Biodegradation Kinetics and Mechanism of a Typical Coal Gasification Pollutant:Quinoline

A strain Pseudomonas sp.PP1 was isolated from activated sludge and characterized by morphological observation,biochemical and physiological identification as well as 16 S rRNA gene sequence analysis.It was a gram-negative,non-motile,rod-shaped with colonies which were white,opaque,small and wrinkled on solid quinoline-MSM.The strain was negative for catalase,gelatin liquefaction,M.R and V.P tests and was unable to reduce / restore nitrate.The 1406 bp 16 S rRNA gene fragment of PP1 was more than 99% identical to the Pseudomonas sp.Biodegradation of quinoline as single substrate was conducted in batch experiments at different temperatures( 15- 40 ℃) and p H values( 5- 10).The results indicate that the optimum conditions for the degradation of quinoline by PP1 were 30 ℃ and p H 7.Pseudomonas sp.PP1 was able to degrade 97.1%,95.4%,94.8%,63.6% and 40.4% quinoline when initial concentrations of quinoline were 50,100,200,300,and 400 mg / L,respectively,and lag phases were prolonged from 2 h to 10 h.The maximum degradation rate( q) was obtained at an initial quinoline concentration( S0) of about 100 mg/L with q of 0.082.The experimentally obtained q values at various initial S0 were fitted by Haldane model,Yano model,Aiba model,Edward model and Webb model,and the results demonstrated that Haldane model gives the best fit for strain PP1 with coefficient of determination,R2= 0.9124 and SDavg= 0.0113208.Five metabolic intermediates were identified by high performance liquid chromatograph( HPLC) and GC / MS.Finally,a possible pathway containing 5,6-dihydroxy-2-oxo-1,2-dihydroquinoline as an intermediate was proposed for the first time.

Coal Gasification Wastewater Pretreatment with Coagulation and N_2 Flotation Combined System

A N 2 flotation tank combined with coagulation was developed as a pretreatment equipment of biological process to remove oil and other pollutants in coal gasification wastewater( CGW). With optimal PAC dosage of 20 mg / L,the sole coagulation process achieves removal efficiencies of 29. 34% and 26. 83% for oil and COD,respectively. For the sole N 2 floatation process,the optimal N 2 flux and HRT are 20 m3/ h and 20 min. Meanwhile,the oil and COD removal efficiencies are 35. 41% and 14. 26%,respectively. For the combined system of coagulation and N 2 floatation,the optimal parameter values are the same as the ones of separate processes. Correspondingly,the removal efficiencies are 46. 28% and 31. 89% for oil and COD, respectively. Besides,BOD 5 / COD of the effluent is improved. In contrast with conventional dissolved air floatation,the inert gas- N 2 prevents the formation of cyclopentenone, pyridine derivatives, and other heterocyclic aromatic hydrocarbons,thus improving the biodegradability of influent for the subsequent biological processes.

Degradation of Phenolic Compounds in Coal Gasification Wastewater by Biofilm Reactor with Isolated Klebsiella sp.

This study was conducted to evaluate the degradation of phenolic compounds by one strain isolated from coal gasification wastewater( CGW). 16S rRNA gene sequences homology and phylogenetic analysis showed that the isolate is belonged to the genus Klebsiella sp. The effect of different phenolic compounds on the isolate was investigated by determining OD600and phenoloxidase activity,of which the results showed that the isolate can utilize phenol,4-methyl phenol,3,5-dimethyl phenol and resorcinol as carbon resources. The biofilm reactor( formed by the isolate) can resist the influent concentration of phenolic compounds as high as750 mg /L when fed with synthetic CGW and incubated at optimum conditions. The capacity of improving the biodegradability of CGW through degrading phenolic compounds was testified with fed the biofilm reactor with real CGW. Thus,it might be an effective strain for bioaugmentation of CGW treatment.