Two case studies are described where partially biodegraded petroleum residues were collected from the marine environment and analysed to investigate the changes in aromatic hydrocarbons with increasing biodegradation.The first of these studies, involved following the weathering of sea-floor residues from drilling discharges from an offshore petroleum exploration and production platform situated off the coast of North Western Australia. During operations, formation cuttings with adhering oil-based drilling muds were discharged into the ocean via a chute into approximately 125n1 of water, forming a substantial mound at the base of the platform. A suite of seabed sediments was collected from 16 sampling sites at various distances from the platform immediately following the cessation of drilling operations. The distribution of hydrocarbons in the sediment directly under tile cuttings chute was consistent with that found in drilling fluids formulated from a kerosene-like fluid. The samples from more remote sites exhibited the successive enhancement of an unresolved complex mixture relative to the n-alkanes, associated with tile presence of residues from petroleum biodegradation processes. In a subsequent sampling some three years later, a 10 cm core was retrieved from the cuttings pile and divided into 1 cm depth intervals. Samples within 6 cm of the surface of the cuttings pile contained biodegraded residues of the drilling mud, where the extent of biodegradation increased with decreasing proximity to the surface, most likely indicative of aerobic biodegradation. Biodegradation was less evident in the underlying sediments, where anaerobic conditions prevailed. / Analysis of the aromatic hydrocarbons in both sets of sediment extracts by using gas chromatography-mass spectrometry (GC-MS) revealed the successive depletion of alkylnaphthalenes, and due to the subtlety of changes in the extent of biodegradation, provided an excellent opportunity to examine the susceptibility of biodegradation towards the individual alkylnaphthalenes in the marine environment. Conventional GC-MS analysis of these mixtures is performed under chromatographic conditions where complete resolution of the mixture is not achieved and several isomers co-elute. The mass spectra of these co-eluting isomers may be so similar that one is unable to differentiate between them, and their abundance may therefore not be determined. Since each isomer has a unique infrared spectrum, however, the abundance of each individual isomer was determined by comparing the infrared spectrum of the co-eluting compounds with the spectrum of each of the isomers. To this end, techniques were developed for the application of direct-deposition gas chromatography - Fourier transform infrared spectroscopy (GCFTIR) to the analysis of the complex mixture of alkylnaphthalenes present in the petroleum. This technique was also extended to discriminate between individual alkylphenanthrene isomers, and to clarify the sorption behaviour of the dimethylphenanthrenes by mordenite molecular sieves. The identification of other compounds of geochemical significance in petroleum is also described. / Analyses of' the aromatic hydrocarbons in the contaminated sea-floor sediments using GC-FTIR enabled the unambiguous identification and quantification of each of the dimethylnaphthalene, trimethylnaphthalene and tetramethylnaphthalene isomers present in the samples, from which the relative extents of depletion of each with increasing extent of biodegradation were determined. It was apparent from the considerable differences in the observed susceptibility to biodegradation that a strong relationship exists between the compound structure and its susceptibility to biodegradation, with 1,6-disubstituted polymethylnaphthalenes being preferentially depleted relative to other isomers that lack this feature. The second case study involved tracking the fate (weathering) of hydrocarbons from an accidental release of condensate from a buried pipeline into intertidal coastal (mangrove) sediments in North Western Australia. Sediment samples were collected on nine occasions over a three-year period. Chemical analysis of the saturated and aromatic hydrocarbon components of the petroleum extracts revealed that both hydrocarbon fractions exhibited an increasingly biodegraded profile with increased residence time in the sediments. In a similar manner to the first case study, detailed analysis of the aromatic hydrocarbons using GC-FTIR techniques was performed to determine the depletion of individual alkylnaphthalene isomers with increasing extent of biodegradation. It was apparent that a relationship similar to that observed for the sea-floor sediments exists between the alkylnaphthalene structure and its susceptibility to biodegradation. / Changes in the distribution of methylphenanthrene and dimethylphenanthrene isomer mixtures were also studied and the susceptibility to biodegradation amongst these determined in a similar manner. These relative susceptibilities to biodegradation of the aromatic hydrocarbons were then related to the established hierarchy of susceptibilities of the saturated hydrocarbons, in effect providing a second parallel system for the assessment of the extent of biodegradation. Finally, a system of ratios calculated from the relative abundances of selected aromatic hydrocarbons was developed and used as indicators to differentiate between several crude oils that have been biodegraded to varying extents. These parameters also offer promise as indicators of multiple accumulation events in oil reservoirs where petroleum fluids biodegraded to differing extents are mixed.

The rate of removal of benzene, toluene, ethylbenzene and the xylene isomers (BTEX) from contaminated groundwater is needed to design remediation processes. Benzylsuccinic acid (BSA) and methyl-benzylsuccinic acid (methyl BSA) are unambiguous metabolites of anaerobic BTEX biodegradation. An analytical method for quantitative determination of BSA in groundwater samples was developed. Samples containing BSA and methyl BSA were extracted onto 0.5 g of styrene-divinylbenzene, eluted with ethyl acetate, and methylated with diazomethane. Gas chromatography coupled to mass spectrometry with electron impact ionization was used for separation and detection. The recovery from spiked 1 L groundwater samples was 88 to 100 %. The precision of the method, indicated by the relative standard error was ± 4% with a method detection limit of 0.2 μg/L. The method was then used to analyze samples from single-well push-pull tests conducted by injecting deuterated toluene and xylene into BTEX-contaminated wells in order to demonstrate in-situ biodegradation. Unambiguous evidence for deuterated toluene and xylene biodegradation was obtained with the observation of deuterated BSA and methyl BSA coupled with the utilization of nitrate presumably due to denitrification as terminal-electron-accepting process. Minimum first-order degradation rates for deuterated toluene estimated from formation of BSA were 0.0004 to 0.001 day⁻¹. Rates of methyl BSA formation were not calculated because methyl BSA, although detected, was not above the quantitation limit. Removal rates of deuterated toluene and o-xylene were not directly measurable because the rates were too low to measure significant changes in parent compound concentrations. Wells for which the formation of deuterated BSA and methyl BSA were observed had lower relative concentrations of toluene and xylenes relative to total BTEX than wells for which no deuterated BSA and methyl BSA were observed. Retardation factors for injected deuterated toluene and background toluene of 2 and 14, respectively, were obtained from push-pull tests conducted to determine toluene transport properties. Differences in retardation factors for injected and background toluene indicate differences between injected and background solute transport and is a topic that requires further study. / Graduation date: 2002

The goal of this research was to mathematically simulate the ability of bioaugmented microorganisms to aerobically cometabolize a mixture of chlorinated aliphatic hydrocarbon (CAH) compounds during in-situ treatment. Parameter values measured from laboratory experiments were applied to the transport model with biotransformation processes included. In laboratory microcosm studies, a butane-grown, enriched culture was inoculated in soil and groundwater microcosms and exposed to butane and several repeated additions of 1,1,1-trichloroethane (TCA), 1,1-dichioroethylene (DCE), and 1,1-dichloroethane (DCA) at aqueous concentrations of 200 ��g/L, 100 ��g/L, and 200 ��g/L, respectively. Microcosms containing the bioaugmented culture showed 1,1-DCE to be rapidly transformed, followed by slower transformation of 1,1-DCA and 1,1,1-TCA. After most of the butane had been consumed, transformation of these latter CAHs increased, indicating strong inhibition by butane. With repeat biostimulations, butane utilization and CAH transformation accelerated, showing the increase in cell mass. These trends occurred in two sets of microcosm triplicates. No stimulation was observed in controls containing only the microorganisms indigenous to Moffett Field, confirming that activity seen in the bioaugmented microcosms was a result of the introduced culture's activity. Batch reactor results were simulated using differential equations accounting for Michaelis-Menten kinetics, transformation product toxicity, substrate inhibition, butane utilization, and CAH transformation. The equations were solved simultaneously by Runge-Kutta numerical integration with parameter values adjusted to match the microcosm data. Having defined the parameter values from laboratory studies, the biotransformation model was combined with 1-D advective-dispersive transport to simulate behavior of the culture and the substrates within an aquifer. The model was used to simulate the results of field studies where the butane-utilizing culture was injected into a 7 m subsurface test site and exposed to alternating pulses of oxygen and butane, along with the contaminant mixture studied in the microcosms. Monitoring wells spaced at 1 m, 2.2 m, and 4 m from the injection well allowed temporal and spatial changes in substrate concentrations to be determined. Model simulations of the field demonstration were performed to determine how well the biotransformation/solute transport model predicted actual field observations. To model the influences of solute transport, simulations were run and compared to breakthrough test data (prior to bioaugmentation) to determine the values for advection, dispersion, and sorption. The simulations showed that flow ranged from 1.0 to 1.5 m��/day (average linear velocity of 2.0 m/day). Dispersion was estimated as 0.31 m��/day. Sediment sorption partitioning coefficients for 1,1-DCE, 1,1-DCA, and 1,1,1-TCA were determined to be approximately 0.69, 0.50, and 0.50 L/kg, respectively. It was more difficult to determine an appropriate value of the mass transfer rate coefficient for non-equilibrium sorption, so simulations were run to compare equilibrium and non-equilibrium cases. Results indicated that non-equilibrium (with mass transfer rate coefficient of approximately 0.2 day�����) better simulated the field data. Using these transport parameters and the biotransformation values determined from the laboratory experiments, simulations of the field data showed that the model was capable of simulating the effects of transformation rates, butane inhibition, and 1,1-DCE product toxicity. Simulations for varying pulsing cycles and durations provided possible improvements for future field demonstrations. Overall, this work proved that there is good potential in extrapolating laboratory based kinetics to simulate biotransformation at a field scale. Although the complexity of such systems makes modeling difficult, such simulations are useful in understanding and interpreting field data. / Graduation date: 2003

Laboratory scale microcosm studies were conducted using site specific groundwater and aquifer solids to assess the feasibility of stimulating indigenous microorganisms in-situ to biologically transform Trichloroethylene (TCE) and its lesser chlorinated daughter products dichloroethylene (DCE) and vinyl chloride (VC). Three different treatments were conducted to determine the best approach for biologically remediating TCE under site specific conditions: anaerobic reductive dechlorination, aerobic cometabolism and sequential anaerobic/aerobic stimulation. Studies were conducted in batch serum bottles containing aquifer solids, groundwater and a gas headspace. Long-term (302 days) TCE anaerobic reductive dechlorination studies compared lactate, benzoate and methanol as potential anaerobic substrates. Site characteristic sulfate concentrations in the microcosms averaged 1,297 mg/L and TCE was added to levels of 2.3 mg/L. Substrates were added at one and a half times the stoichiometric electron equivalent of sulfate. Nutrient addition and bioaugmentation were also studied. Both benzoate and lactate stimulated systems achieved complete sulfate-reduction and prolonged dechlorination of TCE to VC and ethylene. Dechlorination was initiated between 15 to 20 days following lactate utilization and sulfate-reduction in the presence of approximately 300 mg/L sulfate. Benzoate amended microcosms did not initiate dechlorination until 120 to 160 days following the complete removal of available sulfate. After 302 days of incubation lactate and benzoate amended microcosms completely transformed TCE to VC with 7 to 15% converted to ethylene. Re-additions of TCE into both systems resulted in its rapid transformation to VC. The dechlorination of VC to ethylene was very slow and appeared to be dependent on VC concentration. Hydrogen addition at 10����� and 10������ atmospheres had no effect on the transformation of VC. Rapid methanol utilization resulted in its nearly stoichiometric conversion to methane and carbon dioxide without significant sulfate-reduction or dechlorination occurring. Nutrient addition slightly enhanced dehalogenation with lactate but inhibited it with benzoate. Bioaugmentation with a TCE dechlorinating culture from a previous benzoate amended Point Mugu microcosm effectively decreased lag-times and increased overall dechlorination. Aerobic cometabolism studies evaluated methane, phenol and propane as cometabolic growth substrates. Methane and phenol amended microcosms were able to remove only 50 to 60% of the added TCE after four stimulations, while propane utilizers were unable to cometabolize any TCE. Primary substrate utilization lag-times of 4 to 5 days, 0 to 0.5 days and 40 to 45 days were observed for methane, phenol and propane, respectively. Cometabolism of VC was possible in the presence of methane. Complete removal of 210 ��g/L VC was achieved after 2 stimulations with methane under strictly aerobic conditions. Methane utilization and VC oxidation required nitrate addition, indicating that the system was nitrate limited. A sequential anaerobic/aerobic microcosm study failed to achieve methane utilization and VC transformation likely due to oxygen being utilized to re-oxidize reduced sulfate in the system. / Graduation date: 1999

published_or_final_version / Botany / Master / Master of Philosophy

Orientador: Antonio Ludovico Beraldo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-18T21:29:11Z (GMT). No. of bitstreams: 1 Silva_RodolfoGomesda_M.pdf: 6103773 bytes, checksum: 67c3dbb9306dc2536b81c5cacff6876c (MD5) Previous issue date: 2011 / Resumo: A concentração da população mundial em grandes centros urbanos gera uma imensa demanda por madeira, o que tem levado à devastação das florestas tropicais, causando a extinção de várias espécies. O bambu é uma alternativa à madeira convencionalmente utilizada na movelaria, na construção, na produção de energia, na fabricação de papel e celulose e em outras atividades industriais. Apesar das numerosas vantagens econômicas e ambientais do bambu, seu uso esbarra na limitada durabilidade natural da maioria das espécies. A deterioração do bambu, causada por agentes físicos, químicos e biológicos, faz com que esse vegetal seja considerado um material de baixa qualidade, criando a falsa ideia de que o bambu somente deveria ser usado quando da falta de materiais mais apropriados para determinados fins. Os principais agentes deterioradores do bambu são os fungos e os insetos, dentre os quais se destaca a broca do bambu. A proteção do bambu pode ser feita por meio do uso de diversos produtos dentre os quais se destaca o ácido pirolenhoso, obtido a partir da pirólise de madeira e de outros materiais vegetais. No presente trabalho, buscou-se avaliar a eficácia do tratamento aplicado a taliscas de bambu por cozimento em ácido pirolenhoso em três diferentes diluições (10, 20 e 30%) durante cinco intervalos de tempo (15, 30, 60, 120 e 180 minutos), buscandose a sua proteção contra a deterioração pela broca do bambu, avaliando-se o dano nas taliscas de bambu através das variações na massa e na velocidade do pulso ultrassônico (VPU) através dessas taliscas. Os experimentos de deterioração foram realizados durante 20 semanas. Os dados foram sujeitos a testes de correlação e interações entre as variáveis. O teste T pareado indicou haver diferença significativa entre as medidas de VPU e massa no início e depois de 20 semanas de ensaio. Em média, a VPU diminuiu e a massa aumentou, resultado este influenciado pela variação de umidade no período. Buscou-se, ainda, determinar a porcentagem de fibras em relação aos outros tecidos por meio de análise de imagens de cortes transversais dos corpos de prova. Por fim, buscou-se estabelecer um método eficiente de criação de Dinoderus minutus para ensaios de deterioração do bambu / Abstract: The concentration of worldwide population in large urban centers creates huge demand for timber, which can lead to devastation of the rainforest, resulting in the extinction of several species. Bamboo is an alternative to wood commonly used on furniture, building, power generation, pulp and paper and other industrial purposes. Despite its many economic and environmental advantages, the bamboo utilization is hampered by the low natural durability of most species. The bamboo deterioration by physical, chemical and biological agents, makes it to be considered a low quality material, creating the misconception that it should only be used in the abscence of appropriate materials for certain purposes. The major spoilage agents on the bamboo are the fungi and insects, among which stands out the powder-post beetle. The bamboo protection can be done through the use of various protective agents such as the pyroligneous acid, obtained by pyrolysis of wood and other plant materials. This study aimed to evaluate the efficacy of the treatment applied to bamboo splits cooked in pyroligneous acid at three different solutions (10, 20 and 30%) over five time intervals (15, 30, 60, 120 and 180 minutes) searching for the protection against the deterioration of the powder-post beetle by measuring the variation of the mass and the ultrasonic pulse velocity (UPV) across the strips. The deterioration assays were performed during 20 weeks. The data were subjected to correlation and interaction between variables tests. The two-sample pooled t-test indicated significant differences between the measures of UPV and mass at starting and after 20 weeks testing. On average, the UPV decreased and increased mass, a result influenced by the increasing relative moisture. The study also aimed to determine the fiber content by image analysis of transverse sections of the bamboo splits. Finally, the study sought to establish an efficient method of creating Dinoderus minutus for bamboo deterioration tests / Mestrado / Construções Rurais e Ambiencia / Mestre em Engenharia Agrícola

published_or_final_version / abstract / Ecology and Biodiversity / Master / Master of Philosophy

The aims of this project were to study the immobilisation of microorganisms and the use of immobilised cell preparations in biochemical reactors. One particular process, the biodegradation of volatile fatty acids (VFAs), was chosen as a model system. Volatile fatty acids are compounds which are commonly found in odorous wastes and so can present a pollution problem. A bacterium was isolated, which was capable of VFA degradation in a minimal medium. The organism was identified as a strain of Alcaligenes denitrificans. The strain was able to grow on, and degrade, individual straight chain VFAs and mixtures, at concentrations much higher than those used in the isolation conditions. The strain was found to grow at a wide range of pH values, and a moderately wide range of growth temperatures. The strain was also tested for the degradation of VFAs in piggery slurry, but was found to be less effective than the natural population of organisms present in the waste. This bacterium was used to assess various immobilisation techniques, and their suitability for use in bioreactors. Four gel entrapment systems were tested. Conventional polyacrylamide and aluminium alginate gels both resulted in loss of cell viability. Calcium alginate was found to be too fragile for use in bioreactors, and only polyacrylamide hydrazide gel was found to be suitable. Beads of polyacrylamide hydrazide were used for longer term operation in a bubble column reactor, in a series of experiments to study the effects of changes in operating conditions, on bioreactor efficiency. Mathematical correlations were developed to explain the effects. Other parameters such as the mass transfer coefficients were calculated, to assist in the prediction of scale up. The second immobilisation system tested was adsorption to inorganic matrices. Four different types of particle were tested for their ability to adsorb non-growing cells from solution. The capacity to adsorb cells was related to the surface properties of the particles. Celite diatomaceous earth particles were found to have the greatest capacity to adsorb cells. Celite beads could be seeded in this manner, and then operated in a bubble column bioreactor. A biofilm was formed on the beads, which was capable of steady state biodegradation when the reactor was operated at dilution rates above the theoretical maximum for free cell growth. Bubble columns were the most suitable reactor of those tested for use with immobilised cell preparations. Mixing in these reactors was sufficient to provide good mass transfer, but not so violent as to disrupt the immobilised cell particles. Cell immobilisation by adsorption onto Celite was found to have several advantages over the other systems tested. The matrix could adsorb large quantities of cells, resulting in rapid biofilm formation and was also relatively cheap. Therefore, this appears to be an excellent new technique, and its potential applications in industrial processes are discussed.

No description available.

No description available.