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Effect of Alkaline Pretreatment on Anaerobic Digestion of Organic Fraction of Municipal Solid WasteAlqaralleh, Rania Mona 27 March 2012 (has links)
The rapid accumulation of municipal solid waste is a significant environmental concern in our rapidly growing world. Due to its low cost, high energy recovery and limited environmental impact anaerobic digestion (AD) is a promising solution for stabilizing the organic fraction of municipal solid waste (OFMSW). Hydrolysis is often the rate-limiting step during AD of wastes with high solid content; this step can be accelerated by pretreatment of waste prior to AD.
This thesis presents the results of alkaline pretreatment of OFMSW using NaOH and KOH. Four different pH levels 10, 11, 12 and 13 at two temperatures 23±1°C and 80±1°C were examined to study the effects of the pretreatment on (i) enhancing the solubility of the organic fraction of the waste, and (ii) enhancing the AD process and the biogas production. The effects on solubility were investigated by measuring changes in the soluble COD (SCOD) concentrations of pretreated wastes and the enhanced AD was investigated by measuring volatile solids (VS) destruction, total COD (TCOD) and SCOD removal in addition to biogas and methane production using biochemical methane potential (BMP) assay and semi-continuous laboratory reactor experiments. Pretreatment at pH 13 at 80±1°C demonstrated the maximum solubility for both NaOH and KOH pretreated samples; however the BMP analysis demonstrated that pretreatment at pH 12 at 23±1°C showed the greatest biogas yield relative to the removed VS for both chemicals. Thus pretreatment at pH 12 at 23±1°C using NaOH and KOH were examined using semi-continuous reactors at three different HRTs: 10, 15 and 20 days. Pretreatment demonstrated a significant improvement in the AD performance at SRTs of 10 and 15 days.
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The effect of endophytic bacteria on the alfalfa-<i>sinorhizobium</i> symbiosisAl Otaibi, Fahad Nasser 23 July 2010 (has links)
Although plant growth-promoting rhizobacteria (PGPR) have shown tremendous potential to be used as inoculants for many agricultural crops, they may not survive severe environmental conditions in the field which could limit their large scale applications. Endophytic bacteria, which can be recovered from inside plant tissues such as roots, stems and leaves, might overcome this limitation due to their unique ecological niche inside plant roots where they are sheltered from external environmental disturbances. Some of these bacterial endophytes have beneficial effects on their host plants and stimulate plant growth or reduce disease symptoms, apparently through mechanisms that are similar to those proposed for PGPR. The objective of this study was to assess a collection of endophytic bacteria for PGPR traits and potential use to enhance the rhizobial-legume symbiosis. Forty isolates obtained from the roots of various plants were identified by fatty acid methyl ester (FAME) analysis, and 16S RNA gene sequencing analysis. The majority (i.e., 75%) were identified as Pseudomonas species. Many of these isolates were able to solubilize phosphate, produce indole-3-acetic acid (IAA), produce aminocyclopropane-1-carboxylic acid (ACC) deaminase, synthesize siderophores and show antagonistic activities against several soil-borne plant pathogenic fungi under in vitro conditions. Selected isolates were further evaluated for the ability to enhance plant growth and nodulation of alfalfa when co-inoculated with Sinorhizobium meliloti under growth chamber conditions using growth pouch and potted soil assays. Results revealed that P. putida strain EB EE 4-25, P. syringae strain EB XDE 4-48, and P. fluorescens strain EB EE 2-23 significantly increased shoot length, root length, enhanced nodulation and increased lateral root formation of alfalfa plants in growth pouch and potted soil assays when co-inoculated with S. meliloti strain P102 compared to plants inoculated with S. meliloti strain P102 alone. Results also suggested that expression of one or more of the mechanisms, such as solubilization of phosphate, production of IAA, production of siderophores, and ACC deaminase production might have played a role in the enhancement of the alfalfa- Sinorhizobium symbiosis. These results suggest that some endophytic bacterial strains may be useful as biofertilizers and/or biocontrol agents in sustainable agricultural practices.
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Pore-scale analysis of solubilization and mobilization of trapped NAPL blobs in porous mediaYoon, Sun Hee 02 June 2009 (has links)
NAPL (non-aqueous phase liquid) blob mobilization and solubilization models were developed to predict residual NAPL fate and describe flow dynamics of various displacing phases (water and surfactant foam). The models were achieved by pore-scale mass and force balances and were focused on the understanding of the physico-chemical interactions between NAPL blobs and the displacing phases. The pore-level mass balance indicated changes in NAPL saturation instead of mass reduction occurring with blob solubilization. The force balance was used to explain the complex flow configurations among NAPL blobs and the displacing phases. Some factors such as the wettability and the spreading/entering coefficients were useful in determining flow configurations. From the models developed in this study, dimensional analysis was performed to identify NAPL blob motion during water or surfactant foam flooding. In non-dimensionalized forms, a Trapping number employed as an indicator of blob displacement performance was modified to quantify the onset of blob mobilization. Its value for water flooding was nearly 2-3 orders of magnitude greater than that of surfactant foam flooding. Next, to investigate the blob flow regime in porous media, a blob velocity was computed. Regardless of the displacing phases, a blob’s velocity increased with increasing blob sizes after commencement of blob motion, and the velocity of DNAPL (dense non-aqueous phase liquid) blobs was greater than that of LNAPL (light non-aqueous phase liquid) blobs. From this investigation, it is expected that the pore-scale solubilization and mobilization models would provide better understanding leading to a predictive capability for the flow behavior of NAPL blobs removed by various displacing phases in a porous medium. Additionally, the models based on newly approached concepts and modified governing equations would be useful in conceptualization, as well as the model prediction of other immiscible or miscible fluids flowing through a porous medium. Further, the models developed in our study would be a useful contribution to the study of small-scale contaminants or substances such as particle and bacterial transport in porous media.
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New correlation for predicting the best surfactant and co-solvent structures to evaluate for chemical EORChang, Leonard Yujya 03 February 2015 (has links)
The focus of this study was the development of an improved correlation that more accurately quantifies the relationships between optimum salinity, optimum solubilization ratios, chemical formulation variables such as surfactant and co-solvent structures, and the EACN. Entrained in this study are improved correlations for co-solvent partition coefficients and correlations for the optimum salinity and solubilization ratio with EACN. Several trends in the oil-water partition coefficient were observed with the alcohol type (IBA and phenol), the number of ethylene oxide groups in the co-solvent, the EACN of the oil, temperature, and salinity. New EACN measurements were made using optimized formulations containing various combinations of primary surfactants, co-surfactants, co-solvents and alkali. The new EACN measurements ranged from 11.3 to 21.1. These new data significantly expand the total number of reliable EACN values available to understand and correlate chemical EOR formulation results. An improved correlation that more accurately quantifies the relationship between surfactant structure, co-solvents, oil, temperature, and optimum salinity was developed using a new and much larger high quality formulation dataset now available from studies done in recent years in the Center for Petroleum and Geosystems Engineering at the University of Texas at Austin. The correlation is useful for understanding the now very large number of microemulsion phase behavior experiments as well as the uncertainties associated with these data, and for suggesting new chemical structures to develop and test. / text
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Effect of Alkaline Pretreatment on Anaerobic Digestion of Organic Fraction of Municipal Solid WasteAlqaralleh, Rania Mona 27 March 2012 (has links)
The rapid accumulation of municipal solid waste is a significant environmental concern in our rapidly growing world. Due to its low cost, high energy recovery and limited environmental impact anaerobic digestion (AD) is a promising solution for stabilizing the organic fraction of municipal solid waste (OFMSW). Hydrolysis is often the rate-limiting step during AD of wastes with high solid content; this step can be accelerated by pretreatment of waste prior to AD.
This thesis presents the results of alkaline pretreatment of OFMSW using NaOH and KOH. Four different pH levels 10, 11, 12 and 13 at two temperatures 23±1°C and 80±1°C were examined to study the effects of the pretreatment on (i) enhancing the solubility of the organic fraction of the waste, and (ii) enhancing the AD process and the biogas production. The effects on solubility were investigated by measuring changes in the soluble COD (SCOD) concentrations of pretreated wastes and the enhanced AD was investigated by measuring volatile solids (VS) destruction, total COD (TCOD) and SCOD removal in addition to biogas and methane production using biochemical methane potential (BMP) assay and semi-continuous laboratory reactor experiments. Pretreatment at pH 13 at 80±1°C demonstrated the maximum solubility for both NaOH and KOH pretreated samples; however the BMP analysis demonstrated that pretreatment at pH 12 at 23±1°C showed the greatest biogas yield relative to the removed VS for both chemicals. Thus pretreatment at pH 12 at 23±1°C using NaOH and KOH were examined using semi-continuous reactors at three different HRTs: 10, 15 and 20 days. Pretreatment demonstrated a significant improvement in the AD performance at SRTs of 10 and 15 days.
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Inoculação de Pseudomonas via semente e eficiência agronômica de fosfatos na cultura do milho / Inoculation of Pseudomonas via seed and agronomic efficiency of phosphates in maizeZamariolli, Luís Eduardo Rissato [UNESP] 09 September 2016 (has links)
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Previous issue date: 2016-09-09 / Os solos de regiões tropicais necessitam da aplicação de altas doses de fertilizantes fosfatados, cuja utilização é limitada pelo custo. Fosfatos naturais podem ser uma alternativa interessante, porém apresentam baixa solubilidade. A utilização de microorganismos solubilizadores pode aumentar a solubilidade desses fosfatos. O objetivo do trabalho foi avaliar os efeitos da inoculação das bactérias Pseudomonas fluorescens e Pseudomonas SB via semente, associadas a fontes de baixa solubilidade de fósforo, no desenvolvimento e componentes de produtividade do milho. Foram implantados dois experimentos de campo, em um Argissolo vermelho amarelo distrófico arênico no município de Pompéia (SP), na safra 2014. No experimento 1 o delineamento experimental utilizado foi o de blocos casualizados, com quatro repetições, num esquema fatorial 3 x 3 +1, envolvendo fontes de fósforo (sem fósforo, fosfato de Arad, apatita), microorganismos (sem inoculação, Pseudomonas fluorescens, Pseudomonas SB) e um tratamento adicional (superfosfato triplo), com solo corrigido com calcário. No experimento 2, o delineamento experimental foi o mesmo, num esquema fatorial 2 x 3, envolvendo fontes de fósforo (apatita, fosfato de Arad) e microorganismos (sem inoculação, Pseudomonas fluorescens, Pseudomonas SB), com o solo sem correção de acidez. As variáveis analisadas foram: teor de fósforo na folha, altura da planta e diâmetro do colmo (no florescimento), comprimento da espiga, diâmetro da espiga, número de fileira de grãos por espiga, número de grãos por fileira, número de grãos por espiga, massa de 100 grãos, produtividade, teor de fósforo no grão e índice de eficiência agronômica dos fosfatos. No experimento 1, a inoculação não promoveu alterações na altura da planta e diâmetro do colmo. Para teor de fósforo na folha a inoculação com Pseudomonas SB promoveu aumento no teor de fósforo foliar quando não foi utilizada nenhuma fonte de fósforo. Para as variáveis de produção, a inoculação com Pseudomonas fluorescens aumentou o diâmetro da espiga e número de fileira de grãos quando associada com apatita e o número de grãos por espiga. A inoculação com Pseudomonas fluorescens aumentou a produtividade em relação a inoculação com Pseudomonas SB, porém não diferiu das plantas que não receberam inoculação. A associação de Pseudomonas fluorescens com apatita e fosfato de Arad aumentou o teor de fósforo no grão. No experimento 2, a inoculação com Pseudomonas SB proporcionou um decréscimo na altura da planta e diâmetro do colmo em relação às plantas inoculadas com Pseudomonas fluorescens e aumento no teor de fósforo no grão em relação às inoculadas com Pseudomonas fluorescens e não inoculadas e adubadas com apatita. / Tropical soils require the application of high doses of phosphate fertilizers, whichusageis limited by cost.Natural phosphates can be an interesting alternative, but exhibit low solubility.The use of solubilizing microorganisms can increase the solubility of these phosphates.The objective of this paper wastoevaluate the effects of Pseudomonas fluorescensandPseudomonas SBbacteriainoculationon seed, associated with sources of low solubilityphosphorus, on the development and productivity components of maize.Two field experiments were conducted in a yellow Paleudalf in the city of Pompeia (SP), in 2014. In experiment 1 the experimental design was a randomized complete block design with four replications, in a factorial 3 x 3 + 1, involving phosphorus sources (without phosphorus, Arad phosphate, apatite), microorganisms (without inoculation,Pseudomonas fluorescens,Pseudomonas SB)and an additional treatment (triple superphosphate) with soil acidity adjusted with lime.In experiment 2, the experimental design was the same, in a factorial 2 x 3, involving phosphorus sources (apatite, Arad phosphate) and microorganisms (without inoculation,Pseudomonas fluorescens,Pseudomonas SB),without soil acidity adjustment.The variables analyzed were: phosphorus content in the leaf, the plant height and stem diameter (at flowering), ear length, ear diameter, row number of grains per ear, number of kernels per row, number of grains per ear, weight of 100 grains, productivity, phosphorus content in grain and phosphate agronomic efficiency.In experiment 1, inoculation did not change the height of the plant and stem diameter.For phosphorus content in the leaf, the inoculation with Pseudomonas SB promoted increase in leaf phosphorus content when it was not used any source of phosphorus.For production variables, inoculation withPseudomonas fluorescensincreased the ear diameter and row number of grains when associated with apatite and the number of grains per ear.Inoculation withPseudomonas fluorescensincreased productivity compared to inoculation withPseudomonas SB,but did not differ from plants that received no inoculation.Pseudomonas fluorescensassociation with apatite and Arad phosphate increased the phosphorus content in the grain.In experiment 2, inoculation withPseudomonas SBprovided a decrease in plant height and stem diameter compared to plants inoculated withPseudomonas fluorescensand increased phosphorus content in the grain compared to plants inoculated with Pseudomonas fluorescens and not inoculated and fertilized with apatite.
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Effect of Alkaline Pretreatment on Anaerobic Digestion of Organic Fraction of Municipal Solid WasteAlqaralleh, Rania Mona January 2012 (has links)
The rapid accumulation of municipal solid waste is a significant environmental concern in our rapidly growing world. Due to its low cost, high energy recovery and limited environmental impact anaerobic digestion (AD) is a promising solution for stabilizing the organic fraction of municipal solid waste (OFMSW). Hydrolysis is often the rate-limiting step during AD of wastes with high solid content; this step can be accelerated by pretreatment of waste prior to AD.
This thesis presents the results of alkaline pretreatment of OFMSW using NaOH and KOH. Four different pH levels 10, 11, 12 and 13 at two temperatures 23±1°C and 80±1°C were examined to study the effects of the pretreatment on (i) enhancing the solubility of the organic fraction of the waste, and (ii) enhancing the AD process and the biogas production. The effects on solubility were investigated by measuring changes in the soluble COD (SCOD) concentrations of pretreated wastes and the enhanced AD was investigated by measuring volatile solids (VS) destruction, total COD (TCOD) and SCOD removal in addition to biogas and methane production using biochemical methane potential (BMP) assay and semi-continuous laboratory reactor experiments. Pretreatment at pH 13 at 80±1°C demonstrated the maximum solubility for both NaOH and KOH pretreated samples; however the BMP analysis demonstrated that pretreatment at pH 12 at 23±1°C showed the greatest biogas yield relative to the removed VS for both chemicals. Thus pretreatment at pH 12 at 23±1°C using NaOH and KOH were examined using semi-continuous reactors at three different HRTs: 10, 15 and 20 days. Pretreatment demonstrated a significant improvement in the AD performance at SRTs of 10 and 15 days.
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The Effect of Pretreatment Methods on Methane Yield and Nutrient Solubilization During Anaerobic Digestion of MicroalgaeHill, Alexander Scott 01 June 2014 (has links) (PDF)
Microalgal biomass is a candidate feedstock for biofuel production. To improve the sustainability of algae biofuel production, following biofuel recovery, the biomass nutrients should be recycled for additional algae growth. Anaerobic digestion of algae or oil-extracted algae is a means of recovering carbon and other nutrients, while offsetting algae production electricity demand. The major limiting factor in microalgae digestion is the low biodegradability of the cell walls. In the present study, various pretreatment technologies were tested at bench scale for their ability to improve raw, non-lipid-extracted algae biodegradability, which was assessed in terms of methane yield, volatile solids destruction, and solubilization of N, P, and K. The microalgae were harvested by sedimentation from outdoor wastewater-fed raceways ponds operated in coastal southern California. Four pretreatment methods (sonication, high-pressure homogenization, autoclaving, and boiling) were used on the algae slurries, each followed by batch anaerobic digestion (40 days at 35oC). Biomass sonication for 10 minutes showed the highest methane yield of 0.315 L CH4/ g VSIN, which is a 28% increase over the untreated control. Conversely, autoclaved algae slurry inhibited methane production (0.200 vs. 0.228 L CH4/ g VSIN for the treatment and control). A preliminary energy balance indicated that none of the pretreatments led to a net increase in energy conversion to biomethane. However, pretreatment did increase the initial N and P solubilization rates, but, after digestion, the ultimate N and P solubilization was nearly the same among the treatments and controls. After 40 days of digestion, solubilization of N, P, and K reached, respectively, 50-60% of average total Kjeldahl N, 40-50% of average total P, and 80-90% of average total K. Descriptive first-order models of solubilization were developed. Overall, certain pretreatments marginally improved methane yield and nutrient solubilization rate, which cast doubt on the efficacy of, or even the need for, algae biomass pretreatment prior to anaerobic digestion.
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Evaluation of Solubilization with Thermal Hydrolysis Process of Municipal BiosolidsLu, Hung-Wei 18 September 2014 (has links)
The increased demand for advanced sludge stabilization in wastewater treatment facilities over the past decade has led to the implementation of various pretreatment techniques prior to anaerobic digestion. In an attempt to reduce sludge volumes and improve sludge conditioning properties, the use of thermal hydrolysis process before anaerobic digestion has been adopted with an increase in solids destruction, COD removal, and methane gas. In this study, the evaluation of thermal hydrolysis process as a viable pretreatment strategy to anaerobic digestion has been conducted in order to assess its capacity for solids solubilization. Solubilization experiments were conducted at temperatures ranging from 130 to 170℃ and reaction times between 10 and 60 min. Anaerobic biogas production by thermally pre-treated sludge was carried out through a mesophilic anaerobic digester. The results showed that solids solubilization increased with increases in temperature and time, while temperatures above 160℃ for 30 min strongly affected the sludge characteristics. Ammonia production via deamination by thermal hydrolysis was less significant than protein solubilization at a temperature of 170℃. Both protein and carbohydrate solubilization were more dependent on temperature than reaction time. The enhancement of the biogas production was achieved with increases in temperature as pretreatment of 170℃ yielded 20% more biogas than at 130℃. However, it seems the enhancement was linked to the initial biodegradability of the sludge. / Master of Science
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Fluorescence Labeling of Surface Species as an Efficient Tool for Detection, Identification and Quantification of Oxygen Containing Functionalities on Carbon MaterialsDementev, Nikolay January 2011 (has links)
1. Fluorescence labeling and quantification of oxygen-containing functionalities on the surfaces of single walled and multi-walled carbon nanotubes. Nearly all applications of nanotubes (CNTs), from nanoelectronics to composites, require knowledge of the type and concentration of functionalities on the surface of the material. None of the methods conventionally used to characterize CNTs, such as Raman spectroscopy, IR spectroscopy, UV-VIS-NIR spectroscopy, and X-ray photoelectron spectroscopy, provide selectivity in identification together with sensitivity in quantification. Fluorescence labeling of surface species (FLOSS) to identify and quantify oxygen containing functionalities on single-walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) provides a solution that is reported in this dissertation. The high selectivity of covalent attachment combined with the sensitivity of the fluorescence measurements, allowed us reliably determine concentrations of aldehyde (together with ketone), alcohol, and carboxylic functional groups on as-produced and acid treated SWCNTs. The detection limit is as low as ~ 0.5 % at (1 in every 200 carbon atoms).(You never established the lower limit clearly) 2. Purification of carbon nanotubes by dynamic oxidation in air. The outstanding mechanical and electronic properties of carbon nanotubes make them promising materials for use in different areas of nanotechnology. However, the presence of impurities in as-produced nanotubes has been a major obstacle toward their industrial scale applications. Amorphous and graphitic carbon, and catalytic metal particles are the major impurities in raw carbon nanotubes. Isothermal oxidation of as-produced carbon nanotubes, followed by acid treatment, is the most commonly used purification strategy. The thermal oxidation step eliminates carbonaceous impurities and the acid treatment decreases the metal content. Unfortunately, most of the existing oxidation procedures either do not destroy all carbonaceous impurities or partially destroy carbon nanotubes as well. In the dissertation, a novel purification protocol via dynamic oxidation of as-produced single-walled carbon nanotubes (SWCNT) is reported. In the new procedure, carbon nanotubes are exposed to a wide range of temperatures during the heating ramp. The results of the purification of arc-produced and laser vaporization grown SWCNT using dynamic oxidation are presented. Purity analysis of dynamically oxidized samples by UV-VIS-NIR and Raman spectroscopy, as well as transmission electron microscopy, explicitly demonstrate that dynamic oxidation enables obtaining undamaged carbon nanotubes almost free of carbonaceous impurities. 3. Surfactant- free method of solubilization of non-functionalized single-walled carbon nanotubes in common solvents. One of the major factors that hamper the extensive use of carbon nanotubes (CNTs) in large-scale applications are related to the poor purity of CNTs, and the weak dispersibility of CNTs in the most common solvents. The presence of substantial impurities (sometimes up to 80% wt.) in as-produced CNTs almost obliterates the unique properties of the material. Furthermore, the difficulties with solubilization of CNTs slow down the processability of the material in potential applications. A new one-step method of making pure single-walled carbon nanotubes (SWCNTs) via the sequence of sonication cycles is described in the dissertation. Hours long stable solutions of SWCNTs in acetone, methanol and isopropanol of concentrations as high as ~ 15 mg/L were prepared using the procedure. The results of UV-VIS-NIR, Raman and Transmission Electron Microscopy suggest that SWCNTs were not destroyed or damaged by purification and solubilization processes. A possible physico-chemical explanation of the solublization mechanism is discussed. / Chemistry
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