O setor sucroalcooleiro vem ganhando cada vez mais destaque no agronegócio brasileiro. O Produto Interno Bruto (PIB) do setor na safra de 2015 gerou mais de US$113 bilhões ao longo de toda cadeia produtiva (UNICA, 2016). Esse período de ascensão é acompanhado de novos desafios e oportunidades, o que torna o setor um tema fértil para a pesquisa acadêmica, teórica e aplicada. Dada à pluralidade do setor que hoje extravasa seu nicho tradicional, álcool e açúcar, e atua cada vez mais intensamente nos setores energéticos, eletricidade e combustíveis renováveis, faz-se necessário a incorporação da nova dinâmica de produção que esses produtos trazem à realidade administrativa do setor. Assim, além de discutir teoria e metodologia correlatas à modelagem matemática empregada no auxilio à gestão do setor, esse trabalho visa contribuir com a literatura, incorporando e discutindo as novas possibilidades produtivas que a produção de biogás trás ao mix de produção tradicional. As principais ferramentas utilizadas nessa análise são a teoria de portfólios e o arcabouço teórico da otimização robusta. A partir dessas técnicas construiu-se um modelo de otimização onde se busca a minimização do risco para um dado retorno, princípio da teoria de portfólios, avaliando o risco com o CVaR, uma medida de risco mais adequada do que a tradicional variância. Construído esse modelo, analisa-se o papel do biogás, um produto ainda pouco usual nas usinas brasileiras, no portfólio produtivo de uma usina hipotética. Com base nesse modelo implementou-se as técnicas de otimização robusta com o intuito de aferir se os resultados verificados no modelo determinístico se mantém no caso robusto. / The sugarcane sector is gaining a huge prominence in the Brazilian agribusiness. The GDP of the sector in 2015 crop was over then US$ 113 billion along the entire production chain (UNICA, 2016). This auspicious period is accompanied by new challenges and opportunities, which makes the sector a hot field for academic research, theoretical and applied. Given the industry plurality which today goes beyond its traditional niche, alcohol and sugar, the sector is increasingly strongly its share in the energy sector, electricity and renewable fuels. Thus it is necessary to incorporate the new dynamic of production that these products bring to the administrative reality of the sector. Therefore, in addition to discussing theory and methodology related to the mathematical modeling used as a support to sector management, this work aims to contribute to the literature by incorporating and discussing the new production possibilities that biogas production brings to the traditional production mix. The main tools used in this analysis are the portfolio theory and the theoretical and applied framework of robust optimization. From these techniques it is built up an optimization model where one seeks to minimize risk for a given return, the principle of portfolio theory, assessing the risk with CVaR, a better measure of risk than traditional variance. Through this model, the role of biogas, an unusual product in the Brazilian plants, is analyzed considering a hypothetical plant. Based on this model it is implemented robust optimization techniques in order to assess whether the results observed in the deterministic model remains in the case robust.

Orientador: Marney Pascoli Cereda / Resumo: As fecularias são indústrias que processam mandioca para obtenção de amido. São inúmeras as unidades reunidas, principalmente, na região oeste do Estado do Paraná, gerando uma grande quantidade de águas residuárias poluentes. A solução usual é o tratamento em lagoas de estabilização o que, porém, apresenta problemas como emissão de gases poluentes e ocupação de grandes áreas. Os resultados obtidos neste trabalho referem-se ao tratamento de águas residuárias do processamento de uma indústria de fécula de mandioca, através de um sistema contínuo de biodigestão anaeróbia, com separação de fases, em escala piloto. Os biodigestores com separação de fases comprendem um reator acidogênico, cuja função é transformar o substrato bruto em ácidos orgânicos e um reator metanogênico que transforma estes ácidos em biogás e materiais orgânicos estabilizados. A separação de fases aumenta a estabilidade e a capacidade de trabalhar com materiais altamente solúveis, como os resíduos das indústrias de amido. A pesquisa foi conduzida junto a empresa M.C.R. Alimentos Ltda, uma fecularia com capacidade de processar 250 toneladas de mandioca por dia, localizada no município de Mercedes, região Oeste do Estado do Paraná. Está situada no paralelo 24°09'18'' de Latitude Sul e meridiano 54°09'26'' de Longitude... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: It was used a pilot scale two-stage anaerobic reactor to study the biological treatment of cassava wastewater. The research was carried at a Cassava processing factory, with a capacity of 250 metric tons day-1. It is located in West Paraná, South of Brazil, near the border of the Paraná River, at the parallel 24°09'18'' South latitude and meridian 54°09'26'' West longitude of Grw. The system consisted of two settling tanks with 500 L each, connected in series, followed by a two-stage anaerobic biodigester. The acidogenic reactor had a capacity of 1,000 L and the metanogenic had a capacity of 3,000 L. The experiment was conducted at ambient temperature, without nutrients and pH correction. The best result were obtained at a flow rate of 901 L d-1, with a TOC (total organic carbon) loading rate of 0.565 g L-1 d-1 (around a COD (chemical oxigen demand) of 2.49 g L-1 d-1) and a hidraulic residence time of 4.4 days. At this loading rate, the system achieved the following removal efficiencies: 77% of TOC and COD removal; 66% of Total Solids removal; 78% of Volatile Solids removal; 98% of Total Cyanide...(Complete abstract, click electronic access below) / Doutor

Large scale biofuel production from microalgae is expected to be integrated with point source CO2 sources, such as coal fired power plants. Flue gas (CO2) integration represents a required nutrient source for accelerated growth while concurrently providing an environmental service. Heavy metals inherent in coal will ultimately be introduced into the culture system. The introduced heavy metals have the potential to bind to microalgae cells, impact growth due to toxicity, and negatively impact the quality of biofuel and other microalgal derived products. Heavy metals As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se, Sn, V and Zn, commonly present in coal, were introduced to the microalgae growth medium at a concentration expected from a 7 day growth period using coal flue gas. Experimentation was conducted with Nannochloropsis salina cultivated in photobioreactors at a light intensity of 1000 μmol m-2 s-1. Heavy metals negatively impacted the growth with the average productivity being 0.54 ± 0.28 g L-1 d-1, corresponding to a decrease of 52% in biomass yield compared to control growths. Heavy metal analysis showed significant binding of the majority of the heavy metals to the biomass. A lipid content analysis found a decrease in lipid content from 38.8 ± 0.62% to 31.58 ± 0.50% (percent dry biomass). Control and heavy metal contaminated biomass were processed into biofuel through one of two different in-situ transesterification techniques, either acid-catalyzed or supercritical methanol conversion. The acid-catalyzed conversion resulted in an average crude biofuel production decrease from 0.31 ± 0.03 grams biofuel/gram microalgae for the control algae to 0.28 ± 0.02 grams biofuel/gram microalgae for the heavy metal algae, representing a 9.7% reduction. Supercritical methanol conversion exhibited a similar trend corresponding to a 15.8% reduction. Compared to the control, the total production of biofuel from the contaminated system was decreased by 51% for the acid-catalyzed conversion and 55% for the supercritical methanol conversion. Heavy metal analyses were performed on the biofuel, lipid extracted algae, and other biofuel conversion byproducts. Biochemical methane potential testing was performed on the lipid extracted algae to determine the effect of heavy metals on the generation of biogas. The effects of heavy metals in combination with the effects of acid catalyzed transesterification were found to have a positive effect on the amount of methane produced with an average productivity of 105.89 mL g-COD-1 from the heavy metals contaminated LEA compared to the control microalgae biomass which produced 53.25 mL g-COD-1.

Ever since 1976, livestock farmers in Fiji have been intrigued about biogas digesters as an animal waste management measure, but the concept has never evolved into one that is sustainable. Renewed interest came in 1997 after a better Chinese Modified Dome (CMD) design was established, with this came government funding, however by 2002, some failure was also observed. This study set out to investigate the reasons why biogas digesters have never been established as a sustainable concept, its effectiveness as an animal waste management tool and what changes if any, can be made to try and influence the further development of the concept in Fiji. In order to achieve the objectives, which were simply obtaining the answers to the questions presented above, several different approaches had to be followed. This study was the first on biogas digesters in Fiji and it was unique in the sense that the major component dealt with the social aspects of farmers in relation to their biogas digesters. Basically the study was carried out in two parts - desktop studies and field studies. Desktop studies were done to better understand the situation while the field studies included semi-structured interviews with the farmers as well as the collection of biophysical data. Twelve outcomes are presented in chapter 7 of this paper. Two in particular are the improvement of construction and maintenance, which can only come about through training. The research questions are also answered in chapter 7, with recommendations put forward on possible directions to take in terms of trying to influence the development of the concept in Fiji / Master of Science (Hons)

<p>Minskad klimatpåverkan genom mindre användning av fossila bränslen är centralt i miljöpolitiken. För Jämtlands län finns ett regionalt miljömål om en ökad produktion av klimatneutral energi med delmålet att biobränsleproduktionen inom jordbruket ska öka från 0 TWh år 2005 till minst 0,2 TWh år 2015. Syftet med uppsatsen är att ge en bild av vilka hinder som kan finnas för uppfyllandet av delmålet. Åtta intervjuer har genomförts och beskrivna hinder har identifierats och delats in i kategorier. Resultaten har därefter diskuterats mot bakgrund av villkoren för jordbruk och energiproduktion och ur ett systemteoretiskt perspektiv, där implementeringen beskrivs som mötespunkten för tre system: klimatpolitik, jordbruk och energisystem. Slutsatser som dras är att problem med lönsamhet samt en riskovilja är centrala hinder, möjligen kan de minskas genom ekonomiska stöd. En möjlig konflikt mellan livsmedels- och bränsleproduktion framträder också tydligt. Ur ett systemperspektiv betonas interaktionen mellan systemen som den struktur där implementeringshindren uppstår och implementeringen bör därför integrera flera perspektiv.</p>

<p>Det här är en studie om bland annat behandlar vilka konsekvenser som kan uppstå för biogasägare och användare av biogas om efterfrågan på biogas överstiger tillgången. Studien bygger på intervjuer som gjorts med tolv utvalda kommuner vilka alla har en biogasanläggning som tar emot avfall utifrån och dessutom levererar biogas till fordon. Studie består av två typer av frågeområden. Det första som undersökts är varför de svenska biogasanläggningarna byggt där de har och av vilken anledning det inte finns fler anläggningar. Syftet med studien är att uppmärksamma ett troligt framtida problem vilket grundar sig på ett tänkbart scenario om att oljan antigen stiger i pris eller sinar. Den problematik som uppmärksammats är om efterfrågan på biogas, på grund utav scenariot med oljan, överstiger tillgången och hur kommunerna skulle förhålla sig till en sådan situation. Frågeställningarna har analyserats utifrån ekonomisk teori med inriktning på begreppen utbud, efterfrågan, äganderätter och styrmedel. Dessutom har en ekologisk-ekonomisk modell använts för lättare se sambanden mellan de olika ingående delar i studien. Orsaken till att kommunerna har en biogasanläggning skiljer sig relativt mycket åt. De orsaker som nämndes var att vissa hade ett avfall att ta hade om medan en annan kommun hade en efterfrågan på biogasen. Vidare kunde biogastillverkningen motverka dels övergödning och dels föroreningsproblem orsakade av trafiken i innerstaden. Att inte fler kommuner har biogastillverkning tros enligt de undersökta kommunerna bland annat bero på att det dels kan vara svårt att räkna hem en anläggning idag och dels rädsla för luktproblem. Vidare anses det vara en otrygg marknad på grund utav oklara spelregler och dessutom krävs mycket i form av kunskap med mera av de kommuner som vill uppföra en anläggning. Troliga lösningar på det framtida scenariot som uppges av kommunerna är att komplettera med naturgas eller utvidga produktionen av biogasen. Det var endast en kommun som haft någon fundering på scenariot tidigare. Ett par kommuner ansåg dock att det var en viktig fråga att fundera vidare på. Flertalet av kommunerna är emellertid inte oroade över det givna scenariot. Andra tänkbara lösningar på problemet är att antingen privatisera biogasen eller att upprätta avtal mellan biogasanvändare och biogasägare.</p>

<p>As a part of a large project at Norrmejerier, a biogas production plant has been constructed at Umeå Dairy. In this plant wastewater, residual milk and whey are decomposed and biogas is produced. The biogas is burned in a steam boiler. The biogas plant is designed as an anaerobic contact process, with sludge separation and recirculation by a clarifier. The fat in the substrate is treated in a separate reactor.</p><p>The purpose of this study is to evaluate the design and start-up of this biogas production plant. Further, the interaction with the contractor responsible for construction and start-up is evaluated.</p><p>The plant is generally well designed, the process conditions are suitable and the objectives are realistic. However, the seed sludge is unsuitable and the time plan is too optimistic.</p><p>At the end of the period of this study, the plant was running and all central components are performing as intended. Still, the objectives have not been reached. This is mainly attributed to the poor quality of the seed sludge.</p><p>The management of the plant and the interaction with the contractor has generally been good. Most problems that arose were of typical start-up nature. Others were due to insufficient planning or lack of communication. Further, several design flaws were identified during start-up.</p><p>Washout of sludge has been one of the most significant drawbacks during start-up. This inconvenience seems to be the result of improper seed sludge and a too hasty increase of the organic loading rate.</p> / <p>Norrmejerier har som en del av ett större projekt låtit uppföra en anläggning för biogasproduktion vid Umeå mejeri. I anläggningen, som är utformad som en anaerob kontaktprocess, behandlas avloppsvattnen och andra organiska restprodukter från mejeriet tillsammans med vassle från både Umeå och Burträsk mejeri. Fettet i substratet avskiljs och behandlas separat. Den biogas som produceras vid nedbrytningen av det organiska materialet bränns i en brännare och ånga produceras.</p><p>Syftet med den här studien är att utvärdera anläggningens design, valda processförhållanden och förfarandet under uppstarten av biogasanläggningen. Dessutom utvärderas interaktionen med den tyska entreprenör som är ansvarig för konstruktion och uppstart.</p><p>Anläggningens utformning och valda processbetingelser är passande och de uppsatta målen är rimliga. Däremot är valet av ymp olämpligt och tidsplanen för uppstarten är för optimistisk.</p><p>När denna studie avslutades var anläggningen i bruk och biogas producerades. Alla de mål för som formulerats hade dock inte uppnåtts. Ympens dåliga kvalitet är den mest bidragande orsaken till att uppstartsperioden har blivit förlängd.</p><p>Arbetet under uppstarten och samarbetet med entreprenören har generellt sett varit lyckat. Man har dock stött på många komplikationer, varav de flesta har varit av typisk uppstartsnatur. Andra har varit resultatet av bristande planering och kommunikation. En rad konstruktions- och designfel har också identifierats under uppstarten.</p><p>Slamflykt från reaktorerna har varit det mest betydande problemet hos den biologiska processen. Denna förlust av slam förmodas bero på olämpligt val av ymp och en alltför hastig ökning av den organiska belastningen i reaktorerna under uppstarten.</p>

<p>Two species of emergent macrophytes, Typha latifolia (common cattail) and Phalaris arundinacea (reed canary grass) were evaluated as substrates for biogas production. The specific methane yield for each plant was obtained by batch wise anaerobic digestion in 300-mL bottles. Three different pretreatments were evaluated for increased biogas production; mechanical milling, alkaline treatment with lime and fungal degradation with Pleurotus ostreatus (oyseter mushroom).The methane yield for Typha latifolia and Phalaris arundinacea was determined to 300 and 323mL methane per g VS, respectively. There was no statistical difference in methane yield between the two species. Milling pretreatment increased the biogas yield with 16 % by average compared to untreated plant. Alkaline pretreatment with lime increased the biogas yield with 27 % at roomtemp. and 22 % at 55 °C. The fungal pretreatment decreased the biogas production by 20 % and is probably not suitable for this kind of substrate.The results showed that emergent macrophytes have a biogas yield similar to other plants already tested (grasses) and commonly used (pasture crops) in large scale reactors. However, emergent macrophytes and grasses cause mechanical problems in a reactor due to their structure. Probably some kind of milling must be done to decrease the fiber length of the emergent macrophytes. The costs for harvest, transport, handling and possible pretreatment of the emergent macrophytes have to be estimated and included in the overall cost calculations. This can tell if emergent macrophytes should be used as a substrate for biogas production.</p>

<p>Biogasprocessen är en komplex anaerob nedbrytningskedja där olika mikroorganismer är inblandade. Vanligast är att biogas produceras i mesofil rötning (cirka 38 ^oC), men även termofil rötning används (> 50 ^oC).</p><p>Svensk Biogas i Norrköping använder återstoden av etanoldestillationen hos en närliggande etanolproducent (drankvatten) som substrat. Substratets höga temperatur vid leverans motiverar termofilt rötningsförsök av drankvatten.</p><p>Försöket genomfördes i 55 ^oC med två kontinuerligt omrörda tankreaktorer (CSTR) och en termofil ymp. Biogasproduktion av drankvatten undersöktes. Sätt att hantera och motverka höga ammoniumhalter, samt effekter av näringslösningstillsats undersöktes. Det tog cirka 30 dagar för ympen att acceptera det nya substratet och då hade tillsats av processhjälpmedel KMB1 samt järnklorid använts. Reaktorerna kunde belastas med 3 g VS / (L • dygn) (VS, volatile solids, glödförlust). Den specifika gasproduktionen var 0,6 – 0,7 L / g VS och metanhalten ungefär 45 %. Höga ammoniumhalter motverkades genom förkortning av uppehållstiden. Under en period tillsattes nickelklorid i en av reaktorerna och under denna period hade reaktorn med nickelkloridtillsats något bättre specifik gasproduktion jämfört med reaktorn där ingen nickelklorid tillsattes.</p><p>Drankvatten kan rötas under termofila förhållanden. För att temperaturförändring vid biogasanläggningen i Norrköping ska var ekonomiskt försvarbart måste processen klara högre belastning.</p>

<p>Today the use of anaerobic digestion technique emerges as an alternative to the conventional treatment method of pig slurry to the pig producers in Brazil because of the energy demanding intensive pig production and the negative environmental impact that arises during storage and use. The end products of AD technique are biogas as an energy source and digestate that can be used as a fertilizer.</p><p>The study took place at two pig producers in southern Brazil in order to evaluate the biogas production in the area, its applications and environmental impact. The visited pig producers run a confined animal production system where the slurry that is used in the anaerobic digesters is diluted.</p><p>The studied digesters are covered with an air tight flexible plastic membrane that takes the shape of a balloon where each digester has the volume of 620 m3. Sedimentation occurs inside each reactor where the temperature also fluctuates. The produced biogas is conveyed to a torch where</p><p>the biogas is combusted.</p><p>The results of this study show that the digesters are working properly but there is a need for mixing and constant temperature in order to optimize the process. Biogas is primarily suited for heat production and the digestate can be used as a fertilizer. Biogas production is considered to have a positive environmental impact if the biogas is used or combusted in a torch. There is also a need to apply a cover over the digestate during the storage time to avoid ammonia emissions.</p><p>The approximated biogas potential for Rio Grande do Sul is nearly 100 GWh/year. For an</p><p>approximated biogas potential of more consideration it is found that further studies of the housing systems in Rio Grande do Sul are needed. This is due to a greatly varying amount of degradable materials in the pig slurry from one ranch to another.</p>