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Abstract The legitimacy of model transfer in process technology has to date found no noteworthy influence on the design and dimensioning of immobilized cell bioreactors for anaerobic wastewater treatment. The latter still takes place solely on the basis of purely empirical rather than scientific considerations. However, it is possible to carry out design dimensioning on the basis of model theory considerations founded on process technology, as the examples of the design of fixed-bed-loop reactors and that of fluidized-bed reactors demonstrate. Together with the spatial separation of fermentative acid formation and methanogenesis (through a two-stage biology with two different microbial populations), a multi-stage design of methanization through cascade connection of fixed-bed-loop reactors (for the narrowing of the residence time distribution) has proved particularly advantageous when applied to highly loaded and complex constituted wastewater. Technical reaction investigations on appropriately configured variants showed that for a COD conversion of 80–90% (wastewater from the foodstuffs industry), the reactor volume of the two-stage methanization cascade could be reduced by 40–50% compared to that of the simply performed methanization stage. Author Keywords: Anaerobic; Microbial immobilization; Optimization; Reactor design; Scale-up; Treatment; Wastewater Article Outline 1. Introduction 2. Materials and methods 3. Scale transfer and dimensioning of anaerobic fixed-bed-loop and fluidized-bed reactors 4. Influence of residence time distribution on the biomethanization and reactor design considerations 5. Discussion and conclusions Appendix A. Nomenclature References 1. Introduction Immobilized cell reactors are widely utilized in situations where the bioreactor capacity––when using freely suspended microorganisms––is limited by the achievable biomass concentration and the hydraulic residence time. Microbial immobilization is especially useful for slow growing, strong energy limited anaerobic methane producers. Immobilized cell reactors with static carriers (packed beds, filters) and suspended surfaces including systems without external carrier particles where immobilization is provided by cellular self-aggregation and granulation (fluidized beds, UASB reactors), have been developed in the past three decades for anaerobic wastewater treatment [1, 2, 3, 4, 5 and 6].
Approximate Word count = 1151
Approximate Pages = 4.6
(250 words per page double spaced)
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