5 p. / Both honey and sugar are carbohydrate, calorie-dense sweeteners. This article reviews similarities and differences of honey and sugar, and then answers the popular questions: “Is honey better than sugar?” and “What are cooking tips when substituting honey for sugar in recipes?”

The main purpose of this project was an attempt to modulate and simulate two existing biogas plant, situated in Lidköping and Katrineholm, Sweden and evaluate how the process reacts to certain conditions regarding feeding, layout and substrate mixture. The main goal was to optimize the existing processes to better performance. Both the modeling and simulation were executed in SIMBA#Biogas with accordance to the real conditions at the plant in question. The simulation of each model was validated against data containing measurements of, CH4 yield, CH4 production, TS, VS, NH4-N concentration and N-total concentration. The data was obtained from each plant in accordance with scheduled follow ups. Both models were statistically validated for several predictions. Predictions of N-total and NH4-N concentration failed for some cases. Both plants were tested with new process lay outs, where promising results were obtained. The Lidköping model was provided with a post-hygienization step to handle ABPs. The Katrineholm model was provided with a dewatering unit, where 35% of the centrate was recirculated back to the system. Both setups was configured to yield the highest CH4 production. This study suggests that SIMBA#Biogas can be a tool for predictions and optimizations of the biogas process.

This study evaluates the enhancement of anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) by microwave pretreatment (MW) at high temperatures (115, 145 and 175°C). The highest level of solubilization was achieved at 175ºC, with a supplemental water addition of 30% (SWA30). Pretreatments combining two modalities; MW heating in presence or absence of hydrogen peroxide (H2O2) was also investigated. Biochemical methane potential (BMP) tests were conducted on the whole OFMSW, as well as on the liquid fractions. The whole OFMSW pretreated at 115 and 145 ºC showed little improvement in biogas production over control. When pretreated at 175 ºC, biogas production decreased due to formation of refractory compounds, inhibiting digestion. For the liquid fraction of OFMSW, the effect of pretreatment on the cumulative biogas production (CBP) was more pronounced for supplemental water addition of 20% (SWA20) at 145 ºC. Combining MW and H2O2 modalities did not have a positive impact on OFMSW stabilization and enhanced biogas production. Based on the BMP assay results, the effects of MW pretreatment (145 ºC) on the AD of OFMSW (SWA20) were further evaluated in single and dual stage semi-continuous digesters at hydraulic retention times (HRTs) of 20, 15, 12 and 9 days. Overall, MW pretreatment did not enhance the AD of the whole waste at the HRTs tested. However, the use of a dual stage reactor digesting non pretreated whole OFMSW had the best performance with the shortest HRT of 9 days. Conversely, for free liquid after pretreatment in two stage reactors at 20 day HRT methane production was tripled. In general, the performance of the dual stage digesters surpassed that of the single stage reactors. Cyclic BMP assays indicated that using an appropriate fraction of recycled effluent leachate can be implemented without negatively effecting methanogenic activity and biogas production. Based on the results obtained in this study, digestion of OFMSW by dual stage reactors without pretreatment appears to provide the best potential for waste stabilization in terms of biogas production and yield, process stability and volumetric loading rates.

Anaerobic digestion of waste activated sludge can be improved if hydrolysis of particulate substrates is enhanced and available substrate is made more accessible by both breakup of the sludge matrix floc and rupture of the cell wall. Microwave (MW) pretreatment was suggested and studied as a way to improve digestion efficiency. The work done focuses on the effects of MW pretreatment on the characteristics of the sludge, due to thermal and athermal effects. It also evaluates the effects some process variables in the activated sludge process have on the pretreatment efficiency as well as the effect operating conditions in the downstream anaerobic digestion process have on the biodegradability efficiency of those sludges. Effects of athermal and thermal MW radiation were measured by use of a customized MW oven capable of providing MW radiation with uncoupled thermal and athermal effects. Athermal radiation was capable of increasing substrate present in the soluble phase of sludge, and had a positive effect in the digestion of athermal samples. The increases in biogas production and substrate solubilisation were smaller in magnitude than the increases measured for MW thermal tests. Further refining of the tests with athermal and thermal sludge, involved separation by size class of the solubilized substrate by means of ultrafiltration (UF), and revealed that changes in particle size distribution were significant not only for MW thermal tests, but also for athermal tests, with a particular emphasis in proteins in athermal tests. These changes had an effect on the biodegradability of the sludges by class size, with thermally pretreated sludge producing more biogas for smaller particles size classes but also exhibiting more inhibition. Tests were made with several combinations of sludge with different ages and subject to different MW pretreatment temperatures. The work showed that sludge age or solids retention time (SRT) has a significant effect on the pretreatment efficiency with maximum biogas improvements measured at different MW pretreatment temperatures depending on the SRT of the sludge tested, and with different behaviour for mesophilic and thermophilic digestion. Mesophilic tests showed greater improvements in terms of digestion effiency on average, but thermophilic tests showed more uniform performance, with a higher baseline efficiency. The presence of an optimum of MW pretreatment temperature and sludge SRT for maximal biogas production is more defined for mesophilic conditions than for thermophilic conditions. Semi-continuous studies were conducted with several combinations of single and two stage mesophilic and thermophilic digestors treating MW pretreated sludge and non-pretreated sludge. Staging and thermophilic digestion allowed the maintenance of a stable digestion process with high biogas productions and high solids removal efficiencies with production of sludge with good bacteriological characteristics for an very low residence time (5 d).

Pilot-scale ambient and low temperature research into the enhancement of aerobic digestion of waste activated sludge, through control of mixed liquor pH (MLpH), was performed using an extended aeration and a high rate waste sludge. To offset MLpH decreases encountered during nitrification, Ca(OH)₂ and NaHCO₃ were used to control MLpH in the series pH 6, 7 and 8. The performance and behaviour of the digesters, under both controlled and uncontrolled MLpH conditions, were monitored through parameters related to volatile mass reduction, sludge mass metabolism, quality of digested end-product and soluble characteristics of the digester effluent. Volatile mass reduction was significantly affected by MLpH control, under certain conditions. Improvements in reduction performance of >100% over the uncontrolled condition were noted, depending on sludge origin; however, it was concluded that only certain temperature ranges should be targeted for the most effective use of MLpH control, since use of MLpH control in ranges wherein little improvement would be realized was felt to be uneconomical. Analysis of volatile mass reduction rates, based on a series of 1 day batch conditions (necessitated by the reactor flow scheme and the variability of the digestion process), demonstrated that reactor performance oscillated around a mean performance value; MLpH control acted to reduce these oscillations, such that the digesters performed closer to the mean value more of the time. Temperature sensitivity coefficients were quite variable, and a single value did not describe all situations. It was proposed that θ was influenced by digestion system, operating temperature, sludge type and MLpH level. The use of this coefficient for determining the operating ranges most suitable for MLpH control was advanced. The fate of the nutrients nitrogen and phosphorus were greatly influenced by MLpH control. The use of Ca(OH)₂ resulted in less release of phosphorus from the solid phase, with subsequently low effluent PO₄-P concentrations in the neutral MLpH range. The drawback of this reaction was found to be the production of inert inorganic sludge solids, thereby illustrating the need for a trade-off between the various benefits and drawbacks of the enhanced digestion process. Nitrification proceeded at all temperatures, and in conditions previously thought to be inhibitory to the chemolithotrophic organisms. Digester effluent quality was improved through MLpH control, but substantial concentrations of NOx-N were observed under some conditions. Based on direct comparisons with previous lab-scale research, it was concluded that the enhancement process had very good potential for implementation at the full-scale level, either for the improvement of existing underdesigned processes, or for the initial design of more efficient aerobic digestion facilities. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

L’analyse d’échantillons du Patrimoine Culturel est primordiale pour la compréhension des techniques, la conservation des œuvres et leur restauration. Ces échantillons sont rares et précieux et l’analyse doit être effectuée sur une faible quantité de matière, ce qui nécessite le développement et l’optimisation de méthodes analytiques appropriées. L’objectif de ce travail de thèse a donc été de développer de nouvelles méthodes analytiques dans le but d’étudier les glycoprotéines et les polysaccharides de gommes végétales des échantillons du Patrimoine Culturel. Les macromolécules ont été séparées par chromatographie d'exclusion stérique et électrophorèse sur gel de polyacrylamide modifié, révélant la présence de poids moléculaires très élevés pouvant atteindre jusqu’à 1 à 2 millions de Dalton. Une stratégie analytique innovante basée sur la spectrométrie de masse a permis d’obtenir des empreintes caractéristiques de chaques gommes. La stratégie analytique développée a été appliquée avec succès sur un échantillon d'aquarelle daté de 1870 du Metropolitan Museum of Art (New York, USA). / The analysis of Cultural Heritage samples is critical for the understanding of the arstists' technique, the conservation and restoration of artworks. These objects under investigation are rare and precious and the amount of sample available for the analysis is usually very low, thus implying the development and the optimization of adapted analytical methodologies. The objective of this PhD was to develop new analytical methods to study glycoproteins and polysaccharides from plant gums in Cultural Heritage samples.These macromolecules have been separated by size exclusion chromatography and modified polyacrylamide gels, which allowed to reveal the presence of proteins with molecular weights up to 1-2 million Dalton. A novel analytical strategy based on mass spectrometry allowed to obtain the caracteristic fingerprint of each plant gum. This developed method was successfully applied on a watercolor sample dated from 1870 supplied by the Metropolitan Museum of Art (New York, USA).

The aim of this study was to evaluate the methane potential of 35 kg of blue mussels in a batch amanaerobic two-stage dry digestion system (pilot-scale), which consists of aleach bed reactor (LB) and an up-flow anaerobic sludge blanket reactor (UASB). We monitored the process daily by measuring temperature, pH, COD, VFA, NH4+ gas flow rate and gas content. The temperature was approximately 30 C in the LB and 36 C in the UASB reactor. The applied OLR was 1.5 g COD/l*d. After 37 days process run, we obtained a total methamne yield of 0.64 Nm3 respectively 0.29 Nm3/kg VS, of that 70% in the LB reactor and 30% in the UASB reactor.

Esta tesis doctoral se centra en la dinámica de la inhibición y la recuperación del proceso de digestión anaerobia de purines de cerdo para encontrar indicadores, predecir fallos del proceso, minimizar las pérdidas de metano (CH4) y evaluar las mejores prácticas de gestión a nivel de la planta de biogás. Para cumplir con este objetivo, cinco ensayos fueron diseñados y ejecutados. En primer lugar, se diseñó un experimento para controlar los cambios físico-químicos y de emisión de gas de dos tipos de purines envejecidos durante 15 semanas de almacenamiento en condiciones de verano. En segundo lugar, diferentes concentraciones de sulfato (SO42-) fueron evaluadas en digestión anaerobia termofílica de purines de cerdo y vacuno controlando la producción de CH4 y los cambios fisicoquímicos en un ensayo en discontinuo. Así mismo, la degradación anaeróbica de la materia orgánica (MO) y el límite de inhibición de SO42- fueron investigados. En tercer lugar, los efectos de incluir purines de cerdo acidificados con SO42- en un codigestión anaerobia con purines de cerdo convencionales se estudió a dos escalas (a escala laboratorio y a gran escala), donde se evaluó el rendimiento del proceso. Así mismo, los indicadores clave del proceso fueron identificados. En cuarto lugar, una combinación de dos métodos, reacción en cadena de la polimerasa cuantitativa en tiempo real (qPCR) y microscopía electrónica de barrido cualitativa (SEM) fueron utilizados para evaluar los cambios en la población microbiana de los digestores anaerobios durante la adición de los purines. Finalmente, el rendimiento de CH4, la composición físico-química y la estructura y dinámica de la comunidad microbiológica fueron evaluadas durante la puesta en marcha de la digestión anaerobia de purines de cerdo a escala de laboratorio. Se evaluaron cuatro estrategias de puesta en marcha: inanición y no inanición, seguida de una adición gradual o brusca de los purines. Los resultados presentados en esta tesis doctoral per / Moset Hernández, V. (2012). Monitoring anaerobic digestion of animal slurry during inhibition and recovery phases [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/18069 / Palancia

Several operational and environmental conditions can result in poor biogas yield during the operation of anaerobic digesters and anaerobic bioreactor landfills. Over time, anaerobic co-digestion and leachate blending have been identified as strategies that can help address some of these challenges to improve biogas production. While co-digestion entails the co-treatment of multiple substrates, leachate blending involves combination of mature and young landfill leachate. Despite the benefits attributed to these strategies, their impact on recirculating bioreactor landfill scenarios and anaerobic digesters requires further investigation. In the first phase of this thesis, an attempt to assess biogas production improvement from organic fraction of municipal solid waste in simulated bioreactor landfills through recirculation of blended landfill leachate was conducted. Real old and new leachate blends (67%New leachate:33%Old leachate, 33%New leachate:67%Old leachate) as well as 100%New and 100%Old leachate were recirculated through six laboratory-scale bioreactors using open-loop and closed-loops modes. Compared with the control bioreactor where 100% new leachate was recirculated and operated as a closed-loop, cumulative biogas production was improved by as much as 77 to 193% when a leachate blend of 33%New:67%Old was recirculated. Furthermore, comparison of the results from open-loop and closed-loop operated bioreactors indicated that there was approximately 28 to 65% more biogas in open-loop bioreactors. The Gompertz model applied to the methane data produced a better fit (R2 > 0.99) than first order and logistic function models. Leachate blending reduced the lag phase by almost half and thus helps in alleviating the ensiling during the start-up phase. In the second phase, a biochemical methane potential (BMP) assay was conducted to investigate the synergistic effect of percentage sewage scum addition; 10%, 20% and 40% (volatile solids basis) on biogas production during mesophilic co-digestion with various organic substrates viz; organic fraction of municipal solid waste, old leachate, new leachate and a leachate blend prepared from 67%old leachate and 33%new leachate under sub-optimal condition. Results show that the net cumulative bio-methane yield was improved with increased sewage scum percentage during co-digestion because of positive synergism. Meanwhile, the addition of 40% sewage scum to the individual co-substrates improved net cumulative bio-methane yield by 28% - 67% when compared to their respective mono-substrate digestion bio-methane yield. Furthermore, reactors containing leachate blends consistently produced more biogas over other sets because of blending. Kinetic modelling applied to the bio-methane production data shows modified Gompertz equation achieved a better fit with up to an R2 value of 0.999. Finally, co-digestion substantially reduced the lag time encountered during mono-digestion. In the last phase, the biomethane potential involved in the ACo-D of sewage scum, organic fraction of municipal solid waste was investigated in this phase using either thickened waste activated sludge or leachate blend (67%old leachate and 33%new leachate) as a tertiary component. Compared to the mono-digestion of TWAS, results shows that biomethane yield was enhanced in by as much as 32 - 127% in trinary mixtures with SS and OFMSW mainly due to the effect of positive synergism. Furthermore, LB addition improved biomethane production in trinary mixtures of SS:LB: OFMSW by 38% than in corresponding trinary mixtures of TWAS. Whereas an optimal combination of 40%SS:10%TWAS:50%OFMSW and 20%SS:70%LB:10%OFMSW produced the highest biogas yield of 407mL.gVS-1 and 487mL.gVS-1 respectively. The application of the first order model showed that lower hydrolysis rates promoted methanogenesis with k = 0.04day-1 in both 20%SS:70%LB:10%OFMSW and 20%SS:50%LB:30%OFMSW. Estimations by the modified Gompertz and logistic function were conclusive methane production rate improved by as much a 60% in a trinary mixture over the production rate during mono-digestion of TWAS alone. The results of the various experiments of this thesis therefore suggest that leachate blending can be used as a strategy to improve biogas production in both bioreactor landfills and anaerobic digesters. Also, sewage scum as an energy-rich substrate can be better utilized during co-digestion with other low-energy substrates.

This thesis is focused on the bloodmeal digestion of phlebotomine sand flies and its effects on Leishmania development within their midguts. In the first part, we studied various parameters of bloodmeal digestion in four sand fly species differing in susceptibility to Leishmania donovani to evaluate the effects on vector competence. Both proven vectors of L. donovani (Phlebotomus orientalis and P. argentipes) showed lower trypsin activity and slower formation of the peritrophic matrix (PM) than refractory species (P. papatasi and Sergentomyia schwetzi). Remarkably, P. orientalis and P. argentipes strikingly differed from each other in a time course of bloodmeal digestion. Phlebotomus orientalis females showed very slow bloodmeal digestion with low peaks of proteolytic activities and defecated around day five post bloodmeal. In contrast, P. argentipes females digested faster with a very high peak of chymotrypsin activity, their PM was present for only a short time and defecation was finished by day three post bloodmeal. We presume that the period between the degradation of the PM and defecation (i.e. time frame when Leishmania bind to the midgut to avoid expulsion with bloodmeal remnants), is one of crucial parameters affecting the establishment of Leishmania in the sand flies. In both natural...