic removal were fully recovered, however there was no obvious recovery on granules morphology except for the color.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 09/2012; 33(9):3197-201.
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ABSTRACT: Aeration intensity is well known as an important factor in the formation of aerobic granules. In this research, two identical lab-scale sequencing batch reactors with aeration intensity of 0.8 (R1) and 0.2 m(3)/h (R2) were operated to investigate the characteristics and kinetics of matured aerobic granules. Results showed that both aeration intensity conditions induced granulation, but they showed different effects on the characteristics of aerobic granules. Compared with the low aeration intensity (R2), the aerobic granules under the higher aeration intensity (R1) had better physical characteristics and settling ability. However, the observed biomass yield (Y (obs)) in R1 [0.673 kg mixed liquor volatile suspended solids (MLVSS)/kg chemical oxygen demand (COD)] was lower than R2 (0.749 kg MLVSS/kg COD). In addition, the maximum specific COD removal rates (q (max)) and apparent half rate constant (K) of mature aerobic granular sludge under the two aeration intensities were at a similar level. Therefore, the matured aerobic granule system does not require to be operated in a higher aeration intensity, which will reduce the energy consumption.
Applied Microbiology and Biotechnology 07/2012; · 3.42 Impact Factor
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ABSTRACT: The effects of different phosphorus concentrations in culture media on the growth and enzyme production of Phanerochaete chrysosporium was investigated at a glucose concentration of 10 g L(-1). The results showed that the optimal KH(2)PO(4) concentration was 2.0 g L(-1). Optimal phosphorus content not only supported robust growth of P. chrysosporium, but also helped produce higher yields of manganese-dependent peroxidase (MnP) (324.9 U L(-1)). In addition, the results revealed that a relationship between the consumption of total phosphorus (TP) and fungal growth and enzyme production existed in P. chrysosporium cultures. Over a range of 0-0.5 g L(-1) KH(2)PO(4) concentration in the medium, the biomass and MnP activity increased in proportion to phosphorus concentration. When the KH(2)PO(4) concentration reached 0.5 g L(-1), it was generally found that the increase in biomass gradually slowed down, while MnP production decreased greatly with an increase in phosphorus concentration.
Bioresource technology 03/2012; 107:535-8. · 4.25 Impact Factor
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ABSTRACT: In this study, several different carriers were employed in a Phanerochaete chrysosporium BVH-F-1767 cell immobilization study. Polystyrene foam was shown to be the optimum carrier material from organism biomass measurements and maximum MnP production (915.62 U L(-1)). The maximum MnP activity of polystyrene foam system was achieved 2-5 days sooner than with the other carrier systems studied. It was thus clear that the polystyrene foam approach shortened the culture cycle. Analysis of the carrier mechanisms employed in this study revealed that polystyrene foam had larger internal spaces and a greater surface area, and thus the potential to enhance the transfer efficiency of oxygen and nutrients to the fungus and accelerate its growth. The mycelia of the fungus were able to associate closely with the unique internal pore structure of the polystyrene foam, providing a more quiescent microenvironment and helping to maintain the stability of the cultivation system.
Bioprocess and Biosystems Engineering 02/2012; 35(7):1179-84. · 1.81 Impact Factor
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ABSTRACT: We have investigated the effect of sludge discharge location on the steady-state aerobic granules in sequencing batch reactors (SBRs). Two SBRs were operated concurrently with the same sludge retention time using sludge discharge ports at: (a) the reactor bottom in R1; and (b) the reactor middle-lower level in R2. Results indicate that both reactors could maintain sludge granulation and stable operation, but the two different sludge discharge methods resulted in significantly different aerobic granule characteristics. Over 30 days, the chemical oxygen demand (COD) removal of the two reactors was maintained at similar levels (above 96%), and typical bioflocs were not observed. The average aerobic granule size in R2 was twice that in R1, as settling velocity increased in proportion to size increment. Meanwhile, the production yields of polysaccharide and protein content in R2 were always higher than those in R1. However, due to mass transfer limitations and the presence of anaerobes in the aerobic granule cores, larger granules had a tendency to disintegrate in R2. Thus, we conclude that a sludge discharge port situated at the reactor bottom is beneficial for aerobic granule stability, and enhances the potential for long-term aerobic granule SBR operation.
Water Science & Technology 01/2012; 66(8):1722-7. · 1.12 Impact Factor
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ABSTRACT: Anaerobic ammonium oxidation (anammox) is an energy saving biological nitrogen removal process which was limited to slow growth rate of anammox bacteria during start-up period. This study investigated the start-up of anammox process by a laboratory sequential batch reactor (SBR) for 218 days and subsequently modified the reactor as a membrane bioreactor (MBR) for 178 days. Modification of a SBR as MBR with installation of an external membrane module resulted in acceleration of specific anammox activity by 19 times. The acceleration of specific anammox activity with MBR was further confirmed by starting-up another MBR for a 242 day period. Molecular microbial analyses showed that Candidatus "Brocadia anammoxidans" and Candidatus "Kuenenia stuttgartiensis" were the dominant species in the inocula and biomass developed in the reactor. The start-up with MBR appeared to be more effective than SBR for the enrichment of anammox bacteria due to high sludge retention property of MBR configuration.
Bioresource technology 10/2011; 104:73-80. · 4.25 Impact Factor
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ABSTRACT: Pot experiments were conducted to investigate the 23 species of weed accumulation characteristics of phenanthrene, as a representative of polycyclic aromatic hydrocarbons (PAHs), from soil in the northeast of China. The result indicated that among the 23 species, the bioconcentration factors of Taraxacum ohwianum K., Potentilla aiscolor B. and Chelidonium majus L. were all higher than 1, which were 1.01, 4.98, 38.24 respectively. The phenanthrene concentrations in roots were 2.83, 16.34 and 9.66 mg/kg which were lower than those in aboveground part with phenanthrene concentrations were 15.18, 74.70 and 573.62 mg/kg, respectively. The hyperaccumulators were indicated by strong conveyance of phenanthrene from root to aboveground part. The analysis of phenanthrene concentration in aboveground weed and aboveground plant biomass showed that the accumulation of phenanthrene in plant were not correlated with their biomass. It concluded that Taraxacum ohwianum K., Potentilla aiscolor B. and Chelidonium majus L. had hyperaccumulative characteristics of phenanthrene, and it is possible to screen out plants with high biomass and hyperaccumulation capability.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 10/2011; 32(10):3088-93.
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ABSTRACT: This study investigated the effect of magnesium iron content on the enhanced biological phosphorus removal system, which performed differently at magnesium content of 0 mg/L, 8 mg/L and 24 mg/L (R1-R3). The results indicated appropriate Mg addition could enrich phosphorus accumulating organisms and keep stable running. During the steady state period, phosphorus removal rate declined to below 50% gradually, moreover, the system tended to deteriorate with the shortage of magnesium in R1. However, the system with appropriate magnesium kept the higher phosphorus removal rate (more than 90%). The statistical analysis of the experimental data also showed a strong correlation between Mg and phosphorus concentrations in R2 and R3, the ratios of Mg and P were 0.29-0.59 and 0.25-0.54 in two reactors respectively. In the anaerobic phase of EBPR, the magnesium content, the absolute value of ORP and the phosphates release had a correlation. Meanwhile, magnesium was released together with phosphates in the anaerobic phase, and that would uptake under aerobic conditions. Thus it was obvious that magnesium played a key role on the biological phosphorus removal system.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 07/2011; 32(7):2036-40.
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ABSTRACT: With the unique cell compartmentalization and the ability to simultaneously oxidize ammonium and reduce nitrite into nitrogen gas, anaerobic ammonium-oxidizing (anammox) bacteria have challenged our recognitions of microorganism. The research conducted on these bacteria has been extended from bench-scale tryouts to full-scale reactor systems. This review addresses the recently discovered versatile properties of anammox bacteria and the applications and obstacles of implementing the anammox process in ammonia-rich wastewater treatment. We also discuss the merits and drawbacks of traditional and anammox-based processes for nitrogen removal and suggest areas for improvement.
Applied Microbiology and Biotechnology 06/2011; 91(4):887-94. · 3.42 Impact Factor
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ABSTRACT: In this study, a membrane-based process was applied to simultaneously reclaim methane and generate reused water from raw domestic wastewater. The system was comprised of up-flow anaerobic sludge fixed bed (UAFB), anoxic sink (AS) and aerobic membrane bioreactor (MBR). The hydraulic retention time of UAFB (HRT(U)) was gradually shortened from 8h to 6h, 3h and to 1h, while the HRT of AS and MBR kept at 8 h. It is found that HRT(U) of 3h was more suitable for the balancing production of biogas and volatile fatty acids (VFAs), and the VFAs served as carbon source for denitrification. The trans-membrane pressure (TMP) of the MBR kept lower than 0.04 MPa without wash or change of membrane sheet, however, the scanning electron microscopy (SEM) analysis indicated that microbes attached to the inner-surface of membrane, causing irreversible fouling after 133-day operation. The denaturing gradient gel electrophoresis (DGGE) profiles of amplified 16S rDNA gene fragments proved that more functional bacteria and higher microbial diversity emerged at HRT(U) of 3h and 1h. Most bacteria belonged to Betaproteobacteria and were responsible for carbon and nitrogen removal.
Journal of hazardous materials 02/2011; 186(1):383-9. · 4.14 Impact Factor
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ABSTRACT: In order to elucidate how dissolved oxygen (DO) concentration influenced the generation of extracellular polymeric substance (EPS) and soluble microbial products (SMP) in mixed liquor and biocake, 16S rDNA fingerprinting analyses were performed to investigate the variation of the microbial community in an aerobic membrane bioreactor (MBR). The function of microbial community structure was proved to be ultimately responsible for biofouling. Obvious microbial community succession from the subphylum of Betaproteobacteria to Deltaproteobacteria was observed in biocake. High concentration of EPS in biocake under the low DO concentration (0.5 mg L(-1)) caused severe biofouling. The correlation coefficient of membrane fouling rate with EPS content in biocake (0.9941-0.9964) was much higher than that in mixed liquor (0.6689-0.8004).
Bioresource technology 02/2011; 102(10):5626-33. · 4.25 Impact Factor
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ABSTRACT: The anaerobic biological treatment of raw sewage under low ambient temperatures was investigated in an up-flow anaerobic fixed bed (UAFB) reactor, over a 220-day trial period. The operating temperature was lowered stepwisely from 35 to 25, 20 and 15°C. Obvious accumulation of acetic acid was observed in the effluent as the temperature dropped, which almost tripled at 15°C compared to that at 35°C. An interesting psychrophilic-forward-shift trend of methane production rate following the decrease of temperature was discovered. The methane yield at each trial was 169, 201, 256 and 269 L(STP) CH(4)/kg COD(removed). For each temperature trial, about 32.6%, 28.3%, 34.4% and 34.9% were removed in form of methane. Based on PCR-DGGE results, the band corresponded to Methanosphaera spp. only showed up on 15°C profile. Analysis of both methane production and DGGE results indicated that psychro-tolerant microorganisms dominated the archaeal populations in the UAFB under low-temperature.
Bioresource technology 10/2010; 102(3):2248-54. · 4.25 Impact Factor
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ABSTRACT: Two sequencing batch reactors (SBRs) were operated to investigate the effect of Ca(2+) and Mg(2+) augmentation on aerobic granulation. Reactor R1 was augmented with Ca(2+) at 40 mg/L, while Mg(2+) was added to the reactor R2 with 40 mg/L. Results showed that the reactor R1 had a faster granulation process compared with R2, and the mature granules in R1 showed better physical characteristics. However, the mature granules in R2 had the higher production yield of polysaccharides and proteins, and aerobic granules in R2 experienced a faster substrate biodegradation. Microbial and genetic characteristics in mature granules were analyzed using polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) techniques. The results revealed that Mg(2+) addition led to higher microbial diversity in mature granules. In addition, an uncultured bacterium (AB447697) was major specie in R1, and beta-proteobacterium was dominant in R2. It can be concluded that Ca(2+) had an important effect on physical properties of aerobic granules, while Mg(2+) played a key role on biological properties during the sludge granulation.
Journal of hazardous materials 09/2010; 181(1-3):382-7. · 4.14 Impact Factor
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ABSTRACT: The combined treatment process making up of up-flow anaerobic sludge fixed bed (UAFB), anoxic tank and aerobic membrane bioreactor (MBR) was used to treat domestic wastewater. And the ability of reclaiming methane and reusing wastewater was investigated. The efficiency of the combined treatment process treating wastewater at optimized parameters was studied in this paper. The combined treatment process treating domestic wastewater run at optimized parameters (20 degrees C, HRT were 3 h, 3 h, 3.5 h) indicated that, the anaerobic gas production was 1.55 L/d, the COD and NH4+ -N removal efficiency were 93.28% and 90.60% respectively, UAFB effluent including 54.74 mg/L of total VFAs, corresponding NO3- -N accumulating rate was 45.19% and TN removal efficiency was 45.51%. At the same time, it was found that sludge concentration of anoxic tank and aerobic MBR could be maintained at a low level, which is so rich in significance for sludge reduction and delaying membrane fouling.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 08/2010; 31(8):1851-7.
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ABSTRACT: The simultaneous phosphorus and nitrogen removal using denitrifying phosphate-accumulating organisms with NO3(-) and NO2(-) as electron acceptors was investigated in an anaerobic/anoxic process. The results showed that the concentrations of COD, PO4(3-) and electron acceptors (NO3(-) and NO2(-)) have a correlation with the variation of pH and ORP during anaerobic/anoxic process. In anaerobic phase, the occurrence of pH flat indicates the end of phosphorus release. In anoxic process, an inflexion was observed in ORP profile when the phosphorus uptake was finished. In addition, the phosphorus uptake rate was investigated in the process with different electron acceptors (NO3(-) and NO2(-)). The average anoxic phosphate uptake rate was 32.68 mg/(L x h) in the early 30 min during anoxic phase when NO3(-) was as electron acceptor, and every 1 mg PO4(3-)-P uptake would consume 1.14 mg NO3(-)-N. In the process with NO2(-) as electron acceptor, the average anoxic phosphate uptake rate was 17.66 mg/(Lx h) in the early 30 min, and every 1 mg PO4(3-)-P uptake would consume 1.57 mg NO2(-)-N. In conclusion, ORP and pH can be used as control parameters for simultaneous phosphorus and nitrogen removal in an anaerobic/anoxic process, and the system with NO3(-) as electron acceptor is superior to the system with NO2(-) as electron acceptor.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 05/2009; 30(4):1073-8.
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ABSTRACT: Growth of white rot fungus in liquid medium with different trace element and effect of these medium on suppressing the growth of yeast under non-sterile were investigated in agitated Erlenmeyer flasks. Results showed that the size and amount of mycelium pellets in liquid medium with trace element and Fe 3.5 mg/L was more than that with trace element but no iron and without any trace element under sterile condition; moreover, the size and amount of mycelium pellets increased with the rise of the concentration of trace element and iron. In addition, if applying the mode of incubating under sterile condition and degrading under non-sterile condition, the decolorization of reactive brilliant red K-2BP in liquid medium without any trace element and with trace element but no iron was similar to that of degrading under sterile condition; but the decolorization in liquid medium with trace element and Fe 3.5 mg/L was less than the results under sterile condition. Through observing under microscope, it was found that the amount of yeast in liquid medium with Fe 3.5 mg/L was more than the medium without any trace element and with trace element but no iron. Therefore, trace element, especially iron, plays a very important role in suppressing yeast in liquid medium; furthermore, iron also is necessary to the growth of whit rot fungus. So that, to control the concentration of iron in liquid medium could reduce the invasion of yeast under non-sterile condition as long as it does influence the growth of white rot fungus.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 09/2006; 27(8):1623-6.
