Ensuring the health and safety of drinking water is crucial for both nations and their citizens.Since the 20th century,the disinfection of drinking water,effectively controlling pathogens in water sources,has become o...Ensuring the health and safety of drinking water is crucial for both nations and their citizens.Since the 20th century,the disinfection of drinking water,effectively controlling pathogens in water sources,has become one of the significant advances in public health.However,the disinfectants used in the process,such as chlorine and chlorine dioxide,react with natural organic matter in the water to produce disinfection by-products(DBPs).Most of these DBPs contain chlorine,and if the source water contains bromine or iodine,brominated or iodinated DBPs,collectively referred to as Halogenated disinfection byproducts(X-DBPs),are formed.Numerous studies have found that X-DBPs pose potential risks to human health and the environment,leading to widespread concern.Mass spectrometry has become an important means of discovering new types of X-DBPs.This paper focuses on the study of methods for analyzing X-DBPs in drinking water using mass spectrometry.展开更多
Dissolved organic matter （DOM） has been identified as precursor for disinfection by-products （DBPs） formation during chlorination. Recently, it has been demonstrated that the characteristics of DOM influence the D...Dissolved organic matter （DOM） has been identified as precursor for disinfection by-products （DBPs） formation during chlorination. Recently, it has been demonstrated that the characteristics of DOM influence the DBPs formation mechanism. A study was, therefore, initiated to investigate the effects of DOM fractions on DBPs formation mechanism. In the chlorination process, organic acids are dominant precursors of total thihalomethanes （TTHM） because of the vc-o and unsaturated structures. Furthermore, the TTHM formation of organic acids was affected by pH more greatly. Based on the fluorescence spectroscopy analysis, DOM fractions contained several fluorescence substances. During chlorination, humic acid-like substances were found to exhibit high chlorine reactivity and hydrophobic organics decomposed to smaller molecules faster than hydrophilic organics even at lower chlorine dosages. Unlike hydrophobic fractions, hydrophilic organics showed no toxicity following chlorination, suggesting that the toxic structures in hydrophihc organics showed high chlorine reactivity during chlorination.展开更多
Objective To introduce a new sequential chlorination disinfection process in which short-term free chlorine and chloramine are sequentially added. Methods Pilot tests of this sequential chlorination were carried out i...Objective To introduce a new sequential chlorination disinfection process in which short-term free chlorine and chloramine are sequentially added. Methods Pilot tests of this sequential chlorination were carried out in a drinking water plant. Results The sequential chlorination disinfection process had the same or better efficiency on microbe （including virus） inactivation compared with the free chlorine disinfection process. There seemed to be some synergetic disinfection effect between free chlorine and monochloramine because they attacked different targets. The sequential chlorination disinfection process resulted in 35.7%-77.0% TTHM formation and 36.6%-54.8% THAA5 formation less than the free chlorination process. The poorer the water quality was, the more advantage the sequential chlorination disinfection had over the free chlorination. Conclusion This process takes advantages of free chlorine＇s quick inactivation of microorganisms and chloramine＇s low disinfection by-product （DBP） yield and long-term residual effect, allowing simultaneous control of microbes and DBPs in an effective and economic way.展开更多
The removal of disinfection by-products formation potential(DBPFP) in artificially intensified biological activated carbon(IBAC) process which is developed on the basis of traditional ozone granular activated carbon w...The removal of disinfection by-products formation potential(DBPFP) in artificially intensified biological activated carbon(IBAC) process which is developed on the basis of traditional ozone granular activated carbon was evaluated. By IBAC removals of 31% and 68% for THMFP and HAAFP were obtained respectively. Under identical conditions, the removals of the same substances were 4% and 32% respectively only by the granular activated carbon(GAC) process. Compared with GAC, the high removal rates of the two formed potential substances were due to the increasing of bioactivity of the media and the synergistic capabilities of biological degradation cooperating with activated carbon adsorption of organic compounds. A clear linear correlation(R 2=0.9562 and R 2=0.9007) between DOC HAAFP removal rate and Empty Bed Contact Time(EBCT) of IBAC process was observed, while that between THMFP removal rate and EBCT of GAC was R 2=0.9782. In addition certain linear correlations between THMFP, HAAFP and UV 254 (R 2=0.855 and R 2=0.7702) were found for the treated water. For IBAC process there are also more advantages such as long backwashing cycle time, low backwashing intensity and prolonging activated carbon lifetime and so on.展开更多
The high-active bacteria were screened from 8 dominant bacteria obtained from the natural water body,and then the bioaugmentation activated carbon was formed by hydraulic immobilization of the high-active bacteria. Pl...The high-active bacteria were screened from 8 dominant bacteria obtained from the natural water body,and then the bioaugmentation activated carbon was formed by hydraulic immobilization of the high-active bacteria. Plant-scale studies on removal characteristics of disinfection by-products formation potentials (DBPFP) by bioaugmentation activated carbon process were conducted for micro-polluted raw water treatment. The results show that the bioaugmentation activated carbon process has adopted better purification efficiency to THMFP and HAAFP than traditional biological activated carbon process,and that average removal efficiencies of THMFP and HAAFP can reach 35% and 39.7% during the test period,increasing by more than 10% compared with traditional biological activated carbon process. The removal efficiencies of THMFP and HAAFP are stable because of the biodegradation of the high-active bacteria and the adsorption of active carbon. The biodegradability of CHCl3 formation potential is better as compared with that of CHCl2Br and CHClBr2 formation potentials among THMFP,and high removal efficiency of CHCl3formation potential is obtained by bioaugmentation degradation of the high-active bacteria. The biodegradability of HAAFP is better in comparison with that of THMFP,and the chemical properties of HAAFP are propitious to adsorption of activated carbon. Thus,HAAFP is on predominance during the competitive removal process with THMFP.展开更多
Gravity-driven membrane(GDM)systems have been well developed previously;however,impacts of driving(i.e.,transmembrane)pressure on their performance received little attention,which may infuence GDM performance.In this ...Gravity-driven membrane(GDM)systems have been well developed previously;however,impacts of driving(i.e.,transmembrane)pressure on their performance received little attention,which may infuence GDM performance.In this study,we evaluated 4 GDM systems via altering the transmembrane pressure from 50 mbar to 150 mbar with 2 groups,treating surface water in Beijing,China.Results showed that less driving pressure was more favorable.Specifically,compared to groups(150 mbar),groups under a pressure of 50 mbar were found to have greater normalized permeability and lower total resistance.During the whole operation period,the quality of effuents was gradually improved.For example,the removal efficiency of UV254was significantly improved;particularly,under low driving pressure,the removal efficiency of UV254in PES GDM system increased by 11.91%,as compared to the corresponding system under high driving pressure.This observation was consistent with the reduction on disinfection by-products(DBPs)formation potential;groups under 50 mbar achieved better DBPs potential control,indicating the advantages of lower driving pressure.Biofilms were analyzed and responsible for these differences,and distinct distributions of bacteria communities of two GDM systems under 50 and 150 mbar may be responsible for various humic-like substances removal efficiency.Overall,GDM systems under less pressure should be considered and expected to provide suggestions on the design of GDM systems in real applications.展开更多
Permanganate/sulfite(Mn(VII)/S(IV))process is a promising pre-oxidation technology for sequestering the emerging organic contaminants in drinking water treatment plant.Iopamidol(IPM),a representative of iodinated X-ra...Permanganate/sulfite(Mn(VII)/S(IV))process is a promising pre-oxidation technology for sequestering the emerging organic contaminants in drinking water treatment plant.Iopamidol(IPM),a representative of iodinated X-ray contrast media,has been widely detected in water sources and has the risk of forming iodinated disinfection byproducts(I-DBPs)in water treatment system.In this study,we investigated the evolution of iodine species during the IPM degradation by the Mn(VII)/S(IV)process and its effect on the subsequent formation of I-DBPs during chlorination at pH 7.0 and 8.0.IPM could be effectively degraded in the Mn(VII)/S(IV)process at environmentally relevant pH(pH 7.0 and 8.0).The results of quenching and competitive oxidation kinetic experiments revealed that SO^(·-)_(4)was the major reactive oxidizing species contributing to the degradation of IPM whereas the contributions of HO·and reactive manganese species were negligible in the Mn(VII)/S(IV)process.I–and IO–3were generated while no HOI was detected during the degradation of IPM in the Mn(VII)/S(IV)process.The effects of IPM oxidation by Mn(VII)/S(IV)on the subsequent formation of chlorinated disinfection by-products(Cl-DBPs)during chlorination were related to the category of Cl-DBPs.The pre-oxidation of IPM by Mn(VII)/S(IV)resulted in the generation of I-DBPs during the disinfection process although no I-DBPs were detected if no pre-oxidation was applied.The finding of this study suggested that attention should be paid to the toxicity of DBPs when water containing iodinated organic contaminants is treated by Mn(VII)/S(IV)process or other pre-oxidation technologies.展开更多
Identification and characterization of disinfection by-product(DBP)precursors could help optimize drinkingwater treatment processes and improve the quality of finishedwater.This study comprehensively investigated the ...Identification and characterization of disinfection by-product(DBP)precursors could help optimize drinkingwater treatment processes and improve the quality of finishedwater.This study comprehensively investigated the characteristics of dissolved organic matter(DOM),the hydrophilicity and molecule weight(MW)of DBP precursor and DBP-associated toxicity along the typical full-scale treatment processes.The results showed that dissolved organic carbon and dissolved organic nitrogen content,the fluorescence intensity and the SUVA254 value in raw water significantly decreased after the whole treatment processes.Conventional treatment processes were in favor of the removal of high-MW and hydrophobic DOM,which are important precursors of trihalomethane and haloacetic acid.Compared with conventional treatment processes,Ozone integrated with biological activated carbon(O3-BAC)processes enhanced the removal efficiencies of DOM with different MW and hydrophobic fractions,leading to a further decrease in almost all DBP formation potential and DBP-associated toxicity.However,almost 50%of the detected DBP precursors in raw water has not been removed after the coagulation-sedimentation-filtration integrated with O3-BAC advanced treatment processes.These remaining precursors were found to be mainly hydrophilic and low-MW(<1.0 kDa)organics.Moreover,they would largely contribute to the formation of haloacetaldehydes and haloacetonitriles,which dominated the calculated cytotoxicity.Since current drinking water treatment process could not effectively control the highly toxic DBPs,the removal of hydrophilic and low-MW organics in drinking water treatment plants should be focused on in the future.展开更多
Sulfate radicals have been increasingly used for the pathogen inactivation due to their strong redox ability and high selectivity for electron-rich species in the last decade.The application of sulfate radicals in wat...Sulfate radicals have been increasingly used for the pathogen inactivation due to their strong redox ability and high selectivity for electron-rich species in the last decade.The application of sulfate radicals in water disinfection has become a very promising technology.However,there is currently a lack of reviews of sulfate radicals inactivated pathogenic microorganisms.At the same time,less attention has been paid to disinfection by-products produced by the use of sulfate radicals to inactivate microorganisms.This paper begins with a brief overview of sulfate radicals’properties.Then,the progress in water disinfection by sulfate radicals is summarized.The mechanism and inactivation kinetics of inactivating microorganisms are briefly described.After that,the disinfection by-products produced by reactions of sulfate radicals with chlorine,bromine,iodide ions and organic halogens in water are also discussed.In response to these possible challenges,this article concludes with some specific solutions and future research directions.展开更多
Haloacetaldehydes(HALs)are the third largest disinfection by-products(DBPs)class by mass in drinking water.Most of them alone in high doses are more cytotoxic and genotoxic than regulated DBPs.However,the toxic effect...Haloacetaldehydes(HALs)are the third largest disinfection by-products(DBPs)class by mass in drinking water.Most of them alone in high doses are more cytotoxic and genotoxic than regulated DBPs.However,the toxic effects of mixed exposure to HALs at environmentally relevant levels are still unknown.Given that genotoxicity is critical for risk assessment,we employed multiple genotoxic tests including the Salmonella typhimurium revertant mutation assay(Ames assay),the single cell gel electrophoresis(SCGE)assay,the cytoplasmic blocking micronucleus(CBMN)assay,and theγ-H2AX assay to investigate the genotoxicity of HALs based on the HALs concentrations and components detected in the finished drinking water of Shanghai,China.The results demonstrated the concentrations of HALs were low,ranging from 0.04µg/L to 4.47µg/L,and the total concentration was 10.85µg/L.Although the mutagenicity of HALs was negative even at 1000-fold concentrations in the real world,mixed exposure to 100 and 1000-fold concentrations HALs resulted in DNA and chromosomal damage in human hepotocyte(HepG2)cells.HALs significantly increased the levels of reactive oxygen species(ROS)andγ-H2AX and activated nuclear factor erythroid-derived factor 2-related factor 2(NRF2)pathway-related protein expressions in HepG2 cells.The antioxidant NAC could ameliorate NRF2 pathway-related protein expression and DNA damage caused by HALs,suggesting that the genotoxicity of mixed exposure to HALs involved cellular oxidative stress and NRF2 pathway activation.展开更多
Tracing the contamination origins in water sources and identifying the impacts of natural and human processes are essential for ecological safety and public health.However,current analysis approaches are not ideal,as ...Tracing the contamination origins in water sources and identifying the impacts of natural and human processes are essential for ecological safety and public health.However,current analysis approaches are not ideal,as they tend to be laborious,time-consuming,or technically difficult.Disinfection byproducts(DBPs)are a family of well-known secondary pollutants formed by the reactions of chemical disinfectants with DBP precursors during water disinfection treatment.Since DBP precursors have various origins(e.g.,natural,domestic,industrial,and agricultural sources),and since the formation of DBPs from different precursors in the presence of specific disinfectants is distinctive,we argue that DBPs and DBP precursors can serve as alternative indicators to assess the contamination in water sources and identify pollution origins.After providing a retrospective of the origins of DBPs and DBP precursors,as well as the specific formation patterns of DBPs from different precursors,this article presents an overview of the impacts of various natural and anthropogenic factors on DBPs and DBP precursors in drinking water sources.In practice,the DBPs(i.e.,their concentration and speciation)originally present in source water and the DBP precursors determined using DBP formation potential tests—in which water samples are dosed with a stoichiometric excess of specific disinfectants in order to maximize DBP formation under certain reaction conditions—can be considered as alternative metrics.When jointly used with other water quality parameters(e.g.,dissolved organic carbon,dissolved organic nitrogen,fluorescence,and molecular weight distribution)and specific contaminants of emerging concern(e.g.,certain pharmaceuticals and personal care products),DBPs and DBP precursors in drinking water sources can provide a more comprehensive picture of water pollution for better managing water resources and ensuring human health.展开更多
BACKGROUND Aerosols containing disease-causing microorganisms are produced during oral diagnosis and treatment can cause secondary contamination.AIM To investigate the use of graphene material for air disinfection in ...BACKGROUND Aerosols containing disease-causing microorganisms are produced during oral diagnosis and treatment can cause secondary contamination.AIM To investigate the use of graphene material for air disinfection in dental clinics by leveraging its adsorption and antibacterial properties.METHODS Patients who received ultrasonic cleaning at our hospital from April 2023 to April 2024.They were randomly assigned to three groups(n=20 each):Graphene nanocomposite material suction group(Group A),ordinary filter suction group(Group B),and no air suction device group(Group C).The air quality and air colony count in the clinic rooms were assessed before,during,and after the procedure.Additionally,bacterial colony counts were obtained from the air outlets of the suction devices and the filter screens in Groups A and B.RESULTS Before ultrasonic cleaning,no significant differences in air quality PM2.5 and colony counts were observed among the three groups.However,significant differences in air quality PM2.5 and colony counts were noted among the three groups during ultrasonic cleaning and after ultrasonic treatment.Additionally,the number of colonies on the exhaust port of the suction device and the surface of the filter were significantly lower in Group A than in Group B(P=0.000 and P=0.000,respectively).CONCLUSION Graphene nanocomposites can effectively sterilize the air in dental clinics by exerting their antimicrobial effects and may be used to reduce secondary pollution.展开更多
This study aimed to examine the effect of different disinfection methods on the callus of Amorphophallus albus in the tissue culture and rapid propagation system.The calluses induced from buds of A.albus were disinfec...This study aimed to examine the effect of different disinfection methods on the callus of Amorphophallus albus in the tissue culture and rapid propagation system.The calluses induced from buds of A.albus were disinfected with benzalkonium bromide,mercury bichloride,sodium hypochlorite,and ethanol,respectively,for different time periods.The growth of calluses was compared between different treatments and observed in detail by dissection.The results showed that the disinfection with 0.1% mercury bichloride for 5 min and 75% ethanol for 5 s had mild effect on the callus,with the lowest browning rates of 16.32% and 15.46% and the lowest vitrification rates of 3.24% and 9.72%,respectively,after 20 d.The disinfection with benzalkonium bromide and sodium hypochlorite had strong effect on the callus cells,with the lowest browning rate of 50.69% and 25.12% and the lowest vitrification rates of 28.47% and 28.43%,respectively.The cytological observation result showed that the calluses disinfected with ethanol and mercury bichloride showcased compact structures,while those disinfected with sodium hypochlorite and benzalkonium bromide exhibited loose structures.To sum up,it is recommended that 75% ethanol or 0.1% mercury bichloride can be used for disinfection in the tissue culture and rapid propagation of A.albus,while the use of benzalkonium bromide and sodium hypochlorite should be avoided as much as possible.展开更多
Objective:To evaluate the application value of a refined quality control management model for a sterilization supply center.Methods:A retrospective analysis was conducted on the work situation of the sterilization sup...Objective:To evaluate the application value of a refined quality control management model for a sterilization supply center.Methods:A retrospective analysis was conducted on the work situation of the sterilization supply center from January 2021 to January 2023.The work situation before January 31,2022,was classified as the control group;a routine quality control management model was implemented,and the work situation after January 31,2022,was classified as the observation group.The quality of medical device management and department satisfaction between the two groups were compared.Results:The timely recovery and supply rate,classification and cleaning pass rate,disinfection pass rate,packaging pass rate,sterilization pass rate,and department satisfaction score in the observation group were all higher than those of the control group(P<0.05).Conclusion:Implementing a refined quality control management model in the sterilization supply center can improve the quality management level of medical devices and department satisfaction and is worthy of promotion.展开更多
Since the catalytic activity of most nanozymes is still far lower than the corresponding natural enzymes,there is urgent need to discover novel highly efficient enzyme-like materials.In this work,Co_(3)V_(2)O_(8)with ...Since the catalytic activity of most nanozymes is still far lower than the corresponding natural enzymes,there is urgent need to discover novel highly efficient enzyme-like materials.In this work,Co_(3)V_(2)O_(8)with hollow hexagonal prismatic pencil structures were prepared as novel artificial enzyme mimics.They were then decorated by photo-depositing Ag nanoparticles(Ag NPs)on the surface to further improve its catalytic activities.The Ag NPs decorated Co_(3)V_(2)O_(8)(ACVPs)showed both excellent oxidase-and peroxidase-like catalytic activities.They can oxidize the colorless 3,3’,5,5’-tetramethylbenzidine rapidly to induce a blue change.The enhanced enzyme mimetic activities can be attributed to the surface plasma resonance(SPR)effect of Ag NPs as well as the synergistic catalytic effect between Ag NPs and Co_(3)V_(2)O_(8),accelerating electron transfer and promoting the catalytic process.ACVPs were applied in constructing a colorimetric sensor,validating the occurrence of the Fenton reaction,and disinfection,presenting favorable catalytic performance.The enzyme-like catalytic mechanism was studied,indicating the chief role of⋅O_(2)-radicals in the catalytic process.This work not only discovers a novel functional material with double enzyme mimetic activity but also provides a new insight into exploiting artificial enzyme mimics with highly efficient catalytic ability.展开更多
BACKGROUND Pelvic floor dysfunction(PFD)is related to muscle fiber tearing during childbirth,negatively impacting postpartum quality of life of parturient.Appropriate and effective intervention is necessary to promote...BACKGROUND Pelvic floor dysfunction(PFD)is related to muscle fiber tearing during childbirth,negatively impacting postpartum quality of life of parturient.Appropriate and effective intervention is necessary to promote PFD recovery.AIM To analyze the use of hydrogen peroxide and silver ion disinfection for vaginal electrodes in conjunction with comprehensive rehabilitation therapy for postpartum women with PFD.METHODS A total of 59 women with PFD who were admitted to the hospital from May 2019 to July 2022 were divided into two groups:Control group(n=27)received comprehensive rehabilitation therapy and observation group(n=32)received intervention with pelvic floor biostimulation feedback instrument in addition to comprehensive rehabilitation therapy.The vaginal electrodes were disinfected with hydrogen peroxide and silver ion before treatment.Intervention for both groups was started 6 weeks postpartum,and rehabilitation lasted for 3 months.Pelvic floor muscle voltage,pelvic floor muscle strength,vaginal muscle voltage,vaginal muscle tone,pelvic floor function,quality of life,and incidence of postpartum PFD were compared between the two groups.RESULTS Before comprehensive rehabilitation treatment,basic data and pelvic floor function were not significantly different between the two groups.After treatment,the observation group showed significant improvements in the maximum voltage and average voltage of pelvic floor muscles,contraction time of type I and type II fibers,pelvic floor muscle strength,vaginal muscle tone,vaginal muscle voltage,and quality of life(GQOLI-74 reports),compared with the control group.The observation group had lower scores on the pelvic floor distress inventory(PFDI-20)and a lower incidence of postpartum PFD,indicating the effectiveness of the pelvic floor biostimulation feedback instrument in promoting the recovery of maternal pelvic floor function.CONCLUSION The combination of the pelvic floor biostimulation feedback instrument and comprehensive rehabilitation nursing can improve pelvic floor muscle strength,promote the recovery of vaginal muscle tone,and improve pelvic floor function and quality of life.The use of hydrogen peroxide and silver ion disinfectant demonstrated favorable antibacterial efficacy and is worthy of clinical application.展开更多
The UV irradiation is used for removing Antibiotic Resistant Bacteria(ARB)and Antibiotic Resistance Genes(ARG)from wastewater treatment.Bacteriophages are viruses that infect within bacteria,are recognized for bacteri...The UV irradiation is used for removing Antibiotic Resistant Bacteria(ARB)and Antibiotic Resistance Genes(ARG)from wastewater treatment.Bacteriophages are viruses that infect within bacteria,are recognized for bacterial control.The influence of some parameters in quantification and performance influencing of pathogen demobilization could be considered in disinfection of wastewater.The comparison of Polyvalent phage(NE1)versus Coliphage(NE4)in suppressing a bacterium Escherichia coli(NDM-1:b-lactam-resistant)with UV irradiation was observed the efficacy in reduction of cells in the disinfection and parameter process.The results with the effect of UV-C irradiation on NDM-1 infected with 1%of NE4 showed a decrease of cells from 8×10^(6)to 2×10^(5)in 60 min with UV-C dose.The NDM1(E.coli)was infected with 1%of NE4(Polyvalent Phage)under magnetic stirring for 1 h,the cells count was 8×10^(6).After 1 h in UV-C e×posure,the cells number reached 3×10^(5).The NDM1 that was e×posed in 1 h of UV-C irradiation and then was infected with 1%of NE4.Cells counting were done 24 h after this procedure.These cells were e×posed in UV-C and showed a reduction in the number of cells from 1×10^(8)to 4×10^(5)after 60 min.The results indicate that bacteriophages can mitigate bacteria species,and combined the conventional water disinfection technologies that can support the microbial safety control strategies.展开更多
This work investigated the formation of carbonaceous and nitrogenous disinfection by-products （C-DBPs, N-DBPs） upon chlorination of water samples collected from a surface water and a ground water treatment plant （S...This work investigated the formation of carbonaceous and nitrogenous disinfection by-products （C-DBPs, N-DBPs） upon chlorination of water samples collected from a surface water and a ground water treatment plant （SWTP and GWTP） where the conventional treatment processes, i.e., coagulation, sedimentation, and filtration were employed. Twenty DBPs, including four trihalomethanes, nine haloacetic acids, seven N-DBPs （dichloroacetamide, trichloroacetamide, dichloroacetonitrile, trichloroacetonitrile, bromochloroace- tonitrile, dibromoacetonitrile and trichloronitromethane）, and eight volatile chlorinated compounds （dichloromethane （DCM）, 1,2-dichloroethane, tetrachloroethylene, chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene and 1,2,4- trichlorobenzene） were detected in the two WTPs. The concentrations of these contaminants were all below their corresponding maximum contamination levels （MCLs） regulated by the Standards for Drinking Water Quality of China （GB5749-2006） except for DCM （17.1 ~tg/L detected vs. 20 μg/L MCL）. The SWTP had much higher concentrations of DBPs detected in the treated water as well as the DBP formation potentials tested in the filtered water than the GWTP, probably because more precursors （e.g., dissolved organic carbon, dissolved organic nitrogen） were present in the water source of the SWTE展开更多
Dissolved black carbon(DBC)released from biochar can be one of the potential disinfection by-products(DBPs)precursors in the dissolved organic matter pool.However,the physiochemical and structural properties of DBC an...Dissolved black carbon(DBC)released from biochar can be one of the potential disinfection by-products(DBPs)precursors in the dissolved organic matter pool.However,the physiochemical and structural properties of DBC and the effects on the development of DBPs and DBP formation potential(DBPFP)during the disinfection process remain unclear.In this study,the characteristics of two kinds of DBC,namely,animal-derived DBC(poultry litter DBC,PL-DBC)and plant-derived DBC(wheat straw DBC,WS-DBC),were investigated.The effects of different kinds of DBC on the evolution of DBPs and DBPFP in chlorine and chloramine disinfection processes were compared with natural organic matter(NOM).The results showed that the total DBPs concentrations derived from PL-DBC,WS-DBC and NOM were similar during chlorination(i.e.,61.23µg/L,64.59µg/L and 64.66µg/L,respectively)and chloramination(i.e.,44.63µg/L,44.42µg/L and 45.58µg/L,respectively).The lower total DBPs and DBPFP concentrations in chloramination could be attributed to the fact that the introduction of ammonia in chloramine inhibited the breaking of the bond between the disinfectant and the active group of the precursor.Additionally,DBC presented much lower total DBPFP concentrations than NOM in both chlorination and chloramination.However,both kinds of DBC tended to form more monochloroacetic acids and haloacetamides than NOM,which could result from the higher organic strength,higher protein matter,and nitrogen-rich soluble microbial products of DBC.展开更多
The characteristics of dissolved organic matter（DOM） and bromide ion concentration have a significant influence on the formation of disinfection by-products（DBPs）. In order to identify the main DBP precursors, DOM...The characteristics of dissolved organic matter（DOM） and bromide ion concentration have a significant influence on the formation of disinfection by-products（DBPs）. In order to identify the main DBP precursors, DOM was divided into five fractions based on molecular weight（MW）, trihalomethane formation potential and haloacetic acid formation potential were determined for fractions, and the change in contents of different fractions and total DBPs during treatment processes（pre-chlorination, coagulation, sand filtration,disinfection） were studied. Moreover, the relationship between bromide concentration and DBP generation characteristics in processes was also analyzed. The results showed that the main DBP precursors were the fraction with MW 1 k Da and fraction with MW 3-10 k Da, and the DBP＇s generation ability of lower molecular weight DOM（ 10 k Da） was higher than that of higher molecular weight DOM. During different processes,pre-chlorination and disinfection had limited effect on removing organics but could alter the MW distribution, and coagulation and filtration could effectively remove organics with higher MW. For DBPs, trihalomethanes（THMs） were mainly generated in pre-chlorination and disinfection, while haloacetic acids（HAAs） were mostly generated during pre-chlorination; coagulation and sand filtration had little effect on THMs but resulted in a slight removal of HAAs. In addition, the results of ANOVA tests suggested that molecular sizes and treatment processes have significant influence on DBP formation. With increasing bromide concentration, the brominated DBPs significantly increased, but the bromine incorporation factor in the processes was basically consistent at each concentration.展开更多
文摘Ensuring the health and safety of drinking water is crucial for both nations and their citizens.Since the 20th century,the disinfection of drinking water,effectively controlling pathogens in water sources,has become one of the significant advances in public health.However,the disinfectants used in the process,such as chlorine and chlorine dioxide,react with natural organic matter in the water to produce disinfection by-products(DBPs).Most of these DBPs contain chlorine,and if the source water contains bromine or iodine,brominated or iodinated DBPs,collectively referred to as Halogenated disinfection byproducts(X-DBPs),are formed.Numerous studies have found that X-DBPs pose potential risks to human health and the environment,leading to widespread concern.Mass spectrometry has become an important means of discovering new types of X-DBPs.This paper focuses on the study of methods for analyzing X-DBPs in drinking water using mass spectrometry.
基金supported by the National Natural Science Foundation of China (No. 50538090)the Funds for Creative Research Groups of China (No. 50621804)the High-Tech Research and Development Program (863) of China (No. 2007AA06Z338).
文摘Dissolved organic matter （DOM） has been identified as precursor for disinfection by-products （DBPs） formation during chlorination. Recently, it has been demonstrated that the characteristics of DOM influence the DBPs formation mechanism. A study was, therefore, initiated to investigate the effects of DOM fractions on DBPs formation mechanism. In the chlorination process, organic acids are dominant precursors of total thihalomethanes （TTHM） because of the vc-o and unsaturated structures. Furthermore, the TTHM formation of organic acids was affected by pH more greatly. Based on the fluorescence spectroscopy analysis, DOM fractions contained several fluorescence substances. During chlorination, humic acid-like substances were found to exhibit high chlorine reactivity and hydrophobic organics decomposed to smaller molecules faster than hydrophilic organics even at lower chlorine dosages. Unlike hydrophobic fractions, hydrophilic organics showed no toxicity following chlorination, suggesting that the toxic structures in hydrophihc organics showed high chlorine reactivity during chlorination.
基金This work was sponsored by National Natural Science Fundation Committee (No. 50238020).
文摘Objective To introduce a new sequential chlorination disinfection process in which short-term free chlorine and chloramine are sequentially added. Methods Pilot tests of this sequential chlorination were carried out in a drinking water plant. Results The sequential chlorination disinfection process had the same or better efficiency on microbe （including virus） inactivation compared with the free chlorine disinfection process. There seemed to be some synergetic disinfection effect between free chlorine and monochloramine because they attacked different targets. The sequential chlorination disinfection process resulted in 35.7%-77.0% TTHM formation and 36.6%-54.8% THAA5 formation less than the free chlorination process. The poorer the water quality was, the more advantage the sequential chlorination disinfection had over the free chlorination. Conclusion This process takes advantages of free chlorine＇s quick inactivation of microorganisms and chloramine＇s low disinfection by-product （DBP） yield and long-term residual effect, allowing simultaneous control of microbes and DBPs in an effective and economic way.
文摘The removal of disinfection by-products formation potential(DBPFP) in artificially intensified biological activated carbon(IBAC) process which is developed on the basis of traditional ozone granular activated carbon was evaluated. By IBAC removals of 31% and 68% for THMFP and HAAFP were obtained respectively. Under identical conditions, the removals of the same substances were 4% and 32% respectively only by the granular activated carbon(GAC) process. Compared with GAC, the high removal rates of the two formed potential substances were due to the increasing of bioactivity of the media and the synergistic capabilities of biological degradation cooperating with activated carbon adsorption of organic compounds. A clear linear correlation(R 2=0.9562 and R 2=0.9007) between DOC HAAFP removal rate and Empty Bed Contact Time(EBCT) of IBAC process was observed, while that between THMFP removal rate and EBCT of GAC was R 2=0.9782. In addition certain linear correlations between THMFP, HAAFP and UV 254 (R 2=0.855 and R 2=0.7702) were found for the treated water. For IBAC process there are also more advantages such as long backwashing cycle time, low backwashing intensity and prolonging activated carbon lifetime and so on.
基金Sponsered by the National Natural Science Foundation of China (Grant No. 50678046)
文摘The high-active bacteria were screened from 8 dominant bacteria obtained from the natural water body,and then the bioaugmentation activated carbon was formed by hydraulic immobilization of the high-active bacteria. Plant-scale studies on removal characteristics of disinfection by-products formation potentials (DBPFP) by bioaugmentation activated carbon process were conducted for micro-polluted raw water treatment. The results show that the bioaugmentation activated carbon process has adopted better purification efficiency to THMFP and HAAFP than traditional biological activated carbon process,and that average removal efficiencies of THMFP and HAAFP can reach 35% and 39.7% during the test period,increasing by more than 10% compared with traditional biological activated carbon process. The removal efficiencies of THMFP and HAAFP are stable because of the biodegradation of the high-active bacteria and the adsorption of active carbon. The biodegradability of CHCl3 formation potential is better as compared with that of CHCl2Br and CHClBr2 formation potentials among THMFP,and high removal efficiency of CHCl3formation potential is obtained by bioaugmentation degradation of the high-active bacteria. The biodegradability of HAAFP is better in comparison with that of THMFP,and the chemical properties of HAAFP are propitious to adsorption of activated carbon. Thus,HAAFP is on predominance during the competitive removal process with THMFP.
基金supported by the National Natural Science Foundation of China (No.52200026)。
文摘Gravity-driven membrane(GDM)systems have been well developed previously;however,impacts of driving(i.e.,transmembrane)pressure on their performance received little attention,which may infuence GDM performance.In this study,we evaluated 4 GDM systems via altering the transmembrane pressure from 50 mbar to 150 mbar with 2 groups,treating surface water in Beijing,China.Results showed that less driving pressure was more favorable.Specifically,compared to groups(150 mbar),groups under a pressure of 50 mbar were found to have greater normalized permeability and lower total resistance.During the whole operation period,the quality of effuents was gradually improved.For example,the removal efficiency of UV254was significantly improved;particularly,under low driving pressure,the removal efficiency of UV254in PES GDM system increased by 11.91%,as compared to the corresponding system under high driving pressure.This observation was consistent with the reduction on disinfection by-products(DBPs)formation potential;groups under 50 mbar achieved better DBPs potential control,indicating the advantages of lower driving pressure.Biofilms were analyzed and responsible for these differences,and distinct distributions of bacteria communities of two GDM systems under 50 and 150 mbar may be responsible for various humic-like substances removal efficiency.Overall,GDM systems under less pressure should be considered and expected to provide suggestions on the design of GDM systems in real applications.
基金supported by the National Natural Science Foundation of China (Nos.22206050,22025601,21976133 and 52270047)the National Key Research and Development Program of China (No.2019YFC1805202)the State Key Laboratory of Pollution Control and Resource Reuse Foundation (No.PCRRK20014)。
文摘Permanganate/sulfite(Mn(VII)/S(IV))process is a promising pre-oxidation technology for sequestering the emerging organic contaminants in drinking water treatment plant.Iopamidol(IPM),a representative of iodinated X-ray contrast media,has been widely detected in water sources and has the risk of forming iodinated disinfection byproducts(I-DBPs)in water treatment system.In this study,we investigated the evolution of iodine species during the IPM degradation by the Mn(VII)/S(IV)process and its effect on the subsequent formation of I-DBPs during chlorination at pH 7.0 and 8.0.IPM could be effectively degraded in the Mn(VII)/S(IV)process at environmentally relevant pH(pH 7.0 and 8.0).The results of quenching and competitive oxidation kinetic experiments revealed that SO^(·-)_(4)was the major reactive oxidizing species contributing to the degradation of IPM whereas the contributions of HO·and reactive manganese species were negligible in the Mn(VII)/S(IV)process.I–and IO–3were generated while no HOI was detected during the degradation of IPM in the Mn(VII)/S(IV)process.The effects of IPM oxidation by Mn(VII)/S(IV)on the subsequent formation of chlorinated disinfection by-products(Cl-DBPs)during chlorination were related to the category of Cl-DBPs.The pre-oxidation of IPM by Mn(VII)/S(IV)resulted in the generation of I-DBPs during the disinfection process although no I-DBPs were detected if no pre-oxidation was applied.The finding of this study suggested that attention should be paid to the toxicity of DBPs when water containing iodinated organic contaminants is treated by Mn(VII)/S(IV)process or other pre-oxidation technologies.
基金This work was supported by the National Key Research and Development Program of China(No.2021YFC3200700)the National Natural Science Foundation of China(No.52170009)+2 种基金the International Cooperation Project of Shanghai Science and Technology Commission(No.20230714100)the Shanghai Soft Science Project(No.20692113900)the Fundamental Research Funds for the Central Universities.
文摘Identification and characterization of disinfection by-product(DBP)precursors could help optimize drinkingwater treatment processes and improve the quality of finishedwater.This study comprehensively investigated the characteristics of dissolved organic matter(DOM),the hydrophilicity and molecule weight(MW)of DBP precursor and DBP-associated toxicity along the typical full-scale treatment processes.The results showed that dissolved organic carbon and dissolved organic nitrogen content,the fluorescence intensity and the SUVA254 value in raw water significantly decreased after the whole treatment processes.Conventional treatment processes were in favor of the removal of high-MW and hydrophobic DOM,which are important precursors of trihalomethane and haloacetic acid.Compared with conventional treatment processes,Ozone integrated with biological activated carbon(O3-BAC)processes enhanced the removal efficiencies of DOM with different MW and hydrophobic fractions,leading to a further decrease in almost all DBP formation potential and DBP-associated toxicity.However,almost 50%of the detected DBP precursors in raw water has not been removed after the coagulation-sedimentation-filtration integrated with O3-BAC advanced treatment processes.These remaining precursors were found to be mainly hydrophilic and low-MW(<1.0 kDa)organics.Moreover,they would largely contribute to the formation of haloacetaldehydes and haloacetonitriles,which dominated the calculated cytotoxicity.Since current drinking water treatment process could not effectively control the highly toxic DBPs,the removal of hydrophilic and low-MW organics in drinking water treatment plants should be focused on in the future.
基金the Project of the National Key Research and Development Program of China(No.2021YFC1910404)the National Natural Science Foundation of China(Nos.52100008,52100184,and 52100142)+4 种基金the Funds of Hunan Science and Technology Innovation Project(China)(Nos.2021GK4055 and 2022SK2119)Natural Science Foundation of Hunan ProvinceChina(No.2021JJ40091)the Science and Technology Innovation Program of Hunan Province(China)(No.2021RC2056)the Project funded by China Postdoctoral Science Foundation(No.2021M701149).
文摘Sulfate radicals have been increasingly used for the pathogen inactivation due to their strong redox ability and high selectivity for electron-rich species in the last decade.The application of sulfate radicals in water disinfection has become a very promising technology.However,there is currently a lack of reviews of sulfate radicals inactivated pathogenic microorganisms.At the same time,less attention has been paid to disinfection by-products produced by the use of sulfate radicals to inactivate microorganisms.This paper begins with a brief overview of sulfate radicals’properties.Then,the progress in water disinfection by sulfate radicals is summarized.The mechanism and inactivation kinetics of inactivating microorganisms are briefly described.After that,the disinfection by-products produced by reactions of sulfate radicals with chlorine,bromine,iodide ions and organic halogens in water are also discussed.In response to these possible challenges,this article concludes with some specific solutions and future research directions.
基金supported by the Key Project of the National Natural Science Foundation of China(Nos.81630088,81273035,81325017)the Changjiang Scholars Program,Ministry of Education,China(No.T2014089).
文摘Haloacetaldehydes(HALs)are the third largest disinfection by-products(DBPs)class by mass in drinking water.Most of them alone in high doses are more cytotoxic and genotoxic than regulated DBPs.However,the toxic effects of mixed exposure to HALs at environmentally relevant levels are still unknown.Given that genotoxicity is critical for risk assessment,we employed multiple genotoxic tests including the Salmonella typhimurium revertant mutation assay(Ames assay),the single cell gel electrophoresis(SCGE)assay,the cytoplasmic blocking micronucleus(CBMN)assay,and theγ-H2AX assay to investigate the genotoxicity of HALs based on the HALs concentrations and components detected in the finished drinking water of Shanghai,China.The results demonstrated the concentrations of HALs were low,ranging from 0.04µg/L to 4.47µg/L,and the total concentration was 10.85µg/L.Although the mutagenicity of HALs was negative even at 1000-fold concentrations in the real world,mixed exposure to 100 and 1000-fold concentrations HALs resulted in DNA and chromosomal damage in human hepotocyte(HepG2)cells.HALs significantly increased the levels of reactive oxygen species(ROS)andγ-H2AX and activated nuclear factor erythroid-derived factor 2-related factor 2(NRF2)pathway-related protein expressions in HepG2 cells.The antioxidant NAC could ameliorate NRF2 pathway-related protein expression and DNA damage caused by HALs,suggesting that the genotoxicity of mixed exposure to HALs involved cellular oxidative stress and NRF2 pathway activation.
基金supported by the National Natural Science Foundation of China(52325001,52170009,and 52091542)the National Key Research and Development Program of China(2021YFC3200700)+3 种基金the Program of Shanghai Academic Research Leader,China(21XD1424000)the International Cooperation Project of Shanghai Science and Technology Commission(20230714100)the Key-Area Research and Development Program of Guangdong Province(2020B1111350001)Tongji University Youth 100 Program.
文摘Tracing the contamination origins in water sources and identifying the impacts of natural and human processes are essential for ecological safety and public health.However,current analysis approaches are not ideal,as they tend to be laborious,time-consuming,or technically difficult.Disinfection byproducts(DBPs)are a family of well-known secondary pollutants formed by the reactions of chemical disinfectants with DBP precursors during water disinfection treatment.Since DBP precursors have various origins(e.g.,natural,domestic,industrial,and agricultural sources),and since the formation of DBPs from different precursors in the presence of specific disinfectants is distinctive,we argue that DBPs and DBP precursors can serve as alternative indicators to assess the contamination in water sources and identify pollution origins.After providing a retrospective of the origins of DBPs and DBP precursors,as well as the specific formation patterns of DBPs from different precursors,this article presents an overview of the impacts of various natural and anthropogenic factors on DBPs and DBP precursors in drinking water sources.In practice,the DBPs(i.e.,their concentration and speciation)originally present in source water and the DBP precursors determined using DBP formation potential tests—in which water samples are dosed with a stoichiometric excess of specific disinfectants in order to maximize DBP formation under certain reaction conditions—can be considered as alternative metrics.When jointly used with other water quality parameters(e.g.,dissolved organic carbon,dissolved organic nitrogen,fluorescence,and molecular weight distribution)and specific contaminants of emerging concern(e.g.,certain pharmaceuticals and personal care products),DBPs and DBP precursors in drinking water sources can provide a more comprehensive picture of water pollution for better managing water resources and ensuring human health.
基金The Natural Science Research Project of Minhang District,No.2021MHZ070.
文摘BACKGROUND Aerosols containing disease-causing microorganisms are produced during oral diagnosis and treatment can cause secondary contamination.AIM To investigate the use of graphene material for air disinfection in dental clinics by leveraging its adsorption and antibacterial properties.METHODS Patients who received ultrasonic cleaning at our hospital from April 2023 to April 2024.They were randomly assigned to three groups(n=20 each):Graphene nanocomposite material suction group(Group A),ordinary filter suction group(Group B),and no air suction device group(Group C).The air quality and air colony count in the clinic rooms were assessed before,during,and after the procedure.Additionally,bacterial colony counts were obtained from the air outlets of the suction devices and the filter screens in Groups A and B.RESULTS Before ultrasonic cleaning,no significant differences in air quality PM2.5 and colony counts were observed among the three groups.However,significant differences in air quality PM2.5 and colony counts were noted among the three groups during ultrasonic cleaning and after ultrasonic treatment.Additionally,the number of colonies on the exhaust port of the suction device and the surface of the filter were significantly lower in Group A than in Group B(P=0.000 and P=0.000,respectively).CONCLUSION Graphene nanocomposites can effectively sterilize the air in dental clinics by exerting their antimicrobial effects and may be used to reduce secondary pollution.
文摘This study aimed to examine the effect of different disinfection methods on the callus of Amorphophallus albus in the tissue culture and rapid propagation system.The calluses induced from buds of A.albus were disinfected with benzalkonium bromide,mercury bichloride,sodium hypochlorite,and ethanol,respectively,for different time periods.The growth of calluses was compared between different treatments and observed in detail by dissection.The results showed that the disinfection with 0.1% mercury bichloride for 5 min and 75% ethanol for 5 s had mild effect on the callus,with the lowest browning rates of 16.32% and 15.46% and the lowest vitrification rates of 3.24% and 9.72%,respectively,after 20 d.The disinfection with benzalkonium bromide and sodium hypochlorite had strong effect on the callus cells,with the lowest browning rate of 50.69% and 25.12% and the lowest vitrification rates of 28.47% and 28.43%,respectively.The cytological observation result showed that the calluses disinfected with ethanol and mercury bichloride showcased compact structures,while those disinfected with sodium hypochlorite and benzalkonium bromide exhibited loose structures.To sum up,it is recommended that 75% ethanol or 0.1% mercury bichloride can be used for disinfection in the tissue culture and rapid propagation of A.albus,while the use of benzalkonium bromide and sodium hypochlorite should be avoided as much as possible.
文摘Objective:To evaluate the application value of a refined quality control management model for a sterilization supply center.Methods:A retrospective analysis was conducted on the work situation of the sterilization supply center from January 2021 to January 2023.The work situation before January 31,2022,was classified as the control group;a routine quality control management model was implemented,and the work situation after January 31,2022,was classified as the observation group.The quality of medical device management and department satisfaction between the two groups were compared.Results:The timely recovery and supply rate,classification and cleaning pass rate,disinfection pass rate,packaging pass rate,sterilization pass rate,and department satisfaction score in the observation group were all higher than those of the control group(P<0.05).Conclusion:Implementing a refined quality control management model in the sterilization supply center can improve the quality management level of medical devices and department satisfaction and is worthy of promotion.
基金supported by National Natural Science Foundation of China(52208272,41706080 and 51702328)the Basic Scientific Fund for National Public Research Institutes of China(2020S02 and 2019Y03)+3 种基金the Basic Frontier Science Research Program of Chinese Academy of Sciences(ZDBS-LY-DQC025)the Young Elite Scientists Sponsorship Program by CAST(No.YESS20210201)the Strategic Leading Science&Technology Program of the Chinese Academy of Sciences(XDA13040403)the Key Research and Development Program of Shandong Province(Major Scientific and Technological Innovation Project)(2019JZZY020711).
文摘Since the catalytic activity of most nanozymes is still far lower than the corresponding natural enzymes,there is urgent need to discover novel highly efficient enzyme-like materials.In this work,Co_(3)V_(2)O_(8)with hollow hexagonal prismatic pencil structures were prepared as novel artificial enzyme mimics.They were then decorated by photo-depositing Ag nanoparticles(Ag NPs)on the surface to further improve its catalytic activities.The Ag NPs decorated Co_(3)V_(2)O_(8)(ACVPs)showed both excellent oxidase-and peroxidase-like catalytic activities.They can oxidize the colorless 3,3’,5,5’-tetramethylbenzidine rapidly to induce a blue change.The enhanced enzyme mimetic activities can be attributed to the surface plasma resonance(SPR)effect of Ag NPs as well as the synergistic catalytic effect between Ag NPs and Co_(3)V_(2)O_(8),accelerating electron transfer and promoting the catalytic process.ACVPs were applied in constructing a colorimetric sensor,validating the occurrence of the Fenton reaction,and disinfection,presenting favorable catalytic performance.The enzyme-like catalytic mechanism was studied,indicating the chief role of⋅O_(2)-radicals in the catalytic process.This work not only discovers a novel functional material with double enzyme mimetic activity but also provides a new insight into exploiting artificial enzyme mimics with highly efficient catalytic ability.
文摘BACKGROUND Pelvic floor dysfunction(PFD)is related to muscle fiber tearing during childbirth,negatively impacting postpartum quality of life of parturient.Appropriate and effective intervention is necessary to promote PFD recovery.AIM To analyze the use of hydrogen peroxide and silver ion disinfection for vaginal electrodes in conjunction with comprehensive rehabilitation therapy for postpartum women with PFD.METHODS A total of 59 women with PFD who were admitted to the hospital from May 2019 to July 2022 were divided into two groups:Control group(n=27)received comprehensive rehabilitation therapy and observation group(n=32)received intervention with pelvic floor biostimulation feedback instrument in addition to comprehensive rehabilitation therapy.The vaginal electrodes were disinfected with hydrogen peroxide and silver ion before treatment.Intervention for both groups was started 6 weeks postpartum,and rehabilitation lasted for 3 months.Pelvic floor muscle voltage,pelvic floor muscle strength,vaginal muscle voltage,vaginal muscle tone,pelvic floor function,quality of life,and incidence of postpartum PFD were compared between the two groups.RESULTS Before comprehensive rehabilitation treatment,basic data and pelvic floor function were not significantly different between the two groups.After treatment,the observation group showed significant improvements in the maximum voltage and average voltage of pelvic floor muscles,contraction time of type I and type II fibers,pelvic floor muscle strength,vaginal muscle tone,vaginal muscle voltage,and quality of life(GQOLI-74 reports),compared with the control group.The observation group had lower scores on the pelvic floor distress inventory(PFDI-20)and a lower incidence of postpartum PFD,indicating the effectiveness of the pelvic floor biostimulation feedback instrument in promoting the recovery of maternal pelvic floor function.CONCLUSION The combination of the pelvic floor biostimulation feedback instrument and comprehensive rehabilitation nursing can improve pelvic floor muscle strength,promote the recovery of vaginal muscle tone,and improve pelvic floor function and quality of life.The use of hydrogen peroxide and silver ion disinfectant demonstrated favorable antibacterial efficacy and is worthy of clinical application.
基金Fundação de Amparo a Pesquisa do Estado de São Paulo(FAPESP)and the Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq),São Paulo,Brazil for PhD scholarship(Process N°.141086/2015-7)financial support(Process No.870243/1997-7).
文摘The UV irradiation is used for removing Antibiotic Resistant Bacteria(ARB)and Antibiotic Resistance Genes(ARG)from wastewater treatment.Bacteriophages are viruses that infect within bacteria,are recognized for bacterial control.The influence of some parameters in quantification and performance influencing of pathogen demobilization could be considered in disinfection of wastewater.The comparison of Polyvalent phage(NE1)versus Coliphage(NE4)in suppressing a bacterium Escherichia coli(NDM-1:b-lactam-resistant)with UV irradiation was observed the efficacy in reduction of cells in the disinfection and parameter process.The results with the effect of UV-C irradiation on NDM-1 infected with 1%of NE4 showed a decrease of cells from 8×10^(6)to 2×10^(5)in 60 min with UV-C dose.The NDM1(E.coli)was infected with 1%of NE4(Polyvalent Phage)under magnetic stirring for 1 h,the cells count was 8×10^(6).After 1 h in UV-C e×posure,the cells number reached 3×10^(5).The NDM1 that was e×posed in 1 h of UV-C irradiation and then was infected with 1%of NE4.Cells counting were done 24 h after this procedure.These cells were e×posed in UV-C and showed a reduction in the number of cells from 1×10^(8)to 4×10^(5)after 60 min.The results indicate that bacteriophages can mitigate bacteria species,and combined the conventional water disinfection technologies that can support the microbial safety control strategies.
基金supported by the National Major Science and Technology Project on Water Pollution Control and Management of China (No. 2009ZX07424-003)the National Natural Science Foundation of China (No.51108327)the State Key Laboratory of Pollution Control and Resource Reuse Foundation (No. PCRRY11015)
文摘This work investigated the formation of carbonaceous and nitrogenous disinfection by-products （C-DBPs, N-DBPs） upon chlorination of water samples collected from a surface water and a ground water treatment plant （SWTP and GWTP） where the conventional treatment processes, i.e., coagulation, sedimentation, and filtration were employed. Twenty DBPs, including four trihalomethanes, nine haloacetic acids, seven N-DBPs （dichloroacetamide, trichloroacetamide, dichloroacetonitrile, trichloroacetonitrile, bromochloroace- tonitrile, dibromoacetonitrile and trichloronitromethane）, and eight volatile chlorinated compounds （dichloromethane （DCM）, 1,2-dichloroethane, tetrachloroethylene, chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene and 1,2,4- trichlorobenzene） were detected in the two WTPs. The concentrations of these contaminants were all below their corresponding maximum contamination levels （MCLs） regulated by the Standards for Drinking Water Quality of China （GB5749-2006） except for DCM （17.1 ~tg/L detected vs. 20 μg/L MCL）. The SWTP had much higher concentrations of DBPs detected in the treated water as well as the DBP formation potentials tested in the filtered water than the GWTP, probably because more precursors （e.g., dissolved organic carbon, dissolved organic nitrogen） were present in the water source of the SWTE
基金funding from the National Natural Science Foundation of China(Nos.52170021,42177051,and 41977317).
文摘Dissolved black carbon(DBC)released from biochar can be one of the potential disinfection by-products(DBPs)precursors in the dissolved organic matter pool.However,the physiochemical and structural properties of DBC and the effects on the development of DBPs and DBP formation potential(DBPFP)during the disinfection process remain unclear.In this study,the characteristics of two kinds of DBC,namely,animal-derived DBC(poultry litter DBC,PL-DBC)and plant-derived DBC(wheat straw DBC,WS-DBC),were investigated.The effects of different kinds of DBC on the evolution of DBPs and DBPFP in chlorine and chloramine disinfection processes were compared with natural organic matter(NOM).The results showed that the total DBPs concentrations derived from PL-DBC,WS-DBC and NOM were similar during chlorination(i.e.,61.23µg/L,64.59µg/L and 64.66µg/L,respectively)and chloramination(i.e.,44.63µg/L,44.42µg/L and 45.58µg/L,respectively).The lower total DBPs and DBPFP concentrations in chloramination could be attributed to the fact that the introduction of ammonia in chloramine inhibited the breaking of the bond between the disinfectant and the active group of the precursor.Additionally,DBC presented much lower total DBPFP concentrations than NOM in both chlorination and chloramination.However,both kinds of DBC tended to form more monochloroacetic acids and haloacetamides than NOM,which could result from the higher organic strength,higher protein matter,and nitrogen-rich soluble microbial products of DBC.
基金supported by the National Key Research and Development Program of China (No. 2016YFC0401108)
文摘The characteristics of dissolved organic matter（DOM） and bromide ion concentration have a significant influence on the formation of disinfection by-products（DBPs）. In order to identify the main DBP precursors, DOM was divided into five fractions based on molecular weight（MW）, trihalomethane formation potential and haloacetic acid formation potential were determined for fractions, and the change in contents of different fractions and total DBPs during treatment processes（pre-chlorination, coagulation, sand filtration,disinfection） were studied. Moreover, the relationship between bromide concentration and DBP generation characteristics in processes was also analyzed. The results showed that the main DBP precursors were the fraction with MW 1 k Da and fraction with MW 3-10 k Da, and the DBP＇s generation ability of lower molecular weight DOM（ 10 k Da） was higher than that of higher molecular weight DOM. During different processes,pre-chlorination and disinfection had limited effect on removing organics but could alter the MW distribution, and coagulation and filtration could effectively remove organics with higher MW. For DBPs, trihalomethanes（THMs） were mainly generated in pre-chlorination and disinfection, while haloacetic acids（HAAs） were mostly generated during pre-chlorination; coagulation and sand filtration had little effect on THMs but resulted in a slight removal of HAAs. In addition, the results of ANOVA tests suggested that molecular sizes and treatment processes have significant influence on DBP formation. With increasing bromide concentration, the brominated DBPs significantly increased, but the bromine incorporation factor in the processes was basically consistent at each concentration.
