Abstract
Molecular and cultivation techniques were usedto characterize the bacterial communities of biobead reactorbiofilms in a sewage treatment plant to which an Aerated Up-Flow Biobead process was applied. With this biobead process,the monthly average values of various chemical parameters inthe effluent were generally kept under the regulation limits ofthe effluent quality of the sewage treatment plant during thethat the population of denitrifying bacteria was abundant inthe biobead #1 reactor, denitrifying and nitrifying bacteriacoexisted in the biobead #2 reactor, and nitrifying bacteriaprevailed over denitrifying bacteria in the biobead #3 reactor.The results of the MPN test suggested that the biobead #2reactor was a transition zone leading to acclimated nitrifyingbiofilms in the biobead #3 reactor. Phylogenetic analysis of16S rDNA sequences cloned from biofilms showed that thebiobead #1 reactor, which received a high organic loading rate,had much diverse microorganisms, whereas the biobead #2 andProteobacteria.DGGE analysis with the amonia monooxygenase (amoA)gene supported the observation from the MPN test that thebiofilms of September were fully developed and specializedfor nitrification in the biobead reactor #3. All of the DNAsequences of the amoA DGGE bands were very similar to thesequence of the amoA gene of Nitrosomonas species, thepresence of which is typical in the biological aerated filters.The results of this study showed that organic and inorganicpopulations in the anaerobic tank and heterotrophic andnitrifying bacterial biofilms well-formed in the three functionalbiobead reactors in the Aerated Up-Flow Biobead process. KCI Citation Count: 9