| The wastewater containing phenolic compounds is a kind of industrialwastewater, which is universal existence and severely impairs humanity health.Therefore, the treatment of wastewater containing phenolic compounds isattached great importance and has a certain progress. At present, the treatmentsof phenolic compounds wastewater mainly include physical, chemical, andbiological methods. Immobilization of microorganism has been widely used forits advantage.In this work, two strains of degrading phenolic compounds were isolatedfrom the activated sludge obtained from Taiyuan Iron and Steel Corporation,Taiyuan, China. Strain FG-01could utilize phenol as the sole carbon and FG-02could utilize PNP as the sole carbon. Meanwhile, the physiology biochemistrycharacteristics of FG-01and FG-02were analyzed and identified. The strainswere immobilized by Ca-bentonite and sodium carboxymethyl cellulose, andthen were examined for their capabilities on degrading phenolic compounds.The main researches were shown as follows:Firstly, by PCR amplification,16SrDNA gene fragment of FG-01and FG-02were obtained and submitted for sequencing. The blast search of thesequences indicated that FG-01were closely related to the species in genusBacillus pumilus, and FG-02were closely related to the species in genusAeromicrobium erythreum.Secondly, the preparing conditions of the immobilized microorganismbeads were optimized by using orthogonal test. The orthogonal test resultsdemonstrated that the optimum conditions for preparing condutions ofimmobilized microorganism beads were:3%CMC content,1%AlCl3content,5%bentonite content,20%embedding bacteria,100mush in the particle size ofbentonite, and1h crosslinking time. The structure of the immobilized bead wascharacterized, the characterization results illustrated that an agglomerated andirregular surface structure was observed, and also indicated that the materialshad rich internal drape frame, which formed plenty of small space, thus thematerial internal surface area was also greatly increased. Meanwhile, thestability for the reservation and repetitiveness of the immobilized microorganismbeads were also studied. The results showed that the immobilizedmicroorganism beads still achieved a phenol degradation rate of up to90.9%even after storage at4℃for40d and could be reused for at least nine cycles.Thirdly, the biodegradability of immobilized microorganism beads forphenol and PNP in single system was investigated. The effects of initial phenol/PNP concentration, the dosage of immobilized microorganism beads,tempreture and the degradation time on the degradation were studied. The results showed that the optimum conditions of degrading were35℃and0.23g/mL. The immobilized FG-01beads still had a certain degradation ratewhen the initial phenol concentration was up to1000mg/L, while the initialphenol concentration was more than150mg/L, the degrading ability ofimmobilized FG-02beads was inhibited.Fourth, through the comparative study of free strain, the immobilizedmicrooganism beads with CMC and Ca-bentonite, the immobilizedmicrooganism beads with CMC, and the immobilized beads whithoutmicroorganism, the results showed that the degradation rate of the immobilizedmicrooganism beads with CMC and Ca-bentonite was obviously higher than theothers.Fifth, the effect of additional carbon on phenolic compoud degradation wasinvestigated, the restults showed that the additional carbon (PNP) had littleeffect on the degradation of phenol when initial PNP concentration was lowerthan50mg/L, while the initial concentration was higher than100mg/L, thedegradation of phenol was obviously inhibited. At the same time, when theadditional carbon was phenol, the degradation rate of PNP was significantlyinfluenced.Sixth, the mixed wastewater degradation was investigated by theimmobolized hybird microorganisms beads, the results showed thatdegradation rate of phenol and PNP were higher than the others. when the ratioof FG-01/FG-02was4:2in the composite carrier complex carriers. |
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