Aerosolization of microorganisms and risk of infection from reuse of wastewater residuals

Persistent Link:
http://hdl.handle.net/10150/191272
Title:
Aerosolization of microorganisms and risk of infection from reuse of wastewater residuals
Author:
Tanner, Benjamin Dennis.
Issue Date:
2004
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Three experiments were conducted to characterize the concentration of microorganisms in biosolids, the plume of aerosols created during land application of biosolids and the occupational risk of infection due to pathogens aerosolized during land application of biosolids in the United States. In all, more than three-hundred air samples were collected immediately downwind of biosolids applications throughout the United States using liquid impingers, and more than one-hundred air samples were collected downwind of microbially seeded, land applied water, which served as a conservative model system of aerosol generation. The novel model system made it possible to calculate the flux of microorganisms through a virtual plane defined by air samplers in vertical and horizontal arrays, located immediately downwind of a passing spray applicator. The rate of aerosolization during land application of biosolids near Tucson, Arizona, was calculated to be less than 33 plaque forming units (PFU) of coliphage and 10 colony forming units (CFU) of coliform bacteria per meter traveled by the spray applicator. Rates of aerosolization from the model system were shown to be much greater. To assess the risk to occupational health from bioaerosols generated during land application of biosolids, coliform bacteria, coliphages, and heterotrophic plate count (HPC) bacteria were enumerated from air and biosolids at 10 land application sites throughout the nation. The method of land application strongly influenced aerosolization, while relative humidity, temperature and wind speed showed limited correlation to concentrations of fecal indicator microorganisms in air. Occupational risks of infection and illness from aerosolized Salmonella and enteroviruses were calculated for a variety of land application scenarios. Realistic exposure scenarios carried occupational risks of Salmonella infection ranging from of 0.0001% to 0.013% per year. The corresponding occupational risk of infection from enteroviruses, using coxsackievirus A-21 as a model, ranged from 0.78% to 2.1% per year, depending on the type of activity performed by the worker. In addition, samples of biosolids from the Southwestern United States were characterized to provide up-to-date information about pathogens in biosolids for environmental regulators, biosolids producers, researchers, and public health agencies.
Type:
Dissertation-Reproduction (electronic); text
Keywords:
Hydrology.; Waterborne infection.; Aerosol therapy.; Sewage sludge -- Recycling.
Degree Name:
Ph. D.
Degree Level:
doctoral
Degree Program:
Microbiology and Medical Technology; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Gerba, Charles P.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleAerosolization of microorganisms and risk of infection from reuse of wastewater residualsen_US
dc.creatorTanner, Benjamin Dennis.en_US
dc.contributor.authorTanner, Benjamin Dennis.en_US
dc.date.issued2004en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThree experiments were conducted to characterize the concentration of microorganisms in biosolids, the plume of aerosols created during land application of biosolids and the occupational risk of infection due to pathogens aerosolized during land application of biosolids in the United States. In all, more than three-hundred air samples were collected immediately downwind of biosolids applications throughout the United States using liquid impingers, and more than one-hundred air samples were collected downwind of microbially seeded, land applied water, which served as a conservative model system of aerosol generation. The novel model system made it possible to calculate the flux of microorganisms through a virtual plane defined by air samplers in vertical and horizontal arrays, located immediately downwind of a passing spray applicator. The rate of aerosolization during land application of biosolids near Tucson, Arizona, was calculated to be less than 33 plaque forming units (PFU) of coliphage and 10 colony forming units (CFU) of coliform bacteria per meter traveled by the spray applicator. Rates of aerosolization from the model system were shown to be much greater. To assess the risk to occupational health from bioaerosols generated during land application of biosolids, coliform bacteria, coliphages, and heterotrophic plate count (HPC) bacteria were enumerated from air and biosolids at 10 land application sites throughout the nation. The method of land application strongly influenced aerosolization, while relative humidity, temperature and wind speed showed limited correlation to concentrations of fecal indicator microorganisms in air. Occupational risks of infection and illness from aerosolized Salmonella and enteroviruses were calculated for a variety of land application scenarios. Realistic exposure scenarios carried occupational risks of Salmonella infection ranging from of 0.0001% to 0.013% per year. The corresponding occupational risk of infection from enteroviruses, using coxsackievirus A-21 as a model, ranged from 0.78% to 2.1% per year, depending on the type of activity performed by the worker. In addition, samples of biosolids from the Southwestern United States were characterized to provide up-to-date information about pathogens in biosolids for environmental regulators, biosolids producers, researchers, and public health agencies.en_US
dc.description.notehydrology collectionen_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.typetexten_US
dc.subjectHydrology.en_US
dc.subjectWaterborne infection.en_US
dc.subjectAerosol therapy.en_US
dc.subjectSewage sludge -- Recycling.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineMicrobiology and Medical Technologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairGerba, Charles P.en_US
dc.contributor.committeememberPepper, Ianen_US
dc.contributor.committeememberHaas, Charles N.en_US
dc.contributor.committeememberReynolds, Kelly A.en_US
dc.contributor.committeememberRensing, Christopheren_US
dc.identifier.oclc225656369en_US
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