工程科学与技术2025，Vol.57Issue(6)：274-285,12.DOI:10.12454/j.jsuese.202400272
好氧颗粒污泥的培养及其胞外聚合物的分析与应用
Culture of Aerobic Granular Sludge and Analysis and Application of its Extracellular Polymers
摘要
Abstract
Objective Due to the advancement of industry and the improvement of residents'living standards,the urban sewage treatment load continues to increase,making it urgent to develop cost-effective water treatment technologies.In recent years,aerobic granular sludge(AGS)has been increas-ingly applied in practical projects because of its high stability and good pollutant removal efficiency.This study examines the rapid cultivation of stable AGS,records the changes in appearance and morphology of inoculated activated sludge floc(AS)and AGS,and reveals,at the microscopic level,the reasons why the structure and stability of AGS are superior to those of AS.In addition,this study investigates the adsorption mechanism of Cd2+by the extracellular polymeric substances(EPS)of AGS from a mechanical perspective and verifies whether AGS‒EPS exhibits a higher pollutant removal capacity. Methods The sludge was collected from the secondary sedimentation tank of a wastewater treatment plant in Hefei and was pretreated to obtain cleaner inoculating sludge.It was divided into two portions:one was used for research,and the other was concentrated and placed into the SBR reactor.The process of granular sludge cultivation was documented,including morphological transformations and variations in key indicators.The microbial community structure was analyzed through high-throughput sequencing of 16 s rRNA genes.Changes in EPS content before and after sludge granulation were determined,and the EPS was characterized using Three-Dimensional Excitation Emission Matrix Fluorescence Spectroscopy(3D-EEM)and Fourier Transform Infrared Spectroscopy(FTIR)to analyze the structural differences between AS and AGS.At the mechanical level,kinetic and thermodynamic models were employed to fit the adsorption experiments of AS‒EPS and AGS‒EPS for Cd2+. Results and Discussions During the domestication of AS into AGS,on the 85th day,the sludge morphology stabilized,and the sludge particle size increased from 31.59 to 442.72 μm.This experiment successfully produced phosphorus-rich granular sludge,with the phosphorus content of the sludge increasing from 25.93 to 86.27 mg/g.The results of 16 s rRNA gene high-throughput sequencing indicated that Chloroflexi served as the initial particle framework of the granular sludge,while Proteobacteria represented the core bacterial phylum responsible for sludge granula-tion.In addition,Candidatus_Competibacter and Candidatus_Accumulibacter were identified as the dominant bacterial genera involved in the sludge granulation process.Throughout the cultivation period,the EPS content increased from 79.18 mg/g VSS to 133.63 mg/g VSS.The 3D-EEM analysis confirmed that AGS‒EPS contained a higher level of proteins,and the reduction in protein decomposition and solubilization by cells during the domestication process facilitated microbial cell aggregation within the biofilm.FTIR and protein secondary structure analyses re-vealed that both types of EPS contained alcohol phenols,—OH,—CH,C—O,C—C from sugars,carboxylate groups from uronic acids,N—H from proteins,and alkane-like organic compounds.However,AGS‒EPS exhibited a more diverse composition of polysaccharides and a more stable cell structure.The granulation process altered the adsorption mechanism of AGS toward Cd2+.Adsorption kinetic studies demonstrated that the adsorption of Cd2+by AS‒EPS involved both physical and chemical adsorption,whereas the adsorption of Cd2+by AGS‒EPS was better de-scribed by the pseudo-second-order kinetic model,indicating stronger biochemical adsorption properties.Adsorption thermodynamic analyses in-dicated that the adsorption of Cd2+by both types of EPS was best fitted by the Langmuir model,indicating a homogeneous monolayer adsorption process.The theoretical maximum adsorption capacity of AGS‒EPS was higher than that of AS‒EPS,at 617.09 and 542.90 mg/g,respectively. Conclusions The experimental process demonstrated that increasing the COD content in a high-phosphorus environment enhanced the phospho-rus removal performance of sludge and positively influenced the cultivation of granular sludge.In the comparison between AGS and AS,3D-EEM analysis revealed that AGS exhibited a higher protein level,while FTIR indicated that both had similar functional groups;however,AGS contained more abundant polysaccharides.The secondary protein structure confirmed that AGS possessed stronger cell aggregation,greater me-chanical strength,and higher protein compactness.The by-product of granular sludge cultivation,AGS‒EPS,exhibited a stronger Cd2+adsorption capacity,primarily through biochemical interactions,indicating that AGS holds greater potential in wastewater treatment applications.关键词
好氧颗粒污泥/胞外聚合物/重金属/微生物群落/生物吸附剂Key words
aerobic granular sludge/extracellular polymers/heavy metal/microbial community/biosorbent分类
资源环境引用本文复制引用
郑逸涵,杨英,李卫华,冯青原,朱曼丽,陈卉静,杨婷婷..好氧颗粒污泥的培养及其胞外聚合物的分析与应用[J].工程科学与技术,2025,57(6):274-285,12.基金项目
国家自然科学基金项目(52370021) （52370021）
安徽省住房城乡建设科学技术计划项目(2023‒RK025) （2023‒RK025）
安徽省教育厅研究生质量工程项目(2022jyjxggyj314) （2022jyjxggyj314）
