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.

Today's society is facing major challenges. In order to reduce the climate impact fossil fuels should be replaced with fuels that do not contribute to the greenhouse effect. The growing population generates organic waste originating from industry and households so called organic fraction of municipal solid waste (OFMSW). Through Anaerobic Digestion, waste can be utilized to produce energy-rich methane gas. In this way, waste can be a resource instead of a burden on society.

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.

Biogas is a renewable energy produced through Anaerobic Digestion, which means that organic matter is degraded by microorganisms under anaerobic conditions. The produced biogas can then be used for cogeneration, electricity, heat or upgraded to vehicle gas. Eskilstuna Energy & Environment AB has four digesters at Ekeby water sewage treatment plant, Eskilstuna. One of the biogas reactor (RK4) is equipped with a jet-mixing system while the remaining digester uses top-mixing. The mixing system is an important parameter to achieve optimum operating conditions for the process regarding gas production and degree of digestion.

Because of the increasing trends in energy consumption and increased environmental awareness, greater focus has been placed on improvement and development of renewable energy sources. An already proven and accepted method is biogas production from Anaerobic Digestion at municipal wastewater treatment plants.In the waste water treatment process solid material and dissolved pollutants are separated from the water, forming a sludge. The sludge is separated from the process and stabilized during Anaerobic Digestion or aerobic aeration. Most often, mesophilic Anaerobic Digestion is used. Because of degradation by microorganisms, biogas with a high content of methane is formed during the digestion.

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.

The goal of this master thesis project was to develop computer models of some plausiblepretreatment techniques and to assess the potential benefits/costs of using pretreatment andAnaerobic Digestion for waste management of organic waste from a system perspective. Forthis purpose a computer program called ORWARE has been used. ORWARE (organic wasteresearch) is a program for making life cycle assessments of waste management. As the mainpart of the project work the ORWARE system has been provided with three new models ofpretreatment techniques. The additions consist of: One model of pretreatment with ultrasound,one model of thermal hydrolysis and one model of a screw press.

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.

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.

All products will eventually end up as waste, which in a sustainable society has to be handled in an efficient and environment friendly way. This report focuses on waste fractions meant for combustion, often difficult to characterize. However, more homogeneous fractions that are treated biologically are also discussed.The study concerns the region of Borås, Sweden, where the waste plant Sobacken has provided a good starting point. On this site, fuel to the Energy-from-Waste plant of Borås Energi is prepared and the biological waste is treated through Anaerobic Digestion.One important part of the study has been to collect experience-based knowledge from the technical staff at Sobacken and Borås Energi. This information was compiled into an overview of wanted and unwanted fractions to the preparation plant and the boilers respectively.

Food waste from grocery stores - An analysis of municipal management inSweden and a detailed study of the situation in Umeå municipalityThe objective of this thesis was to analyze the municipal management of food waste fromgrocery stores in Sweden in general and in Umeå municipality in particular. Furthermore theobjective was to account for the different waste treatment methods that can be used and toevaluate them from an environmental perspective. In order to analyze the municipalmanagement a survey was sent to all of the municipalities/municipal waste companies inSweden. A general comparison of treatment methods was carried out on the basis of ascientific review and a system analysis was performed in order to compare three differenttreatment alternatives for the food waste generated in grocery stores in Umeå. The surveyshowed that the legal definition of food waste from grocery stores is unclear and variesbetween municipalities.

An analysis of a specific application of anaerobic wastewater treatment at a pulp and board mill, Stora Enso Skoghall, was carried out. A literature study was done and effluent wastewater from CTMP pulp production was analyzed. The analysis consisted of a broad constituent analysis and an anaerobic treatment trial. Results from these test where used to calculate the treatment effectiveness and resulting energy potential at the mill.The literature study and constituent analysis showed that toxicity of the water to be treated, due to wood extractives and sulphur content, was of concern. Detoxification chemicals targeting these constituents where used in the anaerobic treatment trial.

Agricultural soils constitute the base in human food production and soil content of organic matter and plant nutrients together with soil microbial activity are all important parameters for high crop yield of good quality. These parameters are dependant on proper fertilization.Anaerobic Digestion of organic wastes for biogas production generates a liquid residue called biogas residue (BR). It contains organic material and plant nutrients which makes ita potential fertilizer for arable cropping. However, it also contains heavy metals and toxic organic compounds and it is therefore in need of evaluation before usage.Microbial tests were performed aiming to evaluate the agronomic traits of four different BR and to find a viable procedure for evaluating slurry fertilizers. Two experiments where soil respiration and soil potential denitrification activity (PDA) was measured at fertilizer addition were performed.

An analysis of a specific application of anaerobic wastewater treatment at a pulp and board mill, Stora Enso Skoghall, was carried out. A literature study was done and effluent wastewater from CTMP pulp production was analyzed. The analysis consisted of a broad constituent analysis and an anaerobic treatment trial. Results from these test where used to calculate the treatment effectiveness and resulting energy potential at the mill.The literature study and constituent analysis showed that toxicity of the water to be treated, due to wood extractives and sulphur content, was of concern. Detoxification chemicals targeting these constituents where used in the anaerobic treatment trial.

Yeast and Clostridia is a problem in silage for farmers as contaminated silage may result in poor animal health and milk quality. Clostridia can produce toxins that, when consumed, acts as neurotoxins, it may also cause blown cheeses if the Clostridia contaminates milk. The purpose of this study was to investigate the cause, effect and interaction of yeasts and Clostridia in silage. Clostridia are microorganisms which are strictly anaerobic and consume carbohydrates and protein in the silage. Yeast is a fungus that is facultative aerobic and feed on carbohydrates in the silage.