I såväl Brasilien som runt om i världen finns stora mängder organiskt avfall som skulle kunna utnyttjas på ett bättre sätt. Många potentiella substrat för biogasproduktion deponeras, eldas upp eller komposteras utan att den energi som skulle kunna utvinnas vid denna process tas tillvara. Detta examensarbete inriktade sig på att i laboratorium undersöka potentialen för biogasproduktion från några av dessa avfallsprodukter. Från biodieselproduktion, vilket är en snabbt växande industri i Brasilien, fås exempelvis 1 kg av restprodukten råglycerol per 9 kg producerad biodiesel. Detta är en restprodukt som man i dagsläget letar efter fler tillämpningar för och biogasproduktion har visat sig vara en möjlighet. Biogas har som förnybart bränsle dessutom ökat i attraktivitet under de senaste åren som ett alternativ till fossila bränslen. Syftet med undersökningen var att se om en liten mängd tillsatt råglycerol, eller glycerin som det också kallas, till en redan pågående rötningsprocess kunde öka den totala mängden producerad biogas från huvudsubstratet i fråga. Under arbetets gång utfördes två separata laboratorietester på olika typer av substrat. Det ena var slakteriavfall från ett kycklingslakteri och det andra var ett rötslam från en avfallshanteringsanläggning där industriellt avfall behandlas i bassänger med anaerobisk rötning. Dessa två substrat representerade två mycket olika mikrobiologiska processer där den ena var en ganska ostabil, nystartad process medan den andra var mycket stabil och etablerad. Resultaten från testerna visar att den ostabila processen inte alls klarade påfrestningen som det tillsatta glycerinet innebar, samtidigt som den stabila klarade sig mycket bra. Därför är en av slutsatserna som dras av arbetet att stor försiktighet måste tas när glycerin ska fasas in i en pågående rötningsprocess. Testerna visar dock att en satsvis tillsats av glycerin till rötslammet från avfallshanteringsanläggningen Ecocitrus skulle kunna öka biogasproduktionen från denna anläggning markant, vilket är ett intressant resultat då de står nära en investering i en riktig biogasanläggning. En tillsats av 6,0 eller 9,0 vol.% glycerin till en sådan anläggning har potential att fördubbla biogasproduktionen, samtidigt som metanhalten hålls på en godtagbar nivå. / In both Brazil and around the world, there are large amounts of organic waste that could be exploited in a better way. Many potential substrates for biogas production is deposited in land fillings, burned or composted, without taking advantage of the energy that could be extracted in this process. This thesis focuses on the potential for biogas production from some of these waste products. From biodiesel production for example, which is a rapidly growing industry in Brazil, 1 kg of the waste product crude glycerol is obtained per every 9 kg of produced biodiesel. This is a waste product that is beginning to be in a need for more applications, and biogas production has proven to be a possible application. Biogas as a renewable fuel has furthermore increased in attractiveness in the latest years, as an alternative to fossil fuels. The purpose of this study was to see if a small amount of added crude glycerol, also known as glycerine, to an ongoing digestion process could increase the total amount of biogas produced from the main substrate in question. During the test period, two separate laboratory tests were carried out on various types of substrates. One was the waste from a chicken slaughterhouse and the other was sludge from a waste treatment plant where industrial waste is being treated in pools with anaerobic digestion. These two substrates represented two very different microbiological processes of which one was a quite unstable, recently started process, while the second one was very stable and established. The results of the tests show that the unstable process could not manage the stress that the glycerine meant for the microorganisms, while the stable managed to handle it very well. One of the conclusions drawn from the work is that great care must be taken when glycerine is added to an ongoing anaerobic digestion process. The tests show that a batch addition of glycerin to the substrate from the waste treatment plant Ecocitrus could increase the biogas production from this plant considerably. This is an interesting result since this company is close to an investment in a real biogas plant. An addition of 6.0 or 9.0 vol.% glycerine to such a plant has the potential to double the biogas production, while methane concentration is still kept on an acceptable level.

No description available.

Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 69-72). / vii, 89 leaves, bound ill. 29 cm

Thesis (Ph.D.)--University of Western Australia, 2004.

Thesis (Ph.D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on May 1, 2009) Vita. Includes bibliographical references.

Darmstadt, Techn. Universiẗat, Diss., 2008.

Thesis (Ph. D.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on July 31, 2009) Includes bibliographical references.

Part of Thesis (PH. D.)--University of Chicago, 1932. / "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois." eContent provider-neutral record in process. Description based on print version record.

Part of Thesis (PH. D.)--University of Chicago, 1932. / "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois." eContent provider-neutral record in process. Description based on print version record.

Thesis (doctoral)--Lund University, 1994. / Added t.p. with thesis statement inserted.