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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Enhanced oil degradation by bacteria when immobilized to an oleophilic substratum

Wilson, Nicola Gail January 1996 (has links)
Three immobilization matrices, Biofix (kaolinite microspheres), Drizit (polypropylene fibres) and polyester polyurethane were used as substrata for use in bioremediation. Enhanced biodegradation of petrol (Slovene diesel) and Ekofisk crude oil occurred with immobilization of Pseudomonas fluorescens to Biofix and Drizit in freshwater and saltwater systems. When compared to free bacteria, immobilization resulted in; increased growth, accelerated ability of the cells to utilize oil, and enhanced biodegradation as determined by gas chromatography. In the freshwater systems Drizit immobilized cells reduced the lag phase to one day in comparison to six in a free system and increased biodegradation of the n-alkanes by 67 %. Immobilization resulted in enhanced production of a rhamnolipid biosurfactant over the first three days of incubation in comparison to free living bacteria which showed a lag phase of two days. All three supports were compared by; scanning electron microscopy, cell loading capacity, absorption of oil, their abilities to enhance oil biodegradation and the effect of drying and storage on the immobilized cells. Biodegradation of hydrocarbons by immobilized cells was dependent on the biocarrier, with polyurethane immobilized cells failing to enhance biodegradation of Ekofisk crude oil. Drizit was the most effective biocarrier tested and the most suitable immobilization substratum for use as a bioremediation agent. Investigation into the location of the genes for alkane degradation in immobilized Pseudomonas fluorescens was undertaken. Plasmid DNA was detected using gel electrophoresis, and caesium chloride-ethidium bromide gradient was carried out to confirm the presence of the plasmid, but no plasmid band was visualized. The successful immobilization system was scaled-up, optimized by supplementation with nitrates and phosphates and applied to microcosms that modelled environmental conditions. Enhanced biodegradation of Ekofisk crude oil was demonstrated on a larger scale, in an estuarine microcosm, with the immobilized systems showing an average degradation of 41.9 % in comparison to 7.1 % in the microcosm containing free indigenous bacteria.
2

Determination Of Environmental Problems Of The Transboundary Pipeline And Applicable National And International Legal Framework

Guneyli, Yamac 01 January 2003 (has links) (PDF)
Regarding historical tendency and today&amp / #8217 / s future estimations, the global demand of petroleum is expected to reach a huge amount and this will be supplied by fossil fuels. Turkey&amp / #8217 / s geographic location will make it an optimum route for transportation between the energy-rich Caspian regions, and the energy-consuming nations of Europe. Therefore, the transboundary pipeline, the most efficient means of transporting large quantities of hydrocarbons across long distances over land, will gain importance and the decision of a route through Turkey is a logical selection. However, despite all the security measures, pipelines have caused much significant environmental pollution due to accident, intention or negligence. Law is the major applied tool for compensating this environmental pollution and for determining the liable person or organization. According to international law, the rights and obligations of the source State and potentially affected states should be defined in such a way that all transit states can proceed with their operations. Moreover, the source state acts in compliance with its international obligations and adopts the necessary regulations in order to safeguard that the person in control of a potentially harm-causing activity has to bear the costs of additional measures to comply with those regulations. However, if the source state acts in violation of its international obligations, not the person in control of the activity but the state would be primary liable ex delicto. Equally significant, Turkey requires some changes in the existing laws and additional new regulations for constituting more effective Turkish Liability law and being a reference source for internationally liability law. Regarding hazardous facilities, Turkey needs some common provisions to derive new solution possibilities and to identify some criteria for cases in the future.
3

Karakterizacija bioremedijacionih procesa u zemljištu i podzemnim vodama zagađenim naftom i derivatima na lokalitetu Ratno ostrvo / Characterisation of the bioremediation processes in soil and groundwater contaminated by oil and oil derivatives at the site of Ratno Ostrvo

Rončević Srđan 01 June 2007 (has links)
<p>Predmet izučavanja ove disertacije je pasivna bioremedijacija naftom i derivatima nafte&nbsp;zagađenih podzemnih voda na lokalitetu&nbsp; Ratno ostrvo i pospe&scaron;ivanje procesa&nbsp;<br />bioremedijacije zemlji&scaron;ta i podzemne vode zagađenih naftom i derivatima nafte na&nbsp;laboratorijskom postrojenju u ciljusanacije ugroženog lokaliteta.</p><p>Praćenjem podzemnih voda granične zone izvori&scaron;ta Ratno ostrvo i Rafinerije nafte&nbsp;utvrđeno je da je u podzemnoj vodi granične zone izvori&scaron;ta Ratno ostrvo i Rafinerije&nbsp;nafte Novi Sad prisutan proces pasivnebioremedijacije, odnosno, da na pojavu&nbsp;ugljovodoničnog zagađenja u vodi sredina odgovara povećanjem brojnosti, pre svega,&nbsp;ugljovodonik-osidujućih i lipolitskih bakterija i bakterijske enzimatske aktivnosti, i&nbsp;dolazi do transformacije mineralnih ulja u polarna jedinjenja. U vodi većine praćenih&nbsp;objekata uočene su eksponencijalne i linearne funkcionalne zavisnosti bakterijske&nbsp;brojnosti i fosfatazne aktivnosti od koncentracije ugljovodoničnog zagađenja za&nbsp;koncentracije ukupnih ugljovodonika &lt; 400 &micro;g/l (najče&scaron;će &lt; 200 &micro;g/l). Visok nivo&nbsp;podzemnih voda i prisustvo dela zagađenja u gornjim slojevima zemlji&scaron;ta ukazuje nam&nbsp;na mogućnost primene fitoremedijacije navedenog područja, jer je deo zagađenja&nbsp;dostupan korenskom sistemu.</p><p>Ispitivanjem tehničke bioremedijacije zemlji&scaron;ta i podzemne vode zagađenih naftom i&nbsp;<br />derivatima nafte&nbsp; na laboratorijskom postrojenju utvrđeno je da dolazi do opadanja&nbsp;<br />koncentracije ukupnih ugljovodonika u zemlji&scaron;tu sa 38,2 na 14,6 g/kg i mineralnih ulja&nbsp;sa 27,0 na 10,2 g/kg (62%), &scaron;to se može definisati jednačinom C=C<sub>0</sub>e<sup>-kt</sup>, gde je&nbsp;<br />konstanta brzine degradacije ugljovodonika k=0,0082 dan<sup>-1</sup>. U vodi je prisutan veliki&nbsp;<br />broj karboksilnih kiselinanastalih oksidacijom alkana (C10-19), kao i aromata&nbsp;(benzoeva kiselina, kao i benzaldehid), &scaron;to ukazuje na proces biooksidacije&nbsp;ugljovodonika. Proces rastvaranja i emulgovanja nafte se pospe&scaron;uje uvođenjem&nbsp;recirkulacije vode: određena je jednačina zavisnosti koncentracije ugljovodonika u&nbsp;vodenoj fazi od koncentracije u&nbsp; čvrstoj fazi, zavisno od&nbsp; brzine proticanja:&nbsp;C<sub>voda</sub>=(f<sup>*</sup>v+K<sub>0</sub>)C<sub>zemlja</sub>, gde je koeficijent ispiranja f=1400 s/m, a difuzioni koeficijent&nbsp;K<sub>0</sub>=6<sup>*</sup>10<sup>-4</sup>. Proces ispiranja nafte i derivata sa zemlje značajno utiče na aktivnost&nbsp;mikroorganizama i razgradnju zagađenja. Sa porastom koncentracije ugljovodonika&nbsp;generalno opadaju brojnosti svih ispitivanih grupa bakterija i fosfatazna aktivnost i&nbsp;određene su granične vrednosti tolerancije. Proces ispiranja se &nbsp;mora voditi tako da&nbsp;koncentracija mineralnih ulja u vodenoj fazi netreba da pređe 15-35 mg/l, a kad se&nbsp;postignu koncentracije ugljovodonika manje od 400 &micro;g/l treba prepustiti pasivnoj&nbsp;bioremedijaciji da ukloni zagađenje.</p> / <p>This dissertation investigates the passivebioremediation of groundwater from Ratno&nbsp;Ostrvo contaminated by oil and oil derivatives, and a bench-scale experiment to improve the soil and groundwater bioremediation processes, with the goal of sanatising the effected area.</p><p>During groundwater monitoring of the zone between the Ratno Ostrvo spring and the&nbsp;Novi Sad oil refinery, a passive bioremediation process was observed, whereby, &nbsp;in the hydrocarbons-contaminated water, increased counts of hydrocarbon-oxidising and lipolytic bacteria and increasing bacterial enzyme activity were found, along with the transformation of mineral oils to polar&nbsp; compounds. In water, the majority of the&nbsp;monitoring points displayed either exponential or linear functionalal dependence&nbsp; between bacterial count or phosphatase activity and hydrocarbon concentration, for&nbsp; total hydrocarbon concentrations &lt; 400 &micro;g/l (most often &lt; 200 &micro;g/l). The high groundwater level and the presence of contamination inthe upper soil layers makes possible the application of phytoremediation at the site, as part of the contamination is in the rhyzosphere.</p><p>The bench-scale investigation of bioremediation in soil and groundwater contaminated by oil and oil derivatives yielded decreasing concentrations of total hydrocarbons in the soil from 38.2 to 14.6 g/kg and mineral oils from 27.0 to 10.2 g/kg&nbsp; (62%), which can be described by C=C<sub>0</sub>e<sup>-kt</sup>, where the rate constant of&nbsp; hydrocarbon degradation is k=0.0082 day<sup>-1</sup>.</p><p>In water, a large number of carboxylic acids were present, from the oxidation of&nbsp; alkanes (C10-19) and aromatics (benzoic acid, and also benzaldehyde), which indicates a hydrocarbon biooxidation process. The process of dissolving and emulgating the oil is enhanced by recirculating the water: the linear relation between the concentration of hydrocarbons in the liquid and solid phases was found to be dependent on the flow rate: C<sub>water</sub>=(f<sup>*</sup>v+K<sub>0</sub>)C<sub>soil</sub>, where the rinsing coefficient f=1400 s/m, and the diffusion coefficient K<sub>0</sub>=6 x 10<sup>-4</sup>. The process of rinsing the oil and oil derivatives from the soil significantly influences the microbial activity and the degradation of contaminants. With increasing hydrocarbon concentrations, there was&nbsp; generally decreasing bacterial counts and phosphatase activity, and an upper limit for&nbsp; hydrocarbon tolerance was determined. The rinsing process must becontrolled to&nbsp; ensure the mineral oil concentration in water does not exceed 15-35 mg/l, and once the concentration of hydrocarbons becomes less than 400&micro;g/l, passive bioremediation may be left to complete the degradation.</p>

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