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1.
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
2.
High-rate biological conversion of sulfide and nitrate in synthetic wastewater to, respectively, elemental sulfur (S0) and nitrogen-containing gas (such as N2) was achieved in an expanded granular sludge bed (EGSB) reactor. A novel strategy was adopted to first cultivate mature granules
using anaerobic sludge as seed sludge in sulfate-laden medium. The cultivated granules were then incubated in sulfide-laden
medium to acclimate autotrophic denitrifiers. The incubated granules converted sulfide, nitrate, and acetate simultaneously
in the same EGSB reactor to S0, N-containing gases and CO2 at loading rates of 3.0 kg S m−3 d−1, 1.45 kg N m−3 d−1, and 2.77 kg Ac m−1 d−1, respectively, and was not inhibited by sulfide concentrations up to 800 mg l−1. Effects of the C/N ratio on granule performance were identified. The granules cultivated in the sulfide-laden medium have
Pseudomonas spp. and Azoarcus sp. presenting the heterotrophs and autotrophs that co-work in the high-rate EGSB-SDD (simultaneous desulfurization and denitrification)
reactor. 相似文献
3.
The denitrification performance of a lab-scale anoxic rotating biological contactor (RBC) using landfill leachate with high
nitrate concentration was evaluated. Under a carbon to nitrogen ratio (C/N) of 2, the reactor achieved N-NO3
− removal efficiencies above 95% for concentrations up to 100 mg N-NO3
− l−1. The highest observed denitrification rate was 55 mg N-NO3
− l−1 h−1 (15 g N-NO3
− m−2 d−1) at a nitrate concentration of 560 mg N-NO3
− l−1. Although the reactor has revealed a very good performance in terms of denitrification, effluent chemical oxygen demand (COD)
concentrations were still high for direct discharge. The results obtained in a subsequent experiment at constant nitrate concentration
(220 mg N-NO3
− l−1) and lower C/N ratios (1.2 and 1.5) evidenced that the organic matter present in the leachate was non-biodegradable. A phosphorus
concentration of 10 mg P-PO4
3− l−1 promoted autotrophic denitrification, revealing the importance of phosphorus concentration on biological denitrification
processes. 相似文献
4.
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
5.
A laboratory-scale Bardenpho process was established to investigate the proper nitrogen loading rate (NLR) when modified spent caustic (MSC) is applied as electron donor and alkalinity source for denitrification. MSC injection induced autotrophic nitrogen removal with sulfur as electron donor and heterotrophic denitrification. The nitrogen removal rate (NRR) did not increase proportionally to NLR. Based on the total nitrogen concentration in the effluent observed in the trials with MSC, the NLR in the influent should not exceed 0.15 kg N/m3 d in order to satisfy water quality regulations. Microbial communities in the anoxic reactors were characterized by pyrosequencing of 16S rRNA gene sequences amplified by the polymerase chain reaction of DNA extracted from sludge samples. Microbial diversity was lower as MSC dosage was increased, and the injection of MSC caused an increase in SOB belonging to the genus Thiobacillus which is responsible for denitrification using sulfur. 相似文献
6.
The performance of acetic acid-supported pH-heterogenized heterotrophic denitrification (HD) facilitated with ferrous sulfide-based autotrophic denitrification (AD) was investigated in upflow activated carbon-packed column reactors for reliable removal of highly elevated nitrate (42 mg NO3-N l−1) in drinking water. The use of acetic acid as substrate provided sufficient internal carbon dioxide to completely eliminate the need of external pH adjustment for HD, but simultaneously created vertically heterogenized pH varying from 4.8 to 7.8 in the HD reactor. After 5-week acclimation, the HD reactor developed a moderate nitrate removal capacity with about one third of nitrate removal occurring in the acidic zone (pH 4.8–6.2). To increase the treatment reliability, acetic acid-supported HD was operated under 10% carbon limitation to remove >85% of nitrate, and ferrous sulfide-based AD was supplementally operated to remove residual nitrate and formed nitrite without excess of soluble organic carbon, nitrite or sulfate in the final effluent. 相似文献
7.
Jan Peter van der Hoek Paul J. M. Latour Abraham Klapwijk 《Applied microbiology and biotechnology》1988,28(4-5):493-499
Summary In the combined ion exchange/biological denitrification process for nitrate removal from ground water anion exchange resins are regenerated in a closed circuit by way of an upflow sludge blanket denitrification reactor. The regenerant (a concentrated sodium bicarbonate solution) is recirculated through the ion exchanger in the r generation mode and the denitrification reactor. In the closed system sulfate accumulates to very high concentrations. For that reason it was examined under what process conditions sulfate reduction occurs in an upflow sludge blanket denitrification reactor, when the influent contains high sulfate concentrations (5.45 g SO
4
2-
/l) and high sodium bicarbonate concentrations (19.8 g NaHCO3/l) in addition to nitrate and methanol. It appeared that at a hydraulic residence time of 5 h sulfide production started, when the nitrate loading rate was 20% of the denitrification reactor capacity and methanol was added in excess. The excess of methanol was converted into acetate after nitrate was depleted. Conversion of methanol into acetate was a function of the hydraulic residence time. At hydraulic residence times above 8 h this conversion was complete. Also in batch experiments it was observed that excess of methanol was converted into acetate, and that sulfate reduction started when nitrate was depleted. From all experiments it is clear that, provided that methanol is added in good relation to the quantity of nitrate that has to be denitrified, acetate will not be produced and sulfate reduction will not occur in the denitrification reactor, even in the presence of very high sulfate concentrations. 相似文献
8.
During the productive Paleoproterozoic (2.4–1.8 Ga) and less productive Mesoproterozoic (1.8–1.0 Ga), the ocean was suboxic to anoxic and multicellular organisms had not yet evolved. Here, we link geologic information about the Proterozoic ocean to microbial processes in modern low-oxygen systems. High iron concentrations and rates of Fe cycling in the Proterozoic are the largest differences from modern oxygen-deficient zones. In anoxic waters, which composed most of the Paleoproterozoic and ~40% of the Mesoproterozoic ocean, nitrogen cycling dominated. Rates of N2 production by denitrification and anammox were likely linked to sinking organic matter fluxes and in situ primary productivity under anoxic conditions. Additionally autotrophic denitrifiers could have used reduced iron or methane. 50% of the Mesoproterozoic ocean may have been suboxic, promoting nitrification and metal oxidation in the suboxic water and N2O and N2 production by partial and complete denitrification in anoxic zones in organic aggregates. Sulfidic conditions may have composed ~10% of the Mesoproterozoic ocean focused along continental margins. Due to low nitrate concentrations in offshore regions, anammox bacteria likely dominated N2 production immediately above sulfidic zones, but in coastal regions, higher nitrate concentrations probably promoted complete S-oxidizing autotrophic denitrification at the sulfide interface. 相似文献
9.
Effect of alum on nitrification during simultaneous phosphorous removal in anoxic/oxic reactor 总被引:1,自引:0,他引:1
J. Rajesh Banu Khac-Uan Do S. Kaliappan Ick-Tae Yeom 《Biotechnology and Bioprocess Engineering》2009,14(4):543-548
Phosphorus and nitrogen are the important eutrophication nutrients. They are removed in the anoxic/oxic reactor through simultaneous
precipitation and biological nitrogen removal. The effect of alum a commonly used simultaneous precipitant on biological nitrification
and denitrification are investigated in the present study. Simultaneous removal of phosphorus was carried out using the coagulant
alum Al2(SO4)3·14H2O at 2.2 mol ratio. Before the start of simultaneous precipitation the nitrification rate of the A/O reactor was found to
be 0.05 g N-NH4
+/g VSS/d. It starts to decrease with increase in coagulant dosage. The nitrification rate for alum dosage 97.13 mg/L was 0.38
g N- NH4
+/g VSS/d. There was no accumulation of nitrate in anoxic tank. The nitrogen removal efficiency of the reactor was affected
and it fell from 88 to 78%. There was a slight decrease in effluent COD from 16∼20 mg/L to 8∼12 mg/L after the introduction
of simultaneous precipitation into the reactor. The usage of alum as a simultaneous precipitant in the anoxic/oxic reactor
was limited due to its inhibition on nitrification. Alum did not have any affect over denitrification process. 相似文献
10.
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
11.
Sora Park Jeungjin Park Imgyu Byun Taejoo Park Taeho Lee 《Biotechnology and Bioprocess Engineering》2008,13(6):697-704
As spent sulfidic caustic (SSC) from petroleum plants contains a high concentration of alkalinity and sulfur compounds, SSC
can be applied in sewage treatment system as an electron donor for autotrophic denitrification. In our previous study, the
reuse of SSC in the biological nitrogen process was successful, and some neutralization may be required for stable treatment
performance. In this study, the pH of SSC was neutralized to 12.0 from 13.3, and the modified Ludzack-Ettinger process was
conducted for 90 days with the municipal wastewater. Some toxic effects of SSC on microorganisms were tested via a specific
oxygen uptake rate (SOUR) assay. According to the SOUR assay, as compared with no SSC injection condition, SOUR was reduced
by approximately 5.4% when 4 mL SSC/L was injected and the effective concentration of a toxicant causing 50% inhibition of
the microorganism’s activity (EC50) was 22.6 mL/L. During the days of operation, the COD removal and nitrification efficiency were over 53.0 and 98.2%, respectively.
The TN removal efficiency was 56.6% and the nitrogen removal rate (NRR) was 0.15 kg/m3·d when the hydraulic retention time (HRT) in the anoxic tank was 3 h. The ratio of nitrifying bacteria was unaffected by
the HRT, and Nitrobacter spp. and Nitrospira genus existed at similar ratios. The ratio of T. denitrificans increased after the injection of SSC and was approximately 6.5%. 相似文献
12.
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
13.
Nitrate reduction by Citrobacter diversus under aerobic environment 总被引:17,自引:0,他引:17
A new aerobic denitrifier, Citrobacter diversus, was isolated from both nitrification and denitrification sludge. To monitor the variation in the concentration of nitrogen
oxides, aerobic denitrification by C. diversus was carried out in a batch reactor. When the nitrate concentration was greater than 180 mg N l−1, the nitrate reduction rate became stable. The effect of the C/N ratio on the denitrification activity was also investigated.
The results showed that the optimum denitrification activity was obtained when the C/N ratio was 4–5. The range of the C/N
ratio was higher than that for traditional anoxic denitrification. The effect of the dissolved oxygen concentration was further
studied; and it was found that the range of dissolved oxygen concentrations, both for specific growth rates and for specific
denitrification rates, was 2–6 mg−1. From these results, it can be concluded that both the concentration of dissolved oxygen and the C/N ratio are key factors
in the aerobic denitrification by C. diversus.
Received: 23 November 1999 / Received revision: 4 February 2000 / Accepted: 13 February 2000 相似文献
14.
C. Hörber N. Christensen E. Arvin B. Kiær Ahring 《Applied microbiology and biotechnology》1999,51(5):694-699
Tetrachloroethene (C2Cl4) dechlorination kinetics in upflow anaerobic sludge blanket (UASB) reactors was determined after introducing de novo activities into the granular sludge. These activities were introduced by immobilizing Dehalospirillum multivorans in a test reactor containing unsterile granular sludge, and in a reference reactor, R1, containing sterile granular sludge.
A second reference reactor, R2, contained only unsterile granular sludge and served as a control. The kinetic experiments
were performed by pulsing the reactors with C2Cl4 in a recirculating batch mode. Formate and acetate were added as electron donor and carbon source. Both reactors inoculated
with D. multivorans dechlorinated C2Cl4 to an equimolar amount of C2H2Cl2 with only traces of C2HCl3 in the effluent. In the control reactor, C2HCl3 accumulated before C2H2Cl2 was produced. A computer simulation program (AQUASIM) was used to estimate the kinetic parameters. The half-saturation constants
(K
s) for C2Cl4 and C2HCl3 were almost equal in the reactors containing D.␣multivorans (17 μM and 18 μM for C2Cl4; 26 μM and 28 μM for C2HCl3), indicating no influence of sludge bacteria on the affinity of D. multivorans for C2Cl4 and C2HCl3. The maximum dechlorination rates (k
m
X
B) were about twice as high in the reactor containing D.␣multivorans immobilized in sterile sludge (11 mmol C2Cl4 l sludge−1 day−1 and 27 mmol C2HCl3 l sludge−1 day−1) than in the test reactor (4.4 mmol C2Cl4 l sludge−1 day−1 and 15 mmol C2HCl3 l sludge−1 day−1). Compared to other C2Cl4-degrading systems, the dechlorination rates of the inoculated reactors and their affinities for C2Cl4 and C2HCl3 were high. Therefore, introduction of de novo activity is promising for the use of anaerobic reactors to bioremediate C2Cl4-polluted water.
Received: 5 November 1998 / Received revision: 25 January 1999 / Accepted: 31 January 1999 相似文献
15.
Anaerobic ammonium oxidation process in an upflow anaerobic sludge blanket reactor with granular sludge selected from an anaerobic digestor 总被引:1,自引:0,他引:1
The purpose of this work was to evaluate the development of the anammox process by the use of granular sludge selected from
a digestion reactor as a potential seed source in a lab-scale UASB (upflow anaerobic sludge blanket) reactor system. The reactor
was operated for approximately 11 months and was fed by synthetic wastewater. After 200 days of feeding with NH4
+ and NO2
− as the main substrates, the biomass showed steady signs of ammonium consumption, resulting in over 60% of ammonium nitrogen
removal. This report aims to present the results and to more closely examine what occurs after the onset of anammox activity,
while the previous work described the start-up experiment and the presence of anammox bacteria in the enriched community using
the fluorescencein situ hybridization (FISH) technique. By the last month of operation, the consumed NO2
−N/NH4
+-N ratio in the UASB reactor was close to 1.32, the stoichiometric ratio of the anammox reaction. The obtained results from
the influentshutdown test suggested that nitrite concentration would be one key parameter that promotes the anammox reaction
during the start-up enrichment of anammox bacteria from granular sludge. During the study period, the sludge color gradually
changed from black to red-brownish. 相似文献
16.
Rashmi R. Nair Stanislaus F. D’Souza 《Journal of industrial microbiology & biotechnology》2012,39(11):1637-1643
Denitrification of synthetic high nitrate wastewater containing 40,000?ppm NO3 (9,032?ppm NO3-N) was achieved using immobilized activated sludge in a column reactor. Active anoxic sludge adsorbed onto Terry cloth was used in the denitrification of high nitrate wastewater. The operational stability of the immobilized sludge system was studied both in a batch reactor and in a continuous reactor. The immobilized sludge showed complete degradation of different concentrations of NO3-N (1,129, 1,693, 3,387, 6,774, and 9,032?ppm) in a batch process. The reactors were successfully run for 90?days without any loss in activity. The immobilized cell process has yielded promising results in attaining high denitrifying efficiency. 相似文献
17.
Denitrifying granular sludge reactor holds better nitrogen removal efficiency than other kinds of denitrifying reactors, while this reactor commonly needs seeding anaerobic granular sludge and longer period for start-up in practice, which restricted the application of denitrifying granular sludge reactor. This study presented a rapid and stable start-up method for denitrifying granular sludge. An upflow sludge blanket (USB) reactor with packings was established with flocculent activated sludge for treatment of high concentration nitrite wastewater. Results showed mature denitrifying granular sludge appeared only after 15 days with highest nitrogen removal rate of 5.844 kg N/(m3 day), which was much higher than that of compared anoxic sequencing batch reactor (ASBR). No significant nitrite inhibition occurred in USB and denitrification performance was mainly influenced by hydraulic retention time, influent C/N ratio and internal reflux ratio. Hydraulic shear force created by upflow fluid, shearing of gaseous products and stable microorganisms adhesion on the packings might be the reasons for rapid achievement of granular sludge. Compared to inoculated sludge and ASBR, remarkable microbial communitiy variations were detected in USB. The dominance of Proteobacteria and Bacteroidetes and enrichment of species Pseudomonas_stutzeri should be responsible for the excellent denitrification performance, which further verified the feasibility of start-up method. 相似文献
18.
Abbas Rezaee Hatam Godini Said Dehestani Ahmad Reza Yazdanbakhsh Gholamreza Mosavi Anoshiravan Kazemnejad 《World journal of microbiology & biotechnology》2008,24(11):2397-2402
This study demonstrated the feasibility of a biological denitrification process using immobilized Pseudomonas stutzeri. The microbial cellulose (MC) from Acetobacter xylinum was used as the support material for immobilization of the bacterium. Nitrate removal took place mainly in the anoxic system.
The effects of various operating conditions such as the initial nitrate concentration, pH, and carbon source on biological
denitrification were demonstrated experimentally. The system demonstrated a high capacity for reducing nitrate concentrations
under optimum conditions. The denitrification rate increased up to a maximal value of 1.6 kg NO3-N m−3 day−1 with increasing nitrate loading rate. Because of its porosity and purity, MC may be considered as appropriate supports for
adsorbed immobilized cells. The simplicity of immobilization and high efficiency in operation are the main advantages of such
systems. To date, the immobilization of microorganisms onto MC has not been carried out. The results of this research shows
that a pilot bioreactor containing P. stutzeri immobilized on MC exhibited efficient denitrification with a relatively low retention time. 相似文献
19.
The biogeochemical processes that drive nutrient transformations and recycling in organic marine sediment-water environments were studied for 17 months in a zero-effluent intensive recirculating culture system. The system consisted of a 10 m3 gilthead seabream (Sparus aurata) tank coupled to aerobic and anaerobic water treatment elements. Nutrients and alkalinity were measured in the system to quantify the main biogeochemical processes. Fractions of the carbon fed in feed were found in fish (18.3%) and in sludge (11%); the missing carbon was respired by fish (45%) and by aerobic (8.4%) and anaerobic (7.7%) microorganisms. Fractions of the nitrogen fed in feed were found in fish (15.4%) and in sludge (14.3%); the missing nitrogen was eliminated by nitrification-denitrification. Most of the phosphorus and ash fed in feed and not found in fish accumulated within the sludge in the system. The rates of nitrification, denitrification and sulphate reduction increased with time, reaching 0.3 g N m− 2 d− 1, 53 g N m− 2 d− 1 and 145 g S m− 2 d− 1, respectively. Nitrification developed more rapidly than denitrification, leading at first to nitrate accumulation (to 20 mmol NO3 l− 1 by day 200) and a decrease in alkalinity. Once denitrification surpassed nitrification, nitrate concentrations decreased, eventually being reduced to < 0.3 mmol NO3 l− 1 by day 510, and alkalinity stabilized. Toxic hydrogen sulphide, generated within the anaerobic sludge, was oxidized by oxygen and nitrate as it diffused through the anaerobic-aerobic sediment-water interface. When nitrate levels in the water above the sludge dropped below 2 mmol l− 1, sulphide was also oxidized in the fluidized bed reactor. Denitrification reduced nitrate in the water, respired (jointly with sulphate reduction) carbon in the sludge, oxidized the hydrogen sulphide, and contributed to stabilization of alkalinity and accumulation of polyphosphate in bacteria as a major sink of labile P. 相似文献
20.
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