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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Evaluation of microbial health risks associated with the reuse of source-separated humna urine

Höglund, Caroline January 2001 (has links)
Human excreta contain plant nutrients and have the potentialto be used as a fertiliser in agriculture. Urine contributesthe major proportion of the nutrients (N, P and K) in domesticwastewater whereas faeces contribute a smaller amount andinvolves greater health risks if reused due to the possiblepresence of enteric pathogens. Human urine does not generallycontain pathogens that can be transmitted through theenvironment. Source-separation of urine and faeces is possible by usingurine-separating (or urine-diverting) toilets, available assimple dry toilets or porcelain flush toilets with dividedbowls. The risk for transmission of disease when handling andreusing the urine is largely dependent on thecross-contamination by faeces. In this research, the presenceof human faeces in urine samples was successfully determined byanalysing for faecal sterols. Cross-contamination was evidentin 22% of the samples from urine collection tanks, and in thesequantified to an average (± SD) of 9.1 ± 5.6 mgfaeces per litre urine. Testing for indicator bacteria wasshown to be an unsuitable method for determining faecalcontamination in human urine sinceE. colihad a rapid inactivation in the urine and faecalstreptococci were found to grow within the system. The fate of any enteric pathogens present in urine iscrucial for the risk for transmission of infectious diseases.Gram-negative bacteria (e.g.SalmonellaandE. coli) were rapidly inactivated (time for 90%reduction, T90&lt;5 days) in source-separated urine at itsnatural pH-value of 9. Gram-positive faecal streptococci weremore persistent with a T90of approximately 30 days. Clostridia sporenumbers were not reduced at all during 80 days. Similarly,rhesusrotavirus andSalmonella typhimuriumphage 28B were not inactivated inurine at low temperature (5°C), whereas at 20°C theirT90-values were 35 and 71 days, respectively.Cryptosporidiumoocysts were less persistent with a T90of 29 days at 4°C. Factors that affect thepersistence of microorganisms in source-separated human urineinclude temperature, pH, dilution and presence of ammonia. By using Quantitative Microbial Risk Assessment (QMRA), therisks for bacterial and protozoan infections related tohandling and reuse of urine were calculated to be&lt;10-3for all exposure routes independent of the urinestorage time and temperature evaluated. The risk for viralinfection was higher, calculated at 0.56 for accidentalingestion of 1 ml of unstored urine. If the urine was stored at20°C for 6 months the risk for viral infection was reducedto 5.4 × 10-4. By following recommendations for storage and reuse, whichare dependent on the type of crop to be fertilised, it ispossible to significantly decrease the risk for infections. Sofar, the level of risk that is acceptable is unknown. Theacceptable risk will be one of the main factors determining thefuture utilisation of source-separated human urine inagriculture. <b>Keywords:</b>urine-separation, urine, wastewater systems,wastewater reuse, recycling, enteric pathogens, faecal sterols,indicator bacteria, hygiene risks, microbial persistence,microbial risk assessment, QMRA, fertiliser, crop.
2

Evaluation of microbial health risks associated with the reuse of source-separated humna urine

Höglund, Caroline January 2001 (has links)
<p>Human excreta contain plant nutrients and have the potentialto be used as a fertiliser in agriculture. Urine contributesthe major proportion of the nutrients (N, P and K) in domesticwastewater whereas faeces contribute a smaller amount andinvolves greater health risks if reused due to the possiblepresence of enteric pathogens. Human urine does not generallycontain pathogens that can be transmitted through theenvironment.</p><p>Source-separation of urine and faeces is possible by usingurine-separating (or urine-diverting) toilets, available assimple dry toilets or porcelain flush toilets with dividedbowls. The risk for transmission of disease when handling andreusing the urine is largely dependent on thecross-contamination by faeces. In this research, the presenceof human faeces in urine samples was successfully determined byanalysing for faecal sterols. Cross-contamination was evidentin 22% of the samples from urine collection tanks, and in thesequantified to an average (± SD) of 9.1 ± 5.6 mgfaeces per litre urine. Testing for indicator bacteria wasshown to be an unsuitable method for determining faecalcontamination in human urine since<i>E. coli</i>had a rapid inactivation in the urine and faecalstreptococci were found to grow within the system.</p><p>The fate of any enteric pathogens present in urine iscrucial for the risk for transmission of infectious diseases.Gram-negative bacteria (e.g.<i>Salmonella</i>and<i>E. coli</i>) were rapidly inactivated (time for 90%reduction, T<sub>90</sub><5 days) in source-separated urine at itsnatural pH-value of 9. Gram-positive faecal streptococci weremore persistent with a T<sub>90</sub>of approximately 30 days. Clostridia sporenumbers were not reduced at all during 80 days. Similarly,<i>rhesus</i>rotavirus and<i>Salmonella typhimurium</i>phage 28B were not inactivated inurine at low temperature (5°C), whereas at 20°C theirT<sub>90</sub>-values were 35 and 71 days, respectively.<i>Cryptosporidium</i>oocysts were less persistent with a T<sub>90</sub>of 29 days at 4°C. Factors that affect thepersistence of microorganisms in source-separated human urineinclude temperature, pH, dilution and presence of ammonia.</p><p>By using Quantitative Microbial Risk Assessment (QMRA), therisks for bacterial and protozoan infections related tohandling and reuse of urine were calculated to be<10<sup>-3</sup>for all exposure routes independent of the urinestorage time and temperature evaluated. The risk for viralinfection was higher, calculated at 0.56 for accidentalingestion of 1 ml of unstored urine. If the urine was stored at20°C for 6 months the risk for viral infection was reducedto 5.4 × 10<sup>-4</sup>.</p><p>By following recommendations for storage and reuse, whichare dependent on the type of crop to be fertilised, it ispossible to significantly decrease the risk for infections. Sofar, the level of risk that is acceptable is unknown. Theacceptable risk will be one of the main factors determining thefuture utilisation of source-separated human urine inagriculture.</p><p><b>Keywords:</b>urine-separation, urine, wastewater systems,wastewater reuse, recycling, enteric pathogens, faecal sterols,indicator bacteria, hygiene risks, microbial persistence,microbial risk assessment, QMRA, fertiliser, crop.</p>
3

Koupání dětí v krytých bazénech / Bathing of children in indoor swimming pools.

OHEROVÁ, Martina January 2016 (has links)
This diploma thesis deals with bathing children, especially infants and toddlers, in indoor swimming pools. It focuses primarily on the potential health and hygiene risks of this activity. It is divided into theoretical and practical part. The theoretical part provides a deeper insight into the field of artificial swimming pools, is dedicated to current as well as first ever legislation, in more detail is dedicated to the hygienic requirements for swimming pools according to Decree no. 238/2011, as amended; describes the process of pool water treatment, provides an overview of possible types of disinfecting pool water treatment and comparison within the advantages and disadvantages, describes indicators of water quality and their importance, and mostly focuses on hygienic and health risks in connection with the visit of indoor pools. Gives examples from practice (epidemic), mentions the most common sources of pollution including the most common violations of visitors. The theme of hygienic and health risks is then divided according to the origin of risk to the microbiological part (dedicated to infectious agents), to chemical part (disinfection by products) and to the part of accident risks and risks associated with the water temperature. The thesis is also keenly interested in the views of experts for bathing children, especially infants and toddlers, in indoor artificial pools. Research in the practical part was made by a qualitative method using secondary data analysis (operational and guest regulations, operational logbooks for 2015, the results of laboratory analysis of pool water for the 2015, laws and decrees), participant observation and interviews. The research was conducted in indoor swimming pools in towns Jihlava and Prachatice, which run swimming courses for infants and toddlers as well as for older children. For research, I set the following goals: C1: To monitor the microbiological and the physical-chemical indicators of the pool water quality in relation to Decree no. 238/2011 Coll., as amended, in pre-selected artificial indoor pools during annual operation. C2: To focus on the health status of children (infants and toddlers) in swimming classes. C3: To find out the knowledge and attitudes of visitors (parents) and trainers in the field of hygiene principles for swimming in artificial pools and risks arising from them. Based on the targets I have set the following research questions: V1: Are the monitored microbiological and physico-chemical water quality limits exceeded, and if so, which and under what circumstances? V2: What health problems, if they occured, did infants and toddlers after regular visits of indoor pools have ? V3: Are these children suffering from allergic diseases, and if so, from what type? V4: What knowledge and attitudes do visitors (parents) and lecturers in the field of hygienic principles for swimming in artificial pools and potential risks have? This thesis may serve the general public to extend the knowledge in the field of bathing (not only the children) in artificial pools and to give a view on this subject from different perspectives, as well as operators of swimming pools as an information material.

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