• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 140
  • 45
  • 26
  • 22
  • 11
  • 9
  • 9
  • 8
  • 6
  • 6
  • 3
  • 3
  • 3
  • 2
  • 2
  • Tagged with
  • 321
  • 321
  • 116
  • 58
  • 42
  • 41
  • 41
  • 34
  • 31
  • 31
  • 29
  • 27
  • 25
  • 24
  • 23
  • 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.
171

[en] VALUE CREATION IN THE INNOVATION MARKET THROUGH THE REAL OPTIONS THEORY CONCEPTS: A QUALITATIVE FRAMEWORK FOCUSED IN START-UPS PRODUCTS AND SERVICES / [pt] CRIAÇÃO DE VALOR NO MERCADO DE INOVAÇÃO ATRAVÉS DOS CONCEITOS DA TEORIA DE OPÇÕES REAIS: UM FRAMEWORK QUALITATIVO FOCADO NA ESTRUTURAÇÃO DE PRODUTOS E SERVIÇOS DE START-UPS

ADELE BRAZ MAGALHAES 15 February 2019 (has links)
[pt] O constante crescimento da competitividade entre indústrias traz a necessidade de encontrar soluções para sustentar a vantagem competitiva por meio da inovação. Devido à diversidade de projetos e incerteza envolvida na inovação, a gestão dos projetos e o cálculo de valor, assim como sua gestão de risco, deve ser efetivo. Esta dissertação identifica a oportunidade do cálculo do valor de empresas Startups considerando a flexibilidade de projetos de inovação e tem como objetivo a criação de um framework conceitual para avaliar a possibilidade de geração de valor em negócios de produtos e serviços inovadores com base em análise qualitativa dos conceitos de opções reais. Durante a pesquisa e pela da análise dos métodos e processos das teorias da inovação e das opções reais, foi possível delimitar aspectos para desenvolvimento do framework: avaliação qualitativa, inovação de produtos e serviços; empresa alvo Startup, modelo do framework e opções reais a serem avaliadas (Opção de Aprendizado, Opção de Abandono, Opção de Switch e Opção de Expansão).O estudo estrutura e apresenta um framework que inclui um processo de quatro fases, permitindo assim que Startups identifiquem maior valor no seu negócio para melhorá-lo. / [en] The constant growth in competition between companies has brought the need to find solutions to sustain competitive advantage through innovation. Due to projects diversity and the uncertainty inherent to innovation, the project management and value calculation, as well as its risk management, must be effective. This dissertation identifies the opportunity to calculate the value generated by innovation the flexibility to react to the uncertainties inherent to innovation projects, and has as objective to create a conceptual framework focused on Startup Products and Services business plan. During the research and through the analysis of methods and processes of real options and innovation theories, we designed the framework development: qualitative evaluation, product and services innovation, Startups as target companies, framework model and real options to be evaluated (Abandonment Option, Learning Option, Switch Option and Expansion Option). This study structures and presents a framework that includes a four step process, hence allowing Startups to obtain higher value to improve their business.
172

A hardware-based transient characterization of electrochemical start-up in an SOFC/gas turbine hybrid environment using a 1-D real time SOFC model

Hughes, Dimitri O. 08 July 2011 (has links)
Solid oxide fuel cell/gas turbine (SOFC/GT) hybrid systems harness the capability to operate nearly 15 to 20 percentage points more efficiently than standard natural gas or pulverized coal power plants. Though the performance of these systems is quite promising, a number of system integration challenges, primarily with regards to thermal transport, still remain. It is for that reason that the Hybrid Performance Project (HyPer) facility, a Hardware-in-the-Loop SOFC/GT hybrid simulator, was built at the National Energy Technology Laboratory in Morgantown, WV. The HyPer facility couples an actual gas turbine with a combination of hardware and software that are used to simulate an actual SOFC. The facility is used to empirically address the system integration issues associated with fuel cell/gas turbine hybrids. Through this dissertation project, the software component of the SOFC simulator was upgraded from a 0-D lumped SOFC model to a 1-D, distributed, real-time operating SOFC model capable of spatio-temporal characterization of a fuel cell operating with a gas turbine in a hybrid arrangement. Once completed and verified, the upgraded HyPer facility was used to characterize the impact of cold air by-pass and initial fuel cell load on electrochemical start-up in an SOFC/GT hybrid environment. The impact of start-up on fuel cell inlet process parameters, SOFC performance and SOFC distributed behavior are presented and analyzed in comparative manner. This study represents the first time that an empirical parametric study, characterizing system operation during electrochemical start-up has been conducted.
173

Linking entrepreneurial agency to the early life stages of innovative firms : the case of the biotechnology sector / L'agence entreprenariale dans les premiers stades de la vie de firmes innovantes : le cas du secteur des biotechnologies

Lang, Frédérique 19 May 2014 (has links)
Cette thèse s’attache à étudier les premières étapes de vie des entreprises innovantes. Elles sont analysées tant sur le plan théorique, en faisant appel à la littérature sur l’entreprenariat, la théorie des organisations et celle sur l’innovation, que sur le plan empirique, via treize études de cas de start-ups en biotechnologie. Ce travail contribue à la littérature existante en introduisant théoriquement le concept d’agence entreprenariale. Les résultats sont présentés dans trois chapitres analytiques. Le premier analyse l’impact de la contrainte de financement, premièrement sur l’agence entreprenariale, et deuxièmement sur l’évolution de la firme. Le second s’intéresse au lien entre les caractéristiques de l’entrepreneur et les premiers stades de vie de l’entreprise. Enfin, le dernier chapitre examine le processus de transition allant du développement d’un projet d’innovation incubé dans une université jusqu’au début de la création de l’entreprise censée développer ce projet. / The aim of this thesis is to further the understanding of the entrepreneurial process, from opportunity recognition to the development of start-ups. Various literatures are used, such as those of entrepreneurship, innovation studies and theories of organisations. The theoretical framework also introduces the concept of entrepreneurial agency. This framework is tested through thirteen case studies of biotech start-ups. The results are presented in three analytical chapters. The first develops the impact of involving financiers on entrepreneurial agency and firm evolution. The second aims at observing the effects of a change of leadership throughout the entrepreneurial activity, and links the background of the founder with the strategy of the firm. The final chapter attempts to understand the steps that a research project goes through when transitioning from the incubating organisation to a newly created enterprise.
174

Miljöfokuserade start-ups : En empirisk undersökning om nystartade företags förutsättningar att minska sin miljöpåverkan / Environmentally sustainable start-ups : An empirical study on new companies ability to reduce its environmental impact

Karlsson, Daniel, Sjögren, Eric January 2017 (has links)
Purpose: The purpose of this study is to examine what possibilities start-up companies have to work in an environmentally sustainable way, and what barriers they face in that context. The study moreover presents enabling factors which help start-ups realize opportunities and overcome barriers. To fulfill the purpose, it has been divided into two research questions, which follows: What opportunities and barriers do start-up companies, who want to work in an environmentally sustainable way, face? Which enablers can an environmentally sustainable start-up companies make use of to seize opportunities and lower barriers? Method: To fulfill the purpose a single case study was conducted. Empirical data was collected from a case company by semi structured interviews based on the theoretical framework. The selected case company is a start up with high focus on sustainability and the environment. A business incubator was also interviewed using semi structured questions to complement the empirical data collected from the case company. This empirical data was then analyzed against the theoretical framework which then lead to the study’s results. Findings: The study identified three major opportunities which help start-ups in an environmentally sustainable way: an increase in demand for environmentally products; tightened environmental regulations, and increased credibility from stakeholders. Moreover, four major barriers to environmental sustainability in start-ups were found: a low degree of market maturity; lack of financial resources and human capital; competition from established firms; and difficulties in attracting investors. In terms of enablers, the following factors were deemed instrumental in seizing opportunities and overcoming barriers: start-ups’ organizational flexibility, which allows them to rather quickly master necessary organizational change processes towards environmental sustainability; usage of environmental principles; social capital; and incubators as well as other external guidance. Implications: Presented opportunities, barriers and enablers are based on previous studies, the result of this study increase the understanding about how start-ups can work more environmentally focused. The empirical findings about incubators role in helping start-ups becoming more environmentally focused is an unexplored area and needs more attention in the literature. Societies can benefit from this increased understanding since it can lead to a decreased environmental impact, both on a local level by consuming less resources and a global level by slowing down the climate threat. Limitations: By including only one case company and one incubator combined with the qualitative research approach, the study covers a wide but shallow area. By including multiple case companies and incubators the study would have reached a higher level of generalization. Documents could have been studied in order to reach a more quantitative result with could have increased the credibility of the study. / Syfte: Studiens syfte är att skapa en tydligare förståelse för vilka förutsättningar start-up företag har att arbeta miljöfokuserat genom att identifiera väsentliga möjligheter, hinder och möjliggörare. För att uppfylla syftet har det delats upp i två frågeställningar, vilka lyder: Vilka möjligheter och hinder har start-up företag som vill arbeta miljöfokuserat? Vilka möjliggörare finns för start-up företag att ta tillvara på möjligheter samt minska hinder? Metod: För att uppfylla syftet har en enfallsstudie genomförts. Empiriska data har samlats in från ett fallföretag genom semistrukturerade intervjuer som baserats på det teoretiska ramverket. Valt fallföretag är ett start-up med stort fokus på hållbarhet och miljöfrågor. En inkubator har också intervjuats med hjälp av semistrukturerade frågor för att komplettera insamlade data från fallföretaget. Data från empirin har sedan analyserats mot det teoretiska ramverket och genererat i studiens resultat. Resultat: Studien har identifierat tre möjligheter som hjälper start-up företag att arbeta miljöfokuserat: ökad efterfrågan på miljövänliga produkter, bättre förutsättningar tack vare miljöregleringar och ökad trovärdighet mot kunder och intressenter. Det har även identifierats fyra hinder för start-ups att arbeta miljöfokuserat: marknadens bristande mognadsgrad, begränsade resurser i form av kapital och kunskap, konkurrens från etablerade företag samt svårigheter att hitta investerare har identifierats för start-ups som vill arbeta miljöfokuserat. Fyra möjliggörare har även identifierats för att ta vara på dessa möjligheter och minska hindren, nämligen enklare och snabbare förändringsprocess, användning av miljöprinciper, socialt kapital samt inkubatorer och annan extern rådgivning. Implikationer: Presenterade möjligheter, hinder och möjliggörare är baserade på tidigare studier, denna studies resultat skapar en tydligare förståelse för vilka förutsättningar ett start- up har att arbeta mijlfokuserat. Empiriska data kring inkubatorers roll att vägleda start-ups att bli mer miljöfokuserade är ett outforskat område som skulle behöva utvecklas ytterligare. Samhällen kan gynnas av denna tydligare förståelse då det kan leda till en minskad miljöpåverkan, både på en lokal nivå genom ett minskat utnyttjande av resurser samt på en global nivå genom att klimathotet kan bromsas. Begränsningar: Genom att endast studera ett fallföretag och en inkubator kombinerat med den kvalitativa ansatsen blir studiens perspektiv relativt brett och grunt. Genom att inkludera fler fallföretag och fler inkubatorer skulle studien få en större generaliserbarhet. En dokumentstudie hade kunnat genomföras för att nå ett mer kvantitativt resultat vilket skulle leda till en mer trovärdig studie.
175

PERLA Ústí nad Orlicí / PEARL Ústí nad Orlicí

Annová, Denisa January 2016 (has links)
The subject of the diploma thesis is to design reclamation of brownfield PERLA 01 in Ústí nad Orlicí. The construction program consists conversion of existing building to assembly hall, gallery, tourist centre, sheltered workshop, rentable space, office building. New building is Start up centre. The project design a character of public space and a new square.
176

The funding process in female-led capital-intensive start-ups

Samuelsson-Allendes, Ximena, Hein, Kyaw Khaing January 2023 (has links)
The purpose of this study is to present how female entrepreneurs in Sweden raise capital for their start-ups and if there are common key factors presented among those who succeed. The entrepreneurs interviewed have all successfully raised capital. The research shows that female founders only have access to 1% or less of the capital in Sweden. We interview investors to acquire their perception of gender bias in fundraising and the key factors they look for during their due diligence process. The study shows that female entrepreneurs prefer bootstrapping and soft fundings before approaching investors. The majority of the female entrepreneurs were unsecure or did not know if they have been exposed to gender bias from investors during their fundraising process because they succeeded raising capital. They were at the same time aware of the existing gender bias. The majority of the investors expressed that they preferred to invest in female or mixed funded companies because their experience shows that those tend to perform better. The study also shows that key factors during the fundraising process are diversity of the team, resilience, networking, building good relations and that the entrepreneurs appears to be coachable from the investors point of view.
177

Introducing a Framework for Innovation Readiness Levels – A Framework to Evaluate Innovation Efforts / Presentation av innovationsnivåer – Ett ramverk för att mäta mognadsgraden av innovation

Lunner, Carl-Magnus, Worrmann, Emelie January 2018 (has links)
When developing new products, it is important to be able to evaluate their readiness as this helps organizations manage three major challenges of product development, performance, schedule, and budget. The National Aeronautics and Space Administration (NASA) discovered this in 1990 and developed a nine-level framework to measure the progression of technology development, Technology Readiness Levels (TRLs).  The framework has since then been adopted by many different industries, among them OEMs. However, there are more aspects of the innovation process than just technology. Research topics such as user centered design and business model innovation has lately gained much attention, indicating that user and business aspects of the innovation are important. Therefore, the purpose of his thesis was to propose a framework to evaluate the readiness of business, user and technology aspects. To do so, a case study was performed at the Swedish OEM (Original Equipment Manufacturer) Husqvarna Group, a global producer of equipment for garden and park care, as well as for the construction industry. A literature study was performed to create an understanding of the current knowledge on the topic. Semi structured interviews were used to investigate how innovation is performed at the researched company. The result from these interviews was contrasted with the results from interviews at four other Swedish OEMs, to increase external validity. Lastly the findings were validated through focus group interviews at Husqvarna Group. The case study resulted in the identification of important steps when developing viable, desirable, and feasible products. From these, the nine most important for business and user was identified and frameworks for business and user readiness respectively were developed, along with attainment criteria for each level. The findings showed that the TRL framework still holds relevance, however the attainment criteria were adjusted to better suit OEMs. Together these three frameworks create the Innovation Readiness Level (IRL) framework. / Vid utveckling av nya produkter finns det tre stora utmaningar i produktutvecklingen; prestanda, tid och budget, därför är det viktigt att ständig stötta processen genom att utvärdera projektets mognadsgrad. År 1990 utvecklade NASA en niogradig skala som kan tillämpas som ett ramverk för att mäta mognadsgraden av en teknikutveckling, Technology Readiness Levels (TRL), detta har sedan dess införts av många industriföretag. När det kommer till innovation finns det dock fler aspekter än enbart teknik att ta hänsyn till. Forskning inom användarfokuserad design och affärsmodellsinnovation har fått ökad uppmärksamhet den senaste tiden, vilket indikerar att användare och affär är viktiga aspekter inom innovation. Syftet med denna studie är att föreslå ett ramverk för att utvärdera mognadsgraden utifrån ett affärs-, användar- och teknikperspektiv. För att genomföra detta gjordes en fallstudie på det svenska industriföretaget Husqvarna Group, en global tillverkare av skogs-, park- och trädgårdsprodukter samt utrustning för konstruktionsindustrin. För att skapa en förståelse av den befintliga kunskapen inom ämnet gjordes en bred litteraturstudie. Semi-strukturerade intervjuer genomfördes för att undersöka hur innovation hanteras inom Husqvarna Group. Resultatet från det undersökta företaget ställdes i kontrast med intervjuresultat från fyra andra svenska industriföretag för att skapa ett mer generaliserbart resultat. Till sist testades resultatet genom validering med fokusgruppsintervjuer på Husqvarna Group.  Fallstudien resulterade i identifiering av betydelsefulla steg vid utveckling av en ny produkt som ordnades kronologiskt. Vid varje nivå i skalan föreslogs en rad kriterier från ett affärs- respektive användarperspektiv som ett produktutvecklingsprojekt bör uppnå för att öka chansen att bli väl mottagen när den når marknaden. Resultatet visade även att TRL-ramverket fortfarande är aktuellt och relevant, men uppnåendekriterier anpassades för ett industriföretag. Tillsammans skapar dessa tre faktorer det föreslagna ramverket Innovation Readiness Levels (IRL).
178

Value Determinants in Seed Stage SaaS Valuation : Main value determinants to consider when conducting a valuation of a seed stage SaaS company / Värdedeterminanter vid värdering av SaaS-bolag i seed stage : Viktiga värdebestämningsfaktorer att ta hänsyn till när manvärderar ett SaaS-företag i seed stage

Adeli, Emil, Nylund, Daniel January 2022 (has links)
One of the single biggest challenges for start-ups is to find the necessary funding to achieve growth. Software-as-a-service (SaaS) companies are no different and rely on seed stage investments to build and develop a service in order to acquire paying customers. Given the need of external investments, SaaS companies heavily depend on their valuation for each given investor. The purpose of this study was to investigate the main value determinants for seed stage SaaS company valuations. Hence, the research question at issue was “What are the main value determinants for seed stage SaaS company valuations?”. This study was delimited to seed stage SaaS companies with a business to business (B2B) service offering in Sweden. This qualitative research was carried out through semi-structured in-depth interviews with seed stage SaaS B2B founders and investors operating in Sweden. The primary results of the qualitative research show that the main value determinants can be divided into three main factors. Firstly, external factors, such as the region, industry, and market that the company is operating within. Secondly, company factors include team and founder characteristics, firm characteristics, SaaS metrics and financials, and partnership and alliances. Thirdly, investor factors, including investor type as well as reputation and value-add. Following the findings, similarities and differences with literature were discussed. Based on the results, a revised framework including the main value determinants for seed stage SaaS company valuation was developed. The conclusion of this study is that seed stage SaaS company valuations vary among investor types. The valuation tends to not be bound to a specific valuation method, but rather a process where an overall evaluation is made from a set of criteria, which leads up to the valuation process where the final valuation is set. / En av de största utmaningarna för nystartade företag är att genomföra extern kapitalanskaffning för att uppnå tillväxt. Det gäller även för SaaS-företag (Software-as-a-service) vilka är beroende av investeringar i seed stage (fröstadiet) för att bygga upp och utveckla tjänster för att erhålla betalande kunder. Givet behovet av externa investeringar är SaaS-företag starkt beroende av dess värdering från investerare. Syftet med denna studie var att undersöka de viktigaste värdedeterminanterna för värdering av SaaS-bolag i seed stage. Forskningsfrågan var således "Vilka är de viktigaste värdedeterminanterna för värderingar av SaaS-företag i seed stage?". Studien avgränsades till SaaS-företag som erbjuder B2B-tjänster i Sverige. Denna kvalitativa studie genomfördes genom semistrukturerade intervjuer med seed stage SaaS B2B-grundare och investerare som är verksamma i Sverige. De övergripande resultaten visar att de viktigaste värdedeterminanterna kan delas in i tre huvudfaktorer: externa faktorer, företagsfaktorer, och investerarfaktorer. Externa faktorer avser region, bransch, och marknad inom vilka företaget är verksamt. Företagsfaktorer inkluderar teamet och grundarnas egenskaper, företagets egenskaper, SaaS-mått och finansiella data, samt partnerskap och allianser. Investerarfaktorer avser typen av investerare samt investerarens rykte och mervärde. Utfallet från intervjuerna jämfördes med resultat från tidigare litteratur. Baserat på intervjuresultaten utvecklades ett reviderat ramverk med de viktigaste värdedeterminanterna för värdering av SaaS-bolag i seed stage. Slutsatsen av denna studie är att värdering av SaaS-företag i seed stage varierar mellan olika investerartyper. Värderingen tenderar att inte vara bunden till en specifik värderingsmetod, utan en process där en övergripande utvärdering görs baserat på en uppsättning av kriterier, vilket resulterar i en slutgiltig värdering.
179

Avaliação da partida de reator anaeróbio de fluxo ascendente e manta de lodo (UASB), em escala real, sob condições hidráulicas desfavoráveis / Start-up of a full-scale upflow anaerobic sludge blanket (UASB) reactor, treating domestic sewage, under unfavorable hydraulic conditions

Sulita Mendes Pierotti 08 March 2007 (has links)
Este estudo teve como objetivo avaliar a partida de reator anaeróbio de fluxo ascendente e manta de lodo (UASB), em escala real, no tratamento de esgoto sanitário, sob condições hidráulicas desfavoráveis. O reator UASB faz parte do sistema de tratamento da ETE Água Vermelha, e é seguido de um biofiltro aerado submerso e de uma unidade de desinfecção por ultravioleta. Foi utilizado metade do volume do reator (117 \'M POT.3\'), possibilitando menor tempo de detenção hidráulica (TDH). A pesquisa foi dividida em duas fases, uma sem a adição de inóculo (fase I) e outra com inoculação (fase II). Na fase I, foram aplicados vazão de 480 \'M POT.3\'/dia e carga orgânica volumétrica (COV) de 1,74 kgDQO/\'M POT.3\'.dia com TDH de 6 horas. Para a fase II, estes valores foram de 600 \'M POT.3\'/dia, 2,88 kgDQO/\'M POT.3\'.dia e 5 horas. Os resultados mostraram que as excessivas velocidades ascensionais não permitiram que o reator tivesse desempenho satisfatório. Ocorreu remoção de matéria orgânica e sólidos suspensos apenas na fase II, com exceção dos sólidos suspensos voláteis, que apresentaram remoção nas duas fases. Os lançamentos indevidos de lodo de fossas à que a ETE está submetida, provocaram aumento de sólidos dissolvidos e alcalinidade no efluente. Os leitos de lodo formados nas fases I e II possuíam concentrações semelhantes de sólidos, porém o segundo apresentou maior eficiência de tratamento. Na fase I a remoção de matéria orgânica foi pequena e não ocorreu a formação da manta de lodo. Na fase II ocorreu o provável início da estabilização do processo, aproximadamente 60 dias após a inoculação, a partir de quando a remoção de matéria orgânica dissolvida foi considerada constante e foi observada a formação da manta de lodo. O descarte de 8,5 \'M POT.3\' de lodo pode ser feito a cada 30 dias. / The objective of this study was to evaluate the start-up of a full-scale upflow anaerobic sludge blanket (UASB) reactor, treating domestic sewage, under unfavorable hydraulic conditions. The UASB reactor is part of the wastewater treatment plant of Água Vermelha (São Carlos, SP, Brazil), and it is followed by a submerged aerated biofilter and an ultraviolet radiation disinfection unit. Half of the reactor volume was used (117 \'M POT.3\'), making it possible to work with a low hydraulic retention time (HRT). The research was divided in two phases, one without reactor seeding (phase I), and another when the reactor was seeded (phase II). At phase I, a flow rate of 480 \'M POT.3\'/d and a volumetric loading rate of 1,74 kgDQO/\'M POT.3\'.d were applied, with 6 hours of HRT. At phase II, this values were 600 \'M POT.3\'/d; 2,88 kgDQO/\'M POT.3\'d and 5 hours. The results showed that excessive upflow velocities prevented satisfactory performance of the reactor. Removal efficiencies of COD, BOD and TSS were obtained only in phase II, except for VSS, which showed removal in both stages. Unauthorized inputs of septic tanks sludge caused increase in dissolved solids and alkalinity in the effluent. The sludge beds obtained in phases I and II had similar solids concentration; however, the second presented better treatment efficiency. At phase I, organic matter removal efficiency was low and the blanket sludge was not observed. At phase II, the process likely stabilized 60 days after inoculation (operations\' day 240). From then on, dissolved organic matter digestion was constant and the sludge blanket was observed. The removal of the excess sludge can be done every other 30 days.
180

Utilização de lodo anaeróbio imobilizado em gel no estudo de partida de reatores de fluxo ascendente com manta de lodo / not available

Del Nery, Valéria 17 July 1987 (has links)
A utilização de reatores anaeróbios de fluxo ascendente com manta de lodo no tratamento de águas residuárias tem tido grande aceitação dos projetistas e pesquisadores pelas vantagens que esse sistema apresenta sobre os demais (aeróbios e anaeróbios). Uma das principais limitações do processo relaciona-se com o período de partida, normalmente lento e de difícil controle. Esse trabalho apresenta os resultados de pesquisas em laboratório sobre a partida de dois reatores de manta de lodo, um deles inoculado com lodo anaeróbio imobilizado em matrizes de gel agar e o outro com lodo livre. A imobilização de microrganismos em gel surge como uma nova possibilidade de retenção da população microbiana no reator e consequentemente, esse trabalho objetiva também verificar a viabilidade do uso de lodo imobilizado em qel agar no estudo sobre fatores que afetam o desempenho de reatores com manta de lodo. Os dois reatores anaeróbios utilizados neste trabalho eram idênticos e possuiam volume de 10 L cada um. Utilizou-se substrato sintético para que se obtivesse alimento com características estáveis durante a maior parte do tempo necessário à partida dos reatores, preparados de maneira a se obter DQO de aproximadamente 2000 mg/L. Os reatores estiveram em operação durante 179 dias e foram submetidos a cargas orgânicas volumétricas que variaram de 0,47 a 12,83 KgDQO.m-3.d-1 e a cargas hidráulicas volumétricas que variaram de 0,23 a 6,0 m3.m-3.d-1. As principais análises realizadas foram DQO, alcalinidade, ácidos voláteis, pH, temperatura e altura do leito de lodo. A eficiência de remoção de DQO esteve em geral entre 70 e 80%. Em vista dos resultados obtidos, conclue-se que a utilização de lodo anaeróbio imobilizado em matrizes de gel agar pode ser útil no estudo de partida de reatores anaeróbios com manta de lodo. Sugere-se a continuidade dos estudos, utilizando-se as técnicas descritas no trabalho, na ampliação do conhecimento dos processos anaeróbios neste tipo de reator. / The use of Upflow Anaerobic Sludge Blanket (UASB) Reactor for wastewater treatment has been well accepted by designers and researchers due to the advantages shown over athers reactors (aerobic and anaerobic). The reactor start-up remains as one of the most important limitations of the process. It is usualy slow and is difficult to control. This thesis shows the results of a laboratory research on the start-up of two UASB reactors. One of them was seeded with anaerobic sludge immobilized in gel agar and the other with free anaerobic sludge. The immobilization of microorganisms in gel represents a new possibility of biomass retention within the reactors. Consequently this research also aims to check the viability of using immobilized sludge in gel agar in the study of factors affecting UASB reactors performance. Both the UASB reactors used in this research were exatly alike and had a volume 10 L each. Synthetic substrate was used to provide, consistent feed during the most of the start-up period. The substrate was prepared to contain about 2000 mg/L COD. The reactors were aperated for 179 days and were submitted to organic loading rates which varied from 0,47 to 12,83 KgCOD.m-3.d-1 and to hydraulic loading rates which varied from 0,23 to 6,0 m3.m-3.d-1. The main physical-chemical parameters measured were COD, alkalinity, volatite fatly acids, pH, temperature and sludge bed height. The COD removal efficiency was between 70 and 80%. This research comproved the feasibility of sludge immobilized in gel agar for UASB reactor start-up. It is suggested to continue the studies to achieve the best conditions for the use of this technique.

Page generated in 0.0536 seconds