Biodegradation of MTBE and BTEX in an aerobic fluidized bed reactor

2003 ◽  
Vol 47 (9) ◽  
pp. 123-128 ◽  
Author(s):  
A. Pruden ◽  
M. Sedran ◽  
M. Suidan ◽  
A. Venosa
Keyword(s):  
Fluidized Bed ◽  
Flow Rate ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Oxygen Demand ◽  
Fluidized Bed Reactor ◽  
Methyl Tert Butyl Ether ◽  
Reactor Performance ◽  
Butyl Ether ◽  
Acclimation Period ◽  
Gradient Gel Electrophoresis

An aerobic fluidized bed reactor (FBR) was operated for the removal of methyl tert-butyl ether (MTBE) and benzene, toluene, ethylbenzene, and p-xylene (BTEX) from water. The reactor was seeded with a mixed culture adapted to MTBE. Granular activated carbon (GAC) was used as the biological attachment medium. Influent MTBE to the reactor was 7.8 mg/L MTBE, with a flow rate of 22.7 L/day, and an empty bed contact time of 1 hour. The acclimation period required was relatively short, about 30 days before reaching an average stable effluent concentration of 18.5 ± 10 μg/L. BTEX was introduced to the feed at an equivalent chemical oxygen demand (COD) as the MTBE at day 225 and was biodegraded spontaneously with no apparent acclimation period required. The average influent of each of the four BTEX compounds was about 2 mg/L, and the range of the average effluent concentrations was 1.4-2.2 μg/L. After achieving 180 days of stable performance with BTEX addition, the total flow rate to the reactor was gradually increased by 20% increments to 160% of the original flow (36.4 L/day). Increases by 20% and 40% had no apparent effect on reactor performance, but increase by 60% required 30 days before effluent quality returned to previous values. Composition of the culture was monitored throughout operation of the reactor using denaturing gradient gel electrophoresis (DGGE). The culture consisted of Flavobacteria-Cytophaga and organisms with high similarity to the known MTBE degrader PM1.

Denaturing gradient gel electrophoresis analysis of a methyl tert-butyl ether degrading culture applied in a membrane bioreactor

2002 ◽  
Vol 2 (2) ◽  
pp. 207-212 ◽  
Author(s):  
A. Pruden ◽  
M. Suidan ◽  
J. Morrison ◽  
A. Venosa
Keyword(s):  
Gel Electrophoresis ◽  
Membrane Bioreactor ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Selective Pressure ◽  
Methyl Tert Butyl Ether ◽  
Butyl Ether ◽  
Tert Butyl ◽  
Start Up ◽  
Gradient Gel Electrophoresis ◽  
Dramatic Shift

A membrane bioreactor (MBR) was operated for the removal of methyl tert-butyl ether (MTBE) from water. Although the reactor was seeded with several cultures acclimated to MTBE degradation, a long start-up time was observed. Monitoring of the reactor with denaturing gradient gel electrophoresis (DGGE) revealed a dramatic shift in the MBR culture from the original seed culture, indicating that the membrane had exerted a selective pressure on the culture. The MBR culture was found to be dominated almost entirely by Sphingomonas, belonging to the a-4 subclass of the a-Proteobacteria. Several unique properties of Sphingomonas, including their characteristic outer membrane containing glycosphingolipids, as well as their extreme adeptness at xenobiotic degradation are hypothesized to have aided in their selection in this bioreactor.

scholarly journals Identification and Activities In Situ of Nitrosospiraand Nitrospira spp. as Dominant Populations in a Nitrifying Fluidized Bed Reactor

1998 ◽  
Vol 64 (9) ◽  
pp. 3480-3485 ◽  
Author(s):  
Andreas Schramm ◽  
Dirk de Beer ◽  
Michael Wagner ◽  
Rudolf Amann
Keyword(s):  
Fluidized Bed ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Fluidized Bed Reactor ◽  
Molecular Techniques ◽  
Fish Analysis ◽  
Nitrite Oxidizing Bacteria ◽  
Gradient Gel Electrophoresis ◽  
Bacterial Aggregates ◽  
In Situ Detection

ABSTRACT Bacterial aggregates from a chemolithoautotrophic, nitrifying fluidized bed reactor were investigated with microsensors and rRNA-based molecular techniques. The microprofiles of O2, NH4 +, NO2 −, and NO3 − demonstrated the occurrence of complete nitrification in the outer 125 μm of the aggregates. The ammonia oxidizers were identified as members of theNitrosospira group by fluorescence in situ hybridization (FISH). No ammonia- or nitrite-oxidizing bacteria of the genus Nitrosomonas or Nitrobacter, respectively, could be detected by FISH. To identify the nitrite oxidizers, a 16S ribosomal DNA clone library was constructed and screened by denaturing gradient gel electrophoresis and selected clones were sequenced. The organisms represented by these sequences formed two phylogenetically distinct clusters affiliated with the nitrite oxidizerNitrospira moscoviensis. 16S rRNA-targeted oligonucleotide probes were designed for in situ detection of these organisms. FISH analysis showed that the dominant populations of Nitrospiraspp. and Nitrosospira spp. formed separate, dense clusters which were in contact with each other and occurred throughout the aggregate. A second, smaller, morphologically and genetically different population of Nitrospira spp. was restricted to the outer nitrifying zones.

Anaerobic/aerobic biodegradation of pentachlorophenol using GAC fluidized bed reactors: optimization of the empty bed contact time

1997 ◽  
Vol 36 (6-7) ◽  
pp. 107-115 ◽  
Author(s):  
Gregory J. Wilson ◽  
Amid P. Khodadoust ◽  
Makram T. Suidan ◽  
Richard C. Brenner
Keyword(s):  
Fluidized Bed ◽  
Oxygen Demand ◽  
Aerobic Biodegradation ◽  
Fluidized Bed Reactors ◽  
Reactor Performance ◽  
Reactor Operation ◽  
Significant Cost ◽  
Second Stage ◽  
Primary Substrate ◽  
Chlorinated Phenolic Compounds

An integrated reactor system has been developed to remediate pentachlorophenol (PCP) containing wastes using sequential anaerobic and aerobic biodegradation. Anaerobically, PCP was degraded to predominately equimolar concentrations (>99%) of monochlorophenol (MCP) in two GAC fluidized bed reactors at Empty Bed Contact Times (EBCTs) ranging from 18.6 to 1.15 hours. However, at lower EBCTs, MCP concentrations decreased to less than 10% of the influent PCP concentration suggesting mineralization. The optimal EBCT was determined to be 2.3 hours based on PCP conversion to MCPs and stable reactor operation. Decreasing the EBCT fourfold did not inhibit degradation of PCP and its intermediates, thus allowing removal of PCP at much lower detention time and resulting in a significant cost advantage. Analytical grade PCP was fed via syringe pumps into two fluidized bed reactors at influent concentrations of 100 mg/l and 200 mg/l, respectively. Acting as the primary substrate, ethanol was also fed into the reactors at concentrations of 697 and 1388 mg/l. Effluent PCP and chlorinated phenolic compounds were analyzed weekly to evaluate reactor performance. Biodegradation pathways were also identified. 3-chlorophenol (CP) was the predominant MCP and varied simultaneously with 3,5-dichlorophenol (DCP) concentrations. Likewise, 4-CP concentrations varied simultaneously with 3,4-DCP concentrations. A second stage aerobic GAC fluidized bed reactor was added after the anaerobic reactor to completely mineralize the remaining MCP and phenols. Data show no presence of phenol and MCP in the effluent or on the GAC. Overall, the chemical oxygen demand (COD) fed to the system was reduced from 75 g/d in the influent to less than 1.5 g/d in the effluent.

Optimization of Fluidized Bed Reactor of Oxidative Coupling of Methane

2012 ◽  
Vol 10 (1) ◽  
pp. 1-21 ◽  
Author(s):  
Mohammad-Hosein Eghbal-Ahmadi ◽  
Masoud Zaerpour ◽  
Mahdi Daneshpayeh ◽  
Navid Mostoufi
Keyword(s):  
Fluidized Bed ◽  
Oxidative Coupling ◽  
Operating Temperature ◽  
Fluidized Bed Reactor ◽  
Optimization Method ◽  
Oxidative Coupling Of Methane ◽  
Process Variables ◽  
Algorithm Optimization ◽  
Reactor Performance ◽  
Better Than

Optimization of process variables in the oxidative coupling of methane (OCM) over Mn/Na2WO4/SiO2 catalyst in a fluidized bed reactor was carried out. Effects of operating temperature, distribution pattern of oxygen injected to the reactor and the number of injections on the reactor performance on C2 (ethane + ethylene) yield were investigated. Process variables for one, two and three secondary oxygen injections were investigated to obtain the maximum C2 yield by genetic algorithm optimization method. The maximum C2 selectivity and yield of 47.1% and 22.87%, respectively, were achieved for three secondary oxygen injections at operating temperature of 746.05°C. The C2 yield achieved in this study is approximately 4% better than previous works reported in literature while the optimum temperature is lower.

PCR-DGGE analysis of denitrifying bacteria in a metallurgic wastewater treatment process

2002 ◽  
Vol 46 (1-2) ◽  
pp. 333-336 ◽  
Author(s):  
N. Noda ◽  
S. Yoshie ◽  
T. Miyano ◽  
S. Tsuneda ◽  
A. Hirata ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Precious Metals ◽  
Packed Bed ◽  
Population Diversity ◽  
Operating Conditions ◽  
Industrial Wastes ◽  
Wastewater Treatment Process ◽  
Dgge Analysis ◽  
Gradient Gel Electrophoresis

The wastewater generated from the processes of recovering precious metals from industrial wastes contains high concentrations of acids such as nitric acid and of salts. Biological nitrogen removal from this wastewater was attempted by using a circulating bioreactor system equipped with an anoxic packed bed or an anoxic fluidized bed and an aerobic three-phase fluidized bed. The system was found to effectively remove nitrogen from the diluted wastewater (T-N; 1,000–4,000 mg litre−1). The microbial population structure of activated sludge in an anoxic reactor was analyzed by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S ribosomal DNA (rDNA) fragments. DGGE analysis under different operating conditions demonstrated the presence of some distinguishable bands in the separation pattern, which were most likely derived from many different species constituting the microbial communities. Furthermore, the population diversity varied in accordance with the nitrate-loading rate, water temperature and reactor condition. Some major DGGE bands were excised, reamplified and directly sequenced. It was revealed that the dominant population in the anoxic reactor were affiliated with the β subclass of the class Proteobacteria.

scholarly journals Simultaneous sulfide and acetate oxidation in a denitrifying fluidized bed reactor—I. Start-up and reactor performance

1988 ◽  
Vol 22 (9) ◽  
pp. 1075-1083 ◽  
Author(s):  
Peter J.F. Gommers ◽  
Willem Buleveld ◽  
J. Gus Kuenen
Keyword(s):  
Fluidized Bed ◽  
Fluidized Bed Reactor ◽  
Acetate Oxidation ◽  
Reactor Performance ◽  
Start Up

The Efficiency of Phosphorus Removal of Synthetic Wastewater through Struvite Crystallization in an Aerated Fluidized Bed Reactor

2018 ◽  
Vol 789 ◽  
pp. 59-63
Author(s):  
Susmardi Masti Casoni ◽  
Chandra Wahyu Purnomo ◽  
Muslikhin Hidayat
Keyword(s):  
Fluidized Bed ◽  
Flow Rate ◽  
Phosphorus Removal ◽  
Crystallization Process ◽  
Fluidized Bed Reactor ◽  
Aeration Rate ◽  
Synthetic Wastewater ◽  
Influent Flow ◽  
Mgcl2 Solution ◽  
P Removal

The high organic material contained in wastewater released into the environment asresults of various sources of human activities, such as phosphorus, can cause eutrophication. Thestruvite crystallization in an aerated fluidized bed reactor is one of the methods which able toimprove the efficiency of phosphorus removal. In this study, a mixture of synthetic wastewaters andthe MgCl2 solution was treated in a fluidized bed reactor equipped with aeration to produce thestruvite which can be utilized as a slow release fertilizer. Subsequently, the effect of aeration atdifference influent flow rate was investigated to correlate with the changing of phosphorusconcentration in the reactor effluent. The experiments were conducted for 240 minutes with thevariation of aeration are 0.5 L/min to 1.5 L/min; variation of influent flow rate of syntheticwastewater is 150 ml/min to 350 ml/min, with a constant influent flow rate of MgCl2 solution is 50ml/min. These solutions were maintained at the condition of pH 9. The results showed that theoptimal efficiency of phosphor removal which accounted for 82.5% occurred when the aeration rateof 1.5 L/min in the influent flow rate of 150 ml/min. From these findings, it is revealed that theefficiency of P removal in wastewater is obtained by a crystallization process which utilizing anaerated fluidized bed reactor and by increasing the aeration rate and the reactants contact time.

Degradation of Nonylphenol Polyethoxylates and its Microflora Structure in an Anoxic-Oxic Activated Sludge Process

2012 ◽  
Vol 610-613 ◽  
pp. 331-336
Author(s):  
Yuan Hua Xie ◽  
Tong Zhu ◽  
Xiao Jiang Liu ◽  
Hui Liu ◽  
Jin Han
Keyword(s):  
In Situ Hybridization ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Gel Electrophoresis ◽  
Loading Rate ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Oxygen Demand ◽  
Activated Sludge Process ◽  
Gradient Gel Electrophoresis

An anoxic-oxic activated sludge process (AOASP) was carried out to degrade nonylphenol polyethoxylates (NPEOs). The carbon source in influent was replaced stepwise by a mixture of nonylphenol decaethoxylate (M-NP10EO). The 2nd-derivative UV-spectrometry was applied to determine the total amount of M-NP10EO in water samples. Chemical oxygen demand (COD) removal efficiency achieves about 85% under the highest M-NP10EO loading rate, and M-NP10EO removal efficiency is about 80%. Denaturing gradient gel electrophoresis (DGGE) results of activated sludges show that the microbe species decrease but gradually stabilize with the increase of M-NP10EO concentration in influent. Fluorescence in situ hybridization (FISH) results of activated sludges showe that the dominant microflora under the highest M-NP10EO loading rate is β-Proteobacteria (35%), followed by α-Proteobacteria (15%), γ-Proteobacteria (5%) and Actinobateria (4%).

Anaerobic treatment of crude glycerol from biodiesel production

2015 ◽  
Vol 72 (8) ◽  
pp. 1383-1389 ◽  
Author(s):  
M. M. Nakazawa ◽  
W. R. S. Silva Júnior ◽  
M. T. Kato ◽  
S. Gavazza ◽  
L. Florencio
Keyword(s):  
Crude Glycerol ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Experimental Period ◽  
Anaerobic Treatment ◽  
Biodiesel Production ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Reactor Performance

In this study, we evaluated the use of an up-flow anaerobic sludge blanket (UASB) reactor to treat crude glycerol obtained from cottonseed biodiesel production. The laboratory-scale UASB reactor (7.0 L) was operated at ambient temperature of 26.5°C with chemical oxygen demand (COD) concentrations between 0.5 and 8.0 g/L. The volatile fatty acid contents, pH, inorganic salt contents and biogas production were monitored during a 280-day experimental period. Molecular biology techniques were used to assess the microbial diversity in the bioreactor. The reactor achieved COD removal efficiencies of up to 92% except during one phase when the efficiency decreased to 81%. Biogas production remained stable throughout the experimental period, when the fraction converted to methane reached values as high as 68%. The profile of the denaturing gradient gel electrophoresis (DGGE) bands suggested slight changes in the microbial community during reactor operation. The overall results indicated that the crude glycerol from biodiesel production can serve as a suitable substrate for anaerobic degradation with a stable reactor performance and biogas production as long as the applied organic loads are up to 8.06 kg COD/m3·d.

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