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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

Monolith reactors for automobile catalysts

Bennett, Chris January 1990 (has links)
No description available.
2

Rökgasrening för småskalig avfallsförbränning i länder under utveckling : En kartläggning över föroreningar i rökgaser, deras uppkomst och hur de kan reduceras / Flue Gas Treatment for Small-Scale Waste Incineration in Developing Countries

Johansson, Anton, Jonasson, Axel January 2017 (has links)
Företaget Againity AB har planer på att driftsätta avfallsförbränningsanläggningar i områden av världen där avfallsförbränning inte är särskilt vanlig. Againity står därför inför utmaningen att rena rökgaserna till godkända nivåer. För att göra detta krävs först och främst en kartläggning över förbränningstekniker, föroreningsemissioner och de olika utsläppskrav som finns. Vidare utvärderas vilka rökgasreningstekniker som är bäst lämpade för avfallsförbränningsanläggningar i de områden som Againity vill vara verksamt i. Genom att förbränna avfall i en förbränningsanläggning finns förutsättningar att rent förbränningstekniskt minska utsläppen av föroreningar. I en eldstad där förbränningen sker i kontrollerade former kan en önskad temperatur uppnås med hjälp av optimal lufttillförsel. Med kombinationen av en temperatur kring 800 – 1100 ºC och en uppehållstid på minst 2 sekunder kan fullständig förbränning av bränslet uppnås och utsläppen av miljöbelastande ämnen kan reduceras kraftigt. Föroreningar har undersökts baserat på de lagstiftningar som finns för utsläppsbegränsningar. En av dessa är svaveldioxid, som bidrar till försurning av vatten och mark. En annan är dioxiner, som genom biomagnifikation är skadliga för människor och djur. För att uppnå maximal reduktion av föroreningar används kombinationer av olika rökgasreningstekniker. Stoftbundna partiklar kan avskiljas ur rökgaserna med hjälp av olika slags filter, medan sura gaser måste reagera med ett annat ämne för att kunna fångas upp eller avskiljas på annat sätt. Kväveoxider avskiljs inte på samma sätt som de tidigare nämnda föroreningarna, utan reduceras istället med en reaktant som bildar en harmlös gas. Tack vare att data finns angående avfallsfraktioner, har teoretiska halter av vissa ämnen i rökgaserna beräknats. Företaget Testos mätningar vid avfallsförbränningsanläggningar har använts för andra föroreningar. Efter jämförelse med utsläppskrav för olika regioner har rekommendationer av lämpliga röksgasreningstekniker presenterats. Dessa förslag på rökgasreningsanläggningar har tagits fram ur ett miljö- och ekonomiperspektiv. Vi har kommit fram till att fullständig förbränning är en grundläggande princip som verksamhetsutövare behöver lägga stort fokus på. Gemensamt för alla våra anläggningsförslag har varit det elektrostatiska filtret, som vi tycker bör implementeras vid alla förbränningsanläggningar. Vi rekommenderar också andra reningstekniker som skrubber och SNCR, men dessa metoder bör sättas i relation till den miljömässiga kravbild, de ekonomiska resurser som finns och infrastrukturens funktionalitet. / The company Againity AB has plans to apply waste incineration systems in regions where waste management is a major issue. To manage this Againity must take flue gas treatment in consideration. As flue gas treatment isn’t their area of expertise, a disquisition of combustion techniques, pollution and emission standards will be necessary. Henceforth can an evaluation of which flue gas treatment techniques that would be suitable for waste incineration plants in the regions where the plants are intended to be. By incinerate waste in an incineration plant there is good conditions to obtain a less polluted flue gas just by using good combustion techniques. In a plant where you can control the combustion, a certain desired temperature can be achieved by injecting the right amount of air. The combination of a temperature around 800 – 1100 °C and a residence time of at least two seconds, result in complete combustion of the waste and emissions of environmental pollutants will be reduced. Based on emission standards, certain pollutants have been evaluated. One of those pollutants is sulphur dioxide, which contribute to acidification of earth and water. Another relevant pollutant is dioxins, which is harmful for humans and animals due to its capability of biomagnification. To acquire as clean flue gas as possible several flue gas treatment techniques should be applied in combination. By using filters in general, dust and particles bound in dust can be separated from the flue gas. As for acidic gases, these must react with another substance first to be separated. Nitrogen oxides however cannot be separated from the flue gas as the recently mentioned pollutants can, they can only be reduced by reacting with a reducing agent to form harmless gases. Thanks to available data concerning waste fractions, theoretical values of some pollutants in flue gases has been calculated. Emission measurements at waste incineration plants made by the company Testo, has been used for other pollutants. Calculated and measured values has been compared to the emission standards of Vietnam and the European Union and depending on the outcome of the comparison, suggestions of flue-gas techniques has been presented. Different suggestions of flue-gas systems have been presented depending of economic resources and to what extent the emissions should be reduced. Our conclusion is that complete combustion is a fundamental factor that operators must focus on. Electrostatic precipitator is a flue-gas technique that all our suggestions have in common and is a technique that we strongly recommend. We also recommend other flue-gas techniques such as scrubber and SNCR, but these methods are not always necessary. Planning of advanced flue-gas treatment needs consideration of the environmental requirements, the economic resources available and the functionality of the infrastructure.
3

Remoção de matéria orgânica residual e nitrogênio de efluente de reator UASB de indústria de insumos para ração animal em reator de leito estruturado / Residual organic matter and nitrogen removal from UASB reactor effluent of raw materials industry for animal food in a structured-bed reactor

Almeida, Ricardo Gabriel Bandeira de 07 October 2016 (has links)
O objetivo do presente trabalho foi avaliar o desempenho de um reator de leito fixo e fluxo ascendente (RLFFA) em escala de bancada submetido à baixa aeração e recirculação. O reator foi utilizado como um sistema de pós-tratamento do efluente de indústria de fabricação de ração animal (INCOFAP) a partir de resíduos de abatedouro de aves, caracterizado por elevada carga de nitrogênio amoniacal. Para tanto, o RLFFA foi avaliado quanto à remoção da fração remanescente de matéria orgânica e de nitrogênio do efluente do reator UASB instalado na indústria. O RLFFA foi operado em condições mesofílicas (30°C) e tinha volume total de 11,5 L e volume útil de 6,1 L, com leito estruturado composto por 13 estruturas cilíndricas (3 cm de diâmetro) de espuma de poliuretano, dispostas verticalmente no interior do reator. O reator apresentou sistema de recirculação interna, com razão de recirculação igual a 3, suficiente para garantir a mistura completa. O sistema foi operado em três condições distintas, que foram denominadas de fases, todas com tempo de detenção hidráulica (TDH) de 24 horas e concentração de oxigênio dissolvido próxima a 1,0 mg.L-1. Nas fases 1 e 2, o RLFFA foi alimentado com 20% de efluente do UASB diluídos em água, e a alimentação da Fase 3 foi com 10% de efluente. As relações DQO/N para as Fases de 1 a 3 foram de, respectivamente, 0,28, 0,41 e 0,26. Na Fase 1, a alcalinidade foi mantida em concentração estequiométrica para a ocorrência da nitrificação total, enquanto nas fases 2 e 3 a alcalinidade foi adicionada em excesso. As melhores eficiências de remoção de N-total e DQO foram obtidas na Fase 1, com respectivamente, 48 ± 24% e 63 ± 20%, atingindo remoção máxima de N-total de 79% e 92% para DQO. As análises estatísticas demonstraram independência entre a remoção de DQO e a remoção de N-total, e com demanda de doador de elétrons para desnitrificação heterotrófica via nitrato superior à DQO removida, indicando a ocorrência de vias complementares. A desnitrificação via nitrito e a desnitrificação autotrófica foram observadas nos ensaios cinéticos de desnitrificação via nitrito e teste de atividade para desnitrificação autotrófica utilizando sulfeto como doador de elétrons. A modelagem para qualidade da água do rio Chibarro( local de lançamento do efluente da empresa INCOFAP) utilizando uma modificação do modelo de Streeter-Phelps, indicou que o cenário com a adoção do reator estudado no presente trabalho para tratamento do efluente da INCOFAP permitiu reduzir o impacto para a qualidade da água do rio Chibarro ao se comparar ao sistema atual de tratamento do efluente da empresa INCOFAP. Entretando, ainda faz-se necessária a elevação da eficiência de remoção de N-total no sistema, para atingir a concentração máxima de N-amoniacal permitida de 20 mg.L-1 para o efluente para compatibilização com a capacidade de autodepuração do rio Chibarro. / The objective of this study was to evaluate the performance of a bench scale up-flow fixedbed reactor (UFBR) subjected to low aeration and effluent recirculation.The reactor was used as a post-treatment system of effluent from animal food plant (INCOFAP) using poultry slaughterhouse wastes, characterized by high ammoniacal nitrogen load rate.Therefore, the UFBR was evaluated in respect to residual organic matter and nitrogen removal of industrys UASB reactor effluent. The UFBR was operated in mesophilic conditions (30°C) and it had a total volume of 11.5 L and a working volume of 6.1 L, with a structured bed composed by 13 polyurethane foam vertical cylindrical structures (3 cm of diameter) inside the reactor. The reactor was provided with internal recirculation system with recirculation ratio of 3, suficiente to guarantee a complete mixture. The system was operated in three different phases, with hydraulic retention time (HRT)of 24 hours and dissolved oxygen concentration close to 1.0 mg.L-1.On Phases 1 and 2, the UFBR was fed with 20% of UASB effluent diluted in water,and the Phase 3 was fed with 10% of effluent. On phases 1 to 3 COD/N ratios were, respectively, 0.28, 0.41 and 0.26. The alkalinity on Phase 1 was maintained on stoichiometric concentration to total nitrification, while in phases 2 and 3 excess alkalinity was added. The best total nitrogen and COD removal efficiencies were obtained in Phase 1, with respectively, 48 ± 24% and 63 ± 20% , reaching maximum total nitrogen removal of 79% and 92% for COD. Statistical analysis demonstrated independency between COD and total nitrogen removal, and with higher electron donor demand for nitrate denitrification than COD removal, indicating the occurrence of complementary paths. The nitrite denitrification and autotrophic denitrification were noted in kinetics experiments and activity tests for autotrophic denitrification using sulfide as source of electron donors. The modeling for Chibarro river water quality (site of INCOFAPs effluent release) , using a modified Streeter-Phelps model, indicated the scenario with the adoption of the studied reactor on this work for INCOFAP's effluent treatment provided the reduction of the impact on Chibarros water quality in comparison with the current effluent treatment of INCOFAP. However, it is still necessary an increase on system denitrification efficiency to reach the maximum ammoniacal nitrogen concentration allowed of 20 mg.L-1 for the effluent to make compatible with de selfpurification of Chibarro river.
4

Remoção de matéria orgânica residual e nitrogênio de efluente de reator UASB de indústria de insumos para ração animal em reator de leito estruturado / Residual organic matter and nitrogen removal from UASB reactor effluent of raw materials industry for animal food in a structured-bed reactor

Ricardo Gabriel Bandeira de Almeida 07 October 2016 (has links)
O objetivo do presente trabalho foi avaliar o desempenho de um reator de leito fixo e fluxo ascendente (RLFFA) em escala de bancada submetido à baixa aeração e recirculação. O reator foi utilizado como um sistema de pós-tratamento do efluente de indústria de fabricação de ração animal (INCOFAP) a partir de resíduos de abatedouro de aves, caracterizado por elevada carga de nitrogênio amoniacal. Para tanto, o RLFFA foi avaliado quanto à remoção da fração remanescente de matéria orgânica e de nitrogênio do efluente do reator UASB instalado na indústria. O RLFFA foi operado em condições mesofílicas (30°C) e tinha volume total de 11,5 L e volume útil de 6,1 L, com leito estruturado composto por 13 estruturas cilíndricas (3 cm de diâmetro) de espuma de poliuretano, dispostas verticalmente no interior do reator. O reator apresentou sistema de recirculação interna, com razão de recirculação igual a 3, suficiente para garantir a mistura completa. O sistema foi operado em três condições distintas, que foram denominadas de fases, todas com tempo de detenção hidráulica (TDH) de 24 horas e concentração de oxigênio dissolvido próxima a 1,0 mg.L-1. Nas fases 1 e 2, o RLFFA foi alimentado com 20% de efluente do UASB diluídos em água, e a alimentação da Fase 3 foi com 10% de efluente. As relações DQO/N para as Fases de 1 a 3 foram de, respectivamente, 0,28, 0,41 e 0,26. Na Fase 1, a alcalinidade foi mantida em concentração estequiométrica para a ocorrência da nitrificação total, enquanto nas fases 2 e 3 a alcalinidade foi adicionada em excesso. As melhores eficiências de remoção de N-total e DQO foram obtidas na Fase 1, com respectivamente, 48 ± 24% e 63 ± 20%, atingindo remoção máxima de N-total de 79% e 92% para DQO. As análises estatísticas demonstraram independência entre a remoção de DQO e a remoção de N-total, e com demanda de doador de elétrons para desnitrificação heterotrófica via nitrato superior à DQO removida, indicando a ocorrência de vias complementares. A desnitrificação via nitrito e a desnitrificação autotrófica foram observadas nos ensaios cinéticos de desnitrificação via nitrito e teste de atividade para desnitrificação autotrófica utilizando sulfeto como doador de elétrons. A modelagem para qualidade da água do rio Chibarro( local de lançamento do efluente da empresa INCOFAP) utilizando uma modificação do modelo de Streeter-Phelps, indicou que o cenário com a adoção do reator estudado no presente trabalho para tratamento do efluente da INCOFAP permitiu reduzir o impacto para a qualidade da água do rio Chibarro ao se comparar ao sistema atual de tratamento do efluente da empresa INCOFAP. Entretando, ainda faz-se necessária a elevação da eficiência de remoção de N-total no sistema, para atingir a concentração máxima de N-amoniacal permitida de 20 mg.L-1 para o efluente para compatibilização com a capacidade de autodepuração do rio Chibarro. / The objective of this study was to evaluate the performance of a bench scale up-flow fixedbed reactor (UFBR) subjected to low aeration and effluent recirculation.The reactor was used as a post-treatment system of effluent from animal food plant (INCOFAP) using poultry slaughterhouse wastes, characterized by high ammoniacal nitrogen load rate.Therefore, the UFBR was evaluated in respect to residual organic matter and nitrogen removal of industrys UASB reactor effluent. The UFBR was operated in mesophilic conditions (30°C) and it had a total volume of 11.5 L and a working volume of 6.1 L, with a structured bed composed by 13 polyurethane foam vertical cylindrical structures (3 cm of diameter) inside the reactor. The reactor was provided with internal recirculation system with recirculation ratio of 3, suficiente to guarantee a complete mixture. The system was operated in three different phases, with hydraulic retention time (HRT)of 24 hours and dissolved oxygen concentration close to 1.0 mg.L-1.On Phases 1 and 2, the UFBR was fed with 20% of UASB effluent diluted in water,and the Phase 3 was fed with 10% of effluent. On phases 1 to 3 COD/N ratios were, respectively, 0.28, 0.41 and 0.26. The alkalinity on Phase 1 was maintained on stoichiometric concentration to total nitrification, while in phases 2 and 3 excess alkalinity was added. The best total nitrogen and COD removal efficiencies were obtained in Phase 1, with respectively, 48 ± 24% and 63 ± 20% , reaching maximum total nitrogen removal of 79% and 92% for COD. Statistical analysis demonstrated independency between COD and total nitrogen removal, and with higher electron donor demand for nitrate denitrification than COD removal, indicating the occurrence of complementary paths. The nitrite denitrification and autotrophic denitrification were noted in kinetics experiments and activity tests for autotrophic denitrification using sulfide as source of electron donors. The modeling for Chibarro river water quality (site of INCOFAPs effluent release) , using a modified Streeter-Phelps model, indicated the scenario with the adoption of the studied reactor on this work for INCOFAP's effluent treatment provided the reduction of the impact on Chibarros water quality in comparison with the current effluent treatment of INCOFAP. However, it is still necessary an increase on system denitrification efficiency to reach the maximum ammoniacal nitrogen concentration allowed of 20 mg.L-1 for the effluent to make compatible with de selfpurification of Chibarro river.
5

Optimalizace provozu čistíren odpadních vod / Optimizing the operation of wastewater treatment plants

Singrová, Veronika January 2019 (has links)
The aim of this diploma thesis is to evaluate two selected wastewater treatment plants and to propose appropriate measures related to optimization of operation. Wastewater treatment plants are from the Jihomoravský and Zlínský regions and both come under the category 2 001 - 10 000 equivalent inhabitants. In the diploma thesis there is an assessment of construction objects, machinery, cleaning efficiency and energy performance of both WWTPs. The calculations are based on the real measured values for the last three years and on the basic parameters of individual objects and equipment. The present state of the two wastewater treatment plants is summarized and optimization proposals are sorted by importance.

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