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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

Comparison of on-pond measurement and back calculation of odour emission rates from anaerobic piggery lagoons

Galvin, Geordie January 2005 (has links)
Odours are emitted from numerous sources and can form a natural part of the environment. The sources of odour range from natural to industrial sources and can be perceived by the community dependant upon a number of factors. These factors include frequency, intensity, duration, offensiveness and location (FIDOL). Or in other words how strong an odour is, at what level it becomes detectable, how long it can be smelt for, whether or not the odour is an acceptable or unacceptable smell as judged by the receptor (residents) and where the odour is smelt. Intensive livestock operations cover a wide range of animal production enterprises, with all of these emitting odours. Essentially, intensive livestock in Queensland, and a certain extent Australia, refers to piggeries, feedlots and intensive dairy and poultry operations. Odour emissions from these operations can be a significant concern when the distance to nearby residents is small enough that odour from the operations is detected. The distance to receptors is a concern for intensive livestock operations as it may hamper their ability to develop new sites or expand existing sites. The piggery industry in Australia relies upon anaerobic treatment to treat its liquid wastes. These earthen lagoons treat liquid wastes through degradation via biological activity (Barth 1985; Casey and McGahan 2000). As these lagoons emit up to 80 per cent of the odour from a piggery (Smith et al., 1999), it is imperative for the piggery industry that odour be better quantified. Numerous methods have been adopted throughout the world for the measurement of odour including, trained field sniffers, electronic noses, olfactometry and electronic methods such as gas chromatography. Although these methods all have can be used, olfactometry is currently deemed to be the most appropriate method for accurate and repeatable determination of odour. This is due to the standardisation of olfactometry through the Australian / New Zealand Standard for Dynamic Olfactometry and that olfactometry uses a standardised panel of "sniffers" which tend to give a repeatable indication of odour concentration. This is important as often, electronic measures cannot relate odour back to the human nose, which is the ultimate assessor of odour. The way in which odour emission rates (OERs) from lagoons are determined is subject to debate. Currently the most commonly used methods are direct and indirect methods. Direct methods refer to placing enclosures on the ponds to measure the emissions whereas indirect methods refer to taking downwind samples on or near a pond and calculating an emission rate. Worldwide the odour community is currently divided into two camps that disagree on how to directly measure odour, those who use the UNSW wind tunnel or similar (Jiang et al., 1995; Byler et al., 2004; Hudson and Casey 2002; Heber et al., 2000; Schmidt and Bicudo 2002; Bliss et al., 1995) or the USEPA flux chamber (Gholson et al., 1989; Heber et al., 2000; Feddes et al., 2001; Witherspoon et al., 2002; Schmidt and Bicudo 2002; Gholson et al., 1991; Kienbusch 1986). The majority of peer reviewed literature shows that static chambers such as the USEPA flux chamber under predict emissions (Gao et al., 1998b; Jiang and Kaye 1996) and based on this, the literature recommends wind tunnel type devices as the most appropriate method of determining emissions (Smith and Watts 1994a; Jiang and Kaye 1996; Gao et al., 1998a). Based on these reviews it was decided to compare the indirect STINK model (Smith 1995) with the UNSW wind tunnel to assess the appropriateness of the methods for determining odour emission rates for area sources. The objective of this project was to assess the suitability of the STINK model and UNSW wind tunnel for determining odour emission rates from anaerobic piggery lagoons. In particular determining if the model compared well with UNSW wind tunnel measurements from the same source; the overall efficacy of the model; and the relationship between source footprint and predicted odour emission rate.
2

Assessment of the Emission Rate and Distribution of Volatile Organic Compounts in the Sewege System in A Metropolitan City

Li, Chia-yu 23 June 2010 (has links)
This work is study 71 kinds of volatile organic compounds (VOCs) in the sewer system of a metropolitan city during dry/wet weather. The VOCs contains alkanes, alkenes and alkynes, aromatics, chlorinated organics, sulfides, ketones and ethers. The purpose of this work estimated the emission rates of VOCs and cancer risk within 12 kinds of hazardous air pollutants (HAPs) will be part of the investigation 26 HAPs by using risk assessment. TVOCs (concentrations of total VOCs) in dry weather was higher than that in wet weather for both sewer systems. The concentration distributions of dominant were KB7 (C3) in the A (B) sewer system. This system collected sewage from harbor and industrial park. During dry and wet weather, the most common VOCs were chlorinated organics and alkanes in the A sewer system, respectively. The main contribution were chloroethene and isopentane; the most common VOCs were aromatics in the B sewer system. The main contribution was m / p-Xylene. This results show that the most emission rates of TVOCs is C3 (13,834.79 mg/hr) during dry weather and KB2 (1875.25 mg/hr) during wet weather. The emission rates of K1
3

p-Dichlorobenzene and naphthalene : emissions and related primary and secondary exposures in residential buildings

Guerrero, Priscilla Annette 25 October 2013 (has links)
p-Dichlorobenzene (p-DCB) and naphthalene are compounds classified as Group C carcinogens according to the USEPA. Sources of p-DCB and naphthalene include moth repellents and deodorizers typically used in closets, garment bags, and toilet bowls found in pure form. In this study, laboratory, closet, and garment bag experiments were used to determine emission rates of p-DCB and naphthalene from consumer products (closet air freshener, toilet bowl deodorizer, and moth repellent). Emission rates varied considerably between products that contain p-DCB, primarily due to product packaging, and were generally suppressed when the product was used in a closed closet or garments bag, relative to products placed in well-ventilated chambers. Experimental mass emission rates were used in conjunction with a well-mixed reactor model to predict indoor p-DCB and naphthalene concentrations for a range of reasonable residential scenarios. Results suggest that exposures under worst-case scenarios could lead to excess lifetime cancer risks of greater than 20,000 in a million (2%) for those who use consumer products that are pure p-DCB, a risk that dwarfs any reported environmental cancer risks over large segments of the US population. Since such products are typically used where clothing is kept, significant chemical adsorption onto clothing is possible following sublimation from the solid product. Chamber experiments were used to determine the amount of p-DCB and naphthalene mass that adsorbs onto selected clothing materials made of cotton, polyester, or wool. Cloth specimens were kept inside a chamber through which an air stream containing p-DCB or naphthalene was passed for one month. After this time, p-DCB or naphthalene were chemically extracted from the cloth specimens. Polyester was determined to be the most adsorbent material, while cotton was the least adsorbent for each chemical. Equilibrium partition coefficients of 0.01 m³/g for p-DCB and 0.02 m³/g for naphthalene were determined experimentally for wool. Desorption rates were determined in both laboratory chambers and a closet in a test house. Results suggest prolonged persistence of p-DCB and naphthalene on polyester and wool, e.g., half-lives of 12 to 20 days after a moth repellent is removed from the clothes storage environment. An exposure scenario was also carried out to compare the inhalation and dermal exposure risks associated with contaminated clothing. / text
4

Organic Chemical Characterization Of Primary And Secondary Biodiesel Exhaust Particulate Matter

Kasumba, John 01 January 2015 (has links)
Biodiesel use and production has significantly increased in the United States and in other parts of the world in the past decade. This change is driven by energy security and global climate legislation mandating reductions in the use of petroleum-based diesel. Recent air quality research has shown that emission of some pollutants such as CO, particulate matter (PM), SO2, hydrocarbons, and carcinogenic polycyclic aromatic hydrocarbons (PAHs) is greatly reduced with biodiesel. However, studies have also shown that some unregulated emissions, such as gas-phase carbonyls, are increased with biodiesel combustion. Very limited research has been done to investigate the particle-phase carbonyl and quinone emissions from biodiesel combustion. Also, very limited studies have investigated the ozone oxidation of biodiesel exhaust PM. Fatty acid methyl esters (FAMEs) are found in high abundance in biodiesel exhaust PM. The presence of these FAMEs in biodiesel exhaust PM can potentially alter the kinetics of the reactions between ozone and particle-phase PAHs. In this study, an Armfield CM-12 automotive light-duty diesel engine operated on a transient drive cycle was used to generate PM from various waste vegetable oil (WVO) and soybean biodiesel blends (containing 0%, (B00), 10% (B10), 20% (B20), 50% (B50), and 100% (B100) biodiesel by volume). The primary PM emissions were sampled using Teflon-coated fiberfilm filters. Laboratory PAHs, FAMEs, and B20 exhaust PM were exposed to ~0.4 ppm ozone for time periods ranging from 0-24 hours in order to study the effect of FAMEs and biodiesel exhaust PM on the ozonolysis of PAHs. Organic chemical analysis of samples was performed using gas chromatography/mass spectrometry (GC/MS). PAHs, carbonyls, FAMEs, and n-alkanes were quantified in the exhaust PM of petrodiesel, WVO and soybean fuel blends. The emission rates of the total PAHs in B10, B20, B50, and B100 exhaust PM decreased by 0.006-0.071 ng/µg (5-51%) compared to B00, while the emission rates for the FAMEs increased with increasing biodiesel content in the fuel. The emission rates of the total n-alkanes in B10, B20, B50, and B100 exhaust PM decreased by 0.5-21.3 ng/µg (4-86%) compared to B00 exhaust PM. The total emission rates of the aliphatic aldehydes in biodiesel exhaust PM (B10, B20, B50, and B100) increased by 0.019-2.485 ng/µg (36-4800%) compared to petrodiesel. The emission rates of the total aromatic aldehydes, total aromatic ketones, and total quinones all generally decreased with increasing biodiesel content in the fuel. With the exception of benzo[a]pyrene, the pseudo-first order ozone reaction rate constants of all the PAHs decreased by 1.2-8 times in the presence of the FAMEs. Phenanthrene, fluoranthene, and pyrene were the only PAHs detected in the B20 exhaust PM, and their ozone reaction rate constants were about 4 times lower than those obtained when the PAHs alone were exposed to ozone. The findings of this study indicate that there are both positive and negative effects to emissions associated with biodiesel use in light-duty diesel engines operating on transient drive cycle.
5

Electrostatic Precipitators and Electrostatic Spray Scrubbers for Mitigation of Particulate Matter Emissions in Poultry Facilities

Knight, Reyna Madison January 2021 (has links)
No description available.

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