Degradation Characteristics Of Oxadiazon And Its Intermediates By Bacillus Thuringiensis ODPY

The oxadiazon-wastewater, generated in the process of oxadiazon synthesis,which had10steps and was using2,4-dichlorophenol as raw materials containsundetached solvents such as DMF, toluene, intermediates, itro ether, heterocycle,chloroform and chlorinated phenols, besides a certain amount of salts, so that thewastewater was complex and difficult to be treated. Therefore, in this thesis, thestudy on the degradation of oxadiazon and intermediates was using the waterwaterdisposal as the starting point and built the treatment technology based onphysicochemical techniques and biological depth oxidize method to the preliminarydiseussion of the reason and mechanismof oxadiazon wastewater degradation byBacillus thuringiensis ODPY(hereinafter referred to as ODPY). The main resultsincluded as the following:Firstly, the bacterium, which was used to disposal the oxadiazon-wastewater,was idenftificalted to Bacillus thuringiensis, of the genus Bacillus. ODPY was asalt-tolerant strain. The result indicated that the bacterium strain ODPY was acertain efficient Oxadiazon Nicosulfuron wastewater degrading bacterium, and theCOD removal achieved23%. The resistance to salt concentration of oxadiazon ofODPY was130g·L-1, which the foundation and basis for the degradation ofoxadiazon wastewater by ODPY.Secondly, the combination of chemical and bilological methods were used todisposal the oxadiazaon wastewater and the results indicated the optimalwastewater treatment wasy to the oxadiazon-wastewater:1%Ca(OH)2was addedinto the wastewater, the reaction time0.5h, the oxidation stage using Fentontreatment,5%H2O2and0.4%activated carbon, the reaction time4h, during thestage, Ca(OH)2was added into the wastewater to regulate pH as0.4%activatedcarbon and the appropriated amount of NaOH were added into the wastewater toregulated pH as7with the reaction time0.5h. The wastewater disposaled afterchemical treatment was mix with ODPY and the activated sluge, aeration reaction3d, the COD was dropped to473mg·L-1, COD removal:98.4%. The chroma,olfactory threshold had been greatly removal and the effect of treatment was obvious well. Those provided a basis for suchwastewater treatment and industrialapplication.Thirdly, the results indicated that ODPY did not have a degradationcharacteristic for oxadiazon, but the solvent in the process of oxadiazon producingDMF and the product of ether chemical segment especially1,5-dichloro-2-isopropoxy-4-nitrobenzene. The resistance to DMF concentration of thebacterium strain ODPY was4%, and no growth of ODPY was detected if the DMFconcentration was more than5%. And the resistance to1,5-dichloro-2-isopropoxy-4-nitrobenzene concentration of the bacterium strain ODPY was0.6mM. The results indicated that the best efficiency of1,5-dichloro-2-isopropoxy-4-nitrobenzene degradation was obtained under the condition of theconcentration of1,5-dichloro-2-isopropoxy-4-nitrobenzene was0.4mM, temp-erature35℃, pH7,5%ODPY recruitment which was on logarithmic-phase. Thebest degradation rate of1,5-dichloro-2-isopropoxy-4-nitro-benzene was81.3%.based on the results of HPLC and TLC, the result indicated that the degradationprocess of1,5-dichloro-2-isopropoxy-4-nitrobenzene was a process of open-loopfirstly, dehalogenase secondly.Fourthly, through the test of ODPY salt tolerance, physiological property,TLC of the wastewater and processing department products, and the degradationstudy of1,5-dichloro-2-isopropoxy-4-nitrobenzene and DMF, the reason and thetheoretical foundation of oxadiazon wastewater degradation by ODPY wasPreliminary clarified. Also the degradation of1,5-dichloro-2-isopropoxy-4-nitrobenzene analogue could be provided the theoretical support andinfrastructure.