Study On Biodegradation Of Reactive Blue 19 Enhanced By The Resuscitation Promoting Factor

Reactive blue 19(RB 19)is an anthraquinone dye with wide application and high production.During the dyeing process,part of the dye was discharged into the wastewater treatment system without being used.The wastewater containing RB 19has the characteristics of high toxicity and high stability,which can destroy the water ecosystem and threaten human health.At present,the biological treatment method is widely usde because of its environmental friendly,energy saving,no secondary pollution,and has always become a research hotspot.However,under actual adverse environmental stress,most microorganisms will enter into a viable but non-culturable state(VBNC)to cope with environmental stress.The reported dye-degrading microorganisms only account for 0.01～10%of the microbial resources in the environment,and most of the microorganisms are in the VBNC state and have not been discovered.Resuscitation-promoting factor(Rpf)signaling compounds have the role of resuscitating and promoting the growth of bacteria in the VBNC state.The discovery of these substances provides a new way to obtain potential new pollutant-degrading bacteria.In this paper,nitrification and denitrification sludge from landfill leachate plants was used as the inoculation sludge,and the up-flow anaerobic sludge bed(UASB)reactor was used to treat the simulated dye wastewater containing RB 19.The effects of Rpf on RB 19 decolorization,the microbial structure and diversity were investigated.Meanwhile,gas chromatography-mass spectrometer(GC-MS)was used to to analyze the intermediate metabolites of RB 19;Moreover,In the Rpf treatment group,the potential environmentally functional VBNC strains high-efficiency salt-tolerant degradation strains were isolated and cultivated;In addition,the high-efficiency degrading bacteria were immobilized,and different treatments(free bacteria,immobilized beads,vacant beads)were compared for RB 19to explore the best performance and related mechanisms.The main results of the study are as follows:(1)Two sets of UASB reactors were constructed and operated in four different stages(different RB 19 concentrations and Rpf concentration).The results show that the decolorization efficiency of Rpf treatment group on RB 19 is higher than that of the control group without Rpf addition,but Rpf has almost no effect on COD removal.16S rRNA gene high-throughput sequencing results showed that Rpf has a significant growth promoting Proteobacteria and Firmicute phylum,and can stimulate or revive the growth of certain Peptostreptococcaceae families in Clostridia.In addition,during the decolorization process,the aromatic amine structure of RB 19 was broken to form two main intermediates,2-((3-aminophenyl)sulfonyl)ethyl hydrogen sulfate and 2-(sulfooxy)ethanesulfonic acid,which lay the foundation for RB 19decolorization and final mineralization.(2)A total of 12 different strains were isolated from the activated sludge in the Rpf treatment group and the control group,JF1-JF6 were isolated from the Rpf treatment group and belonged to four genera of Pseudomonas,Paracoccus,Bacillus,and Microbacterium.The decolorization efficiency of strain JF1-JF6 to 50 mg/L dye is over 95%,and JF4 has the highest decolorization efficiency,which could completely degrade RB 19 within 6 days.Degradation performance tests show that JF4 can tolerate up to 20 g/L NaCl;For 50 mg/L RB 19,it can degrade completely within 7 days.Under the conditions of 20 g/L NaCl,pH 7-8,temperature 30-35°C,and initial dye concentration less than 50 mg/L,JF4 can completely degrade RB 19within 7 days.(3)Under low concentration dye(RB 19<50 mg/L),the decolorization efficiency of JF4-immobilized beads is lower than that of free bacteria,but it has a postive effect on high concentration of RB 19(?75 mg/L),can completely degrade RB 19 at 100 mg/L.In addition,the repeated-batch experiment showed that JF4-immobilized beads can maintain the decolorization efficiency at a low concentration of RB 19 and the decolorization efficiency is improved.In high concentrations,more than 90%of the dye is still removed.The efficiency of JF4-immobilized beads to degrade RB 19 is completed by two stages of adsorption and degradation.The optimal particle size of the bead is 2 mm.When the initial concentration of RB 19 is increased from 25 mg/L to 200 mg/L,the adsorption amount of beads to RB 19 q_t is increased from 0.052 mg/g to 0.301 mg/g,and the adsorption process conforms to the pseudo-second-order kinetic model and Freundlich model.In summary,the results of this paper provide a new way for biological treatment of dye wastewater,which lays a theoretical foundation for the development of new technologies based on the resuscitation of VBNC bacteria to promote the remediation of organic wasterwater.At the same time,the microbial strain resources of high salt resistant bacterial species has been expanded.