Academic literature on the topic 'Petroleum degradation'

There is a vast worldwide consumption of petroleum hydrocarbons and accidental release in to the environment is common. For example petroleum forecourt retail outlets have 'interceptors' to prevent release of hydrocarbons into the environment. The aim of this study was to investigate options for in-situ bioremediation of the hydrocarbon substrates within these 'interceptors' in a laboratory model. The initial studies on bioremediation were undertaken with diesel as the substrate. It was shown that the addition of nitrogen and phosphorus to the system increased hydrocarbon mineralisation by a factor of 16, resulting in increased carbon dioxide evolution. There was strong evidence indicating that nitrogen and phosphorus were the limiting factor for hydrocarbon metabolism in this aqueous system. Trichoderma harzianum and a soil bacterial isolate LFC D1 FI were assessed and shown to degrade hexadecane and pristane. The positive affect of adding a cosubstrate was evident in flask studies; the rates of degradation by LFC D1 FI and T. harzianum were approximately doubled and tripled respectively in the presence of glucose compared to treatments without glucose. Previous attention has focused on the ability of Phanerochaete chrysosporium to degrade polycyclic aromatic hydrocarbons; in this study the degradation of aliphatics was investigated. Spores from P. chrysosporium induced on the hydrocarbon substrate were found to be necessary to degrade hexadecane. Pseudomonas putida was unable to grow in liquid media containing hydrocarbons, however on solid media and in an aqueous environment containing acid-washed sand, degradation of hydrocarbons was evident, hi the presence of sand P. putida degraded both hexadecane and pristane by 70% of the initial concentration added; in the absence of sand no degradation in the aqueous system was seen. This suggests surface attachment plays an important role in hydrocarbon degradation by P. putida. The attachment and use of the sessile P. putida in aliphatic hydrocarbon degradation is discussed.

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.

The need for a sustainable development of natural resources has, in recent time taken centre stage in most natural resource rich countries. Environmental degradation resulting from the unsustainable development of petroleum resources has also resulted in the impoverishment of a large number of people. In countries like Nigeria, revenue accruing from energy and natural resources projects has become the mainstay of the nation's economy. However, the main beneficiaries of the wealth created by the exploration and production of petroleum are the state who owns all natural resources in line with the provisions of Nigerian law and the companies that exploit these resources. As a result, local landowners, do not directly benefit from petroleum exploitation even though they bear the direct consequences of petroleum exploitation. One consequence is the reduction of productive agricultural lands which has disrupted some of the traditional occupations of the people in the Niger Delta where the bulk of Nigeria's petroleum production takes place. It is this disruption that is the focus of this thesis. Despite Nigeria's support for the sustainable development of Nigeria's petroleum resources, environmental degradation resulting from the exploitation of petroleum has continued unabated. This raises a fundamental question as to the effectiveness of the regulatory regime governing petroleum activities in Nigeria. Using doctrinal and socio-legal methodology, this thesis explores the existing regulatory regime to ascertain if it is robust enough or effective to ensure the sustainable development of Nigeria's petroleum resources. It considers what impact, if any, does a failure in the regulatory regime have on the local population. Having established the failure of the legal regime, the study examines the consequences of the State's failure to sustainably develop its petroleum resources and consider if s Having established the failure of the legal regime, the study examines the consequences of the State's failure to sustainably develop its petroleum resources and consider if such failure has any impact on the stability and sustainability of petroleum projects themselves. Perhaps the most surprising finding to emerge from this study is that while the failure of the regulatory regime has negatively impacted the local population, the resulting social unrest or risks does not negatively impact the stability and sustainability of petroleum projects in real terms when compared with the cost of improving environmetal practices. In the search for solutions to address the failure of the existing regime and its consequences, the study examined relevant provisions of the new Petroleum Industry Bill (PIB) intending to ascertain if there are significant improvements capable of ensuring the sustainable development of Nigeria's petroleum resources. It concludes that while the PIB contains some improvements on the existing regulatory regime, there are problematic provisions that require some attention if the nation is to achieve the goal of sustainable development of its petroleum resources.

High molecular weight (HMW) hydrocarbons (defined herein as C35+ compounds) are difficult to characterise by conventional analytical methods. Very few studies have reported precise and reproducible quantification of such compounds in fossil fuels. Nonetheless, such components have important effects on the physical and biological fate of fossil fuels in the geosphere. For example, the phase behaviour of waxy gas condensates is significantly affected by the varying proportions of HMW compounds. Similarly HMW compounds are amongst the most resistant petroleum components to biodegradation. The current study reports the development of reproducible quantitative high temperature capillary gas chromatography (HTCGC) methods for studying both these aspects of the chemistry of HMW hydrocarbons. In addition those hydrocarbons which remain unresolved when analysed by gas chromatography (so called unresolved complex mixtures UCMs) are also studied. UCMs may account for a large portion of the hydrocarbons in many fossil fuels yet very little is known about their composition. Knowledge of these compounds may be important in enhancing the prediction of phase behaviour. Oxidative degradation and GC-MS is used to elucidate the types of structures present within the UCM. The concentrations of C3S4h. ydrocarbons in two unusually waxy gas condensates from high temperature wells in the North Sea were determined by HTCGC. The whole C, 5+ fraction comprised about 20% of the total hydrocarbons and consisted of compounds with carbon numbers extending up to and beyond Coo. By paying particular attention to sample dissolution and injection, good reproducibility and precision were obtained. For example, for authentic n-C, to n-C60 alkanes a relative standard deviation of under 5% for manual injection, linear response factors (1.01 Cm to 0.99 C6), and a linear calibration for 5 ng to 25 ng on-column were found. Limits of detection are reported for the first time for HMW n-alkanes. The limits were found to be as low as 0.8 ng for Cto to 1.87 ng for C60. Tristearin is proposed as a suitable HTCGC internal standard for quantification since the FID response factor (1.1) was close to that of the HMW n-alkanes and response was linear. Importantly, when co-injected with the two waxy North Sea condensates, tristearin was adequately separated from the closest eluting alkanes, n-C59 and n-C60 under normal operating conditions. Qualitative characterisation of the HMW compounds in the waxy gas condensates and in synthetic wax blends (polywax 1000) using HTCGC-EI MS and HTCGC-CI MS produced molecular ions or pseudo molecular ions for n-alkanes up to n- C6o. The spectra of some HMW compounds contained fragment ions characteristic of branched compounds but detailed characterisation was very limited. This study has also shown, for the first time, the significance of the unresolved complex mixture in gas condensatesU. CM hydrocarbonsa ccountedf or over 20% of the total hydrocarbons in a waxy North sea condensateT. he condensatew as first distilled and the distillate UCMs isolated. Thesew ere found to be between 64 to 97 % unresolved after molecular sieving (5A) and urea adduction. The UCMs were oxidised using CrO3/AcOHw hich produced5 -12% C02, and 55-83% dichloromethane-solublep roducts. Thus 65-94% of the original UCMs were accounted for as oxidation products. The remainder were thought to be water soluble acids which could not be determined in the presence of the AcOH reagent. Of the recovered oxidised products, 27- 81 % were resolved and these comprised mainly n-monocarboxylic acids (19-48 %). The average chain length was found to be C12 indicating the average length of alkyl groups. Branched acids, ketones, ketoacids, ndicarboxylic acids, branched dicarboxylic acids, lactones, isoprenoid acids, alkylcyclohexane carboxylic acids and toluic acids accounted for the majority of the remaining resolved products. The distillate UCMs all showed variations in amountso f productsb ut not in composition. Retro-structurala nalysis suggestedth at the UCM in the gasc ondensatew as mainly aliphatic and branched.T he numbero f isomerso f simple brancheda lkaneso ver the UCM molecular weight range (determined by cryoscopy) was calculated to be over 15000. Overall, oxidation provided structural information for about half of the UCM. HTCGC was also used to measure the biodegradability of HMW alkanes in a waxy Indonesian oil. Traditional alkane isolation techniques (TLC and CC) discriminated against HMW compounds above C40 whereas adsorption onto alumina in a warm cyclohexane slurry provided an aliphatic fraction still rich in HMW compounds and suitable as a biodegradation substrate. A waxy Indonesian oil was subjected to 136 day biodegradation by Pseudomonas fluorescens. Extraction efficiencies of over 90 % (RSD <5 %) were obtained for n-alkanes up to C6o using continuous liquid-liquid extraction. Over 80 % of the oil aliphatic fraction was degraded within 14 days. After 136 days only 14% of the original aliphatic fraction remained, yet surprisingly no decreases in the concentrations of compounds above C45 were observed. However, the use of a rapid screening biodegradation method proved conclusively that Pseudomonasfluorescens was capable of utilising n-alkanes up to C60 once the bacteria had acclimated to the HMW alkanes. This is the first report of bacterial utilisation of an n-alkane as large as C.

Biodegradation of petroleum hydrocarbon can be an effective treatment method applied to control oil pollution in both fresh water and marine environments. Hydrocarbon degraders, both indigenous and exogenous, are responsible for utilizing petroleum hydrocarbon as their substrate for growth and energy, thereby degrading them. Biodegradation of hydrocarbons is often enhanced by bioaugmentation and biostimulation depending on the contaminated environment and the competence of the hydrocarbon degraders present. An evaluation of the performance of the biological treatment of petroleum hydrocarbon by the hydrocarbon degrading microbes at the Brayton Fire School??s 4 million gallon per day (MGD) wastewater treatment plant was the main research objective. Samples were taken for two seasons, winter (Nov 03 ?? Jan 03) and summer (Jun 04 ?? Aug 04), from each of the four treatment units: the inlet tank, equalization tank, aeration tank and the outfall tank. The population of aliphatic hydrocarbon degraders were enumerated and nutrient availability in the system were used to evaluate the effectiveness of on-going bioaugmentation and biostimulation. Monitoring of general effluent parameters was conducted to evaluate the treatment plant??s removal efficiency and to determine if effluent discharge was in compliance with the TCEQ permit. The aeration tank is an activated sludge system with no recycling. Hydrocarbon degraders are supplied at a constant rate with additional nutrient supplement. There was a significant decrease in the population of microbes that was originally fed to the system and the quantity resident in the aeration tank. Nutrient levels in the aeration tank were insufficient for the concentration of hydrocarbon degraders, even after the application of dog food as a biostimulant. The use of dog food is not recommended as a nutrient supplement. Adding dog food increases the nitrogen and phosphorus concentration in the aeration tank but the amount of carbon being added with the dog food increases the total chemical oxygen demand (COD) and biochemical oxygen demand (BOD). An increase in the concentration of total COD and BOD further increases the nitrogen and phosphorus requirement in the system. The main objective of supplying adequate nutrients to the hydrocarbon degraders would never be achieved as there would be an additional demand of nutrients to degrade the added carbon source. This research study was conducted to identify the drawbacks in the treatment plant which needs further investigation to improve efficiency.

Microbial biodegradation is the primary mechanism by which petrogenic hydrocarbons (PHCs) are removed from the environment. Though hydrocarbon biodegradation is widely studied in marine systems, knowledge of how it occurs in freshwater systems is still lacking. The Peace-Athabasca Delta (PAD), located in northeastern Alberta, is an ideal location to study microbial hydrocarbon degradation since it has a long history of exposure to PHCs. What’s more, these PHCs are predominately sourced from bituminous deposits and are therefore relevant to the Canadian Oil Sands Industry. This thesis investigated the genetic potential for hydrocarbon degradation of PHCs via metagenomic reconstruction of microbial communities in lakes of the Peace and Athabasca Deltas, as well as reference lakes in the nearby boreal uplands. In order to properly evaluate the microbial community and its potential for hydrocarbon degradation, a comprehensive analysis of PHCs (including n-alkanes, polycyclic aromatic compounds (PACs), and petroleum biomarkers of terpanes, hopanes, and steranes) was performed. PHC analysis showed that n-alkanes in lake sediments from all three regions were highly similar and predominately biogenic, while PAC composition was significantly different in each region. Restricted-drainage lakes of the Athabasca Delta had the highest concentrations of PACs from petrogenic sources. Closed-drainage lakes in the Peace Delta had lower concentrations of PACs that likely originated from a mixture of pyrogenic and petrogenic sources. Closed-drainage lakes in the boreal upland region had the lowest concentrations of PACs likely sourced from pyrogenic wood combustion with traces of petrogenic PACs, possibly from atmospheric deposition of dust. Petroleum biomarkers of terpanes, hopanes, and steranes were successfully used to identify the long-range fluvial, and possibly atmospheric, transport of bituminous compounds more than one hundred kilometers from their potential source. This validates the future use of these biomarkers in environmental forensics. Microbial communities in all three regions under study were highly diverse, and their composition was significantly different in both sediment and water. Targeted gene analysis identified a total of 3885 genes involved in the degradation of n-alkanes and PACs in sediment and water. The results show that organic carbon, nitrogen, and sulfur content, as well as PAC and short-chain alkane concentrations were important chemical predictors of change in degradation gene composition. Furthermore, genes for anaerobic degradation of PHCs were identified in syntrophic bacteria, methanogens, nitrate and sulfate reducers, demonstrating the potential for syntrophic hydrocarbon degradation in PAD lakes. Though this thesis confirms the genetic potential for hydrocarbon degradation in PAD and boreal upland lakes, further research is necessary to determine whether these microbial communities can actively degrade the PHCs present in these lakes.

Oxydation des asphaltenes de quatre petroles lourds avec du tetroxyde de ruthenium et identification des molecules d'acides formees par spectrometrie de masse. L'etude de la ou des fonction(s) acide(s) sur chaque produit, associee a une experience de simulation de maturation sur argile, a conduit a proposer un mecanisme d'incorporation de ces molecules dans les asphaltenes. Il s'agirait de reactions de type fridel-crafts, catalysees par la matrice minerale. L'etude de la structure des resines a ete etudiee par hydrogenolyse avec du nickel de raney et les molecules formees par chromatographie en phase gazeuse couplee a de la spectrometrie de masse

In this study, a well biofilm-forming bacterial strain was isolated from oil contaminated water and sediment samples collected in petroleum storage Duc Giang, Hanoi. It was identified as Paracoccus sp. DG25 and registered in the GenBank database with the accession numbers KJ608354. Several biophysical and bio-chemical conditions for the biofilm formation of the strain were estimated such as pH, temperature, carbon sources and nitrogen sources. As the results the biofilm forming capacity was highest at pH 7, 37 oC, on maltose and supplemented with KNO3. Using these optimal conditions, the formed biofilm degraded 76.07 % of pyrene after 7 day-incubation, with the initial concentration of 300 ppm by high-performance liquid chromatography (HPLC) analysis. To our knowledge, there is rare publication on pyrene degradation by biofilm-forming bacteria. Therefore, the obtained results show that biofilm formed the strain Paracoccus sp. DG25 may considerably increase the degrading efficiency of pyrene and may lead to a new approach to treat polycyclic aromatic hydrocarbons containing in petroleum oil contaminated water in Vietnam<br>Trong nghiên cứu này, từ các mẫu đất và nước nhiễm dầu lấy tại kho xăng Đức Giang, Hà Nội, chúng tôi đã phân lập được chủng vi khuẩn có khả năng tạo màng sinh học tốt. Chủng vi khuẩn này đã được phân loại và định tên là Paracoccus sp. DG25 với số đăng ký trên ngân hàng Gen là KJ608354. Chúng tôi cũng đã nghiên cứu một số điều kiện hóa lý ảnh hưởng tới khả năng hình thành màng sinh học như pH, nhiệt độ, nguồn Carbon và nguồn Nitơ. Kết quả cho thấy, chủng DG25 có khả năng tạo màng tốt nhất ở các điều kiện pH 7, 37 oC, nguồn Carbon là maltose và nguồn Nitơ là KNO3. Sử dụng các điều kiện tối ưu này để tạo màng và đánh giá khả năng phân hủy pyrene của màng tạo thành. Bằng phương pháp sắc ký lỏng cao áp, chúng tôi đã đánh giá được hàm lượng pyrene bị phân hủy sau 7 ngày nuôi tĩnh bởi màng sinh học của chủng DG25 lên tới 76,07 % với nồng độ ban đầu là 300 ppm. Cho tới nay, chưa có nhiều công bố về hiệu quả phân hủy pyrene của các chủng vi khuẩn tạo màng sinh học. Do vậy, kết quả đạt được này mở ra khả năng sử dụng màng tạo thành bởi chủng DG25 để nâng cao hiệu quả phân hủy pyren và có thể mở ra phương pháp mới nhằm xử lý các hợp chất hydrocarbon thơm có trong nước ô nhiễm dầu ở Việt Nam

Currently available physical and chemical remediation technologies are not effective in the deep sea, where ultimate fate of oil is strongly dependent on degradation by microorganisms. In order to setup an efficient bioremediation strategy, the effect of the environmental constraints on oil degrading communities’ metabolism needs to be assessed. In this work, natural surface seawater communities were incubated under different T, P and in different dilutions of the medium ONR7a. Then, after 1 day, 1 week and 3 weeks, cell number, SO4, NH4 and DIC concentration were assessed. When only one environmental stress (low T or high HP) is applied, a positive effect of nutrients’ concentration is highlighted, with increased growth rates and DIC production; at 23 °C and 20 MPa, a lower cell growth is observed with respect to atmospheric pressure samples, but a relatively high value of oil degradation is mostly sustained by respiration to DIC: this result evidence the possibility to setup an effective biostimulation strategy in deep seas characterized by milder temperatures (Sulu, Mediterranean, Red Sea). High Ammonium concentrations are needed to sustain large production of proteins for cell maintenance process required for adaptation to HP. Moreover, at 23 °C and 20 MPa, significant Sulphate uptake occurs, whose role in HP adaptation needs to be clarified. Also at low T and atmospheric pressure oil biodegradation mostly relies on respiration to DIC, however biodegradation rates seems to be more affected by T reduction than HP increase. When both low T and high HP are applied, cellular metabolism is still active but any growth is observed, drastically reducing the oil biodegradation, that relies only on respiration to DIC. Surface communities subject to combination of 2 stresses may need more than 3 weeks to adapt to the deep sea environment and start a growth phase.