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Start-up Of A Fluidized-bed Bioreactor With A ß-cyclodextrin Polymer Support For Treating Wastewater


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X. Sevillano, A Romo, J R Isasi, G Gonzalez-Gaitano & J Peñas


Start-up of a fluidized-bed bioreactor with a B- cyclodextrin polymer support for treating wastewater X. Sevillano, A. Romo, J.R. Isasi, G. Gonzalez-Gaitano & J. Pefias Department of Chemistry and Soil Science, University of Navarre, Spain Abstract The starting-up process of a fluidized-bed bioreactor using an insoluble p- cyclodextrin polymer, suitable for the removal of organic pollutants in wastewater under aerobic conditions, is presented. p-cyclodextrin is a torus- shaped cyclic oligosaccharide with a hydrophobic cavity made up of seven 1,4- linked D-glucopyranose units. This structure gives rise to an amphiphillic behaviour in water what makes it potentially useful in wastewater purification processes. The polymerisation of P-cyclodextrin has allowed us to obtain insoluble particles with an appropriate size in order to be used as a support for the biomass. The tests on the biodegradability of the support itself, with or without an extra carbon source, show a good stability, despite its hydrocarbon character. The fluidized-bed operation conditions have been determined from the hydrodynamic characterization of the synthesised resin particles. The density of these particles is slightly higher than that of the wastewater so the recirculation rate is below that of other supports which are frequently used in fluidized beds. During the starting-up period, the reactor has worked under room conditions without controlling the temperature. An acclimated microbial culture has been inoculated to the bioreactor, and a low organic load with a high hydraulic residence time has been used to allow the colonisation of the polymer particles by the biomass. The aeration degree has been established to maintain a minimum level of dissolved oxygen in the effluent. The performance of the bioreactor has been studied by means of COD analysis of the effluent stream.