Immobilization Of P-nitrophenol Degrading Bacteria And Its Degradation Characteristics

P-nitrophenol?PNP?wastewater is a kind of widespread industrial wastewater which is extremely difficult to treat.Because of its characteristics of being difficult to degrade and highly toxic,it will cause immeasurable harm to human health after infiltrating into the underground.Therefore,the treatment of p-nitrophenol wastewater has become an urgent problem for the society.Physical,chemical and biological methods are the main ways to treat p-nitrophenol wastewater,and biological methods are most commonly used.However,due to the phenomenon of cell elution,it is difficult to implement biological methods,and the emergence of immobilized microorganism technology can solve such problems,which can improve the metabolic activity of microorganisms and increase the residence time of microorganisms in bioreactors.In this experiment,the highly effective p-nitrophenol-degrading bacteria have been made to prepare immobilized bacteria.By immobilizing the choice of materials and methods,and the study of immobilized microbial degradation characteristics,determine the best immobilization methods and degradation conditions,and the method was applied to indoor simulation of p-nitrophenol wastewater remediation test.The results of this study are as follows:1.The basic degradation characteristics of the highly effective p-nitrophenol degradation bacteria Y9,which were screened from the collected soil samples,were studied.Preliminary determine the degradation bacteria on the nitro phenol?PNP?mass concentration does not exceed 200 mg·L^-1,pH 7.5,rotational speed of 120 r·min^-1,the temperature of 30?condition,the degradation situation is better.Therefore,this condition is applied to the following preliminary immobilization test.2.Immobilized bacteria were prepared by two immobilization methods:carboxymethyl cellulose sodium+bentonite,sodium alginate+polyvinyl alcohol+diatomite and diatomite,and used for degradation of nitrophenol.Immobilized preparation was studied through orthogonal test,the optimum condition,carboxymethyl cellulose sodium?3%?+bentonite?6%,size 20 mesh?mixed with 20%of the bacteria suspension,drop to 1%of AlCl₃·6H₂O,immobilized 2 h,sodium alginate?1%?,polyvinyl alcohol?10%?and diatomite(20g·L^-1)mixed with 4%of the bacteria suspension,drops into saturated boric acid solution of 2%CaCl₂,immobilized 30 h.The ball has good sphericity,mass transfer and mechanical properties.3.The degradation characteristics of two kinds of immobilized method respectively,the test results show that the sodium carboxymethyl cellulose+bentonite in solid-liquid ratio 0.12,temperature of 35?,pH value of 9.0,the initial mass concentration under the condition of less than 150 mg·L^-1,has good degradation efficiency;Sodium alginate,polyvinyl alcohol and diatomite in the solid-liquid ratio 0.02,temperature of 35?,pH value of 9.0,the initial mass concentration under the condition of less than 50 mg·L^-1,degradation efficiency is better.4.Comparing the two immobilization methods with free bacteria and blank particles,the method for the determination of carboxymethyl cellulose sodium+bentonite immobilization was the best method for immobilization.The method is used in laboratory simulation of groundwater treatment plant for degradation.The results showed that after 5 days of degradation,the degradation rate of sodium carboxymethyl cellulose sodium+bentonite was93.80%.To sum up,this study compares the"sodium alginate and polyvinyl alcohol+diatomaceous earth"and"+carboxymethyl cellulose sodium bentonite"two immobilization methods of degradation efficiency,it is concluded that the latter on the nitro phenol wastewater degradation efficiency is higher,for the future of nitro phenol wastewater bioremediation laid a certain research foundation.