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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

Teknikutvärdering av Urintorkning i Pilotskala – ett Fältförsök i Finland : Technical Evaluation of Urine Drying in Pilot Scale - a Field Experiment in Finland

Karlsson, Caroline January 2019 (has links)
Av samtliga globala processer som reglerar jordsystemet är de biogeokemiska flödena av kväve (N) och fosfor (P) mest påverkade av mänskliga aktiviteter. Inerta former av N och P omvandlas till reaktiva former som sprids i miljön, där de orsakar eutrofiering och påverkar marina ekosystem negativt. Majoriteten av de reaktiva N- och P-formerna används för framställningen av mineralgödsel. Ett alternativt sätt att producera gödsel är att återvinna näringsämnena i avloppet. En teknik som återvinner näringsämnen i urin är basisk urintorkning. Teknologin stabiliserar urea med ett basiskt torkningsmedium och koncentrerar näringsämnena genom att evaporera vattnet i urinen. Slutprodukten är ett torrt gödsel i pulverform. I det här projektet testades urintorkningsteknologin för första gången i ett fältförsök. Ett system för urintorkning med kapacitet att förånga 40 kg urin dygn-1 m-2 konstruerades och integrerades i ett befintligt torrt sanitetssystem för användning under en period på tre månader. I projektet utvärderades 13 dygn av de 3 månaderna. Resultaten visade att 24 kg urin tillfördes systemet och att systemet kunde upprätthålla en kontinuerlig torkning av urinen. Efter torkningen återvanns majoriteten (97 %) av N i slutprodukten. På grund av att den tillförda mängden urin var liten blev växtnäringshalterna i slutprodukten och i torrsubstansen (TS) av slutprodukten låga. Systemet hade emellertid potential att torka mycket större kvantiteter urin. Om systemets fulla potential hade använts, det vill säga att torka 40 kg urin dygn-1 m-2, så hade särskilt N- och P-halterna ökat avsevärt. N-halterna hade även ökat ytterligare om torkningen hade utförts vid en lägre temperatur. Systemets energiförbrukning var hög, eftersom systemet hade en kontinuerlig energikonsumtion och även komponenter med hög effekt. I jämförelse med den konventionella avloppsvattenreningen och produktionen av mineralgödsel har systemet en hög energikonsumtion, men i jämförelse med en förbränningstoalett är systemets energiförbrukning likvärdig. För att minska energiförbrukningen kunde reglertekniska åtgärder utföras så att systemets energitillförsel upphör när systemet inte används. Systemets energiförbrukning får även ställas i relation till de problem som dagens system för livsmedelsproduktion och sanitet medför. Till skillnad från nämnda system möjliggör urintorkningsteknologin besparing av dricksvattenresurser, ett slutet kretslopp av näringsämnen och en minskad påverkan på miljön. / Of all global processes that regulate the earth system, the biogeochemical flows ofnitrogen (N) and phosphorus (P) are the most affected by human activities. Inert forms of N and P are converted into reactive forms that are dispersed in the environment, causing eutrophication and affecting marine ecosystems. The majority of the reactive N and P are used for the production of mineral fertilizers. An alternative way of producing fertilizers is to recycle nutrients from waste water. A technology that reuses nutrients in urine is alkaline urine drying. The technology stabilizes urea with an alkaline drying medium and concentrates the nutrients by evaporating the water in urine. The end-product is a dry fertilizer in powder form. In this master project, the alkaline urine drying technology was tested for the first time in field conditions. A system for urine drying with the capacity to evaporate 40 kg of urine day-1 m-2 was constructed and integrated into an existing dry sanitation system for use over a period of three months. The master project evaluated the system for 13 days of the 3 months. The results showed that 24 kg of urine was collected in the system, significantly less than what the system had been designed to dry. Furthermore, the results showed that the system functioned smoothly recovering 97 % of the urine-N in the end-product. The nutrient content in the end-product and the dry matter of the end-product was low due to the low amount of urine that was collected. However, the system had the potential to dry much larger quantities of urine. If the system would have been operated to function at full potential (drying 40 kg of urine day-1 m-2) the N- and P-content in the end-product would be much higher than that observed during the 13 days. Furthermore, the system if operated at lower temperatures has the potential to recover more N. The system’s energy consumption was high, as the system had a continuous energy consumption. In comparison with the conventional waste water treatment and the production of mineral fertilizers, the system has a high energy consumption, but compared to an incineration toilet, the system’s energy consumption is equivalent. In order to reduce the energy consumption, automatic control could be implemented so that the energy is switched off when the system is not used. The system’s energy consumption may also be set in relation to the problems that today’s systems for food production and sanitation entail. Unlike the aforementioned systems, the urine dehydration technology does not consume drinking water, it enables recycling of nutrients as well as a reduced impact on aquatic life.
2

LISTERIA MONOCYTOGENES IN DELI MEATS AND WITHIN DRY BIOFILMS WITH PSEUDOMONAS AERUGINOSA AND SALMONELLA ENTERICA AND ENHANCING FOOD SAFETY RESEARCH OPPORTUNITIES FOR MINORITY SERVING INSTITUTIONS

Gurpreet Kaur (15348217) 29 April 2023 (has links)
<p>Unsafe food is responsible for causing more than 600 million cases of foodborne illnesses and 420,000 deaths each year. These foodborne illnesses have direct impact on growth and development in children, food and nutrition security, national economies, and sustainable development. Food manufactures, research institutions, governments, and consumers, together, play a pivotal role in establishing and implementing effective food safety systems. <em>Salmonella</em> spp. and <em>Listeria monocytogenes</em> are recognized as major threats to global food safety and security among other 31 known and unknown pathogens associated with foodborne illnesses and deaths. Since these pathogens can be transmitted through contaminated food and water, contaminated environmental surfaces, and subsequently from environment to food via cross-contamination, there is an urgent need for data-driven approaches to identify key points of contamination along the food systems to suggest interventions. While it is important to enhance food safety research in developed economies, developing capacity to enable conditions for food safety research translation and practice in developing economies is crucial for global food safety. In this dissertation, we presented three different research projects as summarized below-</p> <p>In Chapter 2 “Evaluating the efficacy of celery powder in ready-to-eat deli style turkey breast against <em>L. monocytogenes</em> under ideal and temperature abuse conditions”. In this study, we artificially inoculated “clean label” deli style turkey breast formulated with celery powder to evaluate the efficacy of this natural antimicrobial in inhibiting the growth of this pathogen. We stored the inoculated samples at ideal (4 °C) and abuse temperature conditions (7 °C, 10 °C, and 15 °C) for 21 d mimicking the possible temperature abuse along the cold chain, transportation, and at consumer refrigerator. Our findings indicated that although deli meat samples stored at 4 °C and 7 °C did not achieve significant growth of <em>L. monocytogenes;</em> increasing temperatures to 10 °C and 15 °C led to significant increase in the growth rate of this pathogen. This study evaluates the use and effectiveness of celery powder as an antimicrobial used by deli meat processors against <em>L. monocytogenes</em> in deli products. These data underscore the importance of maintaining refrigeration temperatures to complement the efficacy of antimicrobials. </p> <p>Chapter 3 “Investigating sanitary solutions to <em>L. monocytogenes, Salmonella enterica</em> ser. Typhimurium, and <em>Pseudomonas aeruginosa</em> dry surface biofilms”. In this study, we developed <em>in vitro</em> mono- and mix-culture dry surface biofilm (DSB) models of <em>L. monocytogenes, Salmonella enterica</em> ser. Typhimurium, and <em>Pseudomonas aeruginosa</em> leveraging the EPA MLB SOP MB-19 standard protocol using the CDC Biofilm Reactor and evaluated sanitation control strategies currently adopted by low-moisture food (LMF) food processors to determine their ability to inactive DSB, a decidedly difficult reservoir to eliminate. This study targets multiple biological hazards in a research area with very limited publicly available data and is the first of its kind to refine mono- and multi-species <em>in vitro</em> DSB models that mimic LMF facility conditions and combinations of relevant microorganisms for use cases (e.g., EPA adoption). The findings from this study indicated that these foodborne pathogens could form DSBs and serve as a source of pathogen reservoir and cross-contamination. Results from the efficacy testing of sanitizer and microfiber swabbing suggested that current sanitation practices may not be sufficient to remove or inactivate DSBs. This study will define future needs and new strategies to improve confidence in sanitation efficacy with private sector practitioners.</p> <p>Chapter 4 “Enhancing research for development opportunities for Minority Serving Institutions: a case study in food safety”. Most developing economies have limited viable food safety systems due to underdeveloped research capabilities, competing resource demands, and insufficient enabling conditions, which undermines food security. United States Minority Serving Institution (MSIs) researchers and outreach specialists are familiar with and arguably best positioned to address global food safety and security challenges and needs, but MSIs implement limited research for development programs (e.g., U.S. university-led Feed the Future (FTF) Innovation Labs (ILs) funded by the United States Agency for International Development (USAID)) aimed to solve these challenges. Recognizing this opportunity, the Feed the Future Innovation Lab for Food Safety (FSIL) led by Purdue University in partnership with Cornell University, created and implemented an MSI-led research partnerships for global food safety research programs. In this chapter, we put together the process of a three-stage Request for Applications (RFA) process, which included non-competitive and competitive stages to encourage partnership and to refine ideas.  At the end of this process, seven individuals were invited to submit full proposals; two were funded. Intentional research opportunities and partnerships are essential to strengthen MSI competitiveness for research for development programs that develop and scale technologies to address urgent global agriculture, food security, and safety challenges.</p>

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