Metanpotentialen för makroalgen Saccharina lattissima varierar beroende på parametrar som odlingsdjup och olika isättnings- och skördedatum. För att utvärdera skillnader i parametrar användes satsvisa utrötningsförsök med ymp från en biogasanläggning som rötar fiskrester och matavfall. Algen som odlades på fyra meters djup gav mer metan än algen av samma art på två meters djup. Detta berodde på att algen på fyra meters djup hade en högre proteinhalt än algen på två meter. För att utvärdera metanpotentialen för alger med olika isättnings- och skördedatum användes sex stycken alger satta i september, oktober och november på två meters djup. Det skördades en alg från varje månad i april och en alg från samma månader i maj på Seafarm vid Strömstad. Algerna som hade skördats i april gav en högre metanpotential än de som skördades i maj. Metanpotentialen var högre för att de hade en högre lipidhalt. När de sattes i havet spelade ingen roll för lipidhalten. Oktober månad skiljde sig för att metanpotentialen var lägre i både april och maj.

<p>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. Two full scale experiments were also studied to compare results from themodel with results from full scale biogas production.This thesis work resulted in a model for calculating biogas, methane and digestate production,including calculations of nutrient content in the digestate, from a given amount of substrate.The model was constructed in Microsoft Office Excel and complemented by a chart,containing template facts for different biogas substrates. The template facts, together with themodel, make it possible to perform calculations of biogas production before any up-to-dateinvestigations are made of the biogas substrate.Comparing results of biogas production calculated with the model with values of biogasproduction from a full scale biogas plant showed that the calculated values where within, orjust outside, the standard deviation of the full scale values. The calculated values from themodel also turned out to be in general lower than the full scale values, which indicate that themodel doesn’t overestimate the biogas production. However, the uncertainties of the values inthe template facts chart and the simplifications made in the model both contribute in tomaking the model calculations somewhat uncertain. The calculations should thus only be seenas an indication of the possible biogas production from planned or existing biogas plants andnot as an exact prediction.</p>

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. Two full scale experiments were also studied to compare results from themodel with results from full scale biogas production.This thesis work resulted in a model for calculating biogas, methane and digestate production,including calculations of nutrient content in the digestate, from a given amount of substrate.The model was constructed in Microsoft Office Excel and complemented by a chart,containing template facts for different biogas substrates. The template facts, together with themodel, make it possible to perform calculations of biogas production before any up-to-dateinvestigations are made of the biogas substrate.Comparing results of biogas production calculated with the model with values of biogasproduction from a full scale biogas plant showed that the calculated values where within, orjust outside, the standard deviation of the full scale values. The calculated values from themodel also turned out to be in general lower than the full scale values, which indicate that themodel doesn’t overestimate the biogas production. However, the uncertainties of the values inthe template facts chart and the simplifications made in the model both contribute in tomaking the model calculations somewhat uncertain. The calculations should thus only be seenas an indication of the possible biogas production from planned or existing biogas plants andnot as an exact prediction.

I detta examensarbete har biogasproduktion med olika typer av gödsel som substrat, med fokus på hönsgödsel, undersökts genom satsvisa utrötningsförsök, BMP. I försöken undersöktes hur biogasutvecklingen såg ut över tid, den totala biogas- respektive metanpotentialen samt hur denna påverkas av tillsats av glycerol. Undersökningen visade att substratblandningar har större biogas- och metanpotential än enskilda substrat samt att tillsats av glycerol inte gynnar biogasproduktionen men kan gynna metanproduktionen. Undersökningen visade också att hönsgödsel har större biogaspotential, och högre metanhalt i den bildade biogasen, än nöt- och svinflytgödsel. / Superbiogödsel för ekologisk spannmålsproduktion