Improving wastewater (WW) treatment process is a major issue in different parts of the world. For a developed country like the UK where eutrophication is a problem that causes environmental and economical losses, and for a developing country like Jordan that is considered one of the most water scarce countries in the world, it is crucially important to improve the quality of the WW for safe reuse. Applying microalgae for WW treatment and biomass production is an economical and environmentally friendly method. However, this method has some challenges that need to be addressed, such as microalgae species selection, harvesting of the microalgae and the large area footprint. In this research, the overall aim was to bioprospect for microalgae that are adapted to the wastewater treatment plants (WWTPs) and evaluate the obtained microalgae depending on specific criteria for a successful application in high rate algal ponds (HRAPs), then there were attempts to improve the phosphorus removal in microalgae to increase the efficiency of the treatment process and reduce the area footprint. Bioprospecting for indigenous microalgae to the WW took place from January to May 2014. Water samples were collected from wastewater treatment plants (WWTPs) in the UK and Jordan. Eight different microalgae isolates were identified from each country. The results showed the Chlorella, Scenedesmus and Desmodesmus are common genera between the two countries and dominated the obtained isolates from the UK and Jordan. The isolates were identified using 18S rDNA and ITS1 5.8S ITS2 DNA barcoding markers. It was difficult to identify some of the isolates at the species level, as the 18S rDNA is too conserved to differentiate between the closely related species and due to the relatively poor representation of algae in GenBank. Then the obtained microalgae isolates were evaluated by their growth, efficiency in removing nutrients (i.e. nitrogen and phosphorus) and the settleability of the microalgae by gravity. Depending on the results the microalgae species were ranked to come up with some promising candidates to be applied on large scale. From the UK, Avonmouth_12 (Av_12) and Avonmouth_10 (Av_10) and from Jordan, Jordan_18 (Jo_18) and Jordan_29 (Jo_29) were distinguished in their performance in the WW. Since phosphorus is a major cause of eutrophication in the fresh water and it is important to reduce the level of phosphorus in the released WW to the legally permitted limits, this research aimed to study the possibility of improving phosphorus removal by microalgae. Using Chlamydomonas reinhardtii as a model to optimise the protocol to be applied in parallel with Av_12, which is a promising microalga isolate that has been applied on large scale in HRAPs in Beckington WWTP, the strategy was to overexpress a Phosphorus Starvation Response (PSR1) gene. The transformation process was successful in C. reinhardtii but not in Av_12. There was an enhancement of the specific phosphate removal rate in the transformed microalgae isolate CC 1010_B2 and CC 1010_A6 in comparison to the wild type strain CC 1010.

Energy use and the environment are inextricably linked and form a key role in concerns over sustainability. All methods of energy production involve resource uncertainties and environmental impacts. A clear example of this is the use of fossil fuels which present three main problems, being: finite resources; significant contribution to environmental pollution; and reliance on imports. Hence there is a clear need to reduce the use of fossil fuels for energy. Bioenergy has the potential to both displace fossil fuels, and reduce the effect of climate change by sequestering carbon dioxide during the production of biomass. It is also possible that bioenergy can reduce the UK’s dependence on energy imports and boost the rural economy. This thesis provides an interdisciplinary assessment of bioenergy production in the UK. Due to the complexities of bioenergy systems several appraisal methods have been used. An initial study examined the barriers to and drivers for UK bioenergy development as a whole. It was found that for projects to be successful, bioenergy schemes need to be both economically attractive and environmentally sustainable. A biomass resource assessment was then completed using the South West of England as a case study. This demonstrates that bioenergy can make a useful contribution to the UK’s energy supply, due to the diverse range of biomass feedstocks currently available. However a range of barriers and constraints will need to be overcome if the UK is to reach its bioenergy potential. To assess the potential environmental impacts of bioenergy production different case studies were selected. Life cycle assessment is widely regarded as one of the best methodologies for the evaluation of burdens associated with bioenergy production. This was applied, alongside net energy analysis, to a small-scale biomass gasification plant which uses wood waste as a feedstock. As an alternative biomass source, the perennial energy crops Miscanthus and Willow were also assessed. Several different scenarios of biomass cultivation, transportation, and energy conversion were then compared, to assess the potential environmental impacts. Biomass gasification offers good potential for reducing fossil fuel use and climate change impacts. Nonetheless embodied energy in the construction phase can be high and other impacts such as particulate emissions, ecotoxicity and land use can be important. Therefore environmental benefits are maximised when both electricity and heat are utilised together, and when waste is used as feedstock. The ultimate applicability of biomass gasification is restricted by the quantity of feedstocks that can be made available for conversion. Perennial energy crops offer several advantages over annual crops including more positive energy balances and reduced agro-chemical inputs. However their cultivation needs to be carefully sited to avoid issues of land use change and the displacement of food crops. This study shows that each bioenergy production pathway needs to be assessed using a range of appraisal techniques, which include: biomass resource assessment, technical and economic feasibility, life cycle assessment and net energy analysis. It concludes that biomass gasification CHP offers an alternative to fossil fuel generation but more technical knowledge is required in the UK if it is to become widely used for biomass energy.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE / Includes bibliographical references. / by Michael Tully Klein. / Sc.D.

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Aerosol particles are ubiquitous in the atmosphere and their properties impact on the atmospheric energy balance. They scatter and absorb incoming sunlight and can perturb cloud microphysical properties, which affects cloud lifetimes and albedo. Africa is one of the world’s largest sources of aerosol due to both its large deserts and prolific biomass burning during the dry seasons. Nevertheless, the continent's atmosphere has, to date, been among the least studied in the world. The southern coast of West Africa is developing rapidly, with both population and anthropogenic emissions being predicted to increase substantially in coming years. It is therefore becoming ever more important to understand the characteristics of aerosols in this region, which will have consequences for issues as diverse as local health and global climate change. This project addresses this problem in two ways: first, laboratory experiments were carried out to characterise biomass burning aerosol at source. Biomass burning is one of the most poorly understood aerosol sources, but one of the most prevalent in tropical regions. Second, aircraft observations were made in southern West Africa during the Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa (DACCIWA) field campaign in summer 2016, to observe the broad-scale distribution of chemical and physical aerosol properties. Results were collected in-situ with Aerodyne Aerosol Mass Spectrometers (AMS) and other online aerosol instrumentation; they were considered alongside observations from DACCIWA ground sites and model results. Distinguishable chemical signatures were reliably observed during three phases of combustion events in the laboratory study. This gave insight into the mechanisms linking combustion phases and emissions. Airborne observations in southern West Africa revealed a remarkably consistent background of aged, accumulation mode aerosol present across the region in the boundary layer, including in the region upwind of the cities on the south coast. It was demonstrated that this likely originated from large-scale biomass burning in central and southern Africa, which had become entrained into the boundary layer above the Atlantic and transported north. A second result from the DACCIWA campaign showed that the hygroscopic growth of these particles, due to the high humidity in the region during June and July, more than doubled the mean dry aerosol optical depth. Taken together, these findings shed light on the substantial impacts that biomass burning aerosol, in particular, has on the atmosphere above southern West Africa.

A busca por segurança energética tem feito com que a maioria dos países empenhe-se na busca por fontes alternativas de energia, procurando mitigar problemas econômicos, sociais e ambientais. Espera-se que a biomassa, disponível de forma geograficamente dispersa, venha a tornar-se um dos principais recursos renováveis na produção de alimentos, materiais, produtos químicos, combustíveis e energia. Nesse cenário, o desenvolvimento de biorrefinarias representa a chave para uma produção integrada, combinando rotas de conversões químicas, bioquímicas e termoquímicas, no processamento da biomassa, visando à utilização otimizada dos recursos disponíveis. As biorrefinarias com estruturas descentralizadas são uma alternativa à centralização de produções em grandes plantas industriais e à monocultura, pois utilizam biomassas disponíveis regionalmente, integram sistemas de produção, potencializando os recursos locais, reduzem custos com logística e impactos ambientais, além de melhorarem a distribuição da renda. O presente trabalho apresenta uma revisão da disponibilidade de biomassa no Brasil e no mundo, com especial interesse no aproveitamento de microalgas e resíduos orgânicos, dos principais produtos de interesse e conceitos de biorrefinarias existentes. O objetivo é discutir qual é o conceito que melhor se adapta às necessidades do cenário brasileiro, bem como propor um modelo com estrutura descentralizada em duas ou três etapas, visando à otimização de um processamento sustentável de biomassa para obtenção de vários produtos comerciáveis e energia, além de delinear diretrizes para investimentos na área. É apresentada uma metodologia para a tomada de decisões na concepção e análise de viabilidade do projeto conceitual de uma biorrefinaria, considerando-se também as restrições de ordem ecológica, econômica e tecnológica. Como estudo de caso, é proposta uma biorrefinaria a partir de microalgas. A escolha por microalgas como matéria-prima é baseada nas vantagens que sua utilização apresenta frente à de outras biomassas, dentre elas cita-se a capacidade de produção rápida e durante todo o ano, a captura do CO2 necessário ao seu crescimento, a necessidade de menos água do que plantas terrestres, são cultiváveis em água salobra e terras não aráveis, apresentam elevado teor de óleo, seus nutrientes podem ser obtidos a partir de águas residuais, sua composição bioquímica pode ser modulada por diferentes condições de crescimento e são capazes de produção fotobiológica de bio-hidrogênio. Das alternativas de rotas possíveis para seu processamento, são apresentadas duas que apontam como sendo as mais promissoras: o uso da microalga como substrato de algum outro microorganismo, visando à obtenção de compostos com maior valor agregado, tais como biopolímeros, e o uso do processo de pirólise rápida para obtenção de bio-óleo, que deve ser processado posteriormente, visando à especificação em biocombustível. As vantagens da otimização do cultivo, colheita, rotas viáveis de processamento e a análise do potencial econômico desse modelo, indicam uma excelente oportunidade para obtenção de um espectro de produtos de alto valor agregado e energia e um grande potencial de aplicação. / The search for energy security has been doing with that most of the countries strive to seek alternative sources of energy that allows mitigating economic, social and environmental problems. It is expected that biomass, available on a geographically dispersed way, will become one of the major renewable resources for food, materials, chemicals, fuels and energy production. Additionally, the development of biorefineries represents the key to an integrated production, combining chemical, biochemical and thermochemical conversion routes for biomass processing, aiming the optimized use of available resources. Biorefineries with decentralized structure are an alternative to the centralization of production in large industrial plants and to the monoculture because it uses biomass regionally available, integrates production systems potentiating local resources, reduces logistics costs and environmental impacts, as well as improves income distribution. This work presents a review of: i) biomass availability in Brazil and in the world, focus on the use of microalgae and organic wastes; ii) the main products of interest; and; iii) concepts of existing biorefineries. The objective is to discuss which one is the concept that better fits the needs of the Brazilian scenario and propose a new model with decentralized structure in two or three stages, seeking to an optimized and sustainable biomass processing to obtain various marketable products and energy, and delineate guidelines for investment in the area. It is presented a methodology for making the conceptions decisions and feasibility analysis of the conceptual design of a generic refinery, considering also the ecological, economic and technological constraints. As a case study, it is proposed a biorefinery from microalgae. The choice of microalgae as a raw material is based on the advantages that their use offers over the others biomasses. Among the advantages it can be cited the ability for rapid production and during all the year, the capture of CO2 for its growth, the need for less water than land plants, they can be cultivated in brackish water and non-arable land, have a high oil content, nutrients can be obtained from waste water, their biochemical composition can be modulated by different growth conditions and are capable of producing photobiology bio-hydrogen. Of the possible alternative routes for microalgae processing, are presented two as the most promising: the use of microalgae as a substrate for some other microorganism in order to obtain compounds with high added value, biopolymers as an example, and use the process of fast pyrolysis for obtaining bio-oil, which will be processed later in order to specify biofuels. The advantages of the cultivation optimization, harvesting, processing viable routes and analyzing the economic potential of this model indicate an excellent opportunity to obtain a spectrum of value-added products and energy and its great potential for application.

Made available in DSpace on 2014-06-11T19:31:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-01-25Bitstream added on 2014-06-13T21:01:55Z : No. of bitstreams: 1 morais_mr_dr_araiq_parcial.pdf: 287117 bytes, checksum: 586ff6c9f682c3a5d34a4e64209e8fee (MD5) Bitstreams deleted on 2015-02-09T14:35:43Z: morais_mr_dr_araiq_parcial.pdf,Bitstream added on 2015-02-09T14:36:22Z : No. of bitstreams: 1 000719056.pdf: 1241756 bytes, checksum: ade866cb60e3e153cf9565f03fe841d5 (MD5) Bitstreams deleted on 2015-02-09T17:15:05Z: 000719056.pdf,Bitstream added on 2015-02-09T17:15:42Z : No. of bitstreams: 1 000719056.pdf: 1241756 bytes, checksum: ade866cb60e3e153cf9565f03fe841d5 (MD5) / Fermentações sucessivas com alta densidade celular são realizadas em Usinas de produção de etanol no Brasil e devido às dificuldades de esterilização, bactérias e leveduras selvagens competem entre si por nutrientes e pela dominância no processo. O objetivo do presente estudo consistiu em melhorar as condições de clarificação do melaço, propagação e fermentação da linhagem de levedura Saccharomyces cerevisiae do laboratório IQAr/45-2, visando a maior produção de etanol sem perda de viabilidade nos processos com e sem reutilização celular. Estudou-se também as associações entre a levedura IQAr/45-2 e as leveduras industriais (PE-2, CAT-1 e SA-1). Para a clarificação do melaço variou-se o acidulante (fosfato e ácido sulfúrico), pH inicial do melaço, temperatura e tempo de decantação, com intuito de levar a uma maior remoção de impurezas presente nesta matéria-prima. A melhor condição de propagação para levedura IQAr/45-2 consistiu em três etapas de concentrações crescentes de açúcar no melaço (4%, 8% e 12%) à 30°C com agitação (100 rpm). Esta condição de propagação levou a um rendimento de biomassa de 6,1g.L-1. Elevando-se a temperatura para 37°C, o tempo de propagação de cada etapa pode ser reduzido para 12h (cada) à custa de um aumento em uma etapa (melaço 3%, 5%, 8% e 12%), com biomassa variando de acordo com a levedura: 7,6g.L-1 para PE-2, 6,7g.L-1 para SA-1, 6,4g.L-1 para CAT-1 e 2,5g.L-1 para IQAr/45-2. Apesar de apresentar um menor crescimento a 37°C, a levedura IQAr/45-2 não mostrou instabilidade genética em meios cromogênios diferenciais. Para otimizar as condições de fermentação da levedura IQAr/45-2 em mini-reatores variou-se o tempo e fluxo de alimentação, temperatura e concentração de açúcar no mosto de alimentação visando um maior rendimento... / Successive fermentations at high cell densities and cell reuse currently take part of the routine of Brazil distilleries for fuel ethanol production. Due to difficulties related to sterilization, bacteria and Saccharomyces and non-Saccharomyces yeasts compete with each other for nutrients and dominance of the process. The aim of the present work is to optimize and improve processes for molasses clarification, inoculum propagation, fermentation conditions and storage of Saccharomyces cerevisiae IQAr/45-2 between fermentation cycles with and without revitalization in order to minimize losses in ethanol production and viability during repetitive fermentations. It was also studied associations between the strain IQAr/45-2 and industrial yeasts (PE-2, CAT-1 and SA-1). In order to improve conditions for molasses clarification, acidification agents (phosphate and sulfuric acid), initial pH, temperature and decantation time were varied during the experiments. The best propagation condition for the strain IQAr/45-2 consisted on three consecutive steps of growth in increasing sugar concentrations (4%, 8% and 12%) at 30°C with agitation (100 rpm). Under these conditions, the biomass accumulated at the end of the propagation was 6.1 g.L-1. On the other hand, raising the propagation temperature from 30°C to 37°C, the time of each step decreased from 24h to 12h, while the biomass formed at the end of the entire propagation varied with the strain as follows: 7,6 g.L-1 for PE-2, 6,7g.L-1 for SA-1, 6,4g.L-1 for strain CAT-1 e 2,5g.L-1for strain IQAr/45-2. Any genetic instability occurred, as shown by the colonies formed on the differential chromogenic medium, when samples from the final culture propagated at 37°C were plated. Optimization of the fermentation conditions for the strain IQAr/45-2 was established in mini-reactors... (Complete abstract click electronic access below)

Orientador: Cecilia Laluce / Banca: Maria Lucia Gonsales da Costa Araujo / Banca: Sandra Regina Ceccato Antonini / Banca: Debora Colombi / Banca: Luiz Carlos Basso / Resumo: Fermentações sucessivas com alta densidade celular são realizadas em Usinas de produção de etanol no Brasil e devido às dificuldades de esterilização, bactérias e leveduras selvagens competem entre si por nutrientes e pela dominância no processo. O objetivo do presente estudo consistiu em melhorar as condições de clarificação do melaço, propagação e fermentação da linhagem de levedura Saccharomyces cerevisiae do laboratório IQAr/45-2, visando a maior produção de etanol sem perda de viabilidade nos processos com e sem reutilização celular. Estudou-se também as associações entre a levedura IQAr/45-2 e as leveduras industriais (PE-2, CAT-1 e SA-1). Para a clarificação do melaço variou-se o acidulante (fosfato e ácido sulfúrico), pH inicial do melaço, temperatura e tempo de decantação, com intuito de levar a uma maior remoção de impurezas presente nesta matéria-prima. A melhor condição de propagação para levedura IQAr/45-2 consistiu em três etapas de concentrações crescentes de açúcar no melaço (4%, 8% e 12%) à 30°C com agitação (100 rpm). Esta condição de propagação levou a um rendimento de biomassa de 6,1g.L-1. Elevando-se a temperatura para 37°C, o tempo de propagação de cada etapa pode ser reduzido para 12h (cada) à custa de um aumento em uma etapa (melaço 3%, 5%, 8% e 12%), com biomassa variando de acordo com a levedura: 7,6g.L-1 para PE-2, 6,7g.L-1 para SA-1, 6,4g.L-1 para CAT-1 e 2,5g.L-1 para IQAr/45-2. Apesar de apresentar um menor crescimento a 37°C, a levedura IQAr/45-2 não mostrou instabilidade genética em meios cromogênios diferenciais. Para otimizar as condições de fermentação da levedura IQAr/45-2 em mini-reatores variou-se o tempo e fluxo de alimentação, temperatura e concentração de açúcar no mosto de alimentação visando um maior rendimento... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Successive fermentations at high cell densities and cell reuse currently take part of the routine of Brazil distilleries for fuel ethanol production. Due to difficulties related to sterilization, bacteria and Saccharomyces and non-Saccharomyces yeasts compete with each other for nutrients and dominance of the process. The aim of the present work is to optimize and improve processes for molasses clarification, inoculum propagation, fermentation conditions and storage of Saccharomyces cerevisiae IQAr/45-2 between fermentation cycles with and without revitalization in order to minimize losses in ethanol production and viability during repetitive fermentations. It was also studied associations between the strain IQAr/45-2 and industrial yeasts (PE-2, CAT-1 and SA-1). In order to improve conditions for molasses clarification, acidification agents (phosphate and sulfuric acid), initial pH, temperature and decantation time were varied during the experiments. The best propagation condition for the strain IQAr/45-2 consisted on three consecutive steps of growth in increasing sugar concentrations (4%, 8% and 12%) at 30°C with agitation (100 rpm). Under these conditions, the biomass accumulated at the end of the propagation was 6.1 g.L-1. On the other hand, raising the propagation temperature from 30°C to 37°C, the time of each step decreased from 24h to 12h, while the biomass formed at the end of the entire propagation varied with the strain as follows: 7,6 g.L-1 for PE-2, 6,7g.L-1 for SA-1, 6,4g.L-1 for strain CAT-1 e 2,5g.L-1for strain IQAr/45-2. Any genetic instability occurred, as shown by the colonies formed on the differential chromogenic medium, when samples from the final culture propagated at 37°C were plated. Optimization of the fermentation conditions for the strain IQAr/45-2 was established in mini-reactors... (Complete abstract click electronic access below) / Doutor

Biomass is a renewable, carbon-neutral resource that produces minimal pollution when used to generate electricity, fuel vehicles, and provide heat for industry. Every year in Iowa, millions of bushels of treated seed corn go unused, and are wasted (sent to the landfill). Old treated seed corn goes unplanted because of low germination rates, but it goes unused because of the toxicity associated with the pesticides and fungicides applied to it. If the toxic additives could be destroyed through gasification with a long, high-temperature residence time, the producer gas from treated seed corn could then be used as a fuel source in regular power plants. The temperature and reactivity required to destroy these chemicals is best achieved in a reactive bed, like one formed by carbon char. This makes a char producing combustion system an ideal candidate for this type of fuel. In this work, a char-producing downdraft gasification system is used to examine system behavior for seed corn fuel. The system is pilot-scale and the producer gas is of primary interest for power production. Both experiments and numerical simulations are carried out and a range of parameters are examined, including the thermal profile, equivalence ratio, bed depth, and producer gas composition. A second downdraft gasifier, with two-stage gasification, is also studied to compare the systems’ behaviors. From these results, a 1-d hybrid model was developed and utilized to predict optimal gas production in these systems. Results show that above the minimal char bed level, higher equivalence ratio (ER) value results in a higher combustion zone temperature and a higher gas yield while leading to a lower CO concentration in the producer gas. Bed height consumes more heat in the combustion zone which brings about a lower combustion zone temperature. In general, ER plays a more dominating role in determining gas yield and combustion zone temperature. The two-stage system, which expands the combustion zone, effectively increases carbon conversion rate and hence generates a producer gas with high cold gas efficiency, although this makes maintaining sufficient char depth difficult.