Treatment of Livestock Odor and Pathogens with Ultraviolet Light

Livestock production systems are associated with aerial emissions of odor, volatile organic compounds (VOCs), other gases, and particular matter including airborne pathogens. Control of those emissions is needed to assure compliance with environmental regulations and long-term viability of the industry. The focus of this research is a novel approach to abatement of livestock odor and pathogens utilizing photocatalysis, i.e., UV irradiation in presence of TiO2 as a catalyst. A standard gas generation system was built and tested to generate ten odorous VOCs commonly defining livestock odors. These VOCs included methylmercaptan, ethylmercaptan, dimethylsulfide, butylmercaptan, acetic, propanoic, butyric, and isovaleric acid, p-cresol, and H2S. Our previous research established a reduction of VOCs with UV light only of 60~98% for sulfur VOCs and 91% for p-cresol, but only 20 to 45% removal for volatile fatty acids (VFAs). Titanium dioxide was used in the current research to catalyze UV reactions in the same gas mixtures of VOCs held in a small photoreactor. The reactor was designed to conduct controlled tests with UV light under dynamic (with airflows) conditions that facilitate experiments simulating exhaust from mechanically-ventilated barns. Six 10W lamps with characteristic bands at (185), 254, 312, 365 nm, respectively, and principle output at 254 nm were used as UV source in dynamic system. Solid phase microextraction (SPME) fibers were used to sample VOCs before and after UV treatment and for transfer of samples to a gas chromatography and mass spectrometry olfactometry (GC-MS-O) system. Odor analysis was completed by a forced-choice dynamic-dilution olfactometer in the Olfactometry lab at ISU. Effectiveness of four different treatment options, i.e., UV254, UV185+254, UV254+TiO2, and UV185+254+TiO2 was assessed. Effect of light energy, catalyst presence and light wavelength was evaluated. More than 50% in chemical reduction was found for all VOCs tested with a treatment time of 18.5 second. A linearly positive correlation was found between the percent conversion of tested VOCs and light energy dose. TiO2 showed to greatly improve the treatment effectiveness on VOCs, VFAs in particular, no matter deep UV was used or not. However, when TiO2 was used, deep UV showed very little improvement in degrading VOCs tested, while significant improvement was observed when no TiO2 was used. Total odor reduction of 70% by certain energy level indicated the feasibility of odor mitigation by UV light. Continued work includes simultaneous inactivation of airborne pathogens with UV light

Novel Treatment of odor and VOCs Using Photolysis

Public concerns about offensive odor from livestock operations are on the rise, bringing up an increasing demand on odor treatment. In this work, a bench-scale standard gases generation and UV treatment system was built up, where standard gas mixtures including sulfuric compounds (H 2 S, methylmercaptan, ethylmercaptan, DMS and butylmercaptan), volatile fatty acids/VFAs (acetic acid, propionic acid, butyric acid and isovaleric acid) and phenolic compounds (p-cresol, 4-ethylphenol, indole and skatole), which have been proposed to be responsible for odor nuisance, were utilized to simulate aerial emissions from swine barn. Permeation tubes that carry unique compounds were weighed around every four weeks and the results showed a stable permeation rate for each compound. Solid-phase micro-extraction (SPME) fiber was used to sample standard gases, and simultaneous chemical and olfactometry analyses of VOCs associated with odor were accomplished in a gas chromatography-mass spectrometry-olfactometry (GC-MS-O) system. Optimization of experimental conditions including the selection of SPME fiber and best extraction time was performed and thus Carboxen/polydimethylsiloxane (PDMS) 85µm fiber and 10 min extraction was used in subsequent experiments. Gas samples with UV light off (control) and on (treatment) were extracted, respectively, and were sent to GC-MS-O system for analysis. When the total flowrate was 400 ml/min, at 10min extraction, reduction rate for methylmercaptan, butyric acid and p-cresol was 96.2%, 48.15%, 92.16%, respectively, on chemical concentration, and 98.4%, 51.1%, 38.9%, on odor area count and 81.48%, 44.69% and 73.36% on odor intensity count. At 24hr extraction, reduction rate for methylmercaptan, butyric acid and p-cresol was 99.99%, 62.78%, 96.23%, respectively, on chemical concentration, and 74.66%, 45.06%, 93.56%, on odor area count and 69.93%, 40.01% and 88.66% on odor intensity count. To better simulate swine barn emissions and evaluate flowrate effect on UV degradation rate, gases were extracted at higher flowrate, 1150ml/min, 2150ml/min and 3150ml/min. The result showed reduction rate decreased as flowrate increased, but still a very good reduction rate of 79.07% on chemical concentration for p-cresol was obtained at flowrate 3150ml/min, which further verified the powerful treatment effect of UV light on VOCs and odor and feasibility of extending this technique to field applications. Chemical reaction mechanism was preliminarily investigated based on the new compounds identified from the treatment sample, which was accordance with previous studies

Historical influences on the current provision of multiple ecosystem services: is there a legacy of past landcover?

Ecosystem service provision varies temporally in response to natural and human-induced factors, yet research in this field is dominated by analyses that ignore the time-lags and feedbacks that occur within socio-ecological systems. The implications of this have been unstudied, but are central to understanding how service delivery will alter due to future land-use/cover change. Urban areas are expanding faster than any other land-use, making cities ideal study systems for examining such legacy effects. We assess the extent to which present-day provision of a suite of eight ecosystem services, quantified using field-gathered data, is explained by current and historical (stretching back 150 years) landcover. Five services (above-ground carbon density, recreational use, bird species richness, bird density, and a metric of recreation experience quality (continuity with the past) were more strongly determined by past landcover. Time-lags ranged from 20 (bird species richness and density) to over 100 years (above-ground carbon density). Historical landcover, therefore, can have a strong influence on current service provision. By ignoring such time-lags, we risk drawing incorrect conclusions regarding how the distribution and quality of some ecosystem services may alter in response to land-use/cover change. Although such a finding adds to the complexity of predicting future scenarios, ecologists may find that they can link the biodiversity conservation agenda to the preservation of cultural heritage, and that certain courses of action provide win-win outcomes across multiple environmental and cultural goods

Nigerian London: re-mapping space and ethnicity in superdiverse cities

This paper explores the idea of ‘superdiversity’ at the city level through two churches with different approaches to architectural visibility: the hypervisible Universal Church of the Kingdom of God and the invisible Igbo Catholic Church, both in North London, guide our exploration of invisible Nigerian London. Although Nigerians have lived in London for over 200 years, they live beneath the radar of policy and public recognition rather than as a vital and visible element of superdiversity. This paper argues that we can trace the journeys composing Nigerian London in the deep textures of the city thus making it visible, but this involves re-mapping space and ethnicity. It argues that visibility is vital in generating more open forms of urban encounter and, ultimately, citizenship

Naval engagements, patriotism, cultural politics, and the Royal Navy, 1793-1815

grantor: University of TorontoThis thesis examines the place occupied by the royal navy in British culture during the wars of 1793-1815 with Revolutionary and Napoleonic France It explores the manner in which images of the navy operated in domestic British culture, and relates their significance to larger dynamics within late eighteenth and early nineteenth century society and political culture. Chapter one is an introduction, which justifies the topic in light of recent writing on British national identity in the period, outlines the sources employed, and introduces necessary terms and concepts. Chapter two investigates the cultural politics of the first major naval engagement of the war, Lord Howe's victory over the French fleet on May 29-June 1, 1794. It traces the attempt made by partisan interests to capitalise upon the naval victory. Chapter three considers the naval mutinies of 1797 and examines their effect on elite perceptions of the navy's ability to function as an effective national symbol. As it was closely followed by Admiral Duncan's victory over the Dutch fleet off Camperdown on October 11, 1797, the manner in which the celebrations for his victory became caught up in a project of national and naval rehabilitation is addressed. Chapter four explores the social and cultural dynamics that were part and parcel of patriotic activity for contemporaries. It examines a range of efforts made, and projects launched, to commemorate and acknowledge naval superiority in the years around the battle of the Nile (August 1, 1798). Admiral Horatio Nelson--the most celebrated naval hero in Britain's history--is the focus of the fifth chapter. It traces the development of his public image, locating it--to a degree that has never been before suggested--in its relationship to some of the manifest social tensions of the period. Chapter six considers the parliamentary career of Lord Cochrane MP, and explores the manner in which he was able to exploit naval symbols and associations in the radical political cause. The thesis concludes by making a revisionist assessment of current interpretations of national identity in the period, arguing that significant class and political tensions have been ignored.Ph.D

Feasibility of breed/burn fuel cycles in pebble bed HTGR reactors.

Thesis. 1978. M.S.--Massachusetts Institute of Technology. Dept. of Nuclear Engineering.MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.Bibliography: leaves 176-178.M.S