Två miljöproblem idag är ökade koncentrationer av växthusgaser i atmosfären och övergödning. Därför är två utmaningar att reducera utsläppen av växthusgaser och flöden av näringsämnen. Ytterligare en utmaning är att trygga energiförsörjningen i en värld där efterfrågan på energi ökar. Nya förnybara energikällor behöver utvecklas både för att trygga energiförsörjningen men även för att minska användandet av fossil energi. En förnybar energikälla är biogas som kan användas till el, värme och fordonsgas. Det förutspås att substrat för biogasproduktion kommer vara en bristvara i framtiden, därför behöver nya substrat utvärderas. Våtmarksväxter är ett alternativt substrat för biogasproduktion och utvärderades i den här studien. Våtmarker och dess växter är intressanta att studera eftersom de kan reducera koncentrationen näringsämnen som når sjöar och hav och kan därför bidra till att minska problemen med övergödning.    Studien genomfördes inom ett projekt vid Biogas Research Center och var en litteraturstudie med studie av ett fall. Metoden som användes har arbetats fram i projektet och är en multikriteriaanalys, (MCA), vilket innebär att det är flera olika områden som studeras. Områdena tar hänsyn till biologiska, ekonomiska, kemiska, miljömässiga och tekniska aspekter. För att strukturera upp informationen användes en matris som bestod av de olika huvudområdena som studerades. För att tydliggöra möjligheter och hinder gjordes en semi-kvalitativ bedömning av varje huvudområde.   Fallet som studerades var en våtmark i odlingslandskapet. Våtmarken är 5 ha och återskapades för några år sedan för att fungera som kväve- och fosforkälla. Det finns ingen växtlighet i våtmarken eftersom den är relativt ny. De växter som studerades under studien var därför växter som är tänkbara att växa i våtmarken i framtiden. Växterna som studerades var vass, rörflen och bredkaveldun. I våtmarken finns möjlighet att reglera vattennivån och därmed tömma den på vatten för att underlätta skörd.   Resultatet visade att den teknik som finns idag för skörd och sönderdelning behöver utvecklas eftersom den inte motsvarar de krav som ställs. Det finns olika tekniker för rötning och eftersom växterna har hög torrsubstanshalt är torrötning att föredra eller ett tvåstegssystem där första steget är torrötning. En våtmark ger en relativt liten mängd biomassa och därför passar det bättre att röta växterna tillsammans med andra substrat till exempel på en gårdsbiogasanläggning.   Våtmarksväxter är inte godkända substrat för certifiering av biogödsel, vilket kan vara ett hinder. Biogödseln har även ett lågt värde eftersom växterna innehåller låg halt näringsämnen. Våtmarker reducerar mängden näringsämnen och skörd kan bidra till att retentionen av fosfor ökar. Samtidigt avger våtmarker metan och lustgas som påverkar växthuseffekten.  Idag finns det ingen ekonomisk lönsamhet att skörda våtmarker. Ett system där ersättning fås för miljönyttan som skörd ger är ett alternativ för att öka lönsamheten. / Two environmental problems today are the increased concentrations of greenhouse gases in the atmosphere and eutrophication.  Therefore, two challenges are reducing greenhouse gas emissions and fluxes of nutrients. Another challenge is to secure the energy supply in a world where energy demand is increasing. New renewable energy sources need to be developed both to secure the energy supply, but also to reduce the use of fossil energy. A renewable energy source is biogas that can be used for electricity, heating and as vehicle fuel. It is predicted that substrate for biogas production will be a limitation in the future, therefore, new substrate need to be evaluated. Wetland plants are an alternative substrate for biogas production and evaluated in this study.  Wetlands and it is plants are interesting to study because they can reduce the concentration of nutrients and therefore help to reduce the problem of eutrophication.  The study was performed within a project at Biogas Research Center and was a literature study with the study of a case. The method used has been developed in the project and is a Multi Criteria Assessment (MCA), which means that there are several different areas being studied. Areas taking into account the biological, economic, chemical, environmental and technological aspects. In order to structure the data, a matrix consisting of the different key areas was used. To clarify the opportunities and obstacles a semi-qualitative assessment was done for each key area. The case studied was a wetland in an agricultural landscape. The wetland is 5 ha and was constructed a few years ago to work as nitrogen and phosphorous trap. There is no vegetation in the wetland because it is relatively new. The plants that were studied during the study was therefore plants that are potential to grow in the wetland in the future. The studied plants were reed, reed canary grass and cattail. In the wetland it is possible to regulate the water and thereby drain the water to facilitate harvesting.   The results showed that the technology available today for the harvesting and chopping needs to be developed because it does not meet the required standards. There are various techniques for digestion, but since the dry matter is high for the plants dry fermentation is preferable, or a two-stage system in which the first step is dry digestion. A wetland provides a relatively small amount of biomass and therefore it is better to co-digest the plants on a farm biogas plant.  Wetland plants are not approved substrates for certification of bio fertilizer, which can be an obstacle. The bio fertilizer also has a low value because the plants contain low levels of nutrients.Wetlands reduce the amount of nutrients and harvest of wetland plants contributes to the retention of phosphorus increases. Wetlands emit methane and nitrous oxide that affect global warming.Today, there is no economic viability of harvesting wetlands. A system in which compensation is obtained for the environmental benefit that harvest provides is an option to increase profitability.

A balanced supply of micronutrients, including metals such as iron (Fe), cobalt (Co), and nickel (Ni), is required for the efficient and stable production of biogas. During biogas formation, the uptake of micronutrient metals by microorganisms is controlled by a complex network of biological and chemical reactions, in which reduced sulfur (S) compounds play a central role. This thesis addresses the interrelationship between the overall chemical speciation of S, Fe, Co, and Ni in relation to the metals bio-uptake processes. Laboratory continuous stirred tank biogas reactors (CSTBR) treating S-rich grain stillage, as well as a number full-scale CSTBRs treating sewage sludge and various combinations of organic wastes, termed co-digestion, were considered. Sulfur speciation was evaluated using acid volatile sulfide (AVS) extraction and S X-ray absorption near edge structure (XANES). The chemical speciation of Fe, Co, and Ni was evaluated through the determination of aqueous metals and metal fractions pertaining to solid phases, as well as kinetic and thermodynamic analyses (chemical speciation modelling). The relative Fe to S content in biogas reactors, which in practice is regulated through the addition of Fe for the purpose of sulfide removal or prior to the anaerobic digestion of sewage sludge, is identified as a critical factor for the chemical speciation and bio-uptake of metals. In the reactors treating sewage sludge, the quantity of Fe exceeds that of S, inducing Fe(II)-dominated conditions under anaerobic conditions, while sulfide dominates in the co-digestion and laboratory reactors due to an excess of S over Fe. Under sulfide-dominated conditions, chemical speciation of the metals is regulated by hydrogen sulfide and the formation of metal sulfide precipitates, which in turn restrict the availability of metals for microorganisms. However, despite the limitations set by sulfide, aqueous concentrations of different Co and Ni species were shown to be sufficient to support metal acquisition by the microorganisms under sulfidic conditions. Comparatively, the concentrations of free metal ions and labile metal-phosphate and -carbonate complexes in aqueous phase, which directly participate in bio-uptake processes, are higher under Fe-dominated conditions. This results in an enhanced metal adsorption on cell surfaces and faster bio-uptake rates. It is therefore suggested that the chemical speciation and potential bioavailability of metals may be controlled through adjustments of the influent Fe concentration in relation to S content. The results also indicated that the pool of metal sulfides in the biogas reactors could be regarded as a source of metals for microbial activities. Thus, the recovery and utilisation of this fraction of metals may be considered as a measure with which to minimise the metal dosing concentrations to CSTBRs. / För att en effektiv och stabil biogasproduktion från organiskt avfall skall uppnås, behöver mikroorganismer i biogasreaktorer ha tillgång till näringsämnen inklusive spårmetaller såsom järn (Fe), kobolt (Co), och nickel (Ni). Mikroorganismernas upptag av spårmetaller styrs av biologiska och kemiska reaktioner som påverkar metallernas tillgänglighet, där framför allt interaktioner mellan metaller och reducerat svavel (S) spelar en viktig roll. Avhandlingen analyserar sambandet mellan kemisk speciering av S, Fe, Co, och Ni i relation till metallernas biologiska upptagsprocesser. Omrörda tankreaktorer (CSTBR) i lab.- och fullskala för produktion av biogas från spannmålsdrank, avloppsslam, och olika kombinationer av organiska avfall (samrötning) har utgjort basen för studierna. Svavelspeciering analyserades med hjälp av AVS (acid volatile sulfide) extraktion och S XANES (sulfur X-ray absorption near edge structure). Speciering av Fe, Co, och Ni utvärderades med hjälp av sekventiell extraktion, mätning av metall koncentrationer i löst och fast faser samt genom kinetiska och termodynamiska analyser (kemisk specieringsmodellering). Biogasreaktorers relativa mängder av Fe och S, identifierades som en central faktor för kemisk speciering och bio-upptag av metaller. Järn-mängden regleras bl a genom tillsats av Fe för att rena biogasen från vätesulfid eller vid diverse fällningsreaktioner i reningsverk före rötningsstegen av avloppsslam. Därför är järnhalterna högre än S-halterna i reaktorer, som behandlar avloppsslam. Detta leder till en Fe(II)-dominerande miljö. Däremot dominerade vätesulfid i de samrötnings- och laboratoriereaktorer, som ingick i studien. Under dessa förhållande styrs den kemiska metallspecieringen av sulfid och fr a genom fällning av metallsulfider, som då begränsar tillgängligheten av metaller för mikroorganismerna. Trots begränsningarna via sulfidfällningen var koncentrationen av de lösta Co och Ni formerna tillräckliga för bio-upptag av dessa metaller. Vid de Fe-dominerade förhållandena var koncentrationer av fria metalljoner och labila komplex (t.ex. med fosfat och karbonat), som direkt deltar i bio-upptagsprocesser, relativt höga, vilket medför relativt goda möjligheter för metalladsorption till cellytor och bio-upptag. Resultaten visar att den kemiska specieringen och därmed biotillgängligheten av metaller skulle kunna regleras genom justering av inflödet Fe i förhållande till S. Resultaten visade också att metallsulfider i fast fas sannolikt utnyttjas av mikroorganismer som en källa till metaller. Det innebär att en återanvändning av denna metallfraktion skulle kunna utnyttjas som en del i att minimera metalldoseringskoncentrationer.

La tesi ha un filo logico che inizia con la quantificazione e caratterizzazione degli impatti ambientali della produzione del latte. La ricerca prosegue con l'analisi delle opzioni per mitigare questi impatti, tra cui la produzione di biogas da reflui zootecnici. Il passo successivo è stato quello di analizzare la sostenibilità ambientale della co-digestione della biomassa da colture dedicate e reflui zootecnici. La digestione anaerobica dei reflui zootecnici per la produzione di biogas e la sua combustione per produrre energia elettrica è risultata un approccio tecnologico efficace per ridurre le emissioni di gas serra in quanto riduce le emissioni dallo stoccaggio dei liquami e sostituisce la produzione di energia elettrica da combustibili fossili. La produzione di biogas da biomassa da colture dedicate, anche se non fornisce benefici ambientali di per sé, può essere considerata come una opzione per facilitare e incrementare la digestione dei reflui, ma la biomassa da colture dedicate deve essere utilizzato in modeste quantità. I risultati di questa tesi - realizzati utilizzando la metodologia LCA - possono aiutare i responsabili politici nella pianificazione delle misure volte ad aumentare la sostenibilità della produzione del latte e del biogas nelle aziende zootecniche. / The thesis has a logical thread that starts with the quantification and characterization of the environmental impacts of milk production. The research continues with the analysis of the options for mitigating these impacts, among which biogas production from manure results very effective. The next step was to analyse the environmental sustainability of co-digestion of manure and energy crops. The anaerobic digestion of manure to biogas and its combustion to produce electricity resulted as an effective technological approach to mitigate GHG emissions because it reduces the emissions from slurry storage and contributes to the displacement of electricity generation from fossil fuels. Biogas production from energy crops, although not providing environmental benefits per se, may be regarded as an option to facilitate and increase the digestion of manure, if allowed only in small shares. The results of this thesis – achieved using LCA methodology – can assist policy makers in the planning of measures aimed at increasing the sustainability of milk and biogas production from dairy farms.

My thesis is aimed at the possiblities of collecting and utilizing the biodegradable component of municipal waste in the specific environment of České Budějovice. The thesis includes a proposal to construct a municipal biogas plant to decrease the volume of mixed municipal waste. The goal of this part of the thesis is to compare expected costs and income of the project and determine the general economic indicators and evaluate the investment, so that the project can be either fully recommended or rejected.

Orientador: Alexandre Amstalden Moraes Sampaio / Banca: Atushi Sugohara / Banca: Rymer Ramiz Tullio / Resumo: O ensaio foi conduzido na FCAV/ Unesp, utilizando 16 bovinos machos não castrados da raça Canchim, com peso médio inicial de 315 kg. Os animais foram alojados em baias individuais onde receberam os seguintes tratamentos: SF - concentrado farelado com farelo de soja; SE - concentrado extrusado com farelo de soja; AF - concentrado farelado com farelo de algodão; AE - concentrado extrusado com farelo de algodão. Como volumoso ofereceu-se a silagem de milho numa relação volumoso:concentrado de 50:50 com base na matéria seca. O período experimental foi de 112 dias. Os resultados foram avaliados num delineamento inteiramente casualizado, segundo esquema fatorial 2 x 2 (fontes protéicas x tratamentos físicos). As médias de ganho de peso, ganho em área de olho de lombo e ganho em espessura de gordura de cobertura, para os tratamentos SF, SE, AF e AE foram 1,64; 1,46; 1,35 e 1,35 kg; 20,24; 18,72; 22,88 e 16,21 cm2; 0,67; 0,58; 0,50 e 0,93 mm respectivamente, não apresentando diferença (P>0,05) entre qualquer um dos tratamentos. Na avaliação da conversão alimentar e eficiência protéica a análise estatística detectou diferença apenas entre fontes protéicas (P<0,05) com médias de conversão alimentar de 4,73 e 5,31 kg MS/kg PC e eficiência protéica de 1,78 e 1,59 kg PC/kg PB, respectivamente para os tratamentos com farelo de soja e farelo de algodão. As médias de balanço de nutrientes para MS, FDN e FDA para os tratamentos SF, SE, AF e AE foram 66,2; 66,7; 64,4 e 64,7%; 47,4; 43,3; 45,8 e 38,47% e 51,3; 45,2; 49,0 e 40,0% respectivamente, não apresentando diferença (P>0,05) entre os tratamentos ...(Resumo completo, clicar no acesso eletrônico abaixo) / Abstract: - The present work was carried out in Beef Cattle Setor of FCA V/Unesp, being used 16 males bovines non castrated of the Canchim crossbreed with initial average body weight of 315 kg. The animais were housed in individual stalls where they received the following treatments: GS - grounded concentrate with soybean meal; ES - extruded concentrate with soybean meal; GC - grounded concentrate with cottonseed meal; EC - extruded concentrated with cottonseed meal. The exclusive houghage offered was the com silage in a relationship of 50:50 in the dry matter basis. The experimental period was 112 days, sub-divided in four sub-periods of 28 days, which it was evaluated the variations of the body weight, loin eye area and the backfat. For the data statistical treatment, the arrangement used was the total randomized design, in a factorial scheme 2 x 2 (two protein sources x two physical treatments), being the averages compared by the Tukey test. The averages of daily weight gain, loin eye area and backfat gains, for the treatments GS, ES, GC and EC were 1.64, 1.46, 1.35 and 1.35 kg; 20.24, 18.72, 22.88 and 16.21 cm2; 0.67, 0.58, 0.50 and 0.93 mm respectively, not presenting difference (P>0,05) among the treatments. In the evaluation of the feed conversion the statistical analysis detected differences among protein sources (P<0,05) with averages of 4.73 and 5.31 kg DM/kg BW respectively for the treatments with soybean meal and cottonseed meal. The averages of DMB, NDFB and ADFB for the treatments GS, ES, GC and EC were 66.16, 66.66, 64.43 and 64.72%; 47.36, 43.30, 45.81 and 38.47% and 51.30, 45.24, 49.03 and 39.98% respectively, not presenting difference (P>0,05) among treatments ... (Complete abstract, click eletronic address below) / Mestre

Made available in DSpace on 2014-06-11T19:30:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-03-03Bitstream added on 2014-06-13T18:40:15Z : No. of bitstreams: 1 ribeiro_gm_me_jabo.pdf: 848451 bytes, checksum: 7e0a8600342eb2f0539ebbb975c83975 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O ensaio foi conduzido na FCAV/ Unesp, utilizando 16 bovinos machos não castrados da raça Canchim, com peso médio inicial de 315 kg. Os animais foram alojados em baias individuais onde receberam os seguintes tratamentos: SF - concentrado farelado com farelo de soja; SE - concentrado extrusado com farelo de soja; AF - concentrado farelado com farelo de algodão; AE - concentrado extrusado com farelo de algodão. Como volumoso ofereceu-se a silagem de milho numa relação volumoso:concentrado de 50:50 com base na matéria seca. O período experimental foi de 112 dias. Os resultados foram avaliados num delineamento inteiramente casualizado, segundo esquema fatorial 2 x 2 (fontes protéicas x tratamentos físicos). As médias de ganho de peso, ganho em área de olho de lombo e ganho em espessura de gordura de cobertura, para os tratamentos SF, SE, AF e AE foram 1,64; 1,46; 1,35 e 1,35 kg; 20,24; 18,72; 22,88 e 16,21 cm2; 0,67; 0,58; 0,50 e 0,93 mm respectivamente, não apresentando diferença (P>0,05) entre qualquer um dos tratamentos. Na avaliação da conversão alimentar e eficiência protéica a análise estatística detectou diferença apenas entre fontes protéicas (P<0,05) com médias de conversão alimentar de 4,73 e 5,31 kg MS/kg PC e eficiência protéica de 1,78 e 1,59 kg PC/kg PB, respectivamente para os tratamentos com farelo de soja e farelo de algodão. As médias de balanço de nutrientes para MS, FDN e FDA para os tratamentos SF, SE, AF e AE foram 66,2; 66,7; 64,4 e 64,7%; 47,4; 43,3; 45,8 e 38,47% e 51,3; 45,2; 49,0 e 40,0% respectivamente, não apresentando diferença (P>0,05) entre os tratamentos... / The present work was carried out in Beef Cattle Setor of FCA V/Unesp, being used 16 males bovines non castrated of the Canchim crossbreed with initial average body weight of 315 kg. The animais were housed in individual stalls where they received the following treatments: GS - grounded concentrate with soybean meal; ES - extruded concentrate with soybean meal; GC - grounded concentrate with cottonseed meal; EC - extruded concentrated with cottonseed meal. The exclusive houghage offered was the com silage in a relationship of 50:50 in the dry matter basis. The experimental period was 112 days, sub-divided in four sub-periods of 28 days, which it was evaluated the variations of the body weight, loin eye area and the backfat. For the data statistical treatment, the arrangement used was the total randomized design, in a factorial scheme 2 x 2 (two protein sources x two physical treatments), being the averages compared by the Tukey test. The averages of daily weight gain, loin eye area and backfat gains, for the treatments GS, ES, GC and EC were 1.64, 1.46, 1.35 and 1.35 kg; 20.24, 18.72, 22.88 and 16.21 cm2; 0.67, 0.58, 0.50 and 0.93 mm respectively, not presenting difference (P>0,05) among the treatments. In the evaluation of the feed conversion the statistical analysis detected differences among protein sources (P<0,05) with averages of 4.73 and 5.31 kg DM/kg BW respectively for the treatments with soybean meal and cottonseed meal. The averages of DMB, NDFB and ADFB for the treatments GS, ES, GC and EC were 66.16, 66.66, 64.43 and 64.72%; 47.36, 43.30, 45.81 and 38.47% and 51.30, 45.24, 49.03 and 39.98% respectively, not presenting difference (P>0,05) among treatments ... (Complete abstract, click eletronic address below)

During this master thesis, the possibility of ammonia removal from digestate in combination with after hygienization has been investigated. The aim of the work was to see how much ammonia that could be removed but also the properties of other process parameters such as TS/VS content, pH and alkalinity of the digestate. It was also of interest to study the energy balances for a process that combines ammonia stripping with after hygienization. The purpose of hygienization in a biogas plant is to kill pathogens. To study ammonia stripping combined with after hygienization, a prototype of an ammonia stripper was built in a laboratory. The digestate was heated to the hygienization temperature of 70 °C and air was led through with the help of a peristaltic pump by the end of the system. Condensate was trapped in a bottle by cooling the tube and the gases were brought to another bottle containing 1 M sulfuric acid. Ammonia and sulfuric acid reacted and formed ammonium sulfate. The process was also tested with closed system using vacuum to decrease the boiling point and thereby create more condensate. The results from the experiments showed that with an air stripping process most of the ammonium was trapped in the sulfuric acid while with a vacuum process more ammonium was trapped in the condensate. The most important parameters to achieve a good ammonia removal were air flow and time. With the vacuum system, more condensate was removed. The removal of condensate could make it possible to recirculate process fluid from the stripping process and thereby save energy in the centrifugation part which is used to create a solid part of the bio digestate. It was concluded from the experiments that air stripping is more effective when it comes to ammonium recovery. The process could be improved by using higher air flow which could decrease the time to less than one hour, which is the desired hygienization time. However, it is desired to keep the pump flow as low as possible since it is energy consuming. A chemical increase of the pH would also be of interest to try since previous tests showed a strong correlation between high pH-value and good ammonia stripping. More tests overall are of interest to ensure a reliable result. Still, the combination of after-hygienization and ammonia stripping would contribute to a better environment and a sustainable agriculture with a natural and nutritious digestate.

La digestion anaérobie est un processus biologique de transformation de la matière organique permettant la production d’énergie sous forme de biogaz et de fertilisant sous forme de digestat. C’est une filière émergente en France, dont les objectifs de développement sont ambitieux. Le développement d’une filière industrielle sur l’ensemble du territoire Français nécessite la mise en oeuvre d’outils d’aide à la décision.Dans le cadre de cette Thèse nous proposons d’évaluer le potentiel de développement de la méthanisation collective, territoriale et agricole par injection du biogaz dans les réseaux de gaz naturel. Les travaux de recherchent portent sur trois axes : (1)l’évaluation du potentiel de mobilisation de biomasse d’origine agricole ; (2) la conception et l’étude de la viabilité économique de « modèle type » d’usine de méthanisation ; (3) l’évaluation de la performance technico-économique d’une exploitation agricole ayant recours à la méthanisation dans but d’accroitre son autonomie face aux énergies fossiles et aux engrais chimiques.Sur le premier volet, nous avons réalisé une étude cartographique des gisements agricoles mobilisables. Nous avons localisé et quantifié les quantités de coproduits de cultures et d’effluents d’élevage présent sur le territoire Français. Nous avons mis en évidence que le potentiel de mobilisation de biomasse agricole est de l’ordre de 57millions de tonnes de matière sèche. Ceci correspond à une production énergétique maximale de l’ordre de 158 TWh/an.Sur le deuxième volet, nous avons conçu des « modèles types » d’usines de méthanisation de différentes tailles, dont le biogaz est valorisé en biométhane par injection dans le réseau. Pour chacun des « modèles types » nous avons comparé la viabilité technico-économiques des modèles selon différentes « recettes » de biomasse. L’évaluation met en avant que pour chaque « modèle type », il existe un nombre limité de « recettes » permettant à chacun d’entre eux de trouver un équilibre technico-économique.Sur le troisième volet, nous nous sommes intéressés à l’autonomie azote et carburant que pourrait atteindre une exploitation agricole en méthanisant des cultures énergétiques dédiées de légumineuse. L’évaluation a été menée sur des fermes présentant des configurations différentes d’assolement et de rendement. Nous avons mis en évidence les conditions nécessaires pour que chaque configuration de ferme puisse atteindre l’autonomie. Il en ressort que dans certaines conditions, une exploitation « autonome » présente des marges brutes supérieures à celle d’une exploitation conventionnelle. / Anaerobic digestion is a biological process of transformation of organicmatter allowing the production of energy in the form of biogas and fertilizer in the formof digestate. It is an emerging sector in France, whose development objectives are ambitious. The development of an industrial sector throughout the French territory requires the implementation of decision support tools.As part of this thesis, we propose to evaluate the development potential of collective,territorial and agricultural methanation by injecting biogas into natural gas networks.Research work focuses on three axes: (1) the evaluation of the biomass mobilization potential of agricultural origin; (2) the design and study of the economic viability of a"typical model" of methanation plant; (3) the evaluation of the technical and economic performance of a farm using methanation in order to increase its autonomy in the face of fossil fuels and chemical fertilizers.We first carried out a cartographic study of mobilizable agricultural deposits. The quantities of co-products of crops and livestock effluents present on the French territor ywere located and quantified. Thus, we have shown that the potential for mobilization of agricultural biomass is of the order of 57 million tons of dry matter. This corresponds to a maximum energy production of about 158 TWh / year.And second, we have designed "model models" of biogas plants of different sizes,whose biogas is valorized in biomethane by injection into the network. For each of the"standard models" we compared the techno-economic viability of the models according to different "recipes" of biomass. The evaluation points out that for each "standard model" there is a limited number of "recipes" allowing each of them to find a technoeconomic balance.Finally, we focused on the nitrogen and fuel autonomy that an agricultural operationcould achieve by methanising dedicated energy crops of legumes. The assessment was conducted on farms with different rotational and yield configurations. We have highlighted the conditions necessary for each farm configuration to achieve autonomy.It shows that under certain conditions, an "autonomous" farm has gross margins higher than that of a conventional farm.

The community Vessigebro, in Falkenberg and its surrounding areas housing one percent of all dairy cattle and two percent of all pigs in Sweden. This means that there is a large amount of manure as a basis for producing biogas in the area. A number of farmers have therefore formed a cooperative named Vessigebro biogas and started the project Green Vessigebro, with the goal of creating the conditions for a more profitable and more sustainable agriculture production. The study deals with the conditions and sale opportunities of the feasibility study Green Vessigebro. The study has looked at the work that was previously carried out for the biogas that could be produced on the farms in Vessigebro, The main pipeline for natural gas on the Swedish west coast and its operators, the Swedish Competition Act , Electricity Act , Natural Gas Act, the District Heating Act , Sustainability Act , previously proposed measures, municipality interest in biogas from Vessigebro , possible collaborations, possible sale opportunities and perform calculations with data from the municipality Ljungby for a suggested transportation of biogas between Vessigebro and Ljungby. The study shows that there are several interesting sale opportunities for biogas from Vessigebro. The production and use of biogas in Sweden is increasing and the trend seems set to continue. Six gas retailers can buy gas, which EON is the most established around Vessigebro with a distribution network. EON: s distribution network runs only a few kilometers from the planned upgrading plant , in Vessigebro. An already built upgrading facility is one mil from Vessigebro. Swedegas is the only main pipeline network owner with storing and balancing responsibility on the main line that is closer than EON distribution network. A number of suppliers and industries have shown interest in purchasing the biogas and the interest from potential buyers are likely to increase when the biogas production starts. A collaboration with, for example, "Arena Bioenergy Halland" increases business intelligence and can provide an increased influence with policy proposals. The use of gas and the interest is too low for the moment for tractors, boats, trains, buses and taxis to be a possible outlet specifically for Vessigebro biogas. The conditions make it interesting for Vessigebro biogas to look at five different options for sale opportunities of the biogas. Three options are based on a pipeline to either the pipeline, owned by Swedegas or EON distribution line alternatively a pipeline to EON upgrading facility. One possibility is to replace vehicles that run on fossil fuels with gas-powered vehicles providing a local use and purpose and the aims of the project Green Vessigebro. The calculations made by the study with different conditions shows that a very interesting and possible sale opportunity is a transportation of biogas between Vessigebro and Ljungby. The conclusion from the study shows that conditions and sale opportunities are good for the planned biogas production of Green Vessigebro to become reality.

Anaerobic digestion technologies have been utilized in Vietnam for more than 30 years with thousands of domestic small scale plants, mostly for agricultural and livestock wastes. For municipal solid waste (MSW) the development of biogas plants is far below the current high waste generation rates. The aim of this paper is to present the results of a feasibility assessment of implementing AD to treat the organic fraction of municipal solid waste (OFMSW) in Vietnam. For this purpose, an environmental analysis was performed comparing three treatment scenarios: two hypothetical AD technologies (a wet and a dry fermentation system) and the existing industrial composting facility at Nam Binh Duong Waste Treatment Complex in South Vietnam. This study sought for the technology to recover the most possible resources and energy from the OFMSW, and reduce greenhouse gas (GHG) emissions. The results were then combined with a policy review to support a holistic approach on the feasibility of these technologies in Vietnam. The outcome indicates that by implementing the dry AD system, up to 16.7 GWh of power and 14.4 GWh of heat energy can be generated annually and it can potentially save up to 5,400 Mg of CO2 equivalent per year, presenting the highest resource/energy benefits. The performance of the wet system and composting facility present some advantages particularly if there is a previous segregation of the organic material from the rest of the household wastes. Moreover, current reforms in Vietnam demonstrate the government’s interest in AD technologies, translated into the development of fiscal and financial revenues which incentivize participation from the public and private sector. Finally, these technologies are constantly under development and have the potential to be further improved, which gives hopes that waste treatment systems can be optimized to meet the waste and energy challenges of the future generations. / Phương pháp lên men kị khí đã được áp dụng tại Việt Nam từ hơn 30 năm nay với hàng nghìn các công trình nhỏ chủ yếu xử lý chất thải nông nghiệp và chăn nuôi. Sự phát triển hiện nay của các nhà máy sinh khí biogas còn quá ít cho xử lý lượng phát thải cao rác thải đô thị. Bài báo này trình bày các kết quả việc đánh giá tính khả thi khi áp dụng công nghệ lên men kị khí xử lý phần hữu cơ của chất thải rắn đô thị tại Việt Nam. Với mục đích này, phân tích môi trường được thực hiện để so sánh ba kịch bản xử lý: hai công nghệ lên men kị khí giả định (một cho công nghệ lên men ướt và một cho công nghệ lên men khô) và nhà máy hiện hữu lên men hiếu khí làm phân bón compost tại khu liên hợp xử lý chất thải Nam Bình Dương ở miền Nam Việt Nam. Nghiên cứu này tìm kiếm giải pháp công nghệ để thu hồi nhiều nhất có thể các tài nguyên và năng lượng từ rác thải đô thị và và giảm phát thải khí nhà kính. Các kết quả sau đó được kết hợp với đánh giá chính sách để hỗ trợ cách tiếp cận toàn diện về tính khả thi của các công nghệ này vào Việt Nam. Kết quả cho thấy áp dụng công nghệ lên men kị khí khô có thể tạo ra đến 16,7 GWh điện năng và 14,4 GWh nhiệt năng hàng năm và có khả năng làm giảm đến 8,000 Mg CO2 tương đương mỗi năm, thể hiện lợi ích cao nhất giữa tài nguyên và năng lượng. Hiệu suất của hệ thống lên men kị khí ướt và lên men hiếu khí thể hiện một số lợi thế đặc biệt khi nguyên liệu hữu cơ cho quá trình lên men được tiền phân loại ra khỏi hỗn hợp rác sinh hoạt. Hơn nữa, các đổi mới hiện nay ở Việt Nam thể hiện sự quan tâm của Chính phủ đến các công nghệ lên men kị khí, thể hiện qua sự tăng trưởng tài chính và doanh thu để khuyến khích sự tham gia của khu vực công và tư nhân. Chắc chắn rằng các công nghệ sẽ liên tục được phát triển và có khả năng được cải tiến tốt hơn, mang đến cho chúng ta những hy vọng rằng các hệ thống xử lý chất thải được tối ưu hóa để đáp ứng được các thách thức về chất thải và năng lượng của các thế hệ tương lai.