Adsorption of Toxic Shocks on Carriers in Anaerobic Biofilm Fluidized Bed Reactors

1993 ◽  
Vol 28 (2) ◽  
pp. 55-65 ◽  
Author(s):  
N. Mol ◽  
O. M. Kut ◽  
I. J. Dunn
Keyword(s):  
Activated Carbon ◽  
Fluidized Bed ◽  
Gas Production ◽  
Fluidized Bed Reactors ◽  
Methane Formation ◽  
Toxic Shock ◽  
Original Activity ◽  
Phenol Adsorption ◽  
Carrier Materials ◽  
The Individual

The influence of different carrier materials on the performance of single stage anaerobic biofilm fluidized bed reactors by toxic shock loadings was studied in parallel experiments. The carrier materials investigated were porous glass (Siran), quartz sand, pumice, shale, activated carbon and anthracite. Since the composition and morphology of the biofilm is influenced by the individual wastewater, vapor condensate from a sulfite cellulose process and mixed brewery wastewaters were used as substrates. The phenol adsorption characteristics were measured on bare and biofilm-coated carriers. Biofilm-coated carriers adsorbed larger amounts of phenol than bare carriers. It was observed that the biofilm morphology and the corresponding adsorption capacity of biofilm carriers depended on the individual wastewater characteristics. It was also shown that activated carbon (and partly anthracite) adsorbed large amounts of phenol, mostly irreversibly. The performance of the individual reactors was studied under short-term dynamic phenol shocks (constant hydraulic retention time (HRT) 10 h, loading rate increase from 12 to 20 kg COD/m3d during the shock period of ca.10 h). During the toxic loading in continuous operation, an increase of phenol concentration was observed in the effluent, coupled with an up to 20% decrease in the gas production rates. During this period, acetic acid accumulation was also observed, indicating the inhibition of methane formation. Following the shock, all reactors showed a relatively rapid recovery to the original activity after 2-3 hydraulic retention times.

Antagonism of sodium toxicity by the compatible solute betaine in anaerobic methanogenic systems

1997 ◽  
Vol 36 (6-7) ◽  
pp. 15-24 ◽  
Author(s):  
D. W. Yerkes ◽  
S. Boonyakitsombut ◽  
R. E. Speece
Keyword(s):  
Fluidized Bed ◽  
Gas Production ◽  
Compatible Solute ◽  
Fluidized Bed Reactors ◽  
Volatile Acid ◽  
Batch Reactors ◽  
Acid Uptake ◽  
Sodium Toxicity ◽  
High Concentrations ◽  
Uasb Reactors

In this paper, the compatible solute betaine is investigated for its antagonistic effects toward sodium toxicity in anaerobic methanogenic systems. Concentrations of betaine as low as 1 mM are shown to be effective at reducing the toxicity symptoms of high concentrations of sodium in the following anaerobic reactor systems: batch reactors seeded with a Methanosarcina enriched culture and batch reactors seeded with a Methanothrix culture, where the acclimation time or lag time before methane production begins is reduced significantly; CSTRs, where the acetic acid uptake rate increases dramatically; fluidized bed reactors, where gas production and pH increase and effluent COD and volatile acid concentration decrease; and UASB reactors, where gas production increases markedly. Because the phenomenon of sodium toxicity antagonism by betaine was demonstrated in anaerobic batch reactors, CSTRs, fluidized bed reactors, and UASB reactors, the usefulness of betaine in an industrial application may be feasible.

scholarly journals An increase in bed temperature on gasification of dual reactor fluidized bed

2018 ◽  
Vol 67 ◽  
pp. 02059
Author(s):  
I Nyoman Suprapta Winaya ◽  
I Ketut Gede Wirawan ◽  
I Wayan Arya Darma ◽  
I Putu Lokantara ◽  
Rukmi Sari Hartati
Keyword(s):  
Fluidized Bed ◽  
Gas Production ◽  
304 Stainless Steel ◽  
Fluidized Bed Reactors ◽  
Endothermic Reaction ◽  
Gasification Process ◽  
Bed Temperature ◽  
Superficial Gas Velocity ◽  
Bed Material ◽  
Co Gas

One of the main issues using biomass as fuel in air gasification is the dilution of its product gas by the nitrogen in the air. A dual reactor fluidized bed (DRFB) overcomes this problem in which the gasification and combustion reactions are decoupled and conducted in two separate fluidized bed reactors connected by circulating bed material. The DFRB unit made of 304 stainless steel pipe with a height of 100 and 150 cm, and inner diameters (i.d.) of 15.2 and 5.1 cm for gasifier and combustor respectively. The rice husk as fuel and quartz sand as bed material having the same size of 0.4 - 0.6 mm were applied in this investigation. Since the gasification process is an endothermic reaction, gasification temperatures are varied at 600°C to 700°C while combustion reactor were kept at 600°C using the electric heaters enclosed in ceramic cover. The superficial gas velocity in this study was kept constant at 17 m/s using the external air volumetric flux of the blower flow entering the DRFB loop. Gas gasification samples are then examined by gas chromatography to determine syngas content (CO, CH4 and H2). The test results showed that by the increasing temperature of the gasification reactor there was an increase in syngas especially CO gas conentration. The temperature increases in the gasification reactor (600°C, 650°C, 700°C) is able to increase the endothermic reaction in the gasification process which is dominated by CO gas production. The syngas efficiency was found to increase from 40.95% to 43.77%.as the temperature of the gasification reactor increased.

Use of activated carbon and natural zeolite as support materials, in an anaerobic fluidised bed reactor, for vinasse treatment

2001 ◽  
Vol 44 (4) ◽  
pp. 1-6 ◽  
Author(s):  
N. Fernández ◽  
F. Fdz-Polanco ◽  
S. J. Montalvo ◽  
D. Toledano
Keyword(s):  
Organic Matter ◽  
Activated Carbon ◽  
Fluidized Bed ◽  
Natural Zeolite ◽  
Cane Sugar ◽  
Raw Material ◽  
Organic Loading Rate ◽  
Fluidized Bed Reactors ◽  
Fluidised Bed ◽  
Support Materials

In Cuba, the alcohol distillation process from cane sugar molasses, produces a final waste (vinasse), with an enormous polluting potential and a high sulfate content. Applying the anaerobic technology, most of the biodegradable organic matter can turn into biogas, rich in methane but with concentrations of sulfide above 1%. The present work develops two experiences with anaerobic fluidized bed reactors (AFBR) using both Cuban raw material, activated carbon and natural zeolite, as support media, with the purpose of obtaining high organic matter removal rates and keeping sulfide and ammonium concentrations in the permissible ranges. The reactors were operated during 120 days, achieving an organic loading rate of 10 kg COD/m3 day, with COD removal above 70%, and a methane production of 2 L/d. The activated carbon and natural zeolite used support materials in anaerobic fluidized bed reactors, and showed good results of distillery waste removal.

Role of adsorption in granular activated carbon-fluidized bed reactors

1995 ◽  
Vol 67 (3) ◽  
pp. 302-309 ◽  
Author(s):  
Jing Shi ◽  
Xianda Zhao ◽  
Robert F. Hickey ◽  
Thomas C. Voice
Keyword(s):  
Activated Carbon ◽  
Fluidized Bed ◽  
Granular Activated Carbon ◽  
Fluidized Bed Reactors

Removal of microcystin-LR from drinking water with TiO2-coated activated carbon

2004 ◽  
Vol 4 (5-6) ◽  
pp. 21-28
Author(s):  
S.-C. Kim ◽  
D.-K. Lee
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Synergistic Effect ◽  
Fluidized Bed ◽  
Continuous Flow ◽  
High Surface ◽  
High Surface Area ◽  
Fluidized Bed Reactor ◽  
Exterior Surface ◽  
Tio2 Particles

TiO2-coated granular activated carbon was employed for the removal of toxic microcystin-LR from water. High surface area of the activated carbon provided sites for the adsorption of microcystin-LR, and the adsorbed microcystin-LR migrated continuously onto the surface of TiO2 particles which located mainly at the exterior surface in the vicinity of the entrances of the macropores of the activated carbon. The migrated microcystin-LR was finally degraded into nontoxic products and CO2 very quickly. These combined roles of the activated carbon and TiO2 showed a synergistic effect on the efficient degradation of toxic microcystin-LR. A continuous flow fluidized bed reactor with the TiO2-coated activated carbon could successfully be employed for the efficient photocatalytic of microcystin-LR.

Influence of Seeding Conditions on Initial Biofilm Development during the Startup of Anaerobic Fluidized Bed Reactors

1989 ◽  
Vol 21 (4-5) ◽  
pp. 157-165 ◽  
Author(s):  
F. Ehlinger ◽  
J. M. Audic ◽  
G. M. Faup
Keyword(s):  
Fluidized Bed ◽  
Future Development ◽  
Protein Concentration ◽  
Specific Activity ◽  
Fluidized Bed Reactor ◽  
Fluidized Bed Reactors ◽  
Support Material ◽  
Biofilm Development ◽  
Initial Biofilm

The characterization of the biofilm of an anaerobic fluidized-bed reactor was completed under standard conditions. The distribution of the fixed protein concentration depended on the level in the reactor. The protein concentration reached 1520 µg.g−1 of support at the top of the reactor and only 1200 µg.g−1 at the bottom after 504 hours of operation but the specific activity of the biofilm was 33×10−4 µM acetate.h−1.mg−1 proteins at the bottom and only 26×10−4 µM.h−1.mg−1 at the top. The efficiency of a fluidized bed reactor and the composition of the biofilm changed with an increase of the pH from 7 to 8.5 during the seeding of the support material. Future development of the biofilm and the specific activity of the support were affected.

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.

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