Anaerobic digestion is a common process for treatment of wastewater sludge from municipal sewage systems. Volatile sulfur compounds, including volatile organic sulfur compounds (VOSCs) and hydrogen sulfide, have been reported as the most odorous compounds in digestion emissions and impurities which can damage facilities for generation, transportation, storage, and utilization of biogas. There has been no comprehensive study on biological generation and degradation kinetics of VOSC or modeling VOSC behaviors through anaerobic sludge digestion. The goal of the present study was to establish a model for VOSC conversions in anaerobic sludge digestion which could facilitate quantitative analysis of VOSC emissions in anaerobic digestion. VOSCs and methionine were employed in dosed batch tests. VOSC conversion processes in anaerobic methionine digestion have been identified. The kinetics for the identified VOSC degradation and conversion processes were determined at 35 and 55 °C respectively. Mixed-second order kinetics were found to best fit the conversion processes. A model was established based on the identified processes and estimated kinetic constants. To extend the model to VOSC release in anaerobic sludge digestion, mesophilic and thermophilic incubations were conducted with four different sludge samples. The effects of temperature and sludge source on VOSC release patterns were assessed. It was found that an unidentified DMS generation mechanism was triggered in the mesophilic incubation of activated sludge in which iron was dosed. To apply the model which was established based on methionine degradation in sludge digestion, hydrolysis of particulate materials was incorporated. The model simulations for VOSC behavior in thermophilic batch incubation were able to represent the observed VOSC releases. However, the simulations could not well fit the observed VOSC release at 35 ° because the model did not include the unidentified DMS generation mechanism. Application of the model to bench-scale digesters was lack-of-fit. It may have been due to imprecise estimation of the degradable sulfur in the feed sludge. In addition, in the batch tests and digester operation the ratios of the raw and digested sludge were different. This might have resulted in different concentrations of the microorganisms which mediated biotransformations and hence resulted in different kinetic constants.

Anaerobic membrane bioreactors may provide a sustainable technological solution for digestion of waste activated sludge due to their capacity to achieve substantial volatile solids (VS) destruction and positive energy balances with reduced digester volumes. However, membrane integrated anaerobic systems may have limitations that are imposed by membrane fouling and a decrease in biomass activity due to possible exposure of biomass to high shear conditions. This study characterised bioprocess and membrane performance under varying conditions, identified foulant type and origin and mechanism of fouling, and developed fouling control strategies by using low cross flow velocity and pressure anaerobic membrane systems. The study employed a pilot scale anaerobic digester integrated with negative and neutral tubular membranes; pilot and bench scale control digesters supported with bench scale filtration unit parametric studies. The membranes were polyvinylidene difluoride based with an average pore size of 0.02 micron and were operated at a constant cross flow velocity of 1 ms-1 and constant trans-membrane pressure of 30 kPa. Four operating conditions consisting of different combinations of HRT and SRT were evaluated. By integrating membranes into the digesters it was possible to simultaneously enhance digestion and increase throughput of the digesters without affecting its performance. The anaerobic membrane digester showed 48-49% volatile solids destruction at 30 days SRT under conventional and higher loadings of 1.2±0.4 and 2.1±0.6 kg COD m-3day-1. This was a 100% increase in performance compared to a control digester subjected to higher loading. This result was supported by the associated specific methane generation. The control digesters operated at a relatively higher SRT showed comparable VS destruction and gas generation to the anaerobic membrane running at a similar SRT. However the extra gas generated didn’t compensate heat required to maintain larger volume of the digester. In case of anaerobic membrane digesters due to the high rate feeding, increase biogas production and co-thickening, the energy balance increased by 144 and 200% under conventional and higher loading conditions respectively. Characterization of membrane performance showed that the average sustainable flux was 23.2±0.4 and 14.8±0.4 LMH during HRT-SRTs of 15-30 and 7-15 days respectively. The critical fluxes were in the range of 30-40, 16-17 and 20-22 LM-2H-1 during HRT-SRTs of 15-30, 7-30 and 7-15 days respectively. The decline in membrane performance at a higher loading was associated with the formation of cake layers on the membrane surface that led to reversible fouling. The additional decline in performance at extended SRT was attributed to irreversible fouling. The colloidal fraction of the sludge showed an overall higher fouling propensity during the long term pilot studies and short term filtration tests. The suspended solids fraction of the sludge showed a positive impact at concentration below 15 g/L but resulted in a decrease of membrane performance at higher concentrations. Further studies of foulant origin through a series of microscopic, membrane cleaning and sludge characterization studies showed that the colloidal proteins, soluble carbohydrates and inorganic materials such as iron, calcium and sulfur and their interaction to have a significant impact on membrane fouling. To control anaerobic membrane fouling by the digested sludge, integration of membrane relaxation techniques in the filtration cycle were found effective. By incorporating a unique relaxation technique to tubular membranes, it was possible to increase the sustainable flux to 29.2±1.8 and 34.5±2.5 LM-2H-1 for neutral and negative membranes during 15-30 HRT-SRT process condition. Addition of cationic polymers and sequential mechanical-citric acid membrane cleaning, that targeted both reversible and irreversible fouling was also found effective.

Copper is one of the most important trace elements in ruminant nutrition. Its deficiency causes certain pathologies that can be cured by supplementation, by either five ("inorganic") or complexed ("chelated") forms. With the objective of being able to quantitatively compare the distribution of copper between the two forms of supplements, the speciation of copper in ruminant fluids was studied here. For this study, copper lysine supplement was used. It was necessary to first study the acid-base and complexation chemistry of lysine with copper (II). In addition, the complexation chemistry of glycine and histidine, were investigated. Mass balance equations were used to describe the distribution of copper (II) amongst different ligands. The results of the distribution of copper (II) ions in McDougall's solution (a simulated form of bovine saliva), indicate no significant differences in the distribution of copper using the different form of supplements. 1H NMR was used to validate the results from the computer model. Using a combination of the results from the saliva simulation model and the chemical shifts from the NMR studies, the chemical shift changes that would accompany the addition of copper (II) to McDougall's solution were predicted. Results from the models do not show any appreciable differences from experimental values. Rumen samples were collected. Important peaks in the 1H NMR spectrum were assigned. The spectrum indicated that acetic acid, resulting from the fermentation in the rumen, was a good probe for monitoring the speciation pattern. Speciation calculation indicated that the bulk of the copper would be bound to ammonia in the rumen. Changes in chemical shifts that result from the introduction of copper (II) to the rumen contents were predicted. Results were compared with experimental values. Agreement between the two sets of results was found to be satisfactory. The study shows that any advantages that result from the use of copper lysine supplement are not as a result of its remaining intact. Though metal bioavailabilities are hard to predict this approach could help better our understanding of this process. The methods developed here could be extended to other metal complexation problems in biological fluids. (Abstract shortened by UMI.)

This study was conducted to determine the effect of forage CP level on intake and digestion of Coastal bermudagrass hay by horses. Four cecally fistulated geldings were used in a 4 x 4 Latin square design with four treatments and four periods. Horses were fed one of four Coastal bermudagrass hays consisting of 7, 10, 13, or 16% CP during each of the 4 15-d periods. Intake and apparent digestibility were determined for each horse at the end of each period by total fecal collection. In addition, cecal fluid and blood samples were collected from each horse on the last day of each period for determination of cecal ammonia, cecal pH, plasma urea nitrogen, and plasma glucose concentrations. Crude protein concentration of Coastal bermudagrass hay influenced equine intake and digestion. Increasing CP concentration linearly increased digestible OM intake (DOMI) from 3.79 to 5.98 kg/d for 7 and 16% CP hay, respectively (P = 0.04). Furthermore, as forage CP level increased, CP intake increased linearly (P < 0.01). Forage CP level had no effect on forage DM intake. Quadratic effects (P less than or equal to 0.05) were observed for forage OM, NDF, ADF, and digestible energy. Overall digestibility was lowest for the 7% CP hay and highest for the 10% CP hay. Cecal pH remained above 6.62 irrespective of treatment and time, indicating that cecal pH was suitable for microbial growth. As forage CP level increased, cecal ammonia concentration increased linearly from 0.03 mM for the 7% to 1.74 mM for the 15% CP hay (P < 0.01). Concentration of plasma glucose also linearly increased (P = 0.04) from 68.77 to 73.68 mg/dL as CP concentration increased from 7% to 16% CP. Plasma urea nitrogen exhibited a quadratic effect as concentration increased (P < 0.01) from 4.34 to 5.61 mM for the 7 and 16% CP hays, respectively.

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­^¤åºK­n Multiplex PCR amplification of 16S rRNA gene¡BvirA¡Btpl¡Band H1d genes was developed enabling simultaneous detection in Escherichia coli¡Aan indicator of fecal contamination and food-borne microbial pathogens¡AShigella flexneri¡BCitrobacter freundii¡BSalmonella typhi¡BVibrio cholerae¡BVibrio parahaemolyticus¡Band Staphylococcus aureus¡CEach of the nine pairs of oligonucleotide primers was found to support PCR amplifications of only its targeted gene¡CThe optimized multiplex PCR reaction utilized a primer annealing temperature of 59 ¢Jand used agarose gel electrophoresis for detection of the PCR-amplified products¡CSelection of appropriate target genes¡Boligonucleotide primers ¡BPCR reaction¡Band cycling parameters resulted in the amplification of four target genes simultaneously in a single PCR reaction with the sensitivity of detection was 102 CFU after 32 cycles¡CMultiplex PCR amplification followed by differential PCR for E. coli / Shigella¡A and Citrobacter / Salmonella¡Asequenced for the PCR-amplified products of 16S rRNA gene of the seven pathogens in this study¡Aand used restriction endonuclease AfaI to confirm the PCR-amplified products of V. cholerae¡AV. parahaemolyticus and Staphylococcus aureus¡Ahas been shown to be an sensitive¡Aspecific¡Aand rapid method to detect food-borne bacterial pathogens¡C

Detection trace compound from human serum by matrix-assited laser desorption ionization mass spectrometry and second dimensional gel ectrophoresis

Plants contain a host of secondary metabolites that may be of dietary use to man. A comprehensive approach to plant-based nutrition would include investigating all aspects of a nutrient, from creation through storage and consumption. Here, experiments address each of these facets for a group of important antioxidant and pigment compounds, the carotenoids. The carotenoid biosynthetic pathway regulatory mechanisms leading to lycopene accumulation are well defined in the model fruit, tomato. Those leading to accumulation of other carotenoids and flesh colors, however, are poorly understood. The variety of flesh colors available in watermelon fruit (red, orange, salmon yellow, and canary yellow) makes it an ideal candidate for investigating the regulation of the full pathway. Carotenoid accumulation was measured in ten watermelon varieties, representing the four flesh colors and three ploidy levels, throughout fruit maturation. It was found that the putative regulatory mechanisms controlling lycopene accumulation in red-fleshed fruit may be applied in a generalized fashion to each flesh color in respect to the major carotenoid accumulated at maturity. Additionally, triploid varieties were generally found to have higher accumulation levels than diploids, and tetraploids were intermediate to both. In addition to total carotenoid content, many factors are important in determining perceived benefit. Several of these factors involve components of the food matrix, cellular and subcellular species-specific characteristics of the food which act as barriers to nutrient release. Cell size, cell wall, and chromoplast (the carotenoid storage organelle) characteristics were observed in nine fruits and vegetables using light and transmission electron microscopy. Watermelon, tomato, and melon have the largest cells. Sweet potato, butternut squash, carrot, and mango have the most fibrous cell walls; mango and papaya additionally had the thickest walls. Chromoplast globular, tubular, crystalline, and membranous substructures were described for each food. These food matrix factors may be related to differences in carotenoid bioaccessibility between food sources. An in vitro digestion experiment was used to determine carotenoid bioaccessibility for each of these foods. Per serving, grapefruit yielded the most lycopene while carrot gave the most ?-carotene, ?-carotene, lutein, and phytoene, and mango proved a good source of violaxanthin.

<p>Stockholm Water is a water and sewage company with Henriksdal as one of two wastewater treatment plants (WWTPs). At Henriksdal wastewater sludge generated in the wastewater treatment process is digested which generate biogas; a mixture of mainly methane and carbon dioxide. If purified to methane content of 96 - 98 % this gas is called biomethane.</p><p>Biogasmax is a project aiming to reduce the use of fossile fuels in Europe by providing that biogas is a good technical, economical and environmental alternative as vehicle fuel. The specific aim for Stockholm Water is to increase the biogas production at the existing plant in Henriksdal. Enzymatic treatment of wastewater sludge is an innovative technique earlier proofed to increase the biogas production from wastewater sludge with up to 60 %. The enzyme activity is in turn proven to significantly increase in the presence of a cation binding agent.</p><p>One aim with this thesis was to investigate if the sludge from Henriksdal wastewater treatment process at all is affected of enzymatic treatment in presence of a cation binding agent since this has shown to have some significance. The chemical oxygen demand (COD) was measured in the liquid phase of sludge after treatment and used as a measurement of treatment effect. Another aim of this thesis was to look into the possibility to increase the methane production from sludge at Henriksdal WWTP. This was investigated through batch laboratory digestion tests.</p><p>The sludge from Henriksdal WWTP was shown to be a good substrate for the enzymes added. COD in the liquid phase was increased with 17 – 32 % depending on the dose of enzymes and sodium citrate added. Digestion of sludge with a total addition of 18.6 mg enzymes per 1 g total solids (TS) and a concentration of 5 mM sodium citrate increased the methane production with almost 18 % compared to untreated sludge. This equals an increase of 18.3 % when converted to represent a totally blended and continuous digestion chamber at Henriksdal WWTP. The increased methane production also results in a sludge reduction out from the digestion chambers. The increased methane production and sludge reduction though does not fulfil the increased costs for the enzymes and sodium citrate applied. These doses must be decreased and the costs for both enzymes and sodium citrate must be reduced for this technique to be economically feasible in a full scale operation.</p>