Talal Gamadi

Testing Tight Gas and Unconventional Formations and Determination of Closure Pressure

Experience indicates that applying the conventional testing techniques such as drawdown-buildup tests to unconventional reservoir may lead to non-unique answers. Diagnostic testing approach is now more commonly used in tight gas formations and unconventional reservoirs. Testing unconventional reservoirs, particularly hydrocarbon-bearing shale formations, presents considerable challenges. In addition determination of the fracture closure pressure is sometime elusive. This paper reviews those challenges faced in analysis of testing of tight gas and unconventional reservoirs both liquid and gas. Conventional testing and analysis methods, although applicable, are often impractical because of excessive test duration. Diagnostic fracture injection test (DFIT) has become the preferred option for unconventional formations. Several methods may be used for interpreting DFIT data. We examine those methods in detail and explore their relative strengths while interpreting field data. We also show ways to determine the fracture closure pressure under various reservoir and fracture conditions.

Laboratory evaluation of cyclic CO2 injection for shale oil reservoirs

I this work we examined the photocatalytic decomposition of hydrogen sulfide on Fe2O3 and TiO2-containing natural materials kaolinites under UV irradiation. As the initial materials were taken kaolinite clays of Kazakhstan deposits (No 1 and No 2). The process was studied in the quartz reactor at the temperature of 40 800C. The source of UV radiation was a mercury UV lamp power of 100 watts. Catalysts was treated preliminary thermal activation in the stream of hydrogen sulfide at 5000C for 2 hours. The catalysts were tested by methods: electron microprobe analysis («Superprobe -733», JEOL), XRD (DRON 4 * 0.7 Cu Kα -irradiation), BET by low temperature nitrogen adsorption, Mössbauer and EPR spectroscopy, electron microscopy (TEM). It is shown that the samples No 1 and No 2 contain 4.8 and 6.0 wt.% Fe2O3 and 0.4 and 0,6% TiO2, accordingly. The specific surface of the samples No 1 and No 2 (49.1 and 92.1 m2 / g), pore volume (0.119 and 0.287 cm3 / g) and their size distribution were determined. It is shown that the sample No 2 is more active than sample No1 that is accounted by high content of iron and titanium oxides and greater specific surface. In case of H2S low concentrations in the gas mixture (3 and 6%) the catalyst decomposed with 100% H2S conversion to H2 and S indefinitely long time at the space velocities of 510 530 h -1. When the concentration of H2S increased to 25% complete decomposition H2S is observed on the sample with high content of titanium and iron oxides at space velocities 311 320 h-1. It was suggested that the active sites of the hydrogen sulphide decomposition are reduced forms of iron and titanium based on the results of Mössbauer, EPR spectroscopy and electron microscopy. N. A. Zakarina et al., J Pet Environ Biotechnol 2013, 4:6 http://dx.doi.org/10.4172/2157-7463.S1.004B is the main partial substitute for petrodiesel. Some biodiesels have low oxidative stability. To solve or minimize this problem, some compounds have been added to biodiesel as antioxidants. Phenolic compounds are common antioxidants used by the vegetable oil industries. There are studies examining commercial antioxidants that are already being used in biodiesel: Baynox® plus (2,2′‐methylene‐bis‐(4‐methyl‐6‐tert.‐butylphenol); N,N′-di-sec-butyl-p-phenylenediamine, PDA) and seven phenolic antioxidants, including butylated hydroxyanisole (BHA); butylated hydroxytoluene (BHT); 2,5-di-tert-butylhydroquinone (DTBHQ); 2,2′-methylene-bis-(4-methyl-6-tert-butylphenol) (MBMTBP); PG; pyrogallol (PY); and Tert butylhidroquinone (TBHQ). However, few studies have reported on the efficiency of aromatic amines used as antioxidants. One of the most efficient classes of compounds used for this is aromatic diamines because of their high antioxidant capacity at low concentration. The advantage of using amines is that this functional group does not often appear as a natural antioxidant in vegetable oils; therefore, these compounds can be used as artificial markers in biodiesel industries. Aromatic diamines can be used as artificial markers. It is sometimes necessary to determine the concentration of antioxidants in biodiesel after long storage times or to control quality. An easy to use spectrophotometric methodology was employed in this work to determine the concentration of aromatic diamines (0 to 500 ppm). We tested a use of this method as screening method based on IR spectroscopy, to identify antioxidant (phenolic and aromatic) into biofuel. Five calibration curves were constructed using 3 absorption frequencies from the infrared spectra of the samples. The standard deviation, correlation coefficient, linearity range, limit of detection and limit of quantification were determined. The better results from the easy to use method (814 cm−1) show a linear range of 0–100 ppm with a strong correlation (R2 = 0.9966) and a limit of quantification of 21.6 ppmWastewater contaminated with olive oil which simulates the olive oil mills has been treated by means of Advanced Oxidation Processes (AOPs). The Fe(II)/H2O2 system (Fenton’s reagent), Fe(II)/H2O2/UV system (solar-photo-Fenton’s reagent) and the UV-photolysis were applied. A synthetic wastewater generated by emulsifying olive oil and water was used. Experiments were carried out using a concentrating Parabolic Trough Reactor (PTR). Oil is readily degradable, the sunlight is captured by ferrioxalate which, in the presence of hydrogen peroxide, generates hydroxyl radicals that oxidizes organic molecules. In addition, the process efficiency is increased by using oxalic acid. Typical operating variables such (H2O2 and Fe(II)) exerted a positive influence on the treatment efficiency. The optimum working pH on the Fenton treatment was found to be in the range 2.5-3.0. Response Surface Methodology (RSM) based on the experimental design was applied to optimize the Fenton oxidation process. هريبك تايمك جاتناب طبترت جاتنلاا هيلمع نكلو طسوتملا رحبلا ضوح هقطنم يف تاعانصلا مدقا نم نوتيزلا تويز جاتنا ربتعي هيمك يلع يوتحت يتلا هلئاسلا تافلخملا نم ك هيوضعلا تافلخملا نم هريب نكادلا اهنولب زيمتتو . ظ هريخلاا هنولاا يف تره ب هجلاعملا هيلمع تايلمعلا هذه مها نمو همدقتملا هدسكلاا تايلمع أم لماع ربتعي يذلاو نوتنف وتوفلا مدحتسي هئيبلل قيدص دسك هيف نيجورديهلا ديسكا قوفو ديدحلا ديساكا . مادختسا مت كلذ يلا هفاضلااب RSM يلثملا ميقلا داجيلا ل لعافتلل قيقحت يلعا هيوضعلا داوملا هلازلا هميق يلثملا هميقلا تناكو ب يصوملا لعافتلا طسو هيضماح هجردل ه 2.5-3.0 . هبسن نا جئاتنلا تحضوا يلا تلصو هيوضعلا داوملا هلازا 56 %article i nfo This study describes a detailed characterization of the oil obtained by co-pyrolysis of Tarfaya oil shale (Morocco) and high density polyethylene (HDPE) and by pyrolysis of oil shale and HDPE individually. The oil (obtained underthemostsuitable conditions, temperatureof500-525 °C and heating rate of10 °C/min) wascharacterised by elemental analysis, nuclear magnetic resonance spectroscopy ( 1 H NMR) and Fourier transform infrared spec- troscopy (FTIR). In addition, column chromatography was used group composition of oil was determined. Gas chromatography was achieved on n-hexanefractions.Adding HDPE to the oil shale results inincreased oil yields, whichindicatessynergeticeffectbetweentheoilshaleandHDPE.TheadditionofHDPEtooilshaleimprovedfuel properties of shale oil leading to a decrease in the oxygen content of shale oil. The results show that the oil obtainedbyco-pyrolysishassimilarpropertieswithcommercialgasoline.HDPEactsasahydrogenationmedium for the oil shale product as revealed by FTIR results.This thesis is a theoretical and empirical examination of the developmentof bioethanol markets since 2005 when sustainability regulations forbiofuels were introduced globally. The experiences of Brazil and Sweden,and the influence of European regulations on the development ofbioethanol markets receive special attention. The work is based onprimary and secondary data sources gathered between 2009 and 2014,including interviews, field research, data from public and private sources,as well as an extensive literature review. The thesis uses case examples ofcountries that have adopted bioethanol as a transport fuel, such as Braziland Sweden.The research is structured using a bottom-up approach, and addressesthree specific angles of the complex issue of how bioethanol marketshave developed under sustainability requirements.The first part introduces an economic sustainability view of ethanol. Thecharacteristics of bioethanol fuel are presented together with conceptsand a theoretical framework for analysing biofuel sustainability. Policytools are also discussed, particularly those used to introduce fuel ethanolin the transport sector. The discussion is centred on the competitionbetween ethanol and gasoline, considering the hypothesis that consumersare sensitive to prices and tend to choose fuels based on their cost-perenergyunit. The analysis is supported by the case examples of Brazil andSweden, with special focus on the delicate balance between fueleconomies of bioethanol and gasoline systems in the face of differentways oil products are priced in those countries. Findings show thatdrivers tend to choose between bioethanol (E85/E100) or gasoline (E5-E25) depending on the relative prices between the two fuels. Theresearch results suggest that different pricing strategies for bioethanoland gasoline affect how consumers perceive the attractiveness of eachfuel. The examples of E100 in Brazil and E85 in Sweden provide insightson the elastic consumer behaviour that new markets may experience,serving to guide strategies in different contexts.The second part of this work bridges experiences in national contextswith the recent trend for biofuel sustainability regulation in internationalmarkets. Based on the hypothesis that the ethanol industry is responsiveto sustainability regulations, an examination of the development of theiiBrazilian bioethanol industry is carried out. This provides a comparisonframework drawing patterns between the industrys reaction to nationalregulations (past) and international regulations (recent). For this purpose,a comparison between the European sustainability requirements forethanol and the industry’s status quo is explored. Findings show that theEU sustainability criteria for biofuels are likely to have three effects onthe bioethanol industry: (i) compliance through incrementalimprovements in sustainability practices and certification; (ii) riskdiversification by engaging in multi-output production models; and (iii)market leakage towards less-regulated markets.The third part of the thesis brings together the first two parts. Itexamines how in a fuel competition context, the incorporation of costsrelated to sustainability certification can change the attractiveness ofhigh-bioethanol blends for consumers. The model of sustainabilityadopted by major international markets is based on regulations enforcedby mandatory certification. As biofuel market share increased, producerswere faced with costs for sustainability certification in order to obtainmarket access. While it was expected that ‘sustainably’ produced biofuelswould be rewarded with higher prices in the EU, this work found thatprice premiums for ethanol have in general been very small or inexistent,with certified fuels becoming the new norm in the market. New costsbrought into the market through sustainability certification can make itdifficult to balance between national policies heavily reliant on consumerchoice between fuels (and associated price-elasticities), and thedeployment of high blends of ethanol, such as E100 and E85.By analysing the three aspects (consumer behaviour and marketdynamics for ethanol in Brazil and Sweden, the introduction ofsustainability criteria for biofuels, and the implications of sustainabilityfor consumer choice between fuels) this work seeks to increaseunderstanding of the highly complex issue of biofuel market formationin the face of sustainability requirements. The key finding is thatsustainability certification has a cost, which needs to be orchestrated withother sectors of the economy to achieve the desired objectives. Thisthesis suggests that crucial areas of economic and environmentalsustainability have been often dealt with separately in biofuelpolicymaking, which has created weaknesses that deserve attention infuture policy efforts in order to improve biofuel systems.T presence of high molecular weight organic compounds such as dyes, pharmaceuticals, and endocrine disruptors in receiving waters is of concern due to their toxicity and carcinogenicity to humans and aquatic organisms. Ozone is a powerful oxidant that can be used to oxidize such compounds in effluents. However, the use of ozone in these applications is somewhat limited at present due to the relatively high cost of ozone and ozonation systems. This is in part due to mass transfer limitations, and the lack of understanding of fundamental factors that contribute to poor utilization of applied ozone. Previous studies have concluded that mass transfer of ozone form the gas to the liquid phase is the main rate limiting step in ozonation. However, with high molecular weight compounds, the diffusion and transport of the compound to the reaction plane, the production of byproducts and secondary reactions, can also influence the overall oxidation kinetics. In this study, the mass transfer and reaction kinetics regimes are modeled based on fundamental principles and applied to analyze the oxidation of a high molecular weight dye in a stirred tank reactor with a bubble diffuser. The oxidation kinetics model for the dye is based on the consideration of two parallel reactions in the reactor. The first step involves a fast decomposition reaction that results in the production of primary products. In the second step, the primary products react further with ozone at a slower rate to produce secondary end products. Depending on the relative rates of reaction and mass transfer, the gas-liquid reactions can occur in the liquid film, the bulk liquid, or a combination of both. The decolorization reaction is moderately fast, and is assumed to occur in the film and the bulk liquid. The second reaction is slow, and is assumed to occur in the bulk liquid only. This paper will present model development, model verification with experimental data, and sensitivity analyses to optimize the performance of stirred tank ozonation systems. A. P. Mathews et al., J Pet Environ Biotechnol 2013, 4:6 http://dx.doi.org/10.4172/2157-7463.S1.004

An experimental study of gas flooding to improve oil recovery in shale oil cores

I this work we examined the photocatalytic decomposition of hydrogen sulfide on Fe2O3 and TiO2-containing natural materials kaolinites under UV irradiation. As the initial materials were taken kaolinite clays of Kazakhstan deposits (No 1 and No 2). The process was studied in the quartz reactor at the temperature of 40 800C. The source of UV radiation was a mercury UV lamp power of 100 watts. Catalysts was treated preliminary thermal activation in the stream of hydrogen sulfide at 5000C for 2 hours. The catalysts were tested by methods: electron microprobe analysis («Superprobe -733», JEOL), XRD (DRON 4 * 0.7 Cu Kα -irradiation), BET by low temperature nitrogen adsorption, Mössbauer and EPR spectroscopy, electron microscopy (TEM). It is shown that the samples No 1 and No 2 contain 4.8 and 6.0 wt.% Fe2O3 and 0.4 and 0,6% TiO2, accordingly. The specific surface of the samples No 1 and No 2 (49.1 and 92.1 m2 / g), pore volume (0.119 and 0.287 cm3 / g) and their size distribution were determined. It is shown that the sample No 2 is more active than sample No1 that is accounted by high content of iron and titanium oxides and greater specific surface. In case of H2S low concentrations in the gas mixture (3 and 6%) the catalyst decomposed with 100% H2S conversion to H2 and S indefinitely long time at the space velocities of 510 530 h -1. When the concentration of H2S increased to 25% complete decomposition H2S is observed on the sample with high content of titanium and iron oxides at space velocities 311 320 h-1. It was suggested that the active sites of the hydrogen sulphide decomposition are reduced forms of iron and titanium based on the results of Mössbauer, EPR spectroscopy and electron microscopy. N. A. Zakarina et al., J Pet Environ Biotechnol 2013, 4:6 http://dx.doi.org/10.4172/2157-7463.S1.004B is the main partial substitute for petrodiesel. Some biodiesels have low oxidative stability. To solve or minimize this problem, some compounds have been added to biodiesel as antioxidants. Phenolic compounds are common antioxidants used by the vegetable oil industries. There are studies examining commercial antioxidants that are already being used in biodiesel: Baynox® plus (2,2′‐methylene‐bis‐(4‐methyl‐6‐tert.‐butylphenol); N,N′-di-sec-butyl-p-phenylenediamine, PDA) and seven phenolic antioxidants, including butylated hydroxyanisole (BHA); butylated hydroxytoluene (BHT); 2,5-di-tert-butylhydroquinone (DTBHQ); 2,2′-methylene-bis-(4-methyl-6-tert-butylphenol) (MBMTBP); PG; pyrogallol (PY); and Tert butylhidroquinone (TBHQ). However, few studies have reported on the efficiency of aromatic amines used as antioxidants. One of the most efficient classes of compounds used for this is aromatic diamines because of their high antioxidant capacity at low concentration. The advantage of using amines is that this functional group does not often appear as a natural antioxidant in vegetable oils; therefore, these compounds can be used as artificial markers in biodiesel industries. Aromatic diamines can be used as artificial markers. It is sometimes necessary to determine the concentration of antioxidants in biodiesel after long storage times or to control quality. An easy to use spectrophotometric methodology was employed in this work to determine the concentration of aromatic diamines (0 to 500 ppm). We tested a use of this method as screening method based on IR spectroscopy, to identify antioxidant (phenolic and aromatic) into biofuel. Five calibration curves were constructed using 3 absorption frequencies from the infrared spectra of the samples. The standard deviation, correlation coefficient, linearity range, limit of detection and limit of quantification were determined. The better results from the easy to use method (814 cm−1) show a linear range of 0–100 ppm with a strong correlation (R2 = 0.9966) and a limit of quantification of 21.6 ppmWastewater contaminated with olive oil which simulates the olive oil mills has been treated by means of Advanced Oxidation Processes (AOPs). The Fe(II)/H2O2 system (Fenton’s reagent), Fe(II)/H2O2/UV system (solar-photo-Fenton’s reagent) and the UV-photolysis were applied. A synthetic wastewater generated by emulsifying olive oil and water was used. Experiments were carried out using a concentrating Parabolic Trough Reactor (PTR). Oil is readily degradable, the sunlight is captured by ferrioxalate which, in the presence of hydrogen peroxide, generates hydroxyl radicals that oxidizes organic molecules. In addition, the process efficiency is increased by using oxalic acid. Typical operating variables such (H2O2 and Fe(II)) exerted a positive influence on the treatment efficiency. The optimum working pH on the Fenton treatment was found to be in the range 2.5-3.0. Response Surface Methodology (RSM) based on the experimental design was applied to optimize the Fenton oxidation process. هريبك تايمك جاتناب طبترت جاتنلاا هيلمع نكلو طسوتملا رحبلا ضوح هقطنم يف تاعانصلا مدقا نم نوتيزلا تويز جاتنا ربتعي هيمك يلع يوتحت يتلا هلئاسلا تافلخملا نم ك هيوضعلا تافلخملا نم هريب نكادلا اهنولب زيمتتو . ظ هريخلاا هنولاا يف تره ب هجلاعملا هيلمع تايلمعلا هذه مها نمو همدقتملا هدسكلاا تايلمع أم لماع ربتعي يذلاو نوتنف وتوفلا مدحتسي هئيبلل قيدص دسك هيف نيجورديهلا ديسكا قوفو ديدحلا ديساكا . مادختسا مت كلذ يلا هفاضلااب RSM يلثملا ميقلا داجيلا ل لعافتلل قيقحت يلعا هيوضعلا داوملا هلازلا هميق يلثملا هميقلا تناكو ب يصوملا لعافتلا طسو هيضماح هجردل ه 2.5-3.0 . هبسن نا جئاتنلا تحضوا يلا تلصو هيوضعلا داوملا هلازا 56 %article i nfo This study describes a detailed characterization of the oil obtained by co-pyrolysis of Tarfaya oil shale (Morocco) and high density polyethylene (HDPE) and by pyrolysis of oil shale and HDPE individually. The oil (obtained underthemostsuitable conditions, temperatureof500-525 °C and heating rate of10 °C/min) wascharacterised by elemental analysis, nuclear magnetic resonance spectroscopy ( 1 H NMR) and Fourier transform infrared spec- troscopy (FTIR). In addition, column chromatography was used group composition of oil was determined. Gas chromatography was achieved on n-hexanefractions.Adding HDPE to the oil shale results inincreased oil yields, whichindicatessynergeticeffectbetweentheoilshaleandHDPE.TheadditionofHDPEtooilshaleimprovedfuel properties of shale oil leading to a decrease in the oxygen content of shale oil. The results show that the oil obtainedbyco-pyrolysishassimilarpropertieswithcommercialgasoline.HDPEactsasahydrogenationmedium for the oil shale product as revealed by FTIR results.This thesis is a theoretical and empirical examination of the developmentof bioethanol markets since 2005 when sustainability regulations forbiofuels were introduced globally. The experiences of Brazil and Sweden,and the influence of European regulations on the development ofbioethanol markets receive special attention. The work is based onprimary and secondary data sources gathered between 2009 and 2014,including interviews, field research, data from public and private sources,as well as an extensive literature review. The thesis uses case examples ofcountries that have adopted bioethanol as a transport fuel, such as Braziland Sweden.The research is structured using a bottom-up approach, and addressesthree specific angles of the complex issue of how bioethanol marketshave developed under sustainability requirements.The first part introduces an economic sustainability view of ethanol. Thecharacteristics of bioethanol fuel are presented together with conceptsand a theoretical framework for analysing biofuel sustainability. Policytools are also discussed, particularly those used to introduce fuel ethanolin the transport sector. The discussion is centred on the competitionbetween ethanol and gasoline, considering the hypothesis that consumersare sensitive to prices and tend to choose fuels based on their cost-perenergyunit. The analysis is supported by the case examples of Brazil andSweden, with special focus on the delicate balance between fueleconomies of bioethanol and gasoline systems in the face of differentways oil products are priced in those countries. Findings show thatdrivers tend to choose between bioethanol (E85/E100) or gasoline (E5-E25) depending on the relative prices between the two fuels. Theresearch results suggest that different pricing strategies for bioethanoland gasoline affect how consumers perceive the attractiveness of eachfuel. The examples of E100 in Brazil and E85 in Sweden provide insightson the elastic consumer behaviour that new markets may experience,serving to guide strategies in different contexts.The second part of this work bridges experiences in national contextswith the recent trend for biofuel sustainability regulation in internationalmarkets. Based on the hypothesis that the ethanol industry is responsiveto sustainability regulations, an examination of the development of theiiBrazilian bioethanol industry is carried out. This provides a comparisonframework drawing patterns between the industrys reaction to nationalregulations (past) and international regulations (recent). For this purpose,a comparison between the European sustainability requirements forethanol and the industry’s status quo is explored. Findings show that theEU sustainability criteria for biofuels are likely to have three effects onthe bioethanol industry: (i) compliance through incrementalimprovements in sustainability practices and certification; (ii) riskdiversification by engaging in multi-output production models; and (iii)market leakage towards less-regulated markets.The third part of the thesis brings together the first two parts. Itexamines how in a fuel competition context, the incorporation of costsrelated to sustainability certification can change the attractiveness ofhigh-bioethanol blends for consumers. The model of sustainabilityadopted by major international markets is based on regulations enforcedby mandatory certification. As biofuel market share increased, producerswere faced with costs for sustainability certification in order to obtainmarket access. While it was expected that ‘sustainably’ produced biofuelswould be rewarded with higher prices in the EU, this work found thatprice premiums for ethanol have in general been very small or inexistent,with certified fuels becoming the new norm in the market. New costsbrought into the market through sustainability certification can make itdifficult to balance between national policies heavily reliant on consumerchoice between fuels (and associated price-elasticities), and thedeployment of high blends of ethanol, such as E100 and E85.By analysing the three aspects (consumer behaviour and marketdynamics for ethanol in Brazil and Sweden, the introduction ofsustainability criteria for biofuels, and the implications of sustainabilityfor consumer choice between fuels) this work seeks to increaseunderstanding of the highly complex issue of biofuel market formationin the face of sustainability requirements. The key finding is thatsustainability certification has a cost, which needs to be orchestrated withother sectors of the economy to achieve the desired objectives. Thisthesis suggests that crucial areas of economic and environmentalsustainability have been often dealt with separately in biofuelpolicymaking, which has created weaknesses that deserve attention infuture policy efforts in order to improve biofuel systems.T presence of high molecular weight organic compounds such as dyes, pharmaceuticals, and endocrine disruptors in receiving waters is of concern due to their toxicity and carcinogenicity to humans and aquatic organisms. Ozone is a powerful oxidant that can be used to oxidize such compounds in effluents. However, the use of ozone in these applications is somewhat limited at present due to the relatively high cost of ozone and ozonation systems. This is in part due to mass transfer limitations, and the lack of understanding of fundamental factors that contribute to poor utilization of applied ozone. Previous studies have concluded that mass transfer of ozone form the gas to the liquid phase is the main rate limiting step in ozonation. However, with high molecular weight compounds, the diffusion and transport of the compound to the reaction plane, the production of byproducts and secondary reactions, can also influence the overall oxidation kinetics. In this study, the mass transfer and reaction kinetics regimes are modeled based on fundamental principles and applied to analyze the oxidation of a high molecular weight dye in a stirred tank reactor with a bubble diffuser. The oxidation kinetics model for the dye is based on the consideration of two parallel reactions in the reactor. The first step involves a fast decomposition reaction that results in the production of primary products. In the second step, the primary products react further with ozone at a slower rate to produce secondary end products. Depending on the relative rates of reaction and mass transfer, the gas-liquid reactions can occur in the liquid film, the bulk liquid, or a combination of both. The decolorization reaction is moderately fast, and is assumed to occur in the film and the bulk liquid. The second reaction is slow, and is assumed to occur in the bulk liquid only. This paper will present model development, model verification with experimental data, and sensitivity analyses to optimize the performance of stirred tank ozonation systems. A. P. Mathews et al., J Pet Environ Biotechnol 2013, 4:6 http://dx.doi.org/10.4172/2157-7463.S1.004