共查询到20条相似文献,搜索用时 15 毫秒
1.
Biodegradation of azo dyes in cocultures of anaerobic granular sludge with aerobic aromatic amine degrading enrichment cultures 总被引:6,自引:0,他引:6
N. C. G. Tan F. X. Prenafeta-Boldú J. L. Opsteeg G. Lettinga J. A. Field 《Applied microbiology and biotechnology》1999,51(6):865-871
A prerequisite for the mineralization (complete biodegradation) of many azo dyes is a combination of reductive and oxidative
steps. In this study, the biodegradation of two azo dyes, 4-phenylazophenol (4-PAP) and Mordant Yellow 10 (4-sulfophenylazo-salicylic
acid; MY10), was evaluated in batch experiments where anaerobic and aerobic conditions were integrated by exposing anaerobic
granular sludge to oxygen. Under these conditions, the azo dyes were reduced, resulting in a temporal accumulation of aromatic
amines. 4-Aminophenol (4-AP) and aniline were detected from the reduction of 4-PAP. 5-Aminosalicylic acid (5-ASA) and sulfanilic
acid (SA) were detected from the reduction of MY10. Subsequently, aniline was degraded further in the presence of oxygen by
the facultative aerobic bacteria present in the anaerobic granular sludge. 5-ASA and SA were also degraded, if inocula from
aerobic enrichment cultures were added to the batch experiments. Due to rapid autoxidation of 4-AP, no enrichment culture
could be established for this compound. The results of this study indicate that aerobic enrichment cultures developed on aromatic
amines combined with oxygen-tolerant anaerobic granular sludge can potentially be used to completely biodegrade azo dyes under
integrated anaerobic/aerobic conditions.
Received: 16 September 1998 / Received revision: 14 December 1998 / Accepted: 21 December 1998 相似文献
2.
In recent years, it has become clear that the rapidly acidifying chemical oxygen demand (RACOD) content of the waste water
and the surface tension of the reactor liquid contribute to the phenomenon of granular growth in upflow anaerobic sludge-blanket
reactors (UASB). By adding 20% of directly soluble RACOD, in the form of a sucrose/starch mixture, on top of the original
COD load and by adjusting the reactor liquid surface tension below 50 mN m−1 with linear alkylbenzenesulphonate, granular growth and sludge-bed stability could be enhanced significantly within 40 days.
Carrot pulp, a waste product having a high short-chain fatty acid precursor potential, was applied as an alternative fibrous
RACOD source. Best results were obtained when adding the carrot pulp freshly to the laboratory-scale UASB reactor in an in-recycle
liquefying chamber. This concept of adding carrot pulp waste product as a granular growth supplement by means of an in-recycle
liquefying chamber therefore merits testing in practice.
Received: 30 October 1996 / Received version: 3 February 1997 / Accepted: 10 February 1997 相似文献
3.
Adsorption and decolorization kinetics of methyl orange (MO) by anaerobic sludge in anaerobic sequencing batch reactors were
investigated. The anaerobic sludge was found to have a saturated adsorption capacity of 36 ± 1 mg g MLSS−1 to MO. UV/visible spectrophotometer and high-performance liquid chromatography analytical results indicated that the MO adsorption
and decolorization occurred simultaneously in this system. This process at various substrate concentrations could be well
simulated using a modified two-stage model with apparent pseudo first-order kinetics. Furthermore, a noncompetitive inhibition
kinetic model was also developed to describe the MO decolorization process at high NaCl concentrations, and an inhibition
constant of 3.67 g NaCl l−1 was estimated. This study offers an insight into the adsorption and decolorization processes of azo dyes by anaerobic sludge
and provides a better understanding of the anaerobic dye decolorization mechanisms. 相似文献
4.
Effect of feed composition and upflow velocity on aggregate characteristics in anaerobic upflow reactors 总被引:4,自引:0,他引:4
V. O'Flaherty P. N. L. Lens D. de Beer E. Colleran 《Applied microbiology and biotechnology》1997,47(2):102-107
Two upflow anaerobic hybrid reactors treated lactose and a mixture of ethanol, propionate and butyrate, respectively, at
a volumetric loading rate of 3.7 kg chemical oxygen demand (COD) m−3day−1, a hydraulic retention time of 5 days and a liquid upflow velocity of 0.01 m/h. Under steady-state conditions, the lactose-fed
sludge had much higher (20%–100%) specific methanogenic conversion rates than the volatile-fatty acid␣(VFA)/ethanol-fed sludge
for all substrates tested, including VFA. In both reactors, a flocculant sludge developed, although a much higher content
of extracellular polysaccharide was measured in the lactose-fed sludge [1900 μg compared to 305 μg uronic acid/g volatile
suspended solids (VSS)]. When the liquid upflow velocity of a third, VFA/ethanol-fed reactor was increased to 0.5 m/h, granulation
of the sludge occurred, accompanied by a large increase (200%–500%) in the specific methanogenic conversion rates for the
syntrophic and methanogenic substrates studied. Granulation reduced the susceptibility of the sludge to flotation. Glucose
was degraded at a high rate (100 mg glucose gVSS−1h−1) by the sludge from the third reactor, despite not having been exposed to a sugar-containing influent for 563␣days.
Received: 7 June 1996 / Received revision: 23 September 1996 / Accepted: 29 September 1996 相似文献
5.
H. M. Poggi-Varaldo R. Rodríguez-Vázquez G. Fernández-Villagómez F. Esparza-García 《Applied microbiology and biotechnology》1997,47(3):284-291
This work focused on determining the effects of ammonia-nitrogen supplementation on the mesophilic solid-substrate anaerobic
digestion of municipal wastes and waste activated sludge (biosolids). Bench-scale, semi-continuous, mesophilic reactors were
operated with a 21-day mass-retention time and dosed with NH4Cl, such that the corresponding chemical O2 demand (COD)/N ratios in their feeds were 90, 80, 65 and 50 (reactors R1 or control, R2, R3 and R4 respectively). Reactor
performance was evaluated in terms of the efficiency of volatile solid removal (efficiency for short), biogas productivity,
methane content in the biogas, pH and volatile organic acid contents, among other monitoring and analytical parameters. The
feedstock was a mixture of urban wastes with biosolids. It was found that the process performance deteriorated at increasing
dosages of ammonia N, the process practically ceasing at COD/N = 50 (R4). Inhibition was characterized by efficiency and biogas
productivity decreases and a more sudden drop of methane content in biogas and pH. A significant rise of propionic, butyric
and valeric acid was found in reactors receiving the highest doses of ammonia N (R3 and R4). This suggested that inhibition
of the syntrophic bacteria present in the anaerobic consortia also occurred. Luong and Pearson inhibition models were fitted
to the data. Both models represented very well the acute effects of N supplementation on solid-substrate anaerobic digestion.
However, the Luong model could also represent the process ceasing at a critical ammonia N concentration of 2800 mg/kg mixed
solids.
Received: 12 April 1996 / Received revision: 23 July 1996 / Accepted: 5 August 1996 相似文献
6.
N. Christiansen S. R. Christensen E. Arvin B. K. Ahring 《Applied microbiology and biotechnology》1997,47(1):91-94
Reductive dechlorination of tetrachloroethene was studied in a mesophilic upflow anaerobic sludge blanket reactor. Operating
the reactor in batch mode the dynamic transformation of tetrachloroethene, trichloroethene and dichloroethene (DCE) was monitored.
Tetrachloroethene was reductively dechlorinated to trichloroethene, which again was dechlorinated at the same rate as DCE
was produced. DCE showed a lag period of 40 h before transformation was observed. During normal reactor operation trans-1,2-DCE was the major DCE isomer, followed by cis-1,2-DCE. Small amounts of 1,1-DCE but no vinyl chloride were detected. When the influent tetrachloroethene concentration
was increased from 4.6 μM to 27 μM, the transformation rate increased, indicating that the system was not saturated with tetrachloroethene.
The main organic component in the effluent was acetate, indicating that the aceticlastic methane-producing bacteria were inhibited
by the chlorinated ethenes.
Received: 29 July 1996 / Received revision: 13 September 1996 / Accepted: 13 September 1996 相似文献
7.
Rajaguru P Kalaiselvi K Palanivel M Subburam V 《Applied microbiology and biotechnology》2000,54(2):268-273
A sequential anaerobic–aerobic treatment process based on mixed culture of bacteria isolated from textile dye effluent-contaminated
soil was used to degrade sulfonated azo dyes Orange G (OG), Amido black 10B (AB), Direct red 4BS (DR) and Congo red (CR).
Under anaerobic conditions in a fixed-bed column using glucose as co-substrate, the azo dyes were reduced and amines were
released by the bacterial biomass. The amines were completely mineralized in a subsequent aerobic treatment using the same
isolates. The maximum degradation rate observed in the treatment system for OG was 60.9 mg/l per day (16.99 mg/g glucose utilized),
for AB 571.3 mg/l per day (14.46 mg/g glucose utilized), for DR 112.5 mg/l per day (32.02 mg/g glucose utilized) and for CR
134.9 mg/l per day (38.9 mg/g glucose utilized).
Received: 6 August 1999 / Received revision: 20 December 1999 / Accepted: 24 December 1999 相似文献
8.
The toxicity of chlorinated aliphatic hydrocarbons on acetoclastic methanogens in anaerobic granular sludge was determined
using a standardized anaerobic bioassay method. Most of the chloroaliphatics tested were strong inhibitors of methanogenesis.
Tri- and tetrachloride derivatives of methane and ethane were the most highly toxic compounds tested, with concentrations
of less than 18 mg/l resulting in 50% inhibition (IC50) of the methanogenic activity. Dichlorinated compounds were less toxic, with IC50 values ranging from 40 mg/l to 100 mg/l. On the other hand, perchlorinated derivatives of ethane and ethene were scarcely
inhibitory at concentrations near their maximum water solubility. The toxicity caused by chlorinated aliphatic hydrocarbons
was reversible. The comparison of structurally related compounds indicated that unsaturated chloroaliphatics were less toxic
than their saturated counterparts. A reverse correlation between the electric dipole moment of these compounds and their methanogenic
toxicity is discussed.
Received: 9 July 1996 / Received revision: 11 October 1996 / Accepted: 18 October 1996 相似文献
9.
M. Kudlich P. L. Bishop H.-J. Knackmuss A. Stolz 《Applied microbiology and biotechnology》1996,46(5-6):597-603
The naphthalenesulfonate-oxidizing bacterium Sphingomonas sp. BN6 was immobilized in calcium alginate. These beads were incubated under aerobic conditions in a medium with the sulfonated
azo dye, Mordant Yellow 3 (MY3), and glucose. The immobilized cells converted MY3, but only a marginal turnover of the dye
was found under these conditions with freely suspended cells of Sphingomonas sp. BN6. Under anaerobic conditions, suspended cells of Sphingomonas sp. BN6 reductively cleaved the azo bond of MY3 to 6-aminonaphthalene-2-sulfonate (6A2NS) and 5-aminosalicylate. The turnover
of MY3 by the immobilized cells under aerobic conditions resulted in the formation of more than equimolar amounts of 5-aminosalicylate,
but almost no (6A2NS) was detected. Cells of Sphingomonas sp. BN6 aerobically oxidize 6A2NS to 5-aminosalicylate. It was therefore concluded that the cells in the anaerobic center
of the alginate beads reduced MY3 to 6A2NS and 5-aminosalicylate and that 6A2NS was oxidized to 5-aminosalicylate by those
cells that were immobilized in the outer aerobic zones of the alginate beads. The presence of oxygen gradients within the
alginate beads was verified by using oxygen micro-electrodes. A coimmobilisate of Sphingomonas sp. BN6 with a 5-aminosalicylate degrading bacterium completely degraded MY3. The immobilized cells also converted the sulfonated
azo dyes Amaranth and Acid Red␣1.
Received: 6 May 1996 / Received revision: 6 August 1996 / Accepted: 12 August 1996 相似文献
10.
Effects of support material on the pattern of volatile fatty acid accumulation at overload in anaerobic digestion of semi-solid waste 总被引:2,自引:0,他引:2
Anaerobic degradation of a semi-solid waste with a total solids content of 4% particulate matter, much of it insoluble, was
investigated in four laboratory-scale reactors. Two of the reactors were equipped with different textile materials for immobilisation
of microorganisms, while the other two were used as continuously-stirred-tank reactor references. A constant organic loading
rate and hydraulic retention time were used in the start-up period; the hydraulic retention time was then decreased and the
effects of this change were monitored. Volatile fatty acid (VFA) concentration and pH were chosen as indicators of the microbial
status in the reactors. The reactors with support material showed a greater resistance to overload than did the continuously-stirred-tank
reactors. This is in agreement with many studies undertaken on the anaerobic treatment of wastewater. However, no problems
with clogging occurred, showing that a support material is also applicable in systems treating waste containing large amounts
of insoluble, particulate matter. The pH was comparable to VFA for indicating an approaching process failure. However, the
pattern of VFA accumulation was qualitatively different between the reactors with and without support material. Obviously
the metabolic pattern of mixed cultures changes when the microorganisms are immobilised.
Received: 3 December 1996 / Received revision: 7 February 1997 / Accepted: 14 February 1997 相似文献
11.
Anaerobic sequencing batch reactors for wastewater treatment: a developing technology 总被引:4,自引:0,他引:4
Zaiat M Rodrigues JA Ratusznei SM de Camargo EF Borzani W 《Applied microbiology and biotechnology》2001,55(1):29-35
This paper describes and discusses the main problems related to anaerobic batch and fed-batch processes for wastewater treatment.
A critical analysis of the literature evaluated the industrial application viability and proposed alternatives to improve
operation and control of this system. Two approaches were presented in order to make this anaerobic discontinuous process
feasible for industrial application: (1) optimization of the operating procedures in reactors containing self-immobilized
sludge as granules, and (2) design of bioreactors with inert support media for biomass immobilization.
Received: 22 May 2000 / Received revision: 20 July 2000 / Accepted: 21 July 2000 相似文献
12.
M. H. A. van Eekert A. J. M. Stams J. A. Field G. Schraa 《Applied microbiology and biotechnology》1999,51(1):46-52
The dechlorinating activity of a methanogenic granular sludge from a methanol-fed upflow anaerobic sludge blanket reactor
was investigated with chlorinated ethanes. This unadapted methanogenic consortium degraded all chloroethanes tested. The product
formation rates decreased with the number of chlorine substituents. The more highly chlorinated ethanes were also converted,
although at a lower rate, in the presence of autoclaved (dead) sludge, indicating the involvement of reduced heat-stable cofactors
like vitamin B12 and F430. Direct chemical dechlorination of hexa-, penta- and tetrachloroethanes was also observed in medium without sludge, although
at a much lower rate. The results show the importance of cometabolic and abiotic (chemical) conversions for the transformation
of chlorinated ethanes by the methanogenic consortium. The types of reaction and the products formed were correlated with
the Gibbs free-energy change (ΔG
0′). Reductive hydrogenolysis and dichloroelimination were important dechlorinating mechanisms. Generally, these reactions have
a higher ΔG
0′ value than dehydrochlorination reactions, which occurred less frequently during the transformation of chloroethanes by the
methanogenic granular sludge.
Received: 8 June 1998 / Received revision: 7 September 1998 / Accepted: 13 September 1998 相似文献
13.
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
14.
S. Raihan N. Ahmed L. E. Macaskie J. R. Lloyd 《Applied microbiology and biotechnology》1997,47(4):352-357
Anaerobically grown cells of Escherichia coli were immobilised within a range of entrapment matrices and packed into a column under standard conditions, and the ability
of the immobilised cells to reduce nitrite (0.5 mM) was measured at a range of flow rates using sodium formate (20 mM) as
the electron donor for nitrite reduction. A flow-rate/activity plot was constructed for each flow-through reactor and RA1/2 values (residence time corresponding to 50 % nitrite removal) calculated for each reactor type. Cells immobilised in flat
and hollow-fibre membranes were the most effective (RA1/2 = 0.35 h and 0.47 h respectively), with cells entrapped by dialysis membrane (1.53 h), alginate beads (1.93 h), Hypol foam
(2.31 h) and polyacrylamide gel (50 % nitrite not removed at maximum residence time tested: 4.9 h) performing progressively
less effectively. Cells grown as a biofilm on a range of support materials were also tested in comparable packed-bed reactors.
Cell loss from these supports was extensive and contributed to poor performance of the reactors despite high initial biomass
loadings (RA1/2 values using raschig rings, coke and activated-carbon supports: 1.6 h, 2.3 h and 1.0 h respectively). Biofilms grown on Pharmacia
microcarrier supports and used in packed and also fluidised beds were more stable and the performance of these reactors was
superior to that of biofilm reactors using other supports, and comparable to that of the membrane reactors (RA1/2 values for Cytoline 2, Cytopore 2 and Cytodex 3: 0.76 h, 0.56 h, 0.68 h respectively).
Received: 12 August 1996 / Received revision: 14 November 1996 / Accepted: 15 November 1996 相似文献
15.
Chloroaromatic compounds are xenobiotics that cause great concern. The degradation of a model molecule, 3,4-dichlorobenzoate
(3,4-DCB), was studied using three aerobic (AE)-anaerobic (AN) biofilm reactor systems: a coupled aerobic-anaerobic recycle
biofilm reactor (CAR) system, an in-series anaerobic-aerobic biofilm reactor (SAR) system; and an independent aerobic and
anaerobic biofilm reactor (IAR) system. In all three systems the inlet substrate concentration was 2.0 g/l and the dilution
rates ranged from 0.045 to 0.142 per hour. The results show that the degradation efficiency of the CAR system (expressed as
dechlorination and xenobiotic disappearance efficiencies, and biomass yield), was higher at all dilution rates tested than
in both SAR and IAR systems. Moreover, dechlorination and xenobiotic disappearance efficiencies for resting suspended aerobic
and anaerobic cells or mixed aerobic-anaerobic growing cells under anaerobic conditions were higher than under aerobic conditions.
These results suggest that a “cooperative metabolism” between aerobic and anaerobic bacteria (caused by an exchange of cells
and metabolites between AE and AN reactors) in the CAR system overcame the metabolic and kinetic limitations of aerobic and
anaerobic bacteria in the AE and AN reactors of IAR and SAR systems. Therefore, the degradation efficiency of persistent and
recalcitrant chloroaromatic xenobiotic compounds could be enhanced by using a CAR system.
Received: 1 March 1999 / Received revision: 11 May 1999 / Accepted: 16 May 1999 相似文献
16.
Metabolic transformations and characterisation of the sludge community in an enhanced biological phosphorus removal system 总被引:4,自引:0,他引:4
M. Christensson L. L. Blackall T. Welander 《Applied microbiology and biotechnology》1998,49(2):226-234
Enhanced biological phosphorus removal was performed in a continuous laboratory-scale two-reactor system with sludge recirculation
over a 75-day period. Influent wastewater was a synthetic medium based on acetate, and the sludge age was kept at 12 days.
The adapted sludge stored poly-β-hydroxyalkanoic acids (PHA) in the anaerobic reactor with a conversion ratio of 1.45 PHA/acetic
acid (based on chemical O2 demand: COD/COD) and gave ratio of a phosphate-P release to acetic acid uptake of 0.51 P/CH3COOH (w/w). Fractionation of anaerobic and aerobic sludges showed that the main part of phosphorus taken up, was eluted in
the trichloroacetic acid fraction indicating that it was polyphosphate. A total of 60% of the phosphorus in the aerobic sludge
was solubilized in the trichloroacetic acid fraction, whereas this fraction accounted for only 32% of the phosphorus in the
anaerobic sludge. Only 4% of the total phosphorus in the aerobic sludge and 2% in the anaerobic sludge was found in the EDTA
fraction, indicating low amounts of metal-bound phosphates. Isolation on acetate-based agar medium showed that Acinetobacter strains were present in the sludge. However, a more complete analysis of the bacterial community of the sludge was obtained
by creating a clone library based on the 16S rRNA gene. A total of 51 partial clone sequences were phylogenetically evaluated.
The predominating group was found in the high-(G+C) (mol%) gram-positive bacterial subphylum (31% of the sequenced clones),
while the gamma proteobacteria only constituted 9.8% of the clones.
Received: 12 June 1997 / Received revision: 26 September 1997 / Accepted: 28 September 1997 相似文献
17.
Crude peroxidase preparations from the lignocellulose-degrading actinomycete, Streptomyces viridosporus T7A, were shown to decolorize several azo dye isomers and showed a correlation of dye structure to degradability similar
to that shown by fungal Mn-peroxidase, an enzyme not previously described in actinomycetes. Addition of the heme-peroxidase
inhibitor KCN did not significantly change the ability of the T7A enzyme(s) to decompose the dyes. These results suggest that
T7A may produce a Mn- or other peroxidase with similar substrate specificity to Mn-peroxidase. Affinity chromatography using
immobilized azo dye isomers was used for purifying peroxidases from T7A. A significantly purified peroxidase preparation was
obtained irrespective of the azo dye used. In comparison, concanavalin A lectin affinity chromatography showed very poor binding
and resolution for T7A peroxidases. Azo dye affinity purification gave preparations sufficiently purified to allow amino acid
microsequencing for two of the bound proteins. N-terminal amino acid sequences were found to share significant homology with
a fungal Mn-peroxidase and actinomycete cellulases.
Received: 20 May 1997 / Received revision: 17 December 1997 / Accepted: 2 January 1998 相似文献
18.
Influence of the starting microbial nucleus type on the anaerobic granulation dynamics 总被引:4,自引:0,他引:4
The influence of four different granulation precursors, syntroph-enriched methanogenic consortia, Methanosaeta-enriched, Methanosarcina-enriched nuclei and acidogenic flocs, on the time course of complex granule development and the lag time for start-up was
investigated in four upflow anaerobic sludge-bed and filter reactors. Although the operational conditions allowed the maintenance
of the same specific growth rate of biomass in the four reactors, granulation proceeded rapidly with syntroph/methanogenic
consortia, Methanosaeta and Methanosarcina nuclei. However, granulation was significantly retarded when acidogenic flocs were used as precursors. The granule mean Sauter
diameter increased rapidly in the reactor inoculated with syntroph/methanogenic consortia, Methanosaeta and Methanosarcina nuclei and reached, at the end of the experiment, 3.1, 2.7 and 2.4 mm compared to 1.1 mm in that inoculated with acidogenic
flocs. This corresponded to a rate of granule size increase of 31, 21, 18 μm/day in syntroph/methanogenic consortia, Methanosaeta and Methanosarcina nuclei, respectively, compared to 7 μm/day in acidogenic flocs. Biomass specific activities (i.e. acidogenic, syntrophic
and methanogenic activities) increased stepwise in all reactors with time, especially in those inoculated with syntroph/methanogenic
consortia and Methanosaeta nuclei. From these results it appears that syntrophs and Methanosaeta spp. play an important role in the anaerobic granulation process.
Received: 25 January 1996 / Received revision: 3 September 1996 / Accepted: 13 September 1996 相似文献
19.
Characterization and optimization of a two-phase partitioning bioreactor for the biodegradation of phenol 总被引:2,自引:0,他引:2
An electrochemical reactor employing activated carbon fibers (ACF) was constructed for the disinfection of bacteria in drinking
water. The application of an alternating potential of 1.0 V and −0.8 V versus a saturated calomel electrode, for disinfecting
and desorbing bacteria, enabled reactor operation for 840 h. Drinking water was passed through the reactor in stop/flow mode:
300 ml/min flow for 12 h and no flow for 12 h, alternately. The bacterial cell density in treated water was always been less
than 20 cells/ml. It was also found that the formation of biofilm on the ACF reactor caused an increase in current, enabling
the self-detection of microbial fouling.
Received: 19 February 1996 / Received last revision: 23 July 1996 / Accepted: 2 September 1996 相似文献
20.
J. Benitez J. Beltran-Heredia J. Torregrosa J. L. Acero V. Cercas 《Applied microbiology and biotechnology》1997,47(2):185-188
The degradation of olive mill wastewater by aerobic microorganisms has been investigated in a batch reactor, by conducting
experiments where the initial concentration of organic matter, quantified by the chemical oxygen demand, and the initial biomass
were varied. The evolution of the chemical oxygen demand, biomass and the total contents of phenolic and aromatic compounds
were followed through each experiment. According to the Contois model, a kinetic expression for the substrate utilization
rate is derived, and its biokinetic constants are evaluated. This final predicted equation agrees well with all the experimental
data.
Received: 12 June 1996 / Received revision: 11 September 1996 / Accepted: 13 September 1996 相似文献