Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains xiii, 149 p. : ill. (some col.), maps. Includes abstract. Includes bibliographical references (p. 149).

Résumé Le Rift Est-Africain comprend plusieurs grands lacs, dont le lac Kivu situé entre 1°34’ et 2°30’ de latitude Sud et compris entre 28°50’ et 29°23’ de longitude Est. Ce lac, localisé au nord-ouest du Rwanda à la frontière avec la République Démocratique du Congo, présente une spécificité unique au monde: ses eaux profondes contiennent une gigantesque quantité de gaz dissous (3/4 de dioxyde de carbone (CO2), 1/4 de gaz méthane (CH4)). Les études antérieures indiquent que les eaux du lac Kivu présentent une structure stratifiée particulière qui se décline en 13 couches dans le bassin principal. Nous avons établi une nouvelle stratification, en quatre couches de la colonne d’eau dans ce bassin sur base des données physico-chimiques mais aussi, en tenant compte tout particulièrement du comportement biogéochimique du carbone. Cette structure simplifiée permettra une meilleure évaluation de l’impact environnemental et une gestion durable de l’exploitation du gisement de gaz méthane du lac Kivu. Un suivi détaillé de plusieurs paramètres physico-chimiques, biogéochimiques ainsi que des éléments majeurs, mineurs et en trace, présents dans le bassin principal du lac, dans sa partie rwandaise en un point fixe au large de Kibuye, durant la petite saison sèche, apporte un éclairage plus précis de leur distribution dans la colonne d’eau. Une étude de la variation spatio-temporelle de ces paramètres est réalisée aussi bien à Kibuye qu’à Gisenyi et ce durant les différentes saisons pour, entre autres, servir de base de données nécessaire à toute comparaison ultérieure. L’origine des gaz dissous dans le lac Kivu a fait l’objet de plusieurs études et hypothèses. Les deux principaux gaz dissous du lac ont un élément biogéochimique en commun: le carbone. Par des mesures isotopiques et par comparaison avec le système limnologique du lac Tanganyika voisin, la correspondance de l’allure générale de la distribution comparée du carbone inorganique dissous (DIC), de l’alcalinité totale et du δ13CDIC dans les deux lacs indique notamment que les processus à l’origine du gaz méthane du lac Kivu ne sont pas liés au magmatisme, ni à des phénomènes thermocatalytiques. Nous pensons que le carbone, et par conséquent le gaz méthane du lac Kivu, est d’origine phytoplanctonique. L’explication par une étude hydrogéologique et pédologique de l’origine de la stratification pérenne de la colonne d’eau du lac Kivu constitue un point de vue intéressant. Une autre perspective serait, celle visant à établir par des données biogéochimiques, le taux de régénération du gaz méthane du lac Kivu afin d’en déterminer la durée d’exploitabilité réelle.

Thesis (Ph. D.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains xiv, 258 p. : ill., maps. Includes abstract. Includes bibliographical references.

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Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-08-10T12:13:20Z No. of bitstreams: 1 PDF - Larissa Barreto Barbosa.pdf: 1228913 bytes, checksum: 2ac5600e4706fd0ad2c049bb9b5dba33 (MD5) / Made available in DSpace on 2016-08-10T12:13:20Z (GMT). No. of bitstreams: 1 PDF - Larissa Barreto Barbosa.pdf: 1228913 bytes, checksum: 2ac5600e4706fd0ad2c049bb9b5dba33 (MD5) Previous issue date: 2016-04-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this study, we investigated the influence of the concentration of total solids and temperature in the process of anaerobic co-digestion of organic solid waste in one batch -1 -1 reactors, using three different concentrations of total solids: 30.5 g.L (ST1); 39.5 g.L -1 (ST2) and 48.2 g.L (ST3), and three levels of temperature: ambient (average 24 ° C) (T1), 35 ° C (T2) and 40C (T3). The experimental system was built, installed and monitored for 180 days in the physical facilities of the Experimental Biological of Sewage Treatment Station (EXTRABES) of the State University of Paraíba, Campina Grande - PB, Brazil. For power reactors was prepared substrate in a proportion of 80% of crushed vegetable solid waste and sieved at 2 mm mesh and 20% anaerobic sludge from UASB reactor treating domestic sewage. The best results with regard to removal of DQOT, TKN, proteins, carbohydrates, besides solubilization of COD and increase the concentration of N-NH4, were coming from the treatment at 35 ° C. On the other hand, the total solids -1 concentration of 30.6 g.L , provided the best efficiency in the bioconversion of organic matter. The highest yield of biogas and CH4 gas was observed for treating the substrate with a lower concentration of total solids and 35 ° C. / Neste trabalho foi investigada a influência da concentração de sólidos totais e da temperatura no processo de co-digestão anaeróbia de resíduos sólidos orgânicos em reatores de batelada única, aplicando três diferentes concentrações de sólidos totais: 30,5 -1 -1 -1 g.L (ST1) ; 39,5 g.L (ST2) e 48,2 g.L (ST3), e três níveis de temperaturas: ambiente (média 24ºC) (T1), 35ºC (T2) e 40ºC (T3). O sistema experimental foi construído, instalado e monitorado por 180 dias nas dependências físicas da Estação Experimental de Tratamentos Biológicos de Esgotos Sanitários (EXTRABES) da Universidade Estadual da Paraíba, Campina Grande – PB, Brasil. Para a alimentação dos reatores foi preparado o substrato numa proporção de 80% de resíduos sólidos vegetais triturados e peneirados em malha de 2 mm e 20% de lodo anaeróbio proveniente de reator UASB tratando esgoto sanitário. Os melhores resultados em relação às remoções de DQOT, NTK, proteínas, carboidratos, além da solubilização de DQO e aumento na concentração de N-NH4, foram advindo do tratamento à temperatura de 35°C. Por outro lado, a concentração de sólidos -1 totais de 30,6 g.L , propiciou a melhor eficiência na bioconversão da matéria orgânica. A maior produção de biogás e de gás CH4 observada foi para o tratamento do substrato com menor concentração de sólidos totais e temperatura de 35°C.

Marine geological surveys in Asköfjärden in the southern Stockholm Archipelago hasrevealed step like features in the sediments on the Baltic sea floor. The aim of this project is toanalyse the steps and possible formation processes from the survey data. The data used aretaken from the acoustic instruments multibeam echosunder and Chirp sonar sediment profiler.The multibeam reveal the seafloor topography and can detect water column features. TheChirp sonar produce sub-bottom profiles showing the sediments down to some tens of metersunderneath the sea floor. The multibeam data show multiple crescent shaped steps as well aselliptically shaped “pockmarks”. Water column data show what could be interpreted as seepsfrom the sea floor under these features. The sub bottom profile show deformation and fluidsignatures under the steps. Gas signatures and what could be other fluids are present. Theinterpretation concludes that the formation could be from either gas or groundwater seeps. Nodefinitive conclusions can be made from the data available for the present study, andapetrophysical or geochemical study of the study area cold provide further understanding ofthe formation of the steps.

Made available in DSpace on 2016-12-12T20:12:28Z (GMT). No. of bitstreams: 1 PGEF14MA007.pdf: 4559322 bytes, checksum: 55d9751d276f23795d861f70ded2cdbc (MD5) Previous issue date: 2014-02-25 / The pollution of soil, surface and groundwater caused by solid waste became the focus of studies around the world, given the recognized potential polluter of environmental liabilities And the large volume of waste generated daily. This study aims to evaluate the environmental liabilities off dump the city of Lages SC. The site in question is located on the left bank of the BR-282 sense Lages / Florianópolis SC, between the coordinates 27º 46 15, 38 S and 50º 15 10, 92 W an area of 48,000 m². the use of this area for waste disposal occurred between the years 1987 and 2005, when it was deactivated. Collection Of leachate, water, benthic macroinvertebrates and methane for a qualitative and quantitative analysis were performed gas were performed. The methodology used in the sampling of water and leachate followed the guidelines in Standard Methods for the Examination of Water and Wastewater (APHA, 1999). As for macroinvertebrates is followed Technical Bulletin Nº 19 EMBRAPA, methane gas was measured at 1 m above the ground surface to 40 cm below the ground surface. Using the Resolution Nº 257/05 of CONAMA as a reference to evaluate the physico-chemical parameters obtained for water samples and calculated the WQI. In addition, the BMWP index was used for analysis of macroinvertebrates. To evaluate the values of the physicochemical parameters of landfil leachate Resolution Nº 430/11 of CONAMA was used, was there was in the same reference value was used in the 357/05. Also analyzed the decomposition phase in which Is the landifill and methane analysis used the Annex 11 of Norm 15 as reference. Using as Reference to Resolution Nº 357/05 of CONAMA, if we take into account the current situation, the stream would be affected by the landfill framed as Class 4, as well as 92,85% of the points listed in the surroundings. According to the WQI, stream analysis, on average, were rated as acceptable, it is noteworthy that the five stream sampling sites were classified as bad and just as good. As BMWP index, the stream presents critical analysis as predominant and considered very polluted water. Taking as reference to Resolution Nº 430/11 of CONAMA, 43,33% of the points of leachate do not meet the same and therefore could not stand being dumped. With regard to the decomposition phase was predominantly in the methanogenic landfill phase. The concentration of methane gas collected at 1m height from the soil surface, both of cells on top of garbage as contour, meet the limits in Annex 11 for Norm 15, the same does not occur with the points sampled at 40 cm below the soil surface, which do not meet the limit of oxygen and, when considering the lower flammability of methane 44% reach this value / A poluição do solo e das águas superficiais e subterrâneas, provocada por resíduos sólidos urbanos passou a ser motivo de estudos em todo o mundo, dado ao reconhecido potencial poluidor dos passivos ambientais e o grande volume de resíduos gerado diariamente. O presente trabalho visa fazer uma avaliação do passivo ambiental lixão desativado do município de Lages-SC. O local em questão está localizado na margem esquerda da BR-282 sentido Lages/Florianópolis-SC, entre as coordenadas 27º46 15,38 S e 50º15 10,92 W em uma área de 48.000 m2. O uso de tal área para depósito de resíduos ocorreu entre os anos de 1987 e 2005, quando o mesmo foi desativado. Foram realizadas coletas de chorume, água, macroinvertebrados bentônicos e gás metano para que uma análise qualitativa e quantitativa fosse realizada. A metodologia utilizada nas amostragens de água e chorume seguiu as orientações estabelecidas no Standard Methods for the Examination of Water and Wastewater (APHA, 1999). Quanto aos macroinvertebrados bentônicos seguiu-se o Comunicado Técnico No19 da Embrapa; o gás metano foi medido a 1m acima da superfície do solo a 40 cm abaixo da superfície do solo. Utilizou-se a Resolução N° 357/05 do CONAMA como referência para avaliar os parâmetros físico-químicos obtidos para as amostras de água, bem como calculou-se o IQA. Além disso, o índice BMWP foi utilizado para análise dos macroinvertebrados bentônicos. Para avaliar os valores dos parâmetros físico-químicos do chorume a Resolução N° 430/11 do CONAMA foi utilizada, quando não existia valor de referência na mesma utilizou-se a No 357/05.Também analisou-se a fase de decomposição em que se encontra o aterro e para análise do metano utilizou-se o anexo 11 da Norma Regulamentadora 15 como norteador. Utilizando como referência a Resolução N° 357/05 do CONAMA, se levarmos em consideração a situação atual, o córrego influenciado pelo lixão seria enquadrado como de Classe 4, assim como 92,85% dos pontos coletados no entorno. De acordo com o IQA, o córrego analisado, em média, foi classificado como aceitável; ressaltando-se que no mesmo cinco pontos amostrados foram classificados como ruins e apenas um como bom. Conforme o índice BMWP , o córrego analisado apresenta águas críticas como predominantes, sendo considerado com água muito poluída. Tomando-se como referência a Resolução N° 430/11 do CONAMA, 43,33% dos pontos de chorume não atendem a mesma e portanto não poderiam estar sendo lançados no ambiente. No que se refere a fase de decomposição o lixão estaria predominantemente na fase metanogênica. A concentração de gás metano coletado a 1m de altura a partir da superfície de solo, tanto encima das células de lixo quanto do contorno, atendem os limites do anexo 11 da Norma Regulamentadora 15; o mesmo não ocorre com os pontos amostrados a 40 cm abaixo da superfície do solo, que não atendem ao limite do oxigênio e, ao considerar o limite inferior de inflamabilidade do metano 44% atingem este valor

La mesure de l'indice de réfraction a été étudiée depuis qu'Ernest Abbé aie initialement conçu un réfractomètre en 1869, appelé le réfractomètre d'Abbé. Depuis lors, de nombreux réfractomètres ont été développés tels que le réfractomètre à prisme optique ainsi que le réfractomètre à fibre optique, en raison de leurs applications étendues pour la détection de divers paramètres physiques, biologiques et chimiques. Récemment, un grand nombre de chercheurs ont mis au point des réfractomètres basés sur des fibres optiques, exploitant des mécanismes tels que la résonance des plasmons de surface (SPR), les interférences multimodes, les fibres à réseaux de Bragg (FBG), les fibres à réseaux à longues périodes (LPG), les fibres optiques coniques et la fibre multimode à gaine dénudée. Les capteurs fibrés sont avantageux grâce à leur immunité contre les interférences électromagnétiques, passivité électrique au niveau de la sonde de détection et potentiel de mesure in situ à long terme. Cette thèse concerne le développement de modèles complets fonctionnels et précis pour les réfractomètres à fibres optiques basés sur la modulation d'intensité optique, en particulier la réfractométrie à fibre multimode à gaine dénudée ainsi que les systèmes hybrides associant fibres monomode et multimode, et un réfractomètre hybride tout fibré utilisant des fibres à cristaux photoniques. L'objectif clé de ce travail est de caractériser les performances de ces réfractomètres à fibres optiques basés sur la modulation d'intensité en termes de réponse en puissance, de sensibilité, de résolution et de dynamique de mesure. Les résultats de simulation qui sont corroborés expérimentalement démontrent que la très grande sensibilité obtenue dans la zone II (c'est-à-dire le régime de détection typiquement utilisé pour mesurer l'indice du milieu supérieur à l'indice de gaine mais inférieur ou égal à l'indice du coeur) pour tous les trois réfractomètres. Cependant, la sensibilité dans la Zone (c’est-à-dire le régime de détection pour lequel l’indice du milieu à mesurer est supérieur à celui du coeur) est très faible. Ainsi, un refractomètre fibré hybride monomode-multimode est utilisé pour améliorer la sensibilité dans la Zone III. D'autre part, la sensibilité pour la zone I (c'est-à-dire le régime de détection pour mesurer l’indice du milieu inférieur à l'indice de la gaine) a été améliorée en augmentant l'absorption des ondes évanescentes à l'aide du réfractomètre hybride tout fibré à base de fibres à cristaux photoniques à coeur solide. En termes d'application réelle du réfractomètre à fibre pour la détection biochimique, une preuve de concept pour un capteur du gaz méthane a été démontrée en utilisant les supramolécules de cryptophane-A qui permettent de piéger les molécules du méthane. Le cryptophane-A incorporé dans un film hôte à base de styrène acrylonitrile (SAN) est appliqué sur la zone dénudée du capteur comme une région fonctionnalisée. L'indice de réfraction de cette couche sensible augmente proportionnellement avec l'augmentation de la concentration du méthane, ce qui induit une variation de la puissance optique transmise dans le capteur fibré. / Refractive index measurement has been studied since Ernest Abbé initially designed a refractometer in 1869, which is named the Abbé refractometer. Since then, numerous types of refractometers have been developed by employing either the optical prism-based refractometer or the optical fiber-based refractometer, due to their wide-ranging applications such as for sensingvarious physical, biological and chemical parameters. Recently, a large number of researchers have been developing refractometers based on optical fibers, exploiting mechanisms such as surface plasmon resonance (SPR), multimode interference, fiber Bragg gratings (FBG), long period gratings (LPG), tapered optical fibers, and striped-cladding multimode fibers (MMF), for their advantages in immunity against electromagnetic interference, electrical passivity at the sensing probe, and capability to long term in-situ measurement. This thesis concerns the development of comprehensively functional and accurate models for optical fiber refractometers based on optical intensity modulation, in particular for stripped-cladding MMF refractometry as well as hybrid systems involving a combination of single-mode-multimode fiber refractometery and the all-fiber hybrid refractometer using photonic crystal fibers. A key objective of this work is to characterize the performance of these intensity-based optical fiber refractometers in terms of their power response, sensitivity, resolution, and dynamic range. The simulation results which are corroborated experimentally demonstrate very high sensitivity being obtained in Zone II (i.e. the sensing regime typically employed for measuring a sensing medium index higher than the cladding index but less than or equal to the core index) for all three types of refractometers. However, the sensitivity in Zone III (i.e. the sensing regime for which the sensing medium index is higher than the core index) is very low. A hybrid single-mode fiber - multimode fiber configuration is used to improve the sensitivity in Zone III. On other hand, the sensitivity for Zone I (i.e. the sensing regime typically employed for measuring a sensing medium index lower than the cladding index) has been improved by increasing evanescent wave absorption using the all-fiber hybrid refractometer based on solid-core photonic crystal fibers. As a further potential of the fiber refractometer for applications in biochemical sensing, the proof-of-concept for a methane gas sensor has been demonstrated using supramolecular cryptophane-A which enables to trap the methane molecules. Cryptophane-A incorporated into a functionalized film of StyreneAcrylonitrile (SAN) host is applied to a de-cladded region of the sensor as the sensitive region. The refractive index of this functionalized layer increases proportionally with increasing methane concentration, subsequently inducing variations in the transmitted optical power along the fiber sensor.

<p>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.</p><p>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. After 15 to 20 days of digestion (average retention time in the digester at Käppala wastewater treayment plant that treats primary sludge) the biogas production was between 0,55 and 0,60 Ndm3/g VS, which is within the range of the production at the digester that treats the primary sludge. This leads to the conclusion that the digestion of primary sludge is well functioning at the plant.</p><p>Batch laboratory tests showed that excess sludge had a potential biogas and methane production of 0,31 and 0,16 Ndm3/g VS respectively after 40 days of digestion.</p><p>Batch laboratory tests with restaurant waste showed a potential biogas and methane production of 0,81 and 0,38 Ndm3/g VS respectively after 47 days of digestion. This means that the total production of methane gas can increase with 7-8 per cent with an annual load of 3500 tonnes of restaurant waste (estimated amount of available restaurant waste). Tests to imitate transport of restaurant waste with influent wastewater showed that 35-60 per cent of the increase of gas production would be “washed out” if the waste was tranported this way to the plant.</p><p>Batch laboratory tests with waste from water works showed that no gas was produced from this substrate.</p><p>The continuous tests with small scale reactors which were fed with restaurant waste resulted in an increase of biogas production with 12 per cent (corresponding to an annual load of 3500 tonnes of restaurant waste) compared to the present process.</p> / <p>Avloppsreningsverket Käppalaverket på Lidingö driver under år 2004-2005 ett projekt med syftet att kartlägga rötningskapaciteten i den befintliga anläggningen där primär- och överskottsslam behandlas i två rötkammare. Syftet med examensarbetet, som är en del av kartläggningsprojektet, var att karakterisera Käppalaverkets nuvarande rötningsprocess och undersöka processens kapacitet att behandla organiskt avfall i form av restaurangavfall och vatttenverksslam. För att bestämma potentialen hos olika substrat har satsvisa utrötningar genomförts. För att efterlikna processen på Käppalaverket har kontinuerliga försök med små reaktorer bedrivits. Till dessa reaktorer har sedan restaurangavfall tillsats.</p><p>De satsvisa utrötningarna av primärslam visade en potentiell bio- respektive metangasproduktion om 0,62 respektive 0,35 Ndm3/g VS efter 40 dagars utrötning. Efter 15-20 dagars utrötning (som är den genomsnittliga uppehållstiden i Käppalaverkets rötkammare där primärslammet behandlas) var biogasproduktionen mellan 0,55 och 0,60 Ndm3/g VS, vilket är inom samma intervall som vid den verkliga driften av rötkamrarna vid Käppalaverket. Detta betyder att utrötningen av primärslammet fungerar bra vid Käppalaverket.</p><p>De satsvisa utrötningarna av överskottsslammet visade en potentiell bio- respektive metangasproduktion om 0,31 respektive 0,16 Ndm3/g VS efter 40 dagars utrötning.</p><p>För restaurangavfallet visade de satsvisa utrötningarna på en potentiell bio- respektive metangasproduktion om 0,81 respektive 0,38 Ndm3/g VS efter 47 dagars utrötning.</p><p>Detta innebär att den totala metangasproduktionen vid Käppalaverket skulle kunna ökas med 7-8 procent om 3500 ton restaurangavfall skulle tas emot årligen (uppskattad mängd restaurangavfall som finns att tillgå). Försök att efterlikna transport av restaurangavfallet via avloppsledningsnätet visade dock att 35-60 procent av den ökade metangasproduktionen skulle ”tvättas ur” om avfallet fördes till verket via avloppsledningsnätet.</p><p>Försöken med satsvis utrötning av vattenverksslam visade att detta substrat inte bidrar med någon produktion av biogas eller metangas.</p><p>De kontinuerliga försöken med tillsats av restaurangavfall (motsvarande en årlig belastning med 3500 ton) resulterade i en ökning av biogasproduktionen med 12 procent.</p>

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. After 15 to 20 days of digestion (average retention time in the digester at Käppala wastewater treayment plant that treats primary sludge) the biogas production was between 0,55 and 0,60 Ndm3/g VS, which is within the range of the production at the digester that treats the primary sludge. This leads to the conclusion that the digestion of primary sludge is well functioning at the plant. Batch laboratory tests showed that excess sludge had a potential biogas and methane production of 0,31 and 0,16 Ndm3/g VS respectively after 40 days of digestion. Batch laboratory tests with restaurant waste showed a potential biogas and methane production of 0,81 and 0,38 Ndm3/g VS respectively after 47 days of digestion. This means that the total production of methane gas can increase with 7-8 per cent with an annual load of 3500 tonnes of restaurant waste (estimated amount of available restaurant waste). Tests to imitate transport of restaurant waste with influent wastewater showed that 35-60 per cent of the increase of gas production would be “washed out” if the waste was tranported this way to the plant. Batch laboratory tests with waste from water works showed that no gas was produced from this substrate. The continuous tests with small scale reactors which were fed with restaurant waste resulted in an increase of biogas production with 12 per cent (corresponding to an annual load of 3500 tonnes of restaurant waste) compared to the present process. / Avloppsreningsverket Käppalaverket på Lidingö driver under år 2004-2005 ett projekt med syftet att kartlägga rötningskapaciteten i den befintliga anläggningen där primär- och överskottsslam behandlas i två rötkammare. Syftet med examensarbetet, som är en del av kartläggningsprojektet, var att karakterisera Käppalaverkets nuvarande rötningsprocess och undersöka processens kapacitet att behandla organiskt avfall i form av restaurangavfall och vatttenverksslam. För att bestämma potentialen hos olika substrat har satsvisa utrötningar genomförts. För att efterlikna processen på Käppalaverket har kontinuerliga försök med små reaktorer bedrivits. Till dessa reaktorer har sedan restaurangavfall tillsats. De satsvisa utrötningarna av primärslam visade en potentiell bio- respektive metangasproduktion om 0,62 respektive 0,35 Ndm3/g VS efter 40 dagars utrötning. Efter 15-20 dagars utrötning (som är den genomsnittliga uppehållstiden i Käppalaverkets rötkammare där primärslammet behandlas) var biogasproduktionen mellan 0,55 och 0,60 Ndm3/g VS, vilket är inom samma intervall som vid den verkliga driften av rötkamrarna vid Käppalaverket. Detta betyder att utrötningen av primärslammet fungerar bra vid Käppalaverket. De satsvisa utrötningarna av överskottsslammet visade en potentiell bio- respektive metangasproduktion om 0,31 respektive 0,16 Ndm3/g VS efter 40 dagars utrötning. För restaurangavfallet visade de satsvisa utrötningarna på en potentiell bio- respektive metangasproduktion om 0,81 respektive 0,38 Ndm3/g VS efter 47 dagars utrötning. Detta innebär att den totala metangasproduktionen vid Käppalaverket skulle kunna ökas med 7-8 procent om 3500 ton restaurangavfall skulle tas emot årligen (uppskattad mängd restaurangavfall som finns att tillgå). Försök att efterlikna transport av restaurangavfallet via avloppsledningsnätet visade dock att 35-60 procent av den ökade metangasproduktionen skulle ”tvättas ur” om avfallet fördes till verket via avloppsledningsnätet. Försöken med satsvis utrötning av vattenverksslam visade att detta substrat inte bidrar med någon produktion av biogas eller metangas. De kontinuerliga försöken med tillsats av restaurangavfall (motsvarande en årlig belastning med 3500 ton) resulterade i en ökning av biogasproduktionen med 12 procent.