This study provided insights into the persistent yellowish color in biological and tertiary effluents of municipal wastewater through a multi-characterization approach and fluores-cence excitation-emission matrix-parallel factor(EEM-PARAFAC)analysis.The characteri-zation was performed on three to five full-scale municipal wastewater treatment plants(WWTPs),including differential log-transformed absorbance(DLnA)spectroscopy,resin fractionation,size-exclusion chromatography for apparent molecular weight analysis(SEC-AMW),and X-ray photoelectron spectroscopy(XPS)analysis.Hydrophobic acids(HPOA)were abundant in visible colored dissolved organic matter(DOM).The SEC-AMW result showed that the molecular weight of the colored substances in the secondary effluents is mainly dis-tributed in the range of 2-3 kDa.Through XPS analysis,C-O/C-N and pyrrolic/pyridonic(N-5)were found to be positively correlated with chroma.PARAFAC component models were built on biological(two components)and tertiary effluent(three components)and the correlation analysis revealed that PARAFAC component 2 in biological effluent(BE-C2)and component 1 in tertiary effluent(TE-C1),which were ascribed to Hydrophobic acids and Humic acid-like,were the responsible visible colored DOM components cause yellowish color.In addition,component similarity testing found that the identified visible colored DOM PARAFAC BE-C2,and PARAFAC TE-C1 were identical(0.96)in physicochemical properties,with 4％removal ef-ficacy on average,compared with 11％for invisible colored DOM.This implied that tertiary effluents containing colorants(TE-C1)were resistant to degradation/removal using differ-ent disinfection and filtration processes in advanced treatments.This sheds light on many physicochemical aspects of PARAFAC-identified visible colored DOM components and pro-vides spectral data to build an online monitoring system.

Ashraful Islam;Guangxi Sun;Ayman N.Saber;Wei Shang;Xingcan Zheng;Yu Zhang;Min Yang

State Key Laboratory of Environmental Aquatic Chemistry,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China;University of Chinese Academy of Sciences,Beijing 100049,China;Pesticide Residues and Environmental Pollution Department,Central Agricultural Pesticide Laboratory,Agricultural Research Center,Dokki,Giza 12618,Egypt;North China Municipal Engineering Design and Research Institute Co.Ltd,Tianjin 300074,China

环境科学学报（英文版）

[1]Ashraful Islam;Guangxi Sun;Ayman N.Saber;Wei Shang;Xingcan Zheng;Yu Zhang;Min Yang-.Identification of visible colored dissolved organic matter in biological and tertiary municipal effluents using multiple approaches including PARAFAC analysis)[J].环境科学学报（英文版）,2022(12):174-183

DLnA,AMW,pyridonic,colorants

Identification,colored,dissolved,organic,matter,biological,tertiary,municipal,effluents,using,multiple,approaches,including,PARAFAC,analysis,This,study,provided,insights,into,persistent,yellowish,wastewater,through,characterization,fluores,cence,excitation,emission,matrix,parallel,EEM,performed,three,five,full,scale,plants,WWTPs,differential,transformed,absorbance,spectroscopy,resin,fractionation,size,exclusion,chromatography,apparent,molecular,weight,SEC,ray,photoelectron,XPS,Hydrophobic,acids,HPOA,were,abundant,DOM,result,showed,that,substances,secondary,mainly,tributed,range,kDa,Through,pyrrolic,found,positively,correlated,models,built,two,components,correlation,revealed,BE,C2,TE,C1,which,ascribed,Humic,like,responsible,cause,In,addition,similarity,testing,identified,identical,physicochemical,properties,removal,ficacy,average,compared,invisible,implied,containing,resistant,degradation,disinfection,filtration,processes,advanced,treatments,sheds,light,many,aspects,vides,spectral,data,build,online,monitoring,system

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