The essential step to improve the coagulation efficiency is to select and optimize the pre-oxidation process.Ultraviolet/sodium percarbonate(UV/SPC)can be employed as an alternative system to UV/H_(2)O_(2) in drinking...The essential step to improve the coagulation efficiency is to select and optimize the pre-oxidation process.Ultraviolet/sodium percarbonate(UV/SPC)can be employed as an alternative system to UV/H_(2)O_(2) in drinking water treatment plant operation,benefiting from the solid stability properties with the equivalent effect.At present,the studies on UV/SPC,and other UV/advanced oxidation processes(UV/H_(2)O_(2),UV/persulfate,UV/chlorine,etc.),mostly focus on the advanced water treatment after filtration.This study notes that UV/SPC has advantages in the pre-oxidized organics.UV/SPC improving the effect of coagulation on dissolved organic carbon(DOC)elimination by up to 25%,the optimal UV dose and SPC dosage are 600 mJ/cm^(2) and 20 mg/L verified by a pilot experiment;the decomposition degree and conversion of organics which is most conducive to follow-up coagulation treatment is obtained through the detailed comparison of the influence range of UV dose or the CSPC on the molecule structure of organics;the disparate role of UV was unraveled in UV photolysis pre-oxidation and UV/SPC pre-oxidation and coagulation,including the influence regularity of UV transmittance(UVT)and processing flow rate on UV dose;confirm that UV/SPC alleviates the risk of the generation of disinfection byproducts(DBPs)to 51.15%.This study corroborates the potential of UV/SPC as a pre-oxidation technology at the application level.展开更多
In Bom Jesus Municipality,a cool breeze drifts in from the Kwanza River,softening the edges of a town marked by landmarks such as António Agostinho Neto International Airport.Yet beneath Luanda’s scenic faç...In Bom Jesus Municipality,a cool breeze drifts in from the Kwanza River,softening the edges of a town marked by landmarks such as António Agostinho Neto International Airport.Yet beneath Luanda’s scenic façade,daily life for many residents is defined by a persistent struggle for water.“We have to walk 5 to 15 km to access water.This perennial problem is so depressing.What’s more,the lack of clean water causes waterborne diseases in our community,”local resident Isabel Fernando told ChinAfrica.展开更多
In this study,the effects of low-dose sodium hypochlorite disinfection on water quality and biofilm growth in drinking water distribution systems(DWDS)after ultrafiltration pretreatment was investigated.The influence ...In this study,the effects of low-dose sodium hypochlorite disinfection on water quality and biofilm growth in drinking water distribution systems(DWDS)after ultrafiltration pretreatment was investigated.The influence of pipeline hydraulic residence time(HRT)on disinfection efficiency,by-product formation,microbial activity,and biofilm growth were considered.The results show that both microbial activities and metabolite secretion were stimulated by increasing HRT,aggravating the potential risk of microbial pollution in DWDS.The enhanced microbial metabolism could further weaken disinfection efficiency by consuming extra residual Chlorine,after which the formation of disinfection by-products was facilitated.Residual Chlorine was found negatively correlated with HRT.With prolonging HRT from 5 to 40 h,the concentration of disinfection by-products(Chlorate,Chlorite,and Trichloromethane)was on a continuously increasing trend by 37%,140%,and 75%,respectively.But the water kept in pipeline still reliably satisfied the Standards for drinking water quality in China(GB5749–2022).Besides,more biofilm with denser morphologies developed on rubber pipeline gaskets rather than the iron/plastic ones.Rubber material was inappropriate for DWDS due to its potential risk of secondary biological pollution.Prolonging HRT also enhanced the accumulation of dominant bacteria(e.g.Bradyrhizobium and Obscuribacter)and decreased microbial diversity.展开更多
In the conventional water treatment process,algae have a propensity to breach the filter barriers and potentially seep into the water distribution system,leading to an elevation in taste and odor compounds(T&O com...In the conventional water treatment process,algae have a propensity to breach the filter barriers and potentially seep into the water distribution system,leading to an elevation in taste and odor compounds(T&O compounds).This investigation delved into the seasonal fluctuations of algae penetration and the production of T&O compounds within the treatment units of Reservoir Water Plant 1(W1)and River Water Plant 2(W2).The findings indicated that despite the application of the‘pre-oxidation,coagulation and sedimentation(PCS),sand filtration,and disinfection’process,certain robust-walled filamentous Cyanobacteria,Bacillariophyta species,and small Chlorophyta genera managed to bypass the filters.The leakage of algal cells during autumn at W1 was particularly striking,with a peak of 1,170,000 cells/L.The concurrent assessment of the potential for T&O compound formation revealed an alarming high potential for 2-methylisoborneol(2-MIB)in the water leaving the plants,with concentrations soaring to 197.20 ng/L at W1 in autumn and 54.78 ng/L at W2 in summer.This underscores the significant capacity of residual algal cells to generate T&O compounds.Tracking the retention and penetration dynamics of algal cells across each drinking water treatment stage is crucial for surface water treatment facilities to develop effective operational and management strategies,thereby enhancing the safety and quality of drinking water for the end consumer.展开更多
基金supported by the Integrated Management of Water Resources and Water Environment in the Yangtze River,Yellow River and Other Key Basins(No.2021YFC3201304)Beijing Water Group Research Institute(China)for its support.
文摘The essential step to improve the coagulation efficiency is to select and optimize the pre-oxidation process.Ultraviolet/sodium percarbonate(UV/SPC)can be employed as an alternative system to UV/H_(2)O_(2) in drinking water treatment plant operation,benefiting from the solid stability properties with the equivalent effect.At present,the studies on UV/SPC,and other UV/advanced oxidation processes(UV/H_(2)O_(2),UV/persulfate,UV/chlorine,etc.),mostly focus on the advanced water treatment after filtration.This study notes that UV/SPC has advantages in the pre-oxidized organics.UV/SPC improving the effect of coagulation on dissolved organic carbon(DOC)elimination by up to 25%,the optimal UV dose and SPC dosage are 600 mJ/cm^(2) and 20 mg/L verified by a pilot experiment;the decomposition degree and conversion of organics which is most conducive to follow-up coagulation treatment is obtained through the detailed comparison of the influence range of UV dose or the CSPC on the molecule structure of organics;the disparate role of UV was unraveled in UV photolysis pre-oxidation and UV/SPC pre-oxidation and coagulation,including the influence regularity of UV transmittance(UVT)and processing flow rate on UV dose;confirm that UV/SPC alleviates the risk of the generation of disinfection byproducts(DBPs)to 51.15%.This study corroborates the potential of UV/SPC as a pre-oxidation technology at the application level.
文摘In Bom Jesus Municipality,a cool breeze drifts in from the Kwanza River,softening the edges of a town marked by landmarks such as António Agostinho Neto International Airport.Yet beneath Luanda’s scenic façade,daily life for many residents is defined by a persistent struggle for water.“We have to walk 5 to 15 km to access water.This perennial problem is so depressing.What’s more,the lack of clean water causes waterborne diseases in our community,”local resident Isabel Fernando told ChinAfrica.
基金supported by the National Natural Science Foundation of China(Nos.52170070,52400022,and 52200088)the Youth S&T Talent Support Programme of Guangdong Provincial Association for Science and Technology(GDSTA)(No.SKXRC202406)+1 种基金the“One hundred Youth”Science and Technology Plan,Guangdong University of Technology,China(No.263113906)China Postdoctoral Science Foundation(No.2023M740754).
文摘In this study,the effects of low-dose sodium hypochlorite disinfection on water quality and biofilm growth in drinking water distribution systems(DWDS)after ultrafiltration pretreatment was investigated.The influence of pipeline hydraulic residence time(HRT)on disinfection efficiency,by-product formation,microbial activity,and biofilm growth were considered.The results show that both microbial activities and metabolite secretion were stimulated by increasing HRT,aggravating the potential risk of microbial pollution in DWDS.The enhanced microbial metabolism could further weaken disinfection efficiency by consuming extra residual Chlorine,after which the formation of disinfection by-products was facilitated.Residual Chlorine was found negatively correlated with HRT.With prolonging HRT from 5 to 40 h,the concentration of disinfection by-products(Chlorate,Chlorite,and Trichloromethane)was on a continuously increasing trend by 37%,140%,and 75%,respectively.But the water kept in pipeline still reliably satisfied the Standards for drinking water quality in China(GB5749–2022).Besides,more biofilm with denser morphologies developed on rubber pipeline gaskets rather than the iron/plastic ones.Rubber material was inappropriate for DWDS due to its potential risk of secondary biological pollution.Prolonging HRT also enhanced the accumulation of dominant bacteria(e.g.Bradyrhizobium and Obscuribacter)and decreased microbial diversity.
基金supported by Shaanxi Provincial Key Research and Development Project(No.2022ZDLSF06-08)Shaanxi Provincial Key Scientific and Technological Innovation Team,China(No.2023-CX-TD-32)+1 种基金the Key Scientific Research Projects of Education Department of Shaanxi Province,China(No.22JY035)the Project of Youth Talent Lift Program of Shaanxi Association for Science and Technology,China(No.20230447).
文摘In the conventional water treatment process,algae have a propensity to breach the filter barriers and potentially seep into the water distribution system,leading to an elevation in taste and odor compounds(T&O compounds).This investigation delved into the seasonal fluctuations of algae penetration and the production of T&O compounds within the treatment units of Reservoir Water Plant 1(W1)and River Water Plant 2(W2).The findings indicated that despite the application of the‘pre-oxidation,coagulation and sedimentation(PCS),sand filtration,and disinfection’process,certain robust-walled filamentous Cyanobacteria,Bacillariophyta species,and small Chlorophyta genera managed to bypass the filters.The leakage of algal cells during autumn at W1 was particularly striking,with a peak of 1,170,000 cells/L.The concurrent assessment of the potential for T&O compound formation revealed an alarming high potential for 2-methylisoborneol(2-MIB)in the water leaving the plants,with concentrations soaring to 197.20 ng/L at W1 in autumn and 54.78 ng/L at W2 in summer.This underscores the significant capacity of residual algal cells to generate T&O compounds.Tracking the retention and penetration dynamics of algal cells across each drinking water treatment stage is crucial for surface water treatment facilities to develop effective operational and management strategies,thereby enhancing the safety and quality of drinking water for the end consumer.
