A clean and affordable energy source for cooking is deficient in developing countries. People rely on fuels that contribute to environmental, social and health problems.Biogas is an alternative energy source and an increased investment in small-scale biogas production can in several developing countries be found. Several projects have started to use the technology in developing countries because of the benefits with biogas. Some cases in the establishment of biogas plants have succeeded and some have not. The study is a literature review supplemented by two field studies.

A clean and affordable energy source for cooking is deficient in developing countries. People rely on fuels that contribute to environmental, social and health problems.Biogas is an alternative energy source and an increased investment in small-scale biogas production can in several developing countries be found. Several projects have started to use the technology in developing countries because of the benefits with biogas. Some cases in the establishment of biogas plants have succeeded and some have not. The study is a literature review supplemented by two field studies.

A growing interest for the climate and the environment has led to an increased interest forenvironmentally friendly and renewable energy sources, such as biogas. Planning new biogasplants requires a decision basis including facts about approximate amounts of biogas possibleto produce at the plant. The purpose of this thesis is to develop a model that calculates theapproximate biogas and digestate production from a planned or existing biogas plant.Developing the model required a literature review and studies of calculations concerningbiogas and digestate production performed by WSP Sweden AB. As a complement to themodel development, facts about substrates for biogas production were compiled through aliterature review. In addition the methane potential from selected materials was determined bybatch experiments.

Biogas is an expanding sector within the broad field of agriculture and animal production. Small-scale biogas offers local combined power and heating production and the substrate is transformed into high-quality biological fertilizer. This bachelor thesis focuses on a pig farm in south-western Sweden, where biogas is produced from pig manure, evaluates and suggests ways of optimizing the process and investigates whether investing in an upgrading plant would be a feasible and more cost-efficient option. The results show that the biogas plant is working well, although the production differs from the original plans. This shows in turn that planning and examining the basic conditions before making the investment is of great importance, as well as monitoring and keeping detailed statistics of the running process.

Käppala wastewater treatment plant situated on the island of Lidingö northeast of Stockholm is running a project during 2004 and 2005 with the purpose to map out the capacity of anaerobic digestion in the digesters that treat primary and excess sludge. The purpose of this thesis work, which is part of that project, was to characterize the present anaerobic digestion process and to investigate its capacity to treat other organic wastes such as restaurant waste and waste from water works. To decide the potential of both methane and biogas production from different substrates batch laboratory tests were carried out. To imitate the anaerobic digestion process at Käppala continuous tests with small scale reactors were carried out. These reactors were later fed with restaurant waste.The batch laboratory tests showed that primary sludge had a potential biogas and methane production of 0,62 and 0,35 Ndm3/g VS respectively after 40 days of digestion.

The aim of the study was to install a biogas system consisting of three tubular polyethylene biogas digesters at a rural household in Malawi and to evaluate the constructed biogas system with regards to relevant system parameters. The purpose was to evaluate if the technology is a possible solution to reduce deforestation and support Malawi in climate change mitigation and adaptation. The study was carried out in the southern part of Malawi in cooperation with the University of Malawi. Locally available materials were used to construct and install the system. Three different feed materials, cow, goat and a mix of cow and goat manure, were used in order to determine which one was best suited to utilise as a digester substrate. After the installation, measurements of temperature, pH, biogas production, biogas composition and system functionality were made. The results of the study show that a biogas system with tubular polyethylene biogas digesters can be successfully installed at a rural household and that the most suitable feed material is a mix of cow and goat manure.

Until 2020, 49% of Sweden's use of energy must derive from renewable sources. Greenhouse gases must as well decline with 40% compared to 1990 as a part of Sweden's 16 environmental objectives. Biogas is part of the effort to achieve these objectives, but as the demand for biogas increases, more substrates are needed to meet the demand. The purpose is to investigate the conditions for pea residue as substrate by performing lab-scale mesophilic digestion with different fractions and notch lengths and then to summarize pea residue as a substrate for biogas production. During anaerobic digestion, 1000 ml bottles were used as reactors for digestion.

Biogas mainly consists of methane and carbon dioxide, where methane is theenergy-rich gas, and is naturally created when organic matter breaks down in absenceof oxygen, also known as anaerobic digestion. A biogas plant re-creates the anaerobicconditions inside a digester where the organic substrate is fed into and digests toproduce biogas. The gas is then used to produce energy by combustion and can beseen as a completely renewable fuel.Today, energy from biogas is used primarily by major stakeholders such asmunicipalities and thus the plants become very large with high investment- andconstruction costs. There are currently few small plants in Sweden, even though thepotential for agriculture and medium-sized to smaller farms to become self-sufficientin terms of electricity and heat is great. Farms have a natural stock of digestibleorganic material in form of manure or crops for example, which are constantlyavailable.

Swedish biogas is currently produced mainly by anaerobic digestion of sewage sludgeat sewage treatment plants, landfills and anaerobic digestion of household or industrialwaste. Also cattle ma-nure from farms can be used to produce biogas. Upgradingbiogas represents an increase in methane concentration from about 65 % to about 97%. In addition, particles and contaminants must be sepa-rated from the upgradedbiogas. There are various methods for upgrading and this report compares sixdifferent methods with respect to environment and economy: water scrubber,Biosling, cryo technology, chemical absorption, Pressure Swing Adsorption (PSA) andmembrane separation.According to the used ORWARE model, chemical adsorption with amine has the leastenvironmen-tal impact (methane emissions) and the lowest costs.

The purpose of this study was to evaluate the different substrates that enter the digestion on Sundet wastewater treatment plant for production of biogas.This work have done an analysis of data about the biogasproduction from January 2012 to feburari 2013, this showed that the food substrates has a greater gas production than internal sludge.Through laboratory test the VS, TS and COD values for all the substrates used in the biogas production could be determinded. But the COD-method was less optimal for analysis of fat and food, therefore it optimized the method for fat but due to time constraints, this could not be done on the food substrates..

The energy sector of modern time is currently faced with several challenges. These are both production oriented and environmental oriented in nature. The energy of the future is intended to support an increasing demand while at the same time reduce its environmental affection. This stresses a development towards production methods of renewable energy. Among the existing methods, biogas is presented as an attractive alternative.

To achieve the Government's milestones for 2018, which means that 50 % of food waste shall be separated from household waste and undergo biological treatment (composting or anaerobic digestion).   Hultsfred, Högsby and Vimmerby are three adjacent municipalities of Kalmar, county Småland. During 2012 and 2013 analyzes were performed on their household waste to determine its composition. The household waste is currently collected in one fraction. The work, examines how much food waste the household waste contains. From the amount of food waste, the biogas potential is examined - how much food waste biogas generates and how much energy it corresponds to.   Food waste is broken down by microorganisms under anaerobic conditions (anaerobic digestion) in a biogas plant.

Biogas is a renewable fuel that can be extracted from anaerobic digestion of many differentsubstrates, for example biological household waste. An alternative handling of the waste is tomix it with other wastes and incinerate it in a combined heat and power (CHP) plant. Thisstudy uses life cycle assessment to investigate which type of waste handling that is betterfrom an environmental point of view, anaerobic digestion with biogas production orincineration. The results are based on a case study of a biogas production plant owned by thecompany Ragn-Sells in Vänersborg. The alternative is incineration at a CHP plant inGothenburg.

BackgroundThis paper is based on an issue raised by the organization Energigas Sverige, which together with the Ministry of Finance has posed the question about the fiscal impact of an increase in biogas production. Since the fiscal effects of an increased biogas production are both positive and negative, due to reduced use of fossil fuels, we want to investigate this further.PurposeThe purpose is to describe and explain the obtained fiscal impacts of an increased biogas production and based on our problem: ?What are the obtained fiscal effects caused by an increase in biogas production?? we could see the following fiscal effects: positive impact on employment, increased revenues of social security contributions and income taxes, reduced unemployment costs and reduced tax revenues on fossil fuels. These effects are summarized in a negative tax revenue of 2,6 billion SEK. Along the summarized negative effect we also accepted one of the two prepared hypotheses, which stated that an increase in biogas production leads to a negative fiscal impact. Design/Methodology/ApproachWe have chosen to work from an Anglo-Saxon scientific tradition and furthermore, we have a positivistic approach when we want to explain the relationship between cause and effect of an increase in biogas production and the following fiscal impacts.

This report is focused on marketing opportunities for small-scale mango farmers in the Nyanza Province in Kenya. Kenya is a large horticultural producer in the world. Horticulture is an important income for a large share of the rural population in Kenya but profitability is low due to inefficiencies in marketing systems and poor infrastructure. The conditions for growing mango in the Nyanza Province are very beneficial and there are two harvesting seasons. Mango offers good income opportunities for small-scale farmers in the Nyanza Province.The aim of this study is to identify marketing conditions that will enable prospering business for small-scale mango farmers in the Nyanza Province, Kenya.