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1.
Biological breakdown of denitrifying sulfide removal process in high-rate expanded granular bed reactor 总被引:1,自引:0,他引:1
This work conducted a denitrifying sulfide removal (DSR) test in an expanded granular sludge bed (EGSB) reactor at sustainable
loadings of 6.09 kg m−3 day−1 for sulfide, 3.11 kg m−3 day−1 for nitrate–nitrogen, and 3.27 kg m−1 day−1 for acetate–carbon with >93% efficiency, which is significantly higher than those reported in literature. Strains Pseudomonas sp., Nitrincola sp., and Azoarcus sp. very likely yield heterotrophs. Strains Thermothrix sp. and Sulfurovum sp. are the autotrophs required for the proposed high-rate EGSB-DSR system. The EGSB-DSR reactor experienced two biological
breakdowns, one at loadings of 4.87, 2.13, and 1.82 kg m−3 day−1; reactor function was restored by increasing nitrate and acetate loadings. Another breakdown occurred at loadings of up to
8.00, 4.08, and 4.50 kg m−1 day−1; the heterotrophic denitrification pathway declined faster than the autotrophic pathway. The mechanism of DSR breakdown is
as follows. High sulfide concentration inhibits heterotrophic denitrifiers, and the system therefore accumulates nitrite.
Autotrophic denitrifiers are then inhibited by the accumulated nitrite, thereby leading to breakdown of the DSR process. 相似文献
2.
Chuan Chen Aijie Wang Nanqi Ren Duu-Jong Lee Juin-Yih Lai 《Bioresource technology》2009,100(7):2316-2319
An expanded granular sludge bed (EGSB) reactor was adopted to incubate bio-granules that could simultaneously convert 4.8 kg-S m?3 d?1 of sulfide in 97% efficiency; 2.6 kg-N m?3 d?1 of nitrate in 92% efficiency; and 2.7 kg-C m?3 d?1 acetate in 95% efficiency. Mass balance calculation of sulfur, nitrogen, and carbon over the EGSB reactor confirmed the performance results. This noted reactor performance is much higher than those reported in literature. Stoichiometric relation suggests that the nitrate was reduced to nitrite via autotrophic denitrification pathway, then the formed nitrite was converted via heterotrophic denitrification pathway to N2. 相似文献
3.
Sunil S. Adav Duu-Jong Lee Juin-Yih Lai 《Applied microbiology and biotechnology》2010,85(5):1601-1610
Aerobic sludge granules are compact, strong microbial aggregates that have excellent settling ability and capability to efficiently
treat high-strength and toxic wastewaters. Aerobic granules disintegrate under high organic loading rates (OLR). This study
cultivated aerobic granules using acetate as the sole carbon and energy source in three identical sequencing batch reactors
operated under OLR of 9–21.3 kg chemical oxygen demand (COD) m−3 day−1. The cultivated granules removed 94–96% of fed COD at OLR up to 9–19.5 kg COD m−3 day−1, and disintegrated at OLR of 21.3 kg COD m−3 day−1. Most tested isolates did not grow in the medium at >3,000 mg COD l−1; additionally, these strains lost capability for auto-aggregation and protein or polysaccharide productivity. This critical
COD regime correlates strongly with the OLR range in which granules started disintegrating. Reduced protein quantity secreted
by isolates was associated with the noted poor granule integrity under high OLR. This work identified a potential cause of
biological nature for aerobic granules breakdown. 相似文献
4.
ImGyu Byun JeungJin Park SoRa Park TaeHo Lee TaeJoo Park 《Biotechnology and Bioprocess Engineering》2008,13(1):96-101
Spent sulfidic caustic was applied to sulfur utilizing autotrophic denitrification as the simultaneous source of electron
donor and alkalinity. The two experiment set-up of upflow anoxic hybrid growth reactor (UAHGR) and upflow anoxic suspended
growth reactor (UASGR) was adopted and nitrate removals were similar in both reactors. Approximately 90% of the initial nitrate
was denitrified at nitrate loading rate of 0.15∼0.40 kgNO3
−/m3·d. The experimental stoichiometric ratio of sulfate production to nitrate removal was ranged from 1.5 to 2.1 mgSO4
2−/mgNO3
−. During the operation period, denaturing gradient gel electrophoresis (DGGE) analysis of polymerase chain reaction (PCR)-amplified
16S rDNA fragments for the sludge sample of both reactors showed the change of microbial communities. Thiobacillus denitrificans-like microorganism occupied 28.5% (18 clones) of the 63 clones by cloning the PCR products from the sludge sample of UAHGR.
Acidovorax avenae, which can reduce nitrate to nitrogen gas while oxidizing phenol (heterotrophic denitrifier), was also found in 7 clones
(11.1%). Although an organic carbon source was not added to the medium, a microorganism (Kaistella koreensis) capable of oxidizing organic compounds was found in 7 clones (11.1%). Therefore, the microbial community of spent sulfidic
caustic applied autotrophic denitrification process well corresponds to the substrate components of spent sulfidic caustic.
Through the batch cultivation of microorganisms in UAHGR, the microbial kinetic coefficients of spent sulfidic caustic applied
autotrophic denitrification were estimated to be μ
max
= 0.097 h−1, k
d
= 0.0021 h−1, K
s
= 200 mgNO3
−/L, and Y = 0.31 mgMLVSS/mgNO3
−. 相似文献
5.
Sunil S. Adav Duu-Jong Lee Juin-Yih Lai 《Applied microbiology and biotechnology》2009,84(6):1181-1189
Efficient nitrification and denitrification of wastewater containing 1,700 mgl−1 of ammonium-nitrogen was achieved using aerobic granular sludge cultivated at medium-to-high organic loading rates. The cultivated
granules were tested in a sequencing batch reactor (SBR) fed with 6.4 or 10.2 kg NH4+-N m−3 day−1, a loading significantly higher than that reported in literature. With alternating 2 h oxic and 2 h anoxic operation (OA)
modes, removal rate was 45.5 mg NH4+-N g−1 volatile suspended solids−1 h−1 at 6.4 kg NH4+-N m−3 day−1 loading and 41.3 ± 2.0 at 10.2 kg NH4+-N m−3 day−1 loading. Following the 60 days SBR test, granules were intact. The fluorescence in situ hybridization and confocal laser
scanning microscopy results indicate that the SBR-OA granules have a distribution with nitrifers outside and heterotrophs
outside that can effectively expose functional strains to surrounding substrates at high concentrations with minimal mass
transfer limit. This microbial alignment combined with the smooth granule surface achieved nitrification–denitrification of
wastewaters containing high-strength ammonium using aerobic granules. Conversely, the SBR continuous aeration mode yielded
a distribution with nitrifers outside and heterotrophs inside with an unsatisfactory denitrification rate and floating granules
as gas likely accumulated deep in the granules. 相似文献
6.
Flores A Nisola GM Cho E Gwon EM Kim H Lee C Park S Chung WJ 《Bioprocess and biosystems engineering》2007,30(3):197-205
The performance of enriched sludge augmented with the B21 strain of Alcaligenes defragrans was compared with that of enriched sludge, as well as with pure Alcaligenes defragrans B21, in the context of a sulfur-oxidizing denitrification (SOD) process. In synthetic wastewater treatment containing 100–1,000 mg
NO3−-N/L, the single strain-seeded system exhibited superior performance, featuring higher efficiency and a shorter startup period,
provided nitrate loading rate was less than 0.2 kg NO3−-N/m3 per day. At nitrate loading rate of more than 0.5 kg NO3−-N/m3 per day, the bioaugmented sludge system showed higher resistance to shock loading than two other systems. However, no advantage
of the bioaugmented system over the enriched sludge system without B21 strain was observed in overall efficiency of denitrification.
Both the bioaugmented sludge and enriched sludge systems obtained stable denitrification performance of more than 80% at nitrate
loading rate of up to 2 kg NO3−-N/m3 per day. 相似文献
7.
Biodegradation and kinetics of aerobic granules under high organic loading rates in sequencing batch reactor 总被引:1,自引:0,他引:1
Biodegradation, kinetics, and microbial diversity of aerobic granules were investigated under a high range of organic loading
rate 6.0 to 12.0 kg chemical oxygen demand (COD) m−3 day−1 in a sequencing batch reactor. The selection and enriching of different bacterial species under different organic loading
rates had an important effect on the characteristics and performance of the mature aerobic granules and caused the difference
on granular biodegradation and kinetic behaviors. Good granular characteristics and performance were presented at steady state
under various organic loading rates. Larger and denser aerobic granules were developed and stabilized at relatively higher
organic loading rates with decreased bioactivity in terms of specific oxygen utilization rate and specific growth rate (μ
overall) or solid retention time. The decrease of bioactivity was helpful to maintain granule stability under high organic loading
rates and improve reactor operation. The corresponding biokinetic coefficients of endogenous decay rate (k
d), observed yield (Y
obs), and theoretical yield (Y) were measured and calculated in this study. As the increase of organic loading rate, a decreased net sludge production (Y
obs) is associated with an increased solid retention time, while k
d and Y changed insignificantly and can be regarded as constants under different organic loading rates. 相似文献
8.
A new method based on sulfide utilizing autotrophic denitrification was adopted to remove nitrate from wastewater and to reuse
spent sulfidic caustic containing high sulfide and alkalinity levels. The experiments were performed using a bench-scale upflow
anoxic hybrid growth reactor (UAHGR) and an upflow anoxic suspended growth reactor (UASGR) to characterize the stoichiometric
relationship between sulfur and nitrate in the process as well as the performance of the reactors. The level of nitrate removal
from the UAHGR and UASGR were maintained at over 90% at a nitrate loading rate ranging from 0.15∼0.40 kgNO3
−/m3·d and no significant nitrite accumulation was observed in either reactor. Although the influent pH values were higher than
the optimum range of autotrophic denitrification at 8.7∼10.1, the effluent pH was stable at 7.2∼7.9 due to the production
of hydrogen ions during operation. The stoichiometric ratio of sulfate production to nitrate removal was 1.5∼2.1 mgSO4
2−/mgNO3
− in both reactors. A comparison of the reactor performance revealed that the chemical parameters of the UAHGR operation corresponded
to a plug flow like type reactor while the chemical parameters of the UASGR operation corresponded to a completely stirred
tank reactor like type reactor. UAHGR did not require sludge recycling due to the packed media while UASGR required 300∼700%
sludge recycling. Therefore, spent sulfidic caustic could be used in the sulfur utilizing autotrophic denitrification processes
as substrate and alkalinity sources. 相似文献
9.
Rapid formation of denitrifying sulfide removal granules is of practical interest to start up an expanded granular sludge bed reactor for wastewater treatment. This study demonstrates that methanogenic granules can be easily acclimated into DSR granules in one day, removing all 1.30 kg m−3 d−1 sulfide and converting >90% of 0.56 kg-N m−3d−1 nitrate into di-nitrogen gas. Under high loadings, reactor performance, however, declined. Under high loading rates, sulfide first inhibited the heterotrophic denitrifier (Caldithrix sp.), thereby accumulating nitrite in the system; the autotrophic denitrifier (Pseudomonas sp. C23) was then inhibited by accumulated nitrite, leading to breakdown of the entire DSR process. 相似文献
10.
In order to understand the fate of PCP in upflow anaerobic sludge blanket reactor (UASB) more completely, the sorption and
biodegradation of pentachlorophenol (PCP) by anaerobic sludge granules were investigated. The anaerobic granular sludge degrading
PCP was formed in UASB reactor, which was seeded with anaerobic sludge acclimated by chlorophenols. At the hydraulic retention
time (HRT) of 20–22 h, and PCP loading rate of 200–220 mg l−1 d−1, UASB reactor exhibited good performance in treating wastewater which containing 170–180 mg l−1 PCP and the PCP removal rate of 99.5% was achieved. Sequential appearance of tetra-, tri-, di-, and mono-chlorophenol was
observed in the reactor effluent after 20 mg l−1 PCP introduction. Sorption and desorption of PCP on the anaerobic sludge granules were all fitted to the Freundlich isotherm
equation. Sorption of PCP was partly irreversible. The Freundlich equation could describe the behavior of PCP amount sorbed
by granular sludge in anaerobic reactor reasonably well. The results demonstrated that the main mechanism leading to removal
of PCP on anaerobic granular sludge was biodegradation, not sorption or volatization. 相似文献
11.
A spiral packed-bed bioreactor inoculated with microorganisms obtained from activated sludge was used to conduct a feasibility
study for phenol removal. The reactor was operated continuously at various phenol loadings ranging from 53 to 201.4 g m−3 h−1, and at different hydraulic retention times (HRT) in the range of 20–180 min to estimate the performance of the device. The
results indicated that phenol removal efficiency ranging from 82.9 to 100% can be reached when the reactor is operated at
an HRT of 1 h and a phenol loading of less than 111.9 g m−3 h−1. At an influent phenol concentration of 201.4 g m−3, the removal efficiency increased from 18.6 to 76.9% with an increase in the HRT (20–120 min). For treatment of phenol in
the reactor, the maximum biodegradation rate (V
m) was 1.82 mg l−1 min−1; the half-saturation constant (K
s), 34.95 mg l−1. 相似文献
12.
The effects of temperature (20, 24 and 28 °C) and irradiance (15 and 40 μmol photon m−2 s−1) on the nitrate and ammonium uptake rates of the subtropical red alga, Laurencia brongniartii, were investigated to prepare for tank cultivation. Nitrate uptake followed saturation kinetics and was faster at higher
irradiances and temperatures. In contrast, ammonium uptake was linear over the experimental range and was not affected by
an increase in temperature. A parameter, β, was calculated to compare substrate uptake rates of nitrate along the linear portion
of the uptake curve with that of ammonium. For nitrate, β was lower at low irradiance and higher at high irradiance (β = 0.007
± 0.003 and 0.030 ± 0.002 [μmol N L−1 (μmol N gww−1 d−)−1], respectively). However, β was 0.023 ± 0.002 and 0.034 ± 0.002 [μmol N L−1 (μmol N gww−1 d−1)−1] for ammonium, suggesting a preference for ammonium over nitrate. 相似文献
13.
V. M. Samoylov D. M. Tucker W. A. Parrott 《In vitro cellular & developmental biology. Plant》1998,34(1):8-13
Summary To improve proliferation of soybean cultures in liquid medium, the effects of sucrose; total inorganic nitrogen; content of
No3
−, NH4
+, Ca2+, PO4
3−, K+; NH4
+/NO3
− ratio; and medium osmotic pressure were studied using cv. Jack. Sucrose concentration, osmotic pressure, total nitrogen content,
and ammonium to nitrate ratio were found to be the major factors controlling proliferation of soybean embryogenic cultures.
Growth decreased linearly as sucrose concentration increased from 29.7 mM to 175.3 mM. A sucrose concentration of 29.2 mM, a nitrogen content of 34.9 mM, at 1 to 4 ammonium to nitrate ratio were found to be optimal for the fastest proliferation of soybean embryogenic cultures.
There was no significant effect on proliferation of cultures when concentrations of NH4
+, Ca2+, PO4
3−, and K+ were tested in the range of 3.50 to 10.50, 1.02 to 3.06, 0.68 to 2.04, and 22.30 to 36.70 mM, respectively. The relative proliferation of embryogenic cultures of four soybean genotypes was evaluated in Finer and Nagasawa
medium and in the new medium formulation. Despite genotype-specific differences in growth, the genotypes tested showed a biomass
increase in the new formulation equal to 278, 269, 170, and 251% for Chapman, F138, Jack, and Williams 82, respectively, relative
to their growth on standard FN medium. Due to its lowered sucrose and nitrogen content, we are referring to the new medium
as FN Lite. 相似文献
14.
Outdoor tank cultivation of several Porphyra (nori) species was carried out from late November 2002 through early May 2003 using 40 L (with a surface of 0.25 m2), 600 L (1 m2), and 24,000 L (30 m2) fiberglass or PVC tanks provided with continuous aeration and seawater flow. Sexual and asexual spores produced from cultured conchocelis and frozen thalli in the laboratory, respectively, were subsequently grown to produce young fronds (ca. 5-10 cm) in an average time of 8 weeks. Growth in outdoor tanks and ponds was possible for a period of up to 20 weeks (i.e. growth season), with yields above 100 g FW m−2d−1occurring during 12-14 weeks from late December through late March, when seawater temperatures were below 20 ∘ C. These yields correlated with the species and depended on the type of tanks in which the algae were cultivated, with the highest yields observed for Porphyra sp. and Porphyra yezoensis when fertilized twice a week with NH4 Cl and NaH2 PO4in 40 L tanks. Calculations of productivity for an entire growth season based on ≥ 100 g FW m−2d−1yields exceed the average productivities using seeded nets in open sea, for all Porphyra species tested (0.96-4.06 kg DW m−2 season−1vs. 0.7-1.0 kg DW m−2of net season−1). Therefore, tank cultivation of Porphyra can offer an additional source of nori biomass to international markets. Land-based tank cultivation also offers an environmentally friendly practice that allows for the manipulation of growth conditions to enrich seaweeds with specific, valuable chemicals such as protein and minerals. 相似文献
15.
Nitrifying granules cultivation in a sequencing batch reactor at a low organics-to-total nitrogen ratio in wastewater 总被引:4,自引:0,他引:4
It is possible to cultivate aerobic granular sludge at a low organic loading rate and organics-to-total nitrogen (COD/N) ratio
in wastewater in the reactor with typical geometry (height/diameter = 2.1, superficial air velocity = 6 mm/s). The noted nitrification
efficiency was very high (99%). At the highest applied ammonia load (0.3 ± 0.002 mg NH4+–N g total suspended solids (TSS)−1 day−1, COD/N = 1), the dominating oxidized form of nitrogen was nitrite. Despite a constant aeration in the reactor, denitrification
occurred in the structure of granules. Applied molecular techniques allowed the changes in the ammonia-oxidizing bacteria
(AOB) community in granular sludge to be tracked. The major factor influencing AOB number and species composition was ammonia
load. At the ammonia load of 0.3 ± 0.002 mg NH4+–N g TSS−1 day−1, a highly diverse AOB community covering bacteria belonging to both the Nitrosospira and Nitrosomonas genera accounted for ca. 40% of the total bacteria in the biomass. 相似文献
16.
The activated sludge process (ASP) has high operational costs due to the need for aeration at dissolved O2 (DO) levels of ≥2 mg l−1 and high capital costs to construct large reactors due to a low organic loading [typically 1 kg chemical oxygen demand (COD) m−3 day−1]. A novel method for improving the energy use and treatment efficiency of the ASP via limited oxygenation (0.4 mg DO l−1) and high organic loading (6.2 kg COD m−3 day−1) is proposed based on a laboratory-scale ASP for ammonia-rich industrial wastewaters. The sludge blanket phenomenon and granulation
occurred simultaneously in the upflow microaerobic reactor. 相似文献
17.
Björn Lindman 《Antonie van Leeuwenhoek》1981,47(4):297-306
The initial rate ofd-glucosamine uptake by the non-halotolerant yeastSaccharomyces cerevisiae was approximately halved as the apparent half saturation constant (Km) and the apparent maximum velocity (Vmax) changed from 6.6mm to 16.4mm and from 22 μmol · g−1 · min−1 to 16 μmol · g−1 · min−1, respectively, when the salinity in the medium was increased from zerom to 0.68m NaCl. Corresponding changes in a high affinity transport system in the halotolerant yeastDebaryomyces hansenii were from 1.1mm to 4.6mm and from 3.1 μmol · g−1 · min−1 to 4.5 μmol · g−1 · min−1, implying a practically unchanged transport capacity. In 2.7m NaCl, Km and Vmax in this system were 24.5mm and 1.1 μmol · g−1 · min−1, respectively, representing a marked decrease in transport capability. Nevertheless, the degree of affinity in this extreme
salinity must still be regarded as noteworthy. In addition to the high affinity transport system inD. hansenii, a low affinity system, presumably without relevance ind-glucosamine transport, was observed. 相似文献
18.
An N2 strip gas was used in a packed bed sulfate-reducing bioreactor to recover the dissolved sulfide product and improve sulfate
conversion. The highest volumetric productivity obtained was 261 mol H2S m−3 d−1. Lowering the initial pH of the medium from 7 to 6 increased the H2S content of the strip gas from 3.6 to 5.8 mol%. The ratio of strip gas to liquid flow rates (G/L) was found be to a suitable basis for scaling the process. Calculations indicated that modest G/L values (<102) were required to recover the residual dissolved sulfide in a downstream stripping column. 相似文献
19.
Treatment of food processing wastewater in a full-scale jet biogas internal loop anaerobic fluidized bed reactor 总被引:1,自引:0,他引:1
Chaohai Wei Tao Zhang Chunhua Feng Haizhen Wu Zhiyi Deng Chaofei Wu Bin Lu 《Biodegradation》2011,22(2):347-357
A full-scale jet biogas internal loop anaerobic fluidized bed (JBILAFB) reactor, which requires low energy input and allows
enhanced mass transfer, was constructed for the treatment of food processing wastewater. This reactor has an active volume
of 798 m3 and can treat 33.3 m3 wastewater per hour. After pre-treating the raw wastewater by settling, oil separating and coagulation-air floating processes,
the reactor was operated with a relatively shorter start-up time (55 days). Samples for the influent and effluent of the JBILAFB
reactor were taken and analyzed daily for the whole process including both the start-up and stable running periods. When the
volumetric COD loading fluctuated in the range of 1.6–5.6 kg COD m−3 day−1, the COD removal efficiency, the volatile fatty acid(VFA)/alkalinity ratio, the maximum biogas production and the content
of CH4 in total biogas of the reactor were found to be 80.1 ± 5%, 0.2–0.5, 348.5 m3 day−1 and 94.5 ± 2.5%, respectively. Furthermore, the scanning electron microscope (SEM) results showed that anaerobic granular
sludge and microorganism particles with biofilm coexisted in the reactor, and that the bacteria mainly in bacilli and cocci
were observed as predominant species. All the data demonstrated that the enhanced mass transfer for gas, liquid and solid
phases was achieved, and that the formation of microorganism granules and the removal of inhibitors increased the stability
of the system. 相似文献
20.
Photoautotrophic micropropagation of Spathiphyllum 总被引:2,自引:0,他引:2
In order to maximize yield, Spathiphyllum, an ornamental plant, was cultured in vitro in novel culture vessels termed Vitron. The best growth was obtained by culturing plantlets on sugar-free liquid medium under CO2 enrichment (3 000 μmol mol−1 24 h−1 d−1) at a low photon flux density (PPFD of 45 μmol m−2 s−1), suggesting that the novel Vitron culture system is suitable for the photoautotrophic micropropagation of Spathiphyllum. 相似文献