Fluidized bed biofilm reactor

Simultaneous degradation of 2,4- and 2,6-DNT has been achieved in a fluidized-bed biofilm reactor (Lendemann et al. 1998) that was successfully operated with contaminated groundwater containing 2- and 4-nitrotoluenes and 2,4- and 2,6-DNTs. The nitrite that was produced during degradation was recovered as nitrate. 

Kryst K, Karamanev DG (2001) Aerobic phenol biodegradation in an inverse fluidized-bed biofilm reactor. Ind Eng Chem Res 40 5436—5439... 

Denac, M., and Dunn, I. J., Packed- and Fluidized-Bed Biofilm Reactor Performance for Anaerobic Wastewater Treatment, Biotechnol. Bioeng., 32 159 (1988)... 

Nikolov, L., and Karamanev, D. G., The Inverse Fluidized Bed Biofilm Reactor A New Laboratory Scale Apparatus for Biofilm Research, J. Ferm. Bioeng. 69 265 (1990)... 

Kurt, M., Dunn, I. J. and Bourne, J. R. (1987) Biological denitrification of drinking water using autotrophic organisms with H2 in a fluidized- bed biofilm reactor. Biotechnol. Bioeng. 29, 493-501. 

List of abbreviations BOD, biological oxygen demand CA, chloroanisol CCA, copper-chromate-arsenate CP, chlorophenol 2,4-D, dichlorophenoxyacetic acid DCP, dichlorophenol CFSTR, continuous-flow stirred tank reactor FBBR, fluidized-bed biofilm reactor MCP, monochlorophenol NAPL, non-aqueous phase liquid PAH, polycyclic aromatic hydrocarbon PCPP, polychlorinated phenoxyphenol PCDF, polychlorinated dibenzofuran PCDD, polychlorinated dibenzodioxin PCR, polymerase chain reaction PCP, pentachlorophenol PCA, pentachloroanisole TeCP, tetrachlorophenol TeCA, tetrachloroanisole TCC, trichlorocatechol TCP, trichlorophenol TOC, total organic carbon 2,4,5-T, trichlorophenoxyacetic acid UASB, upflow anaerobic sludge blanket reactor VSS, volatile suspended solids. 

FBBR, fluidized-bed biofilm reactor CFSTR, completely mixed stirred tank reactor PUR, polyurethane immobilized cells UASB, upflow anaerobic sludge blanket reactor NS, not specified. 

Lendemann, U., J.C. Spain, and B.F. Smets. 1998. Simultaneous biodegradation of 2,4-dinitrotoluene and 2,6-dinitrotoluene in an anerobic fluidized-bed biofilm reactor. Environ. Sci. Technol. 32 82-87. 

The effectiveness factor varies only with the biofilm thickness and the support particle size at constant voidage of the fluidized bed. This leads to the conclusion that an optimal biofilm thickness exists for fluidized bed biofilm reactors (Kargi and Park, 1982). The effect of biofilm thickness on the performance of a fluidized bed reactor was also examined by Shieh (1981), who showed the same results. Neither maintenance of thicknesses with 10 to 100 jum nor the highest biomass will be beneficial to optimum reactor operation. 

Figure 6.46. Block diagram of the fluidized bed biofilm reactor model according to Mulcahy and La Motta (1978), containing reactor flow equation, biofilm effectiveness equations, and fluidization model with 13 system (fixed and design) parameters and six empirical correlations.

Nikolov LN, Karamanev, DG. The inverse fluidized bed biofilm reactor a new laboratory scale apparatus for biofilm research. J. Fermentation and Bioengineering... 

Recent research development of hydrodynamics and heat and mass transfer in inverse and circulating three-phase fluidized beds for waste water treatment is summarized. The three-phase (gas-liquid-solid) fluidized bed can be utilized for catalytic and photo-catalytic gas-liquid reactions such as chemical, biochemical, biofilm and electrode reactions. For the more effective treatment of wastewater, recently, new processing modes such as the inverse and circulation fluidization have been developed and adopted to circumvent the conventional three-phase fluidized bed reactors [1-6]. 

During start-up, the microbial population distribution in the biofilm varies with time. Initial colonization of the particle may be by one or more species that alter the surface favorably for colonization by other species. For instance, in the operation of a butyrate-degrading fluidized bed bioreactor, methanogens attached to the sand particles early in the start-up process and produced a primary matrix of heteropolysaccharides that allowed attachment of other bacterial species (Sreekrishnan et al., 1991 Zellner et al., 1991 Yongming et al., 1993). This is contrary to findings in an acetate-propionate-butyrate degrading reactor, in which facultative anaerobes were found to be the initial colonizers (Lauwers et al., 1990). 

Araki, N., and Harada, H., Population Dynamics of Methanogenic Biofilm Consortium during a Start-Up Period of Anaerobic Fluidized Bed Reactor, Wat. Sci. Tech., 29(10-11) 361 (1994)... 

Coelhoso, I., Boaventura, R., and Rodrigues, A., Biofilm Reactors An Experimental and Modeling Study of Wastewater Denitrification in Fluidized-Bed Reactors of Activated Carbon Particles, Biotechnol. Bioeng., 40 625 (1992)... 

Trinet, F., Fleim, R., Amar, D., Chang, H. T., and Rittmann, B. E., Study of Biofilm and Fluidization of Bioparticles in a Three-Phase Liquid-Fluidized-Bed Reactor, Wat. Set. Tech., 23 1347 (1991)... 

Zellner, G., Geveke, M., de Macario, E. C., and Diekmann, H., Population Dynamics of Biofilm Development During Start-Up of a Butyrate-Degrading Fluidized-Bed Reactor, Appl. Microbiol. Biotechnol., 36 404 (1991)... 

Table 1 reports a wide spectrum of typologies of biofilm reactor upflow anaerobic sludge bed (UASB), fluidized bed, airlift, fixed bed with and without recycle, mechanically agitated vessel, rotating drum and rotating biological contactor. Each reactor is characterized by positive features and drawbacks. 

Fluidized beds, both in the conventional and in the airlift configurations, require more careful operation. Proper selection of the operating conditions makes it possible to control biofilm-growth while preventing reactor clogging. Typically, the reactor is operated as a CSTR by establishing large recycle of the liquid stream [36, 37],... 

External mass transfer resistance was neglected, as reported by [63] in biofilm reactors with granular particles (fluidized bed, airlift) the Biot number was generally larger than 100. 

Industrial hazardous wastewater can be treated aerobically in suspended biomass stirred-tank bioreactors, plug-flow bioreactors, rotating-disc contactors, packed-bed fixed-biofilm reactors (or biofilters), fluidized bed reactors, diffused aeration tanks, airlift bioreactors, jet bioreactors, membrane bioreactors, and upflow bed reactors [28,30]. 

The advantages of fluidized beds compared to fixed bed reactors are improved heat and mass transfer, an easier passage through the bed for foreign material and unwanted micro-organisms, a lower pressure drop, better control of the thickness of the biofilm and the easy removal of particles from the bed in order to remove excess biomass (Epstein, 2003). 

The basic advantage of the suspended biofilm membrane reactors over the suspended biomass system (either with dispersed cells or with floes) is that the former are able to retain much more biomass [22]. It substantially reduces the biomass wash out and allows a more stable operation with higher biomass concentration. A moving-bed-biofilm membrane reactor is illustrated in Figure 14.5. The biomass is immobilized inside and outside of the fluidized particles. The structure of the biofilm continuously... 

Liquid-fluidized beds predate gas-fluidized beds, but they have considerably fewer applications because of a smaller number of advantages. Most applications are physical, with bioreactors being the sole significant reactor application. Much of the recent attention has focused on aerobic wastewater treatment and fermentation processes, e.g., with methane as the organic substrate (see Refs. " for more details). In these processes, microbial cells are attached to the surface of inert particles (e.g., sand or activated carbon) as a biofilm, or trapped within the pores or interior of particles, causing the particle size and/or density to vary with time. Loaded particles therefore have... 

The main reactor types are upflow sludge blankets, biofilm fluidized beds, expanded granular sludge blankets, and biofihn airlift suspension and internal circulation reactors. 

Performance models of biofilm reactors (fixed and fluidized bed) following the concepts of pseudohomogeneous and true heterogeneous modeling are outlined in Sect. 6.7. 

Recently, the application of fluidized beds to bioprocessing stimulated the modeling of FBBRs. In this complex case, however, models of the hydraulics must be combined with a model of biofilm kinetics, including mass transport-affected substrate conversion. This truly heterogeneous case of reactor operation will be presented here. 

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