Study On Screening Of Phenol-degrading Bacteria And Bioaugmentation In Aerobic Granular Sludge For The Treatment Of Phenolic Wastewater

In this paper,bioaugmentation of aerobic granular sludge in the treatment of phenolic wastewater was studied.Phenol degrading bacteria were screened by conventional plate method and in-situ diffusion chamber method,and the consortia were constructed,respectively.The differences of bacteria screened by different methods in the bioaugmentation process were investigated from the aspects of effluent quality,sludge performance and microbial community structure.The results showed that nine strains of phenol degrading bacteria were screened by plate method,and they were P3(Cellulosimicrobium),P3-2(Cupriavidus),P5-1(Pseudomonas),B3-1(Comamonas),B4-2(Acinetobacter),B5(Stenotrophomonas),B7-2(Kerstersia),B8(Ochrobactrum)and B33(Gordonia),respectively,showing phenol removal rate of >90%.Six strains of phenol degrading bacteria were screened by in-situ diffusion chamber method,and they were K1(Aeromonas),K2(Acinetobacter),K4(Bacillus),K5(Acinetobacter),K5-1(Acidovorax)and K5-2(Acinetobacter),respectively,showing phenol removal rate of more than 85%.The performance of 27 groups of consortia constructed with two methods were evaluated by orthogonal experiment.The optimum inoculation volume proportion of bacterial strains by plate method was P3:P3-2: P5-1: B3-1: B4-2: B5: B7-2: B8: B33 =1,and the inoculation volume proportion of bacterial strains by diffusion chamber method was K1: K2: K4: K5: K5-1: K5-2 = 1:1:1:1.5:1.5.Both of C12 O and C23 O were detected in the consortium,with capable of catechol ring opening by two cleavage modes(i.e.,o-and inter-site cleavage).The phenol degradation rate and enzyme activity of the conventional plate method were higher than those of the in situdiffusion chamber method and had stronger phenol tolerance and environmental adaptability.The bioaugmented SBR showed better pollutant removal rate and resistant to high loading rate.The COD removal rates of R1 and R2 reactors were 97.47% and 97.72%,respectively.R0 reactor was greatly affected by phenol load,and the effluent quality deteriorated in the later stage of operation.Bioaugmentation can promote the stable growth of activated sludge in the reactor and improve the settleability.At the end of the operation,the sludge particles > 0.25 mm in R1 and R2 reactors were as high as51.86% and 54.58%,respectively.The granular sludge formed had compact structure and good settleability.In comparison of R0 showed poor sludge settleability and a lot of sludge lost.The microbial community results showed the dominant genera in R0 was Zoogloea with abundance of 66.02%.Phenol removal was mainly by adsorption.TM7a、Pajaroellobacter、Luteococcus、unclassified＿f＿Comamonadaceae、Flavobacterium and Phreatobacter were dominant in R1 and R2.Those strains initially inoculated in the reactor lost their dominance during the domestication of phenol,but bioaugmentation played important roles in the whole operational processes.