@phdthesis{Lu2017, author = {Lu, Yanjuan}, title = {Optimization of converting food waste to hydrogen and Biogas in double-stage-fermentation}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-43209}, school = {BTU Cottbus - Senftenberg}, year = {2017}, abstract = {Aim of this study The aim of this research is to develop batch scale and continuous reactor systems to evaluate technical and practical feasibility of sequential hydrogen and methane from food waste by two step dark fermentation process. Methodology The effects of limiting factors, like pH, temperature, as well as inoculum sources and pretreatment methods on H₂ yields were studies in batch assays. In addition, the feasibility of sequencing producing H₂+CH₄ via two stage dark fermentation process was evaluated in lab-scale tests based on batch assay results. Three kinds of Acid producing reactor, like CSTR, semi-percolator, and ASBR had been tested for bioH₂ production and well inoculated ASBR methane was used for further degradation of volatile organic acids produced in these acid producing reactor which acts as by-products of bioH₂. Different limiting factors on fermentation process have been investigated in each reactor type for optimum energy recovery. Monodigestion of food waste for methane production was also studied and used as reference value for energy recovery from food waste. Main results and technical application from this study Hydrogen production results from food waste were shown to be possible with aerated inoculum in batch assays in thermophilic range, with highest H₂ yields of 19.72L/(kg oTS) from food waste. The inoculated HPB (Hydrogen producing bacterial) sludge taken from ASBR acid producing reactor was proved the optimum H₂ yields with the value of 61.41 L/(kg oTS) in this batch test. Inoculum to substrates ratio at 3 was found the best situ for H₂ yields in batch test. Even H₂ productivity at hyperthermophilic range has been confirmed with faster and higher performance, thermophilic fermentation process was taken in continuously lab-scale investigation due to too high process requirements in hyperthermophilic process. Two-stage sequencing producing H₂+CH₄ was shown the potential in H₂ yields in the first acid producing phase. Methane yields from monodigestion in ASBR methane reactor with OLR of 3.88 kg oTS/(m3.d) and average CH₄ yields at 312.71L/kg oTS were achieved and act as reference value for total energy recovery. In CSTR+ASBRMe system, the max. hydrogen yields of 69.15 L/(kg oTS) and CH₄ yields at 291.77. L/(kg oTS) were achieved; In semi-Percolator+ASBRMe system, the max. hydrogen yields of 77.34 L/kg oTS and average CH₄ yields at 293.87 L/(kg oTS) were achieved; In ASBR+ASBRMe system, the max. hydrogen yields of 196.85L/(kg oTS) and average CH₄ yields at 293.87 L/(kg oTS) were achieved. The max. H₂ concentration in hydrolysis gas was got in ASBR acid producing reactor at 54\%. The experimental results indicated that food wastes can be considered as suitable substrates for BioH₂ and CH₄ sequencing production. Moreover, the less production cost for H₂ due to higher OLR and shorting HRT.}, subject = {CSTR; Semi-percolator; ASBR; Methane; Two stage dark fermentation process; Biohydrogen; Food waste; Factor; OLR; Biogas; Biowasser; Methan; Speiseabf{\"a}lle; Verg{\"a}rungsprozess; Faktor; ASBR; CSTR; Perkulator; ORB; Biogas; Fermentation; G{\"a}rung; Lebensmittelabfall; Biogas}, language = {en} } @phdthesis{Andolfo2017, author = {Andolfo, Franco}, title = {Energieeffizientes N{\"a}hrstoffsplitting von fl{\"u}ssigen Wirtschaftsd{\"u}ngern mittels Membranfiltration}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-42805}, school = {BTU Cottbus - Senftenberg}, year = {2017}, abstract = {Die definierte Selektivit{\"a}t der Membranfiltration kann dazu genutzt werden, einzelne spezifische G{\"u}lle-Separationsprobleme in {\"u}bergeordneten Aufbereitungsklassen zusammenzufassen. Mit dem Ansatz einer gesteuerten N{\"a}hrstofftrennung bzw. Teilzusammenf{\"u}hrung von modifizierten Str{\"o}men, und der Zuordnung von spezifischen Aufgaben an die Mischprodukte, werden die Nachteile des Ausgangsrohstoffs reduziert und der Wertstoff G{\"u}lle r{\"u}ckstandsfrei nutzbar gemacht. Mit einem Anlagenmodell, bestehend aus einer Hydrotankpresse als Vorfiltration und einer Ultrafiltration als Kernkomponenten, ist es {\"u}ber empirisch ermittelte Betriebsparameter m{\"o}glich, einen energetisch optimierten und kontinuierlichen Produktionsbetrieb durchzuf{\"u}hren. Als Produkte der dezentralen Aufbereitungsanlage werden ein emissionsreduzierender Fl{\"u}ssigd{\"u}nger, eine als Brennstoff und als G{\"a}rsubstrat geeignete Feststoffphase, sowie das Retentat als aktivierendes Material zur Biogasertragssteigerung gewonnen. Das untersuchte Anlagenmodell ist auf den innerbetrieblichen Einsatz in Milchviehhaltungsbetrieben abgestimmt. Mit der Erarbeitung von stabilen und energetisch g{\"u}nstigen Anlagenbetriebspunkten wird das Anlagenverhalten hydraulisch steuerbar. Durch die Zuordnung von Anlagenzust{\"a}nden zu differenziertem Sp{\"u}lverhalten, wird die direkte Einflussnahme der Temperatur auf den Permeat-Flux erkennbar. Der Einsatz eines Tauchk{\"u}hlers, mit voreingestellten Grenztemperaturen, stabilisiert signifikant das Anlagenverhalten im Vergleich zu konventionellen Anlagenkonfigurationen. Die Anwendung einer Hydropresse gestattet h{\"o}here TDS-Belastungen im UF-Kreislauf, bietet aber kein Potenzial zur Steigerung der N{\"a}hrstoffdurchs{\"a}tze. Dies gilt auch f{\"u}r den Einsatz einer 300 kDa-Variante, im Vergleich zur priorisierten 150 kDa-UF-Membran. Mit der Hydropresse kann eine h{\"o}here Feststoffabscheidung wie mit Verstopfungs- bzw. Siebfiltrationen erreicht werden, die TDS-Belastungen sind im Retentat auf 5.000 - 7.000 ppm limitiert, oder m{\"u}ssen durch Verd{\"u}nnung auf diese Werte eingegrenzt werden. Mit der zus{\"a}tzlichen Anwendung einer Gassp{\"u}lung in der Anstr{\"o}mung der UF-Module, k{\"o}nnen TDS-Belastungen {\"u}ber 10.000 ppm erstmals dauerhaft bew{\"a}ltigt werden. {\"U}ber die so erweiterte Verfahrenstechnik sind Standzeiten von mehreren Wochen, ohne betrieblich bedingte Unterbrechungen, m{\"o}glich. Die durch Fluoreszenzmikroskopie nachweisbare Anreicherung von Methanbildnern im Retentat, best{\"a}tigt eine m{\"o}gliche Anwendung des Retentats als Biogassubstraterg{\"a}nzung. Der Biogasertrag wird durch Zusatz von Retentat zu den bisher verf{\"u}gbaren Substraten generell erh{\"o}ht. Eine Mischung aus Retentat und dem Feststoff aus der Hydropresse unterst{\"u}tzen die biochemische Stabilisierung in Fermentern. In Kombination mit Anteilen an Feststoff ist das Permeat bei der Bewertung von pflanzenbaulichen Ertr{\"a}gen, als konkurrenzf{\"a}hig zu Rohg{\"u}lle und Mineralstoffd{\"u}nger einzustufen. Das auf landwirtschaftliche Fl{\"a}chen ausgebrachte Permeat ist geruchslos.}, subject = {N{\"a}hrstoffsplitting; Nutrient splitting; Membranfiltration; Membrane filtration; Wirtschaftsd{\"u}nger; Farm fertilizer; Klimaschutz; Climate protection; Umweltschutz; Environment protection; Membranfilter; Wirtschaftsd{\"u}nger; Technikumsanlage; Klimaschutz}, language = {de} } @phdthesis{Apau2017, author = {Apau, Kwaku Boakye}, title = {Developing a conceptual solution for domestic wastewater management in developing countries: Kumasi (Ghana) as a case study}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-41544}, school = {BTU Cottbus - Senftenberg}, year = {2017}, abstract = {Wastewater treatment systems abound as a result of technological improvements in treatment processes. Therefore in the selection of a wastewater treatment system for a particular wastewater treatment situation there are many alternatives to choose from. Despite this development municipal wastewater treatment in communities in developing countries are not always sustainable due to the application of inappropriate treatment systems. The question is how can an appropriate treatment system be identified for a certain location? The answer to this question is of importance to developing countries where wastewater treatment is usually not sustainable. In this study a framework for assessing wastewater treatment systems was developed. First, a comprehensive set of indicators representing parameters of treatment systems and properties of the study area that impacts on wastewater treatment were identified. Secondly, assessment of these indicators were carried out through expert and community survey to identify a final set of indicators whose composition consist of efficiency, reliability and simplicity of treatment systems and resource constraint, resource recovery and environmental concerns of the study area. Thirdly, four wastewater treatment systems, namely: Waste Stabilization Ponds, Trickling Filter, reed bed and free water surface Constructed Wetlands considered to be feasible for the study area were evaluated by the application of the identified indicators. Finally, a decision matrix produced was processed by multi-attribute decision making methods using two indicator weights to identify the most appropriate treatment system among the four alternatives. Results of the study show that in a scenario where equal indicator weights are assumed, reed bed is identified as the most appropriate with stabilization ponds being ranked as the least appropriate. In a more practical scenario where the weights of the indicators are allocated to reflect conditions of the study area, free water surface is ranked as the most appropriate. This outcome is at variance with stabilization pond technologies currently installed at communities in the study area. The performance of constructed wetlands is at the midpoint as far as most of the high to medium weighted assessment indicators are concern. It therefore represents a compromising solution between waste stabilization pond and trickling filter. The study also shows a change in variants of constructed wetland with a change in indicator weights. An indication that the decision situation determines the appropriateness of a treatment system and not the treatment system itself. The selection framework employed in this study can be said to be reliable and capable of identifying a treatment system that can be appropriate for a particular location. This is because the choice of a constructed wetland for the study area fits the definition of appropriate treatment system defined by the final indicators identified in this study.}, subject = {Wastewater treatment; Treatment efficiency; Land requirement; Multi-attribute decision making; Assessment indicators; Behandlungseffizienz; Bodenbedarf; Abwasserbehandlung; Entscheidungsfindung f{\"u}r Mehrfachattribute; Bewertungsindikatoren; Entwicklungsl{\"a}nder; Abwasserreinigung; Umweltbewertung}, language = {en} }