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Junxin Liu - One of the best experts on this subject based on the ideXlab platform.

  • Study of the generation and diffusion of bioaerosol under two aeration conditions.
    Environmental pollution (Barking Essex : 1987), 2020
    Co-Authors: Yunping Han, Tang Yang, Chao Han, Junxin Liu
    Abstract:

    Abstract Given that studies on actual sewage treatment plants are often affected by environmental conditions, it is challenging to clearly understand the associated bioaerosol generation and diffusion characteristics during the aeration process. Therefore, to enhance understanding in this regard, in this study, bioaerosol generator was used to simulate bioaerosol generation and diffusion under two aeration modes, i.e., bubble bottom aeration and brush surface aeration. The total concentration range of culturable bacteria in the bioaerosol produced by bubble bottom aeration and that produced by brush surface aeration were 300–3000 CFU/m3. Under bubble bottom aeration, the generated bioaerosol was symmetrically distributed around the source point, whereas under brush surface aeration, it was primarily distributed in the forward direction of the rotating brush surface. These Bioaerosols from bubble bottom aeration predominantly consisted of particles with sizes below 3.3 μm, particularly those with sizes in the range 1.1–2.1 μm. On the contrary, the Bioaerosols produced via brush surface aeration predominantly consisted of particles with sizes above 3.3 μm. The distribution characteristics of population structure in the two aeration modes were consistent with the distribution characteristics of concentration in the corresponding models. Additionally, the results showed that when the aeration process is unaffected by environmental conditions (particle matters, wind direct, wind speed, etc.), the bioaerosol components originate primarily from the parent sewage or sludge, and do not diffuse far from the source point. Therefore, source reduction (capping or sealing) can be recommended as the primary control strategy for Bioaerosols in sewage treatment plants. The adoption of such measures will significantly limit the diffusion of Bioaerosols, thereby reducing the potential risks associated with human exposure.

  • composition dispersion and health risks of Bioaerosols in wastewater treatment plants a review
    Frontiers of Environmental Science & Engineering in China, 2020
    Co-Authors: Yunping Han, Chao Han, Ying Wang, Junxin Liu
    Abstract:

    Bioaerosols are defined as airborne particles (0.05–100 μn in size) of biological origin. They are considered potentially harmful to human health as they can contain pathogens such as bacteria, fungi, and viruses. This review summarizes the most recent research on the health risks of Bioaerosols emitted from wastewater treatment plants (WWTPs) in order to improve the control of such Bioaerosols. The concentration and size distribution of WWTP Bioaerosols; their major emission sources, composition, and health risks; and considerations for future research are discussed. The major themes and findings in the literature are as follows: the major emission sources of WWTP Bioaerosols include screen rooms, sludge-dewatering rooms, and aeration tanks; the bioaerosol concentrations in screen and sludge-dewatering rooms are higher than those outdoors. WWTP Bioaerosols contain a variety of potentially pathogenic bacteria, fungi, antibiotic resistance genes, viruses, endotoxins, and toxic metal(loid)s. These potentially pathogenic substances spread with the Bioaerosols, thereby posing health risks to workers and residents in and around the WWTP. Inhalation has been identified as the main exposure route, and children are at a higher risk of this than adults. Future studies should identify emerging contaminants, establish health risk assessments, and develop prevention and control systems.

  • Characteristics and interactions of bioaerosol microorganisms from wastewater treatment plants.
    Journal of hazardous materials, 2020
    Co-Authors: Yunping Han, Tang Yang, Xu Guangsu, Junxin Liu
    Abstract:

    Bacteria and fungi are abundant and ubiquitous in Bioaerosols from wastewater treatment plants (WWTPs). However, the specificity and interactions of bioaerosol microorganism, particularly of potential pathogens, from WWTPs are still poorly understood. In this study, we investigated 9 full-scale WWTPs in different areas of China for 3 years, and found microbial variations in Bioaerosols to be associated with regions, seasons, and processes. Relative humidity, total suspended particulates, wind speed, temperature, total organic carbon, NH4+, Cl- and Ca2+ were the major factors influencing this variation, and meteorological factors were more strongly associated with the variation than chemical composition. In total, 95 and 22 potential bacterial and fungal pathogens were detected in Bioaerosols, respectively. The linear discriminant analysis effect size method suggested that Serratia, Yersinia, Klebsiella, and Bacillus were discriminative genera in Bioaerosols on the whole, and were also hub niches in the interactions within potential bacterial pathogens, based on network analysis. Strong co-occurrences such as Serratia-Bacillus and Staphylococcus-Candida, and co-exclusions such as Rhodotorula-Cladosporium and Pseudomonas-Candida, were found within and between potential bacterial and fungal pathogens in Bioaerosols from WWTPs. This study furthers understanding of the biology and ecology of Bioaerosols from WWTPs, and offers a theoretical basis for determining bioaerosol control.

  • Characteristics of Bioaerosols Emitted from WWTP with SBR Treatment Process
    Huan jing ke xue= Huanjing kexue, 2018
    Co-Authors: Kaixiong Yang, Yunping Han, Hong-xun Hou, Ying-zhe Wang, Hao-ran Shi, Junxin Liu
    Abstract:

    Sampling sites were located in a wastewater treatment plant (WWTP) with a sequencing batch reactor activated sludge process to investigate the characteristics of bioaerosol emissions. The results indicated that Bioaerosols were detected from each treatment section of the WWTP, and concentrations of Bioaerosols were in the range of 82-1525 CFU·m-3. The coarse screen, aeration tank, and sludge dewatering house were the main sources of Bioaerosols. The dominant species in each treatment section was Cyanobacteria, and the other main bacterial taxa were Aeromonas, Peptostreptococcaceae, Moraxellaceae, Chroococcidiopsis, Sphingomonas, Arcobacter, and Acinetobacter. Among the identified bacterial genera, Aeromonas, Arcobacter, Acinetobacter, and Sphingomonas were potential pathogens. Bioaerosol concentration and abundance decreased along the vertical and horizontal directions. Appropriate temperature and relative humidity benefited the survival of Bioaerosols in the air (P

  • characteristics of Bioaerosols emitted from wwtp with sbr treatment process
    Huan jing ke xue= Huanjing kexue, 2018
    Co-Authors: Kaixiong Yang, Yunping Han, Hong-xun Hou, Ying-zhe Wang, Hao-ran Shi, Junxin Liu
    Abstract:

    Sampling sites were located in a wastewater treatment plant (WWTP) with a sequencing batch reactor activated sludge process to investigate the characteristics of bioaerosol emissions. The results indicated that Bioaerosols were detected from each treatment section of the WWTP, and concentrations of Bioaerosols were in the range of 82-1525 CFU·m-3. The coarse screen, aeration tank, and sludge dewatering house were the main sources of Bioaerosols. The dominant species in each treatment section was Cyanobacteria, and the other main bacterial taxa were Aeromonas, Peptostreptococcaceae, Moraxellaceae, Chroococcidiopsis, Sphingomonas, Arcobacter, and Acinetobacter. Among the identified bacterial genera, Aeromonas, Arcobacter, Acinetobacter, and Sphingomonas were potential pathogens. Bioaerosol concentration and abundance decreased along the vertical and horizontal directions. Appropriate temperature and relative humidity benefited the survival of Bioaerosols in the air (P<0.01), whereas a negative relationship between bioaerosol concentration and wind speed was observed (P<0.05). Although exposure risks caused by Bioaerosols were negligible in this study, the accumulation of Bioaerosols would increase potential health risks. The bioreactor for odor treatment could effectively reduce bioaerosol emissions.

Yunping Han - One of the best experts on this subject based on the ideXlab platform.

  • Study of the generation and diffusion of bioaerosol under two aeration conditions.
    Environmental pollution (Barking Essex : 1987), 2020
    Co-Authors: Yunping Han, Tang Yang, Chao Han, Junxin Liu
    Abstract:

    Abstract Given that studies on actual sewage treatment plants are often affected by environmental conditions, it is challenging to clearly understand the associated bioaerosol generation and diffusion characteristics during the aeration process. Therefore, to enhance understanding in this regard, in this study, bioaerosol generator was used to simulate bioaerosol generation and diffusion under two aeration modes, i.e., bubble bottom aeration and brush surface aeration. The total concentration range of culturable bacteria in the bioaerosol produced by bubble bottom aeration and that produced by brush surface aeration were 300–3000 CFU/m3. Under bubble bottom aeration, the generated bioaerosol was symmetrically distributed around the source point, whereas under brush surface aeration, it was primarily distributed in the forward direction of the rotating brush surface. These Bioaerosols from bubble bottom aeration predominantly consisted of particles with sizes below 3.3 μm, particularly those with sizes in the range 1.1–2.1 μm. On the contrary, the Bioaerosols produced via brush surface aeration predominantly consisted of particles with sizes above 3.3 μm. The distribution characteristics of population structure in the two aeration modes were consistent with the distribution characteristics of concentration in the corresponding models. Additionally, the results showed that when the aeration process is unaffected by environmental conditions (particle matters, wind direct, wind speed, etc.), the bioaerosol components originate primarily from the parent sewage or sludge, and do not diffuse far from the source point. Therefore, source reduction (capping or sealing) can be recommended as the primary control strategy for Bioaerosols in sewage treatment plants. The adoption of such measures will significantly limit the diffusion of Bioaerosols, thereby reducing the potential risks associated with human exposure.

  • composition dispersion and health risks of Bioaerosols in wastewater treatment plants a review
    Frontiers of Environmental Science & Engineering in China, 2020
    Co-Authors: Yunping Han, Chao Han, Ying Wang, Junxin Liu
    Abstract:

    Bioaerosols are defined as airborne particles (0.05–100 μn in size) of biological origin. They are considered potentially harmful to human health as they can contain pathogens such as bacteria, fungi, and viruses. This review summarizes the most recent research on the health risks of Bioaerosols emitted from wastewater treatment plants (WWTPs) in order to improve the control of such Bioaerosols. The concentration and size distribution of WWTP Bioaerosols; their major emission sources, composition, and health risks; and considerations for future research are discussed. The major themes and findings in the literature are as follows: the major emission sources of WWTP Bioaerosols include screen rooms, sludge-dewatering rooms, and aeration tanks; the bioaerosol concentrations in screen and sludge-dewatering rooms are higher than those outdoors. WWTP Bioaerosols contain a variety of potentially pathogenic bacteria, fungi, antibiotic resistance genes, viruses, endotoxins, and toxic metal(loid)s. These potentially pathogenic substances spread with the Bioaerosols, thereby posing health risks to workers and residents in and around the WWTP. Inhalation has been identified as the main exposure route, and children are at a higher risk of this than adults. Future studies should identify emerging contaminants, establish health risk assessments, and develop prevention and control systems.

  • Characteristics and interactions of bioaerosol microorganisms from wastewater treatment plants.
    Journal of hazardous materials, 2020
    Co-Authors: Yunping Han, Tang Yang, Xu Guangsu, Junxin Liu
    Abstract:

    Bacteria and fungi are abundant and ubiquitous in Bioaerosols from wastewater treatment plants (WWTPs). However, the specificity and interactions of bioaerosol microorganism, particularly of potential pathogens, from WWTPs are still poorly understood. In this study, we investigated 9 full-scale WWTPs in different areas of China for 3 years, and found microbial variations in Bioaerosols to be associated with regions, seasons, and processes. Relative humidity, total suspended particulates, wind speed, temperature, total organic carbon, NH4+, Cl- and Ca2+ were the major factors influencing this variation, and meteorological factors were more strongly associated with the variation than chemical composition. In total, 95 and 22 potential bacterial and fungal pathogens were detected in Bioaerosols, respectively. The linear discriminant analysis effect size method suggested that Serratia, Yersinia, Klebsiella, and Bacillus were discriminative genera in Bioaerosols on the whole, and were also hub niches in the interactions within potential bacterial pathogens, based on network analysis. Strong co-occurrences such as Serratia-Bacillus and Staphylococcus-Candida, and co-exclusions such as Rhodotorula-Cladosporium and Pseudomonas-Candida, were found within and between potential bacterial and fungal pathogens in Bioaerosols from WWTPs. This study furthers understanding of the biology and ecology of Bioaerosols from WWTPs, and offers a theoretical basis for determining bioaerosol control.

  • Bioaerosols emission and exposure risk of a wastewater treatment plant with a2o treatment process
    Ecotoxicology and Environmental Safety, 2019
    Co-Authors: Yunping Han, Kaixiong Yang, Tang Yang, Mengzhu Zhang
    Abstract:

    Abstract The characteristics of bioaerosol emissions from wastewater treatment plants (WWTPs) have attracted extensive attention. The anaerobic-anoxic-oxic (A2O) process, which uses the activated sludge approach to wastewater treatment, is the most widely used process in WWTPs. Concentration, size distribution, population, and exposure risk from bacteria and fungi in Bioaerosols of WWTPs using the A2O process were studied in this work. The results showed that the maximum concentration of airborne bacteria (1.00 × 104 Colony Forming Units per cubic meter (CFU m−3)) and fungi (1.44 ×104 CFU m−3) occurred from the facility's aerobic tank, in summer. As one of the main factors affecting bioaerosol exposure risk, particle size distribution was related to season. The study found that particles larger than 3.3 µm in diameter were detected mainly in spring and summer, while particles less than 3.3 µm were detected mainly in autumn and winter, whether bacterial aerosol or fungal aerosol. In addition, pathogenic bacteria were observed in Bioaerosols from WWTPs, with 18 of the 65 species of bacteria detected found to be potentially or opportunistically pathogenic, such as Chryseobacterium, Stenotrophomonas, Alcaligenes, Micrococcus, Pantoea, Enterobacter and Escherichia-Shigella. The presence of these pathogens further increased the exposure risk from Bioaerosols. The results of an inhalation risk assessment for airborne bacteria and fungi indicated that potential adverse health risks for adults mainly occurred in spring, summer, and autumn. On this basis, it was concluded that WWTP operators should set up effective bioaerosol controls as soon as possible to protect the health of workers, and of residents near the plant.

  • Characteristics of Bioaerosols Emitted from WWTP with SBR Treatment Process
    Huan jing ke xue= Huanjing kexue, 2018
    Co-Authors: Kaixiong Yang, Yunping Han, Hong-xun Hou, Ying-zhe Wang, Hao-ran Shi, Junxin Liu
    Abstract:

    Sampling sites were located in a wastewater treatment plant (WWTP) with a sequencing batch reactor activated sludge process to investigate the characteristics of bioaerosol emissions. The results indicated that Bioaerosols were detected from each treatment section of the WWTP, and concentrations of Bioaerosols were in the range of 82-1525 CFU·m-3. The coarse screen, aeration tank, and sludge dewatering house were the main sources of Bioaerosols. The dominant species in each treatment section was Cyanobacteria, and the other main bacterial taxa were Aeromonas, Peptostreptococcaceae, Moraxellaceae, Chroococcidiopsis, Sphingomonas, Arcobacter, and Acinetobacter. Among the identified bacterial genera, Aeromonas, Arcobacter, Acinetobacter, and Sphingomonas were potential pathogens. Bioaerosol concentration and abundance decreased along the vertical and horizontal directions. Appropriate temperature and relative humidity benefited the survival of Bioaerosols in the air (P

Kaixiong Yang - One of the best experts on this subject based on the ideXlab platform.

  • Bioaerosols emission and exposure risk of a wastewater treatment plant with a2o treatment process
    Ecotoxicology and Environmental Safety, 2019
    Co-Authors: Yunping Han, Kaixiong Yang, Tang Yang, Mengzhu Zhang
    Abstract:

    Abstract The characteristics of bioaerosol emissions from wastewater treatment plants (WWTPs) have attracted extensive attention. The anaerobic-anoxic-oxic (A2O) process, which uses the activated sludge approach to wastewater treatment, is the most widely used process in WWTPs. Concentration, size distribution, population, and exposure risk from bacteria and fungi in Bioaerosols of WWTPs using the A2O process were studied in this work. The results showed that the maximum concentration of airborne bacteria (1.00 × 104 Colony Forming Units per cubic meter (CFU m−3)) and fungi (1.44 ×104 CFU m−3) occurred from the facility's aerobic tank, in summer. As one of the main factors affecting bioaerosol exposure risk, particle size distribution was related to season. The study found that particles larger than 3.3 µm in diameter were detected mainly in spring and summer, while particles less than 3.3 µm were detected mainly in autumn and winter, whether bacterial aerosol or fungal aerosol. In addition, pathogenic bacteria were observed in Bioaerosols from WWTPs, with 18 of the 65 species of bacteria detected found to be potentially or opportunistically pathogenic, such as Chryseobacterium, Stenotrophomonas, Alcaligenes, Micrococcus, Pantoea, Enterobacter and Escherichia-Shigella. The presence of these pathogens further increased the exposure risk from Bioaerosols. The results of an inhalation risk assessment for airborne bacteria and fungi indicated that potential adverse health risks for adults mainly occurred in spring, summer, and autumn. On this basis, it was concluded that WWTP operators should set up effective bioaerosol controls as soon as possible to protect the health of workers, and of residents near the plant.

  • Characteristics of Bioaerosols Emitted from WWTP with SBR Treatment Process
    Huan jing ke xue= Huanjing kexue, 2018
    Co-Authors: Kaixiong Yang, Yunping Han, Hong-xun Hou, Ying-zhe Wang, Hao-ran Shi, Junxin Liu
    Abstract:

    Sampling sites were located in a wastewater treatment plant (WWTP) with a sequencing batch reactor activated sludge process to investigate the characteristics of bioaerosol emissions. The results indicated that Bioaerosols were detected from each treatment section of the WWTP, and concentrations of Bioaerosols were in the range of 82-1525 CFU·m-3. The coarse screen, aeration tank, and sludge dewatering house were the main sources of Bioaerosols. The dominant species in each treatment section was Cyanobacteria, and the other main bacterial taxa were Aeromonas, Peptostreptococcaceae, Moraxellaceae, Chroococcidiopsis, Sphingomonas, Arcobacter, and Acinetobacter. Among the identified bacterial genera, Aeromonas, Arcobacter, Acinetobacter, and Sphingomonas were potential pathogens. Bioaerosol concentration and abundance decreased along the vertical and horizontal directions. Appropriate temperature and relative humidity benefited the survival of Bioaerosols in the air (P

  • characteristics of Bioaerosols emitted from wwtp with sbr treatment process
    Huan jing ke xue= Huanjing kexue, 2018
    Co-Authors: Kaixiong Yang, Yunping Han, Hong-xun Hou, Ying-zhe Wang, Hao-ran Shi, Junxin Liu
    Abstract:

    Sampling sites were located in a wastewater treatment plant (WWTP) with a sequencing batch reactor activated sludge process to investigate the characteristics of bioaerosol emissions. The results indicated that Bioaerosols were detected from each treatment section of the WWTP, and concentrations of Bioaerosols were in the range of 82-1525 CFU·m-3. The coarse screen, aeration tank, and sludge dewatering house were the main sources of Bioaerosols. The dominant species in each treatment section was Cyanobacteria, and the other main bacterial taxa were Aeromonas, Peptostreptococcaceae, Moraxellaceae, Chroococcidiopsis, Sphingomonas, Arcobacter, and Acinetobacter. Among the identified bacterial genera, Aeromonas, Arcobacter, Acinetobacter, and Sphingomonas were potential pathogens. Bioaerosol concentration and abundance decreased along the vertical and horizontal directions. Appropriate temperature and relative humidity benefited the survival of Bioaerosols in the air (P<0.01), whereas a negative relationship between bioaerosol concentration and wind speed was observed (P<0.05). Although exposure risks caused by Bioaerosols were negligible in this study, the accumulation of Bioaerosols would increase potential health risks. The bioreactor for odor treatment could effectively reduce bioaerosol emissions.

  • chemicals and microbes in Bioaerosols from reaction tanks of six wastewater treatment plants survival factors generation sources and mechanisms
    Scientific Reports, 2018
    Co-Authors: Yanjie Wang, Kaixiong Yang, Huachun Lan, Junxin Liu
    Abstract:

    Sampling was conducted from biochemical reaction tanks of six municipal wastewater treatment plants in the Yangtze River and Zhujiang deltas and the Jing-Jin-Ji region to assess their morphology, level, and composition. Morphological observations suggested that particles were scattered amorphously with C, O, and Si as the major elements. Bioaerosols are composed of spatially varying levels of microorganisms and chemicals. As the sampling height increased, the level of the components in the Bioaerosols decreased. Wastewater in the biochemical reaction tanks was identified as an important source of Bioaerosols using SourceTracker analysis. The aerosolization of film drops produced by bursting of bubbles was the main reason for the generation of Bioaerosols. Increasing the aeration rate of water may promote bioaerosol generation. Relative humidity, temperature, wind speed, and solar illumination influenced the survival of Bioaerosols. Large particle sedimentation and wind diffusion significantly decreased the atmospheric aerosol concentration. When the sampling point height increased from 0.1 m to 3.0 m, the concentrations of the microorganisms and total suspended particles decreased by 23.71% and 38.74%, respectively. Considerable attention should be paid to the control of total suspended particles and microorganisms in Bioaerosols.

  • intestinal bacteria in Bioaerosols and factors affecting their survival in two oxidation ditch process municipal wastewater treatment plants located in different regions
    Ecotoxicology and Environmental Safety, 2018
    Co-Authors: Yanjie Wang, Yunping Han, Junxin Liu, Kaixiong Yang
    Abstract:

    Samples from two oxidation ditch process municipal wastewater treatment plants (MWTPs) (HJK and GXQ) in two regions of China were analysed for bacteria, particles, total organic carbon, and water-soluble ions in Bioaerosols. Diversity and potential pathogen populations were evaluated by high-throughput sequencing. Bioaerosol sources, factors affecting intestinal bacterial survival, and the relationship between Bioaerosols and water were analysed by Source tracker and partial least squares-discriminant, principal component, and canonical correspondence analyses. Culturable bacteria concentrations were 110-846 and 27-579 CFU/m3 at HJK and GXQ, respectively. Intestinal bacteria constituted 6-33% of bacteria. Biochemical reaction tank, sludge dewatering house (SDH), and fine screen samples showed the greatest contribution to bioaerosol contamination. Enterobacter aerogenes was the main intestinal bacteria (> 99.5%) in HJK and detected at each sampling site. Enterobacter aerogenes (98.67% in SDH), Aeromonas sp. (76.3% in biochemical reaction tank), and Acinetobacter baumannii (99.89% in fine screens) were the main intestinal bacteria in GXQ. Total suspended particulate masses in SDH were 229.46 and 141.6 μg/m3 in HJK and GXQ, respectively. Percentages of insoluble compounds in total suspended particulates decreased as height increased. The main soluble ions in Bioaerosols were Ca2+, Na+, Cl-, and SO42-, which ranged from 3.8 to 27.55 μg/m3 in the MWTPs. Water was a main source of intestinal bacteria in Bioaerosols from the MWTPs. Bioaerosols in HJK but not in GXQ were closely related. Relative humidity and some ions positively influenced intestinal bacteria in Bioaerosols, while wind speed and solar illumination had a negative influence.

Matthew W. Nonnenmann - One of the best experts on this subject based on the ideXlab platform.

  • Bioaerosols generated from toilet flushing in rooms of patients with Clostridioides difficile infection.
    Infection control and hospital epidemiology, 2020
    Co-Authors: Geneva Wilson, Virgil B Jackson, Linda D Boyken, Marin L. Schweizer, Daniel J. Diekema, Christine A. Petersen, Patrick Breheny, Matthew W. Nonnenmann, Eli N. Perencevich, Cdc Prevention Epicenter Program
    Abstract:

    Background Clostridioides difficile infection (CDI) is the most frequently reported hospital-acquired infection in the United States. Bioaerosols generated during toilet flushing are a possible mechanism for the spread of this pathogen in clinical settings. Objective To measure the bioaerosol concentration from toilets of patients with CDI before and after flushing. Design In this pilot study, Bioaerosols were collected 0.15 m, 0.5 m, and 1.0 m from the rims of the toilets in the bathrooms of hospitalized patients with CDI. Inhibitory, selective media were used to detect C. difficile and other facultative anaerobes. Room air was collected continuously for 20 minutes with a bioaerosol sampler before and after toilet flushing. Wilcoxon rank-sum tests were used to assess the difference in bioaerosol production before and after flushing. Setting Rooms of patients with CDI at University of Iowa Hospitals and Clinics. Results Bacteria were positively cultured from 8 of 24 rooms (33%). In total, 72 preflush and 72 postflush samples were collected; 9 of the preflush samples (13%) and 19 of the postflush samples (26%) were culture positive for healthcare-associated bacteria. The predominant species cultured were Enterococcus faecalis, E. faecium, and C. difficile. Compared to the preflush samples, the postflush samples showed significant increases in the concentrations of the 2 large particle-size categories: 5.0 µm (P = .0095) and 10.0 µm (P = .0082). Conclusions Bioaerosols produced by toilet flushing potentially contribute to hospital environmental contamination. Prevention measures (eg, toilet lids) should be evaluated as interventions to prevent toilet-associated environmental contamination in clinical settings.

  • Bioaerosol concentrations generated from toilet flushing in a hospital-based patient care setting
    Antimicrobial Resistance & Infection Control, 2018
    Co-Authors: Samantha D. Knowlton, Daniel J. Diekema, Eli N. Perencevich, Corey L. Boles, Matthew W. Nonnenmann
    Abstract:

    Background In the United States, 1.7 million immunocompromised patients contract a healthcare-associated infection, annually. These infections increase morbidity, mortality and costs of care. A relatively unexplored route of transmission is the generation of Bioaerosols during patient care. Transmission of pathogenic microorganisms may result from inhalation or surface contamination of Bioaerosols. The toilet flushing of patient fecal waste may be a source of Bioaerosols. To date, no study has investigated bioaerosol concentrations from flushing fecal wastes during patient care. Methods Particle and bioaerosol concentrations were measured in hospital bathrooms across three sampling conditions; no waste no flush, no waste with flush, and fecal waste with flush. Particle and bioaerosol concentrations were measured with a particle counter bioaerosol sampler both before after a toilet flushing event at distances of 0.15, 0.5, and 1 m from the toilet for 5, 10, 15 min. Results Particle concentrations measured before and after the flush were found to be significantly different (0.3–10 μm). Bioaerosol concentrations when flushing fecal waste were found to be significantly greater than background concentrations ( p -value = 0.005). However, the bioaerosol concentrations were not different across time ( p -value = 0.977) or distance ( p -value = 0.911) from the toilet, suggesting that aerosols generated may remain for longer than 30 min post flush. Toilets produce aerosol particles when flushed, with the majority of the particles being 0.3 μm in diameter. The particles aerosolized include microorganisms remaining from previous use or from fecal wastes. Differences in bioaerosol concentrations across conditions also suggest that toilet flushing is a source of Bioaerosols that may result in transmission of pathogenic microorganisms. Conclusions This study is the first to quantify particles and Bioaerosols produced from flushing a hospital toilet during routine patient care. Future studies are needed targeting pathogens associated with gastrointestinal illness and evaluating aerosol exposure reduction interventions.

Yanjie Wang - One of the best experts on this subject based on the ideXlab platform.

  • chemicals and microbes in Bioaerosols from reaction tanks of six wastewater treatment plants survival factors generation sources and mechanisms
    Scientific Reports, 2018
    Co-Authors: Yanjie Wang, Kaixiong Yang, Huachun Lan, Junxin Liu
    Abstract:

    Sampling was conducted from biochemical reaction tanks of six municipal wastewater treatment plants in the Yangtze River and Zhujiang deltas and the Jing-Jin-Ji region to assess their morphology, level, and composition. Morphological observations suggested that particles were scattered amorphously with C, O, and Si as the major elements. Bioaerosols are composed of spatially varying levels of microorganisms and chemicals. As the sampling height increased, the level of the components in the Bioaerosols decreased. Wastewater in the biochemical reaction tanks was identified as an important source of Bioaerosols using SourceTracker analysis. The aerosolization of film drops produced by bursting of bubbles was the main reason for the generation of Bioaerosols. Increasing the aeration rate of water may promote bioaerosol generation. Relative humidity, temperature, wind speed, and solar illumination influenced the survival of Bioaerosols. Large particle sedimentation and wind diffusion significantly decreased the atmospheric aerosol concentration. When the sampling point height increased from 0.1 m to 3.0 m, the concentrations of the microorganisms and total suspended particles decreased by 23.71% and 38.74%, respectively. Considerable attention should be paid to the control of total suspended particles and microorganisms in Bioaerosols.

  • intestinal bacteria in Bioaerosols and factors affecting their survival in two oxidation ditch process municipal wastewater treatment plants located in different regions
    Ecotoxicology and Environmental Safety, 2018
    Co-Authors: Yanjie Wang, Yunping Han, Junxin Liu, Kaixiong Yang
    Abstract:

    Samples from two oxidation ditch process municipal wastewater treatment plants (MWTPs) (HJK and GXQ) in two regions of China were analysed for bacteria, particles, total organic carbon, and water-soluble ions in Bioaerosols. Diversity and potential pathogen populations were evaluated by high-throughput sequencing. Bioaerosol sources, factors affecting intestinal bacterial survival, and the relationship between Bioaerosols and water were analysed by Source tracker and partial least squares-discriminant, principal component, and canonical correspondence analyses. Culturable bacteria concentrations were 110-846 and 27-579 CFU/m3 at HJK and GXQ, respectively. Intestinal bacteria constituted 6-33% of bacteria. Biochemical reaction tank, sludge dewatering house (SDH), and fine screen samples showed the greatest contribution to bioaerosol contamination. Enterobacter aerogenes was the main intestinal bacteria (> 99.5%) in HJK and detected at each sampling site. Enterobacter aerogenes (98.67% in SDH), Aeromonas sp. (76.3% in biochemical reaction tank), and Acinetobacter baumannii (99.89% in fine screens) were the main intestinal bacteria in GXQ. Total suspended particulate masses in SDH were 229.46 and 141.6 μg/m3 in HJK and GXQ, respectively. Percentages of insoluble compounds in total suspended particulates decreased as height increased. The main soluble ions in Bioaerosols were Ca2+, Na+, Cl-, and SO42-, which ranged from 3.8 to 27.55 μg/m3 in the MWTPs. Water was a main source of intestinal bacteria in Bioaerosols from the MWTPs. Bioaerosols in HJK but not in GXQ were closely related. Relative humidity and some ions positively influenced intestinal bacteria in Bioaerosols, while wind speed and solar illumination had a negative influence.

  • bacterial population and chemicals in Bioaerosols from indoor environment sludge dewatering houses in nine municipal wastewater treatment plants
    Science of The Total Environment, 2018
    Co-Authors: Yunping Han, Yanjie Wang, Junxin Liu, Kaixiong Yang
    Abstract:

    Abstract Municipal wastewater treatment plants (MWTPs) are regarded as sources of airborne microorganisms. Sludge dewatering house (SDH) is one of the most serious indoor bioaerosol pollution treatment sectors in MWTPs. In this study, properties of Bioaerosols from SDHs of nine MWTPs were investigated in China. Results suggested that Bioaerosols were generated mainly from the mixed liquor and will be promoted by the mechanical motion of belts of dewatering devices. They will accumulate in the SDHs due to the treatment devices placed inside. Levels of airborne bacteria and chemicals showed regional variations. In Hefei and Yixing, the emissions of total suspended particles (TSP) and airborne bacteria were higher than those in Beijing and Guangzhou. Results of bacterial population showed that bacterial species in Bioaerosols from SDHs also presented significant regional disparity; these regional disparities were closely related with the source of Bioaerosols in SDHs. Among these identified bacterial species, some common potential pathogens were detected in all SDHs, such as Aeromonas caviae, Flavobacterium sp., and Staphylococcus lentus. Relative humidity (RH) and temperature were the major parameters on Bioaerosols to survive. As shown in this study, SDHs in wastewater treatment plants should be provided considerable attention for being an emission source of indoor Bioaerosols.