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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.
71

Proposta metodológica e avaliação da inativação de endósporos de Geobacillus stearothermophilus no tratamento de resíduos de serviços de saúde por autoclavagem / Methodological proposal and evaluation of the inactivation of endospores of Geobacillus stearothermophilus in the treatment of healthcare waste by autoclaving

Amanda Borges Ribeiro de Oliveira 27 January 2017 (has links)
Resíduos de Serviços de Saúde (RSS), ainda que tratados e dispostos em aterros sanitários, podem ser causas de impactos ambientais por apresentarem algum indicador de periculosidade. Segundo o apêndice IV da Resolução da Agência Nacional de Vigilância Sanitária (Anvisa) RDC nº 306/2004, para as tecnologias de tratamento desses resíduos é necessário que se atinja pelo menos o Nível III de inativação microbiana. Perante a ausência de dados na literatura que revelassem o tempo de exposição, temperatura e pressão ideais para a inativação microbiana no tratamento de RSS por autoclavagem e se a fração ocupada dos resíduos na autoclave poderia interferir na eficiência da desinfecção definiu-se o objetivo do trabalho para otimização do processo. Para os testes foram utilizados endósporos de Geobacillus stearothermophilus como bioindicadores e instalados cinco termopares na autoclave para aferição da temperatura dentro de todo o espaço da câmara. O RSS foi sintetizado diante das caracterizações como composição gravimétrica, distribuição granulométrica, densidade específica aparente, massa específica aparente e teor de umidade. Apresentou-se uma proposta metodológica para a avaliação do tratamento de RSS frente às dificuldades encontradas. Realizou-se ensaios com 116ºC, 125ºC e 134ºC, observando a fração de inativação em seis tempos de exposição diferentes. Sabendo-se que é padronizada em estabelecimentos de saúde a temperatura ideal para esterilização de materiais de 121ºC, apesar de não terem sido encontrados trabalhos científicos que comprovem a eficiência da esterilização nessa circunstância, foram realizados testes a 50 e 60 minutos de exposição para avaliar essa condição. Inoculou-se 106 endósporos nas amostras e a recuperação foi feita com filtração após a lavagem dos resíduos, sendo realizada a técnica de pour plate para contagem das unidades formadoras de colônias (UFC). O mesmo procedimento foi feito com a amostra retirada da autoclave. A fração de inativação dos endósporos atingiu 100% no tempo de 30 minutos de exposição à temperatura máxima de 134ºC e pressão absoluta de 2,3 kgf/cm2, resultado obtido através da relação do número de micro-organismos recuperados considerados como inoculados e o número de micro-organismos sobreviventes ao tratamento. A 121ºC houve recuperação de UFC após tratamento. A fração de ocupação não foi um fator delimitante para a inativação de endósporos, pois a temperatura se manteve a mesma independentemente da quantidade de resíduo submetido à autoclavagem. Um outro objetivo era avaliar experimentalmente a reprodução dos micro-organismos frente às condições operacionais de autoclavagem e do tempo de permanência do rejeito em condições ambientais. Esse estudo comprovou que a inativação nessas condições otimizadas esteriliza o resíduo, sendo que nenhum micro-organismo voltou a se reproduzir após dias expostos em temperatura ambiente, ou seja, não haveria riscos de contaminação em aterro sanitário quando depositados os rejeitos. Ter encontrado essas condições ideais e avaliado o processo de autoclavagem pode significar um grande avanço nas próprias unidades de tratamento, que terão um parâmetro estabelecido para trabalho. / Healthcare waste, even when treated and disposed of in landfills, can be causes of environmental impacts because they present some hazard indicator. According to appendix IV of Resolution of the National Health Surveillance Agency of Brazil (Anvisa) RDC nº 306/2004, for technologies of healthcare waste treatment, it is necessary to achieve at least Level III of microbial inactivation. The purpose of this research to optimize the process was defined taking into account the absence of data in the literature that revealed the optimal exposure time, temperature and pressure for microbial inactivation through the healthcare treatment by autoclaving and whether the fraction occupied by waste in the autoclave could interfere with the effectiveness of the disinfection. For the tests, endospores of Geobacillus stearothermophilus were used as bioindicators and five thermocouples were installed in the autoclave for temperature measurement throughout the chamber space. The healthcare waste was synthesized by characterizations such as gravimetric composition, granulometric distribution, apparent specific density, apparent specific mass and moisture content. A methodological proposal for the evaluation of waste treatment was introduced taking into consideration the difficulties encountered. Tests were performed at 116ºC, 125ºC and 134ºC, observing the fraction of inactivation at six different exposure times. Since the sterilization of materials at 121ºC is standardized in health establishments, even though no scientific studies were found to prove the sterilization efficiency in these conditions, tests were performed at 50 and 60 minutes of exposure to evaluate this condition. The concentration of 106 endospores were inoculated in the samples and the recovery was done with filtration after washing the waste, and the \"pour plate\" technique was used to count the colony forming units. The same procedure was done with the sample removed from the autoclave. The inactivation fraction of the endospores reached 100% in the time of 30 minutes of exposure to the maximum temperature of 134ºC and absolute pressure of 2.3 kgf/cm2, a result obtained by the ratio of the number of recovered microorganisms considered as inoculated and the number of microorganisms surviving the treatment. At 121ºC there was recovery of colony forming units after treatment. The occupation fraction was not a limiting factor for the inactivation of endospores, since the temperature remained the same regardless of the amount of waste submitted to autoclaving. Another objective was to experimentally evaluate the reproduction of the microorganisms taking into consideration the operational conditions of autoclaving and the amount of time that the waste remains under environmental conditions. This study proved that the inactivation under these optimized conditions sterilizes the waste, and that no microorganism would reproduce again after days exposed at room temperature, therefore, there would be no risk of contamination in a landfill when the waste is deposited. Having found these ideal conditions and evaluated the autoclaving process can mean a major advance in the treatment units themselves, which will have an established parameter for work.
72

Bioprocess development for removal of nitrogenous compounds from precious metal refinery wastewater

Manipura, Walappuly Mudiyanselage Janakasiri Aruna Shantha Bandara January 2008 (has links)
Removal of nitrogenous compounds from precious metal refinery (PMR) wastewater is important in terms of avoiding eutrophication (environmental protection), metal recovery (increased overall process efficiency and value recovery) and reuse of treated water (maximum use of natural resources). Extreme pH conditions (4 to 13 depending on the wastewater stream), high chemical oxygen demand (> 10,000 mg/I), numerous metals and high concentrations of those metals (> 20 mg/l of platinum group metals) in the wastewater are the main challenges for biological removal of nitrogenous compounds from PMR wastewater. Nitrogenous compounds such as NH₄⁺-N and N0₃-N are strong metal ligands, which make it difficult to recover metals from the wastewater. Therefore, a bioprocess was developed for removal of nitrogenous compounds from carefully simulated PMR wastewater. A preliminary investigation of metal wastewater was carried out to determine its composition and physico-chemical properties, the ability to nitrify and denitrify under different pH conditions and denitrification with different carbon Source compounds and amounts. Even at pH 4, nitrification could be carried out. A suitable hydraulic retention time was found to be 72 hours. There was no significant difference between sodium acetate and sodium lactate as carbon sources for denitrification. Based on these results, a reactor comparison study was carried out using simulated PMR wastewater in three types of reactors: continuously stirred tank reactor (CSTR), packed-bed reactor (PBR) and airlift suspension reactor (ALSR). These reactors were fed with 30 mg/l of Rh bound in an NH₄⁺ based compound (Claus salt: pentaaminechlororhodium (III) dichloride). Total nitrogen removal efficiencies of > 68 % , > 79 % and > 45 % were obtained in the CSTR, PBR and ALSR, respectively. Serially connected CSTR-PBR and PBR-CSTR reactor configurations were then studied to determine the best configuration for maximum removal of nitrogenous compounds from the wastewater. The PBR-CSTR configuration gave consistent biomass retention and automatic pH control in the CSTR. Ammonium removal efficiencies > 95 % were achieved in both reactors. As poor nitrate removal was observed a toxicity study was carried out using respirometry and the half saturation inhibition coefficients for Pt, Pd, Rh and Ru were found to be 15.81, 25.00, 33.34 and 39.25 mg/l, respectively. A mathematical model was developed to describe the nitrogen removal in PMR wastewater using activated sludge model number 1 (ASMl), two step nitrification and metal toxicity. An operational protocol was developed based on the literature review, experimental work and simulation results. The optimum reactor configuration under the set conditions (20 mg/I of Rh and < 100 mg/I of NH₄⁺-N) was found to be PBR-CSTR-PBR process, which achieved overall NH₄⁺-N and N0₃⁻-N removal efficiencies of > 90 % and 95 %, respectively. Finally, a rudimentary microbial characterisation was carried out on subsamples from the CSTR and PBRsecondary. It was found that the CSTR biomass consisted of both rods and cocci while PBRsecondary consisted of rods only. Based on these experimental works, further research needs and recommendations were made for optimisation of the developed bioprocess for removal of nitrogenous compounds from PMR wastewater.
73

Senzory pro decentralizovaný systém čištění odpadních vod / Sensors for decentralized system of water purification

Plotěný, Miroslav January 2009 (has links)
Main task of the Master Thesis is to study and propose appropriate sensors that can monitor standard operations of small waste treatment plant. This small plants may replace one big central waste water treatment plant, minimizing interference with the human factor and thus reducing the cost of its operation. Master Thesis deals with the sensors for level measurement, air flow, identifying the operator and others. The most important parameter is the quality of drainage water, which can be derived from the amount of ammoniacal nitrogen. This work discusses the possibility of continuous measurements of ammoniacal nitrogen in water and try to select the optimum solution. At the end of the work is carried out experimental measurements are selected ammonia probe to verify the practical features.
74

Návrh spalovny odpadu s parní turbinou / Waste heat recovery vith steam turbine

Korytár, Zbyněk January 2012 (has links)
The aim of this thesis is the design of municipal waste incinerator using the generated steam for power generation and distribution of heat. At the beginning is engaged in development of waste issues and the current state of waste management. The next section describes the options of waste treatment and possible solutions to the current state of waste issues. The concept of waste incineration plants: For waste incineration is used line for burning 100,000 tons of municipal waste per year.Combustion takes place in a grate boiler. Its advantage is the versatility and flexibility to waste. Electricity generation is dealt with condensing turbine with controlled consumption. The flue gas cleaning is designed to semi-wet method. The final stage involves the calculation of the balance, the calculation of electric energyand basic economic evaluation.
75

Verfahrenstechnische Untersuchungen zum Betriebsverhalten statischer Rottereaktoren

Weichelt, Kay 04 March 2020 (has links)
Statische Rottereaktoren sind mit ihrem Festbett das vorherrschende technologische Konzept zur biologischen Behandlung von Restabfall (MBA) und zur Bioabfallkompostierung. Auftretende prozesstechnische Probleme beim Reaktorbetrieb waren die Motivation zur vorliegenden Arbeit. Untersucht wurde das Betriebsverhalten am Beispiel von MBA-Anlagen. Die Bedingungen und Vorgänge wurden im Kontext von Stoffsystem und technischem System unter Anwendung verfahrenstechnischer Methoden analysiert. Für Großanlagen geeignete experimentelle Methoden wurden entwickelt und das Betriebsverhalten im Istzustand und im modifizierten Anlagenzustand beschrieben. Es wurden signifikante Beeinflussungen der Rottebedingungen durch Stoffsystem und Prozessführung unter Einwirkung der Technik deutlich. Die prozessrelevanten Einflussfaktoren sowie deren Ursachen und Wirkungen auf das Betriebsverhalten konnten analysiert und zahlreiche konzeptions- und konstruktionsbedingte Probleme statischer Rottereaktoren identifiziert werden. Als besonders problematisch zeigten sich stochastisch und systematisch auftretende Vorzugsströmungen aufgrund der Heterogenität des Haufwerks und undefinierte Bedingungen zur Belüftung aufgrund schwankender Druckbedingungen im Prozessluftsystem und gegenseitiger Beeinflussungen. Aus den Ergebnissen wurden Maßnahmen für einen verbesserten Betrieb bestehender Anlagen und Lösungen für zukünftige Anlagen abgeleitet / With their fixed bed, static reactors are the predominant technological concept for the biological treatment of residual waste (MBT) and for the composting of bio-waste. Process-based problems in the reactor operation were the motivation for the present work. The operating behavior was examined using the example of MBT plants. The conditions and processes were analyzed in the context of the material system and the technical system using process engineering methods. Experimental methods suitable for real plants were developed and the operating behavior in the current state and in the modified plant state was described. Significant influences on the rotting conditions by the material system and process management under the effect of technology became apparent. The process-relevant influencing factors and their causes and effects on the operating behavior could be analyzed and numerous concept- and construction-conditioned problems of static reactors could be identified. Stochastic and systematic preference flows due to the heterogeneity of the material in the reactor and undefined conditions for ventilation due to fluctuating pressure conditions in the process air system and mutual influences were particularly problematic. Technical measures for improved operating behavior of existing plants and solutions for future plants were derived from the results.
76

BIOCHEMICAL METHANE POTENTIAL TESTING AND MODELLING FOR INSIGHT INTO ANAEROBIC DIGESTER PERFORMANCE

Sarah Daly (9183209) 30 July 2020 (has links)
<p>Anaerobic digestion uses a mixed, microbial community to convert organic wastes to biogas, thereby generating a clean renewable energy and reducing greenhouse gas emissions. However, few studies have quantified the relationship between waste composition and the subsequent physical and chemical changes in the digester. This Ph.D. dissertation aimed to gain new knowledge about how these differences in waste composition ultimately affect digester function. This dissertation examined three areas of digester function: (1) hydrogen sulfide production, (2) digester foaming, and (3) methane yield. </p> <p>To accomplish these aims, a variety of materials from four different large-scale field digesters were collected at different time points and from different locations within the digester systems, including influent, liquid in the middle of the digesters, effluent, and effluent after solids separation. The materials were used for biochemical methane potential (BMP) tests in 43 lab-scale lab-digester groups, each containing triplicate or duplicate digesters. The materials from field digesters and the effluents from the lab-digesters were analyzed for an extensive set of chemical and physical characteristics. The three areas of digester function were examined with the physical and chemical characteristics of the digester materials and effluents, and the BMP performances. </p> <p>Hydrogen sulfide productions in the lab-digesters ranged from non-detectable to 1.29 mL g VS<sup>-1</sup>. Higher H<sub>2</sub>S concentrations in the biogas were observed within the first ten days of testing. The initial Fe(II) : S ratio and OP concentrations had important influences on H<sub>2</sub>S productions. Important parameters of digester influents related to digester foaming were the ratios of Fe(II) : S, Fe(II) : TP, and TVFA : TALK; and the concentrations of Cu. Digesters receiving mixed waste streams could be more vulnerable to foaming. The characteristics of each waste type varied significantly based on substrate and inoculum type, and digester functioning. The influent chemical characteristics of the waste significantly impacted all aspects of digester function. Using multivariate statistics and machine learning, models were developed and the prediction of digester outcomes were simulated based on the initial characteristics of the waste types. </p>
77

Potential for Renewable Energy Sources (RES) in Grenoble, Delft &amp; Växjö

Turesson, Jonas January 2011 (has links)
Sustainable cities is an area that has grown in size over the last couple of years. The SESAC (Sustainable Energy Systems in Advanced Cities) is a EU-project looking at the potential to increase the share of Renewable Energy Sources (RES) and promote energy efficiency measures in different EU cities. This master thesis is a part of that project. Specifically, the thesis examines the cities of Grenoble, Delft and Växjö and looks at what measures regarding RES and energy efficiency have been taken historically, both under the SESAC project and otherwise, and assesses the possibility of further measures in the cities. The main RES evaluated are wind power (large scale and urban), solar (PV and thermal) and waste treatment (waste incineration and biogas production). The feasibility of these renewable technologies is evaluated both physically, technically and economically for each city. Further, the historical and current hinders and promoters in the form of different support schemes and other economic and institutional schemes are summarized for each country and city and the effects of which included in the feasibility calculations. Also, current CO2 emissions of Grenoble, Delft and Växjö are stated and the impact of implementing the measures examined is calculated. A comparison between the three cities is also made and suggestions are made to what they can learn from each other and what synergies there are.    Results show that the technical potential for RES is sizeable in the cities, as seen in Table 1. Important to note are the differences between the cities. Besides from their differences in population size, ranging from 83 000 (Växjö) and 96 000 (Delft) to 400 000 (Grenoble), available land area as well as climate are very different in the cities, therefore affecting the potential for the RES technologies.   RES potential [GWh] Grenoble Delft Växjö Wind 458 1,2 (Urban only) 297-2000 Solar PV 375 150 0,06-0,3 Waste treatment 41 11 10 Table 1. Technical potential of RES in Grenoble, Delft and Växjö Looking at the economic potential, however, the picture is not as optimistic. The only economically feasible investments of the options in Table 1 are investing in solar PV in Grenoble and Delft (IRR of 0-10%) and wind in Växjö (IRR of 4%). All other investments have negative NPV:s and IRR:s, meaning that either the cost of the technologies must be reduced or more favorable support scheme be introduced in order to make the them profitable.
78

Opportunities for Industrial Symbiosis BetweenCHP and Waste Treatment Facilities : (Case Study of Fortum and Ragn Sells, Brista)

Arushanyan, Yevgeniya January 2011 (has links)
Pursuing the possibilities of increasing efficiency, saving costs and improving environmental performance more and more companies today are looking into the possibilities of industrial synergies between companies andprocesses. This study is considering the possibilities of industrial symbiosis between combined heat and power plant (Fortum) and a waste sorting facility (Ragn Sells). The paper shows possible scenarios of utilization heat fromCHP for the various processes within the waste treatment facility. The work includes the overview of previous research done in this area as well as theoretical analysisand estimation of the probable economic and environmental effects from the application of industrial symbiosis. The study covers several possibilities for the industrial symbiosis between CHP and waste treatment facility in form of heat application for the waste streams upgrading.The study proposes the heat application for the following processes: composting speed-up, anaerobic digestion, sludge drying, waste oil treatment and concrete upgrading. In the result of the work the conclusions are made concerning the possibility and feasibility of application of the proposed scenarios and their environmentaland economic effects. / Division Industrial Ecologywww.kth.se/itm/indecowww.ima.kth.se
79

House of Waste / House of Waste

Strömbäck, Miriam January 2021 (has links)
I Sverige är industrin och samhället i stort sett helt skilda, där det är näst intill omöjligt att närma sig och observera vad som faktiskt sker i våra kraftverk eller återbruk. Placeringen långt ifrån städerna, avsaknaden av design eller koppling till omgivningen, och de stora skyltarna med “inträde förbjuden” förstärker inte bara känslan av alienation - men också tron om att industrin är något smutsigt, som är negativt för miljön och samhället. Estetiken spelar en avgörande roll i att minska den allmänt negativa synen kopplat till industribyggnader samt att integrera dem i våra samhällen.  Ett mindre industriellt utseende möjliggör en mer central placering, vilket förbättrar många typer av industriers effektivitet och kapacitet. Genom att skapa en lokal kraftproduktion, använda oss av de lokala resurserna, samt lyfta fram våra industribyggnader som landmärken så som de var i början av 1900-talet kan arkitekturen skapa en ny samhörighet, syfte och stolthet i samhällena. Mitt mål har varit att omdefiniera samspelet mellan avfall, energiproduktion och arkitektur, för att bjuda in samhället att vara en del av vår energiproduktion. Med House of waste har jag undersökt hur en biogasanläggning, som med fördel placeras på landsbygden i närhet till gårdar, inte bara kan inhysa ett socialt program utan vara publik i sin kärna. / The Swedish industry and society are widely separated and it is more or less impossible to approach and observe our industries. The location of the industries far away from our cities, the lack of connection to the surrounding context, and the many signs of “no entry” do not only strengthen the idea of alienation - but also the belief that industry is something dangerous hazardous as well as negative for the environment and our societies. Aesthetics play an important role in reducing the negative associations with industrial buildings as well as integrating them into our communities. A less industrial appearance can make a more central location acceptable, which is beneficial for the efficiency and capacity of most plants. By creating an infrastructure regarding local energy production, using the local resources and giving our industrial buildings aesthetic consideration, the architecture can create a new type of belonging, purpose and pride in our communities. The aim of the project has been to redefine the relationship between waste, energy production and architecture. House of Waste investigates how a biogas plant, not only can house a social program - but be a public building at its core.
80

Cow raising in the Mekong Delta - The current status of waste treatment and risk of greenhouse gas emissions

Nguyen, Le Phoung, Nguyen, Hong Tam, Thach, Si Nuo, Nguyen, Vo Chau Ngan 22 February 2019 (has links)
This study was aimed to assess the status of waste treatment for cow raising at small farm households in Can Tho, Tra Vinh, Soc Trang, and Hau Giang. The interview of 120 cow farmer households indicated that local farmers normally treat their waste by sun-drying, storing in ponds, discharging directly into rivers, or applying to anaerobic biogas. The farmers select ways to treat cow excrement according to seasons of the year: in the dry season cow waste is mostly sun-dried for sale (76.7%); stored for use (10%), untreated (7.5%) or applied to biogas plants (5.8%); however, in the rainy season most of the farmers leave the waste untreated (94.2%), except for those owning biogas tanks. Biogas treatment is applied mainly by dairy cow-raising households, accounting for 85.7% of biogas users. The cow farmer households have limited knowledge about biogas application; 23.3% of the interviewed farmers knew about biogas technology; 47.5% had little knowledge about this technology, however, 29.2% of the selected persons had no idea about biogas technology. Based on the quantity of beef cattle herds in the surveyed areas, it is estimated that CH4 gas emissions account for around 252.3 tons, 61.4 tons, 8.2 tons, and 2.5 tons in Soc Trang, Tra Vinh, Can Tho, and Hau Giang, respectively. / Nghiên cứu này nhằm đánh giá hiện trạng xử lý chất thải tại các hộ chăn nuôi bò ở thành phố Cần Thơ và các tỉnh Trà Vinh, Sóc Trăng, Hậu Giang. Tổng số 120 hộ chăn nuôi đã được phỏng vấn cho thấy có 4 phương pháp xử lý chính để xử lý chất thải chăn nuôi phát sinh: ủ yếm khí (biogas), phơi khô và bán, trữ lại trong ao để sử dụng, và không xử lý. Tùy theo thời điểm trong năm người dân sẽ thay đổi cách thức xử lý chất thải chăn nuôi bò: vào mùa khô có nhiều nắng chủ yếu người dân phơi khô để bán (76,7%), để lại và sử dụng (10%), dùng để ủ biogas (5,8%), và không xử lý (7,5%); tuy nhiên vào mùa mưa hầu hết các hộ dân không xử lý chất thải chăn nuôi (94,2%), chỉ trừ những hộ dân đã có hầm ủ biogas để xử lý. Xử lý chất thải chăn nuôi bằng công nghệ biogas được áp dụng phổ biến ở các hộ nuôi bò sữa, chiếm 85,7% số hộ có hầm ủ biogas. Sự hiểu biết về công nghệ biogas của các hộ chăn nuôi còn khá giới hạn, chỉ 23,3% hộ dân được phỏng vấn biết về công nghệ biogas, 47,5% hộ biết ít về công nghệ này, trong khi 29,2% hộ dân hoàn toàn không biết. Dựa trên số lượng đàn bò thịt trong vùng khảo sát, có thể tính được lượng CH4 phát thải hàng năm từ chất thải chăn nuôi là 252,3 tấn, 61,4 tấn, 8,2 tấn và 2,5 tấn từ các địa phương Sóc Trăng, Trà Vinh, Cần Thơ, và Hậu Giang.

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