| EPS are mainly high-molecular-weight secretions from microorganisms under certain environmental condition.EPS are usually present in wastewater treatment reactors, and play an important role in wastewater treatment. The EPS related with the microbial metabolism may make more sense in microbial aggregates related studies,and can affect various physicochemical characteristics of microbial aggregates. In addition, in the process of biological enhanced treatment of refractory wastewater, EPS also have an apparent effect on on the physicochemical properties and adsorption properties of porous adsorption material such as activated carbon, macroporous adsorption resin and so on. Thus, study on the characteristics of kinds of EPS and their effect on the resin should be focused on. In this paper, the activated sludge was acclimated to obtain the catechol-degrading microbes strain, the extraction of kinds of EPS and EPS secretion under different environment also were studied. In addition, the effect of EPS on the surface morphological change of EPS preliminaryly explorated. The results are as follows:1) Two microbes strain which could grow well on the medium with the substrate of catechol as the sole source of carbon and energy were isolated from activated sludge, one (called A)was identified as belonging to Aspergillus genus and the other (called B)was identified as belonging to Stenotrophomonas genus.They had certain ability to degradate catechol, and the ability of A strain was better than B strain.With the increase of initial concentration of catechol, the gradation ability of A strain and B strain would decrease.2) The content of kinds of EPS (such as activated sludge, A strain and B strain) would be changed according to the EPS types and extraction methods. The order of three methods for the extraction of EPS of actived sludge was:heat extraction>ultrasonic method> high-speed centrifugation. Protein accounted for a major portion of the EPS of A strain using high speed centrifugal. The order of four methods for the extraction of EPS of B strain was:heat extraction>NaOH method>H2SO4>high-speed centrifugation.The H2SO4extraction was good for PS yield. According to the comparison of Infrared spectrum of various EPS, it was found that no matter what kind of EPS, there were characteristic groups of protein and polysaccharide.3) The content of EPS has a significant relationship with growth period, the type of substrate. EPS would change with the increase of concentration of catechol. However However when the concentration of catechol exceeds a threshold, the content of EPS would not increase. On the contrary, it would decrease.The EPS of B strain woule increase in in the presence of chemical toxins(O-aminophenol, P-aminophenol, M-aminophenol). It's order was M-aminophenol.>P-aminophenol.>Catechol> Glucose> O-aminophenol.Relative to the change of protein, the content of polysaccharide changed little.4) Two kinds of resins had little difference in the adsorption ability of polysaccharide,As for protein, the adsorption ability of resin11#was stronger than resin28#. Through SEM analyseis, it was found that after the resins contacting EPS, EPS will cover on the resin surface to form an attachment and form a gel layer, it would have an effect on mass transfer of the resins. But EPS is not evenly distributed in the resin surface. Acorrding to EDX analysis, the resins would include the elements of EPS content,it provided further proof that EPS was adsorpted by the reseins. The results of FTIR showed that some peaks will appear and disappear and the enhancmed functional groups of resins were just the functional groups which EPS included.It was guessed that the resin's adsorption for EPS belonged to complex adsorption. |
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