The Research Of DBP Contaminated Soil Remediation With Immobilized Degradation Bacterium Pseudomonas Sp.DNB-S1

Phthalate(PAEs) is very extensive in soil pollution source. Soil PAEs pollution was generated by fertilizers, agricultural deposits, pesticides, living trash and manure irrigation.Therefore, the immobilized material of DBP degradation bacteria as the research object in this study, utilizing the immobilized microbial technology, the role of immobilized microbes was examined from their structure and functions, the remediation rate of immobilized microbial organisms on DBP in soil and the harmless performance.The degradation rate of immobilized microbial on DBP as investigation target, to optimize the parameters fastened into a ball, the orthogonal test with four factors three levels L9(34) was performed, choosing different sodium alginate/bentonite ratios, concentrations of Calcium chloride, concentrations of chitosan chemical solution and bacterial quantity,Orthogonal analysis identified the optimal set requirements into a ball were, sodium alginate/bentonite was 2:1, the concentration of chitosan was 0.5%, the concentration of calcium chloride is 0.15mol/L, the bacterial concentration was 10%.Using FIRT, SEM and BET and other large equipments, the function of immobilized microbial organisms was epitomized. Observation results showed that the surface of the bentonite had a lot of-OH, and carboxyl of alginate calcium ionized, the two formed ionic bonds, generating poor electrostatic attraction. Bentonite holds plenty of hydroxyl groups alongwith sodium alginate in aqueous medium can construct hydrogen bonding linkage,which can efficiently restrain the higher ratio of swelling in sodium alginate. When the amount of the carrier substance of immobilized microbes, sodium alginate and bentonite, was2:1, which had larger specific surface area and higher number of pores, the bacterial survival in its inner and efficient degradation of pollutants DBP can be better analyzed.Investigate the actual recovering consequence of immobilized microbial organism in 28 d and their characteristics, In the repair course, DBP residues in all the treatment groups were more than 66% at 14 d. At 28 d, the residues of DBP in the immobilized microorganism treatment group was less than 20%. Immobilized microorganism after three times of repeated use, the degradation rate of DBP stayed at 22.30%.} Under the condition of 4℃, at 28 d, DBP retention rate of the immobilized microorganism treatment group was 78.04%.Analyse the modification in soil microbial community structure after reinstate usingPCR-DGGE Technology.The 19 bandson the DGGE gel were cut and then cloned, identified by sequencing and homology evaluation, identification results showed that the test soil represented rich diversity. The main points belonged to 3 categories, the Actinobacteria,Firmicutes, and Proteobacteria(Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria). The microbial richness of soil samples polluted by DBP and inoculating free bacteria did not have large fluctuations over time. The diversity index of immobilized microbial treatment and free bacteria treatment showed a trend of rising first and then decline.Changes in blank group was not obvious, reached the highest at 28 d. The microbial consistency had no significant variation, in which the microbial evenness of the blank group showed decreasing tendency latterly. Inoculation of different forms of degrading bacteria and dosing of DBP were both changed the soil microbial community structure.Adopting the chloroform fumigation extraction technique, under the simulation test conditions of immobilized microorganisms on soil polluted by DBP, dynamic transformations of soil microbial biomass carbon, nitrogen and phosphorus in the soil with the restore time were measured. The results revealed were compared with the control group, the experiment indicated that the addition of immobilized microorganisms can effectively alleviate the effect of DBP on soil microbial activity. In short, the immobilized microorganism inoculation can effectively repair DBP contaminated soil, reduce the damage to the soil from the DBP. It presents some theoretical background and technical support for eradication of organic pollutants in soil.