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Characteristics Of Three Phenol Degradability Of Phenolic Compounds In Coal Gasification Wastewater

Posted on:2015-11-13Degree:MasterType:Thesis
Country:ChinaCandidate:J S YuFull Text:PDF
GTID:2181330467450656Subject:Environmental Engineering
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In the next few decades, the energy transition will make a new generation of coal gasification industries play a special role in the new clean and renewable energy market. Phenolic compounds, occupied more50%COD, was the main organic components in coal gasification wastewater. The treatment technologies of coal gasification wastewater from abroad and domestic usually had several problems, such as unsatisfactory effluents, poor stability and high handling costs. Bioaugmentation technology was an effective way for coal gasification wastewater treatment. The bacterial agent were composed of phenol-degrading bacteria. Based on methods and theories of bioaugmentation technology, molecular ecology and envrionmental engineering, the paper gave a systematic expatiation on phenol-degrading bacteria isolation, bacterial agent construction. Based on lab-scale and pilot-scale tests, the purpose was to spread the application of bioaugmentaion technology with phenol-degrading bacteria to more demonstration project of coal gasification wastewater.Based on analysis of typical phenolic compounds in coal gasification wastewater, the bacteria which could used phenol,4-mythlphenol,3,5-dimethyl phenol and resorcinol as carbon sources and energy were isolated. Three phenol-degrading bacteria were isolated by lots of isolation and accumulation experiments.16S rRNA gene sequences homology and phylogenetic analysis showed that the isolate was belonged to the genus of Enterobacter. The potential capacity of phenol-degrading bacteria was predicted by referring phenol-degrading capacity of Enterobacter.Phenolic compounds could be degrading to organic compounds which were easy to be degradation. Lots of tests were conducted based on this conclusion. The results show that phenol-degrading bacteria could degrading phenol,4-methylphenol,3,5-dimethyl phenol and resorcinol to easily biodegradable organics at conditions of DO1-2mg/L,30-35℃and pH7-7.5. And the best Through single factor experiments and orthogonal analysis, the results show that the optimum ratio for these three phenol-degrading bacteria was1:1:1. The phenol-degrading bacteria agent could resist influent phenol concentration as high as750mg/L. It showed that the constructed bacterial agents were effective and economical. The results of lab-scale test show that phenol-degrading bacteria agent could effectively shorten the start-up of biological wastewater treatment systems and improve its performances and stability. PCR-DGGE results showed that under the same operational conditions, stable and diverse microbial community was formulated in the bioagumented system. The numbers of effluent organic compounds from the bioaugmented system were obviously lower than the control system.By referring lots of results, the phenol-degrading capacity and phenol-degrading bacteria agent construction were explanted systematically. Based on these theory, series of experiments were conducted for testing the effectiveness and economic of the phenol-degrading bacteria. The operation parameters from the lab-scale were applied in real coal gasification wastewater treatment. Bioaugmentation with phenol-degrading bacterial agent could remarkablely shorten the start-up period and improve the pollutants removal. Besides, a great many cost for start-up and upgrade was saved. The application of phenol-degrading bacterial agent was a fesible and effective pathway for the coal gasification wastewater treatment.
Keywords/Search Tags:Coal gasification wastewater, Phenol-degrading bacteria, Phenoliccompounds, Bioaugmentation
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