Biodegradation And Toxicity Study Of The Nitrogen Heteroeyelic Compounds Wastewater

The characteristic representative of Nitrogen heterocyclic compounds (NHCs)wastewater is coking wastewater. The characteristic of wastewater is high nitrogen,toxic and inhibitiory. The typical organic pollutant in the NHCs wastewater is pyridine,quinoline and carbazole, which are teratogenesis, cancerogenic and mutagenesis.The traditional treatment of wastewater is biological treatment, but the efficient oftreatment is not good. So the problem of running coking wastewater is difficult.Compared with chemical, physical or advanced oxidation method, thetraditional biological method has much superiority. The traditional biological methodis no secondary pollution, low toxic and cost. So the biological treatment is stillcompetitiveness. The aim of the study is that the biodegradation mechanism of NHCswastewater by bacterium or bacterial consortium is analysed, and thetransformational toxicity of biological degrading process is searched. The content ofstudy is that bacterium comes from microbial bank, and then the best bacteria isselected and the best bacterial consortium is matched; The simulative or cokingwastewater is biodegraded by the mircroorganism, the biodegradation mechanism ofNHCs and the structure of system mircroorganism is discussed, and the toxictransformation is analysed; the relationship during the water-quality, system bacteriaand toxicity is studied.In this study4bacteria are selected, which are Paracoccus sp. BW001, Shinellazoogloeoides BC0026, Pseudomonas sp. BW003, Pseudomonas sp. BW004,Pseudomonas sp. BC039å'ŒPseudomonas sp. BC046. And then4bacteria are mixed,according to the proportion of OD602(BC026：BW00：BC039：BC046=0.10:0.10:0.05:0.05), named M19. The biodegradation of pyridine (quinoline or carbazole) or coexist NHCs bysingle strain or M19, the degrading efficient of M19is well, especially in the NHCscoexist condition. The result show: The degrading time of only pyridine is12.1h bysingle strain or10.1h by M19, the degrading time of pyridine in the coexist NHCs is14.2h by M19; The degrading time of only quinoline is9.8h by single strain or6.2h byM19, the degrading time of quinoline in the coexist NHCs is4.2h by M19; The90.0%degrading time of only carbazole is21.7h by single strain, The95.7%degrading timeof only carbazole20h by M19, the degrading time of carbazole in the coexist NHCs is20h by M19. So the simultaneous degradation efficiency of the M19is better thansingle bacterium. The degrading gene of the qorL and carAa is analysed, which isexpressed in the degrading process; the intermediate of simultaneous degradation,2(1H)-Quinolinone and8-Hydroxycoumarin are found, the degrading pathway issame with biodegradation of quinoline by BW004. Therefore4bacteria degrade thetargeted pollutant by each.Finally, the relationship of indicators of water quality, microbiological andgenetic toxicity is analysed by related analysis on redundancy analysis (RDA).Discovery the genetic toxicity indicators of the simulated wastewater, TailDNA%,TailLength and TailMoment associated，with the concentration of pyridine,quinoline, and carbazole; The coking wastewater results show that the comet raterelated with some pollutants, such as phenol concentration. TailDNA%, theHeadDNA%TailLength and TailMoment are not directly related to major pollutantsconcentration, maybe in the degradation process related to the intermediatein thedegradation process.In summary, the biodegradation effeicient of pyridine, quinoline, and carbazoleis higher by M19; the degradation of the actual coking wastewater process by M19,the bacterial system is changed and the microbial activity of microbial communities isimproved, the NHCs are degraded by microorganism, and the reduced genotoxicity ofcoking wastewater played a certain role.