Chlorine is usually applied in the urban water treatment process to deactivate pathogens and prevent waterborne diseases.As a pre-treatment,it remains unclear whether chlorinated water can effectively alleviate membra...Chlorine is usually applied in the urban water treatment process to deactivate pathogens and prevent waterborne diseases.As a pre-treatment,it remains unclear whether chlorinated water can effectively alleviate membrane fouling during ultrafiltration(UF).In this study,tap water was investigated for its effect on biofilm formation and biofouling in a gravity-driven membrane(GDM)filtration system.For comparison,biofilm/biofouling with untreated surface(lake)water was studied in parallel.It was found that more severe membrane fouling occurred with the filtration of tap water than lake water,and larger quantities of polysaccharide and extracellular DNA(eDNA)were present in the tap-water biofilm than in the lake-water biofilm.The tap-water biofilm had a densely compact morphology.In contrast,a porous,spider-like structure was observed for the lake-water biofilm,which was assumed to be associated with the bacteria in the biofilm.This hypothesis was verified by 16S ribosomal RNA(rRNA)sequencing,which demonstrated that Xanthobacter was the dominant taxon in the tap-water biofilm.Additionally,membrane hydrophobicity/hydrophilicity played a minor role in affecting the membrane fouling properties and microbial community.This study revealed the significant role of chlorine-resistant bacteria in biofouling formation and provides a deeper understanding of membrane fouling,which can potentially aid in searching for effective ways of controlling membrane fouling.展开更多
The performance and mechanism of manganate preoxidation process for organics removal were investigated in the present paper.The results showed that manganate was a potentially powerful oxidizing agent and could make t...The performance and mechanism of manganate preoxidation process for organics removal were investigated in the present paper.The results showed that manganate was a potentially powerful oxidizing agent and could make the natural organic matter(NOM)concentration of sample solution increase.The process of manganate in combination with ferrous sulphate(FeMnO)was effective for organics removal and with the highest removal rate of 89%when the FeMnO dose was 0.18 mmol/L.The fluorescence analysis showed that the fluorescence intensity values related to hydrophobic acids and model humic acid polymers were the highest and the relative position of the main peak fluorescence intensity was shifted towards lower emission wavelengths,which indicated the reduction in the degree of aromaticity of residual organic matter fraction.展开更多
基金financially supported by the Key Research and Development Plan of the Ministry of Science and Technology,China(2019YFD1100104 and 2019YFC1906501)。
文摘Chlorine is usually applied in the urban water treatment process to deactivate pathogens and prevent waterborne diseases.As a pre-treatment,it remains unclear whether chlorinated water can effectively alleviate membrane fouling during ultrafiltration(UF).In this study,tap water was investigated for its effect on biofilm formation and biofouling in a gravity-driven membrane(GDM)filtration system.For comparison,biofilm/biofouling with untreated surface(lake)water was studied in parallel.It was found that more severe membrane fouling occurred with the filtration of tap water than lake water,and larger quantities of polysaccharide and extracellular DNA(eDNA)were present in the tap-water biofilm than in the lake-water biofilm.The tap-water biofilm had a densely compact morphology.In contrast,a porous,spider-like structure was observed for the lake-water biofilm,which was assumed to be associated with the bacteria in the biofilm.This hypothesis was verified by 16S ribosomal RNA(rRNA)sequencing,which demonstrated that Xanthobacter was the dominant taxon in the tap-water biofilm.Additionally,membrane hydrophobicity/hydrophilicity played a minor role in affecting the membrane fouling properties and microbial community.This study revealed the significant role of chlorine-resistant bacteria in biofouling formation and provides a deeper understanding of membrane fouling,which can potentially aid in searching for effective ways of controlling membrane fouling.
文摘The performance and mechanism of manganate preoxidation process for organics removal were investigated in the present paper.The results showed that manganate was a potentially powerful oxidizing agent and could make the natural organic matter(NOM)concentration of sample solution increase.The process of manganate in combination with ferrous sulphate(FeMnO)was effective for organics removal and with the highest removal rate of 89%when the FeMnO dose was 0.18 mmol/L.The fluorescence analysis showed that the fluorescence intensity values related to hydrophobic acids and model humic acid polymers were the highest and the relative position of the main peak fluorescence intensity was shifted towards lower emission wavelengths,which indicated the reduction in the degree of aromaticity of residual organic matter fraction.
