Development and Evaluation of a Screening Type Dispersion Model for Bioaerosols Emissions from Land Application of Class B Biosolids

Bibliographic Details
Main Author:	Bhat, Abhishek S.
Language:	English
Published:	University of Toledo / OhioLINK 2008
Subjects:	Environmental Engineering
Online Access:	http://rave.ohiolink.edu/etdc/view?acc_num=toledo1213124433

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spelling	ndltd-OhioLink-oai-etd.ohiolink.edu-toledo12131244332021-08-03T06:07:17Z Development and Evaluation of a Screening Type Dispersion Model for Bioaerosols Emissions from Land Application of Class B Biosolids Bhat, Abhishek S. Environmental Engineering Agricultural fields are annually spread with thousands of liters of biosolids from waste water treatment plants. The objective of the thesis is to develop a screening model to study the dispersion and transport of the aerosols released from such biosolids. The model has been developed to incorporate the effect of wind shear near the ground for ground level releases. An analytical solution to convective-diffusivity equation is derived for change in magnitude of wind velocity in vertical profile. Supplementary models are also defined based on the classical Gaussian dispersion model used in air quality applications. The coliforms present in the biosolids, and subsequently in bioaerosols are used as the measuring tape to calculate the concentration of bioaerosols at various downwind distances. It is assumed that all bacteria, pathogens and viruses will be aerosolized like coliforms. The proposed model has three distinct components: i) emission rate module, ii) dispersion and transport module, and iii) risk module. The emission rate module is based on the simple concept of emission factors that are derived from the reported studies on the release of different components of class B bioaerosols. The dispersion and transport module uses three different variations: variation I-a and I-b based on a simple Gaussian model for a point source, variation II-a and II-b based on a modified Gaussian model for an aerial source and variation III incorporating the wind shear near ground. Two sets of dispersion coefficients derived for ground level sources based on the reported experimental data are used for Gaussian models. The risk module uses the risk equation based on a conventional one hit exponential model to determine the one time daily and annual probability of infection. A spreadsheet model BDRM 1.0 (Bioaerosols Dispersion and Risk Model version 1.0) is developed incorporating all three modules. Limited field data from only one study is available to evaluate the proposed screening model. Therefore, dispersion and risk components of the model are evaluated based on the regression equation reported by authors based on field studies in the literature. The three different variations, as defined earlier, are evaluated to determine the best performing equation to predict the concentrations and risk. Sensitivity and uncertainty analyses have been conducted, using Monte-Carlo technique to understand the limitation of the models. The results show that the predicted concentrations at 100 m are within the 54 to 63% certainty for 10% uncertainty of all input parameters depending on the stability class. The uncertainty of the predictions for daily risk of infection ranges from 60 to 70% and for annual risk of infection from 58 to 68% for 10% uncertainty in all input parameters. The sensitivity analysis shows that the concentration models are most sensitive to emission rate, wind speed; annual risk assessment model is sensitive to emission rate, exposure time and exposure duration. 2008-06-10 English text University of Toledo / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=toledo1213124433 http://rave.ohiolink.edu/etdc/view?acc_num=toledo1213124433 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection	NDLTD
language	English
sources	NDLTD
topic	Environmental Engineering
spellingShingle	Environmental Engineering Bhat, Abhishek S. Development and Evaluation of a Screening Type Dispersion Model for Bioaerosols Emissions from Land Application of Class B Biosolids
author	Bhat, Abhishek S.
author_facet	Bhat, Abhishek S.
author_sort	Bhat, Abhishek S.
title	Development and Evaluation of a Screening Type Dispersion Model for Bioaerosols Emissions from Land Application of Class B Biosolids
title_short	Development and Evaluation of a Screening Type Dispersion Model for Bioaerosols Emissions from Land Application of Class B Biosolids
title_full	Development and Evaluation of a Screening Type Dispersion Model for Bioaerosols Emissions from Land Application of Class B Biosolids
title_fullStr	Development and Evaluation of a Screening Type Dispersion Model for Bioaerosols Emissions from Land Application of Class B Biosolids
title_full_unstemmed	Development and Evaluation of a Screening Type Dispersion Model for Bioaerosols Emissions from Land Application of Class B Biosolids
title_sort	development and evaluation of a screening type dispersion model for bioaerosols emissions from land application of class b biosolids
publisher	University of Toledo / OhioLINK
publishDate	2008
url	http://rave.ohiolink.edu/etdc/view?acc_num=toledo1213124433
work_keys_str_mv	AT bhatabhisheks developmentandevaluationofascreeningtypedispersionmodelforbioaerosolsemissionsfromlandapplicationofclassbbiosolids
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Development and Evaluation of a Screening Type Dispersion Model for Bioaerosols Emissions from Land Application of Class B Biosolids

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