Analytical Model to Quantify Crude Oil Spill Volume in Sandy Layered Aquifers

Crude oil spills have far-reaching consequences not only from the point of view of economic considerations but also from the point of view of environmental pollution. This is particularly important in oil-producing countries like Saudi Arabia. In an attempt to study this phenomenon further, an analytical and experimental study was undertaken. In this study analytical estimation of crude oil spills in layered sandy soils was performed by vertically integrating the oil content function. This function exhibits discontinuities at the interfaces of different soil layers. The influence of layering on the estimation process was examined by comparing the analytical results with and without the layering. An experimental setup was used to assess the predictions of the analytical model formulated. The experimental results, for homogeneous soils, were compared with predictions of previous analytical and empirical models. This study shows that analytical as well as empirical models consistently underestimate the actual spill volume in soils. Furthermore, analytical predictions were shown to depend on how close the system was to hydrostatic equilibrium. It also shows that soil layering is a very significant factor that should be incorporated in quantifying the extent of aquifer contamination.     

Oil Spill Dispersant Effectiveness Protocol. I: Impact of Operational Variables

The current U.S. Environmental Protection Agency protocol for testing the effectiveness of dispersants, the swirling flask test, has been found to give widely varying results in the hands of different testing laboratories. The sources of the ambiguities in the test were determined by considering several options in a rigorous systematic fashion. Options considered were variability among three operators and the variability and limitations of three analytical instruments in establishing a calibration curve for oil/dispersant mixtures. Other options included flask type, impact of operational variables (rotational speed, mixing time, settling time, and oil:dispersant ratio), development of a revised procedure for dispersant effectiveness, reproducibility and repeatability of the revised procedure, and development of selection criteria for screening of dispersants. A redesign of the test flask, which is characterized by having baffles with a stopcock at the bottom for sample collection, was deemed necessary to accomplish reproducibility within operator and between operators. The results indicated that the baffled flask provided a total coefficient of variation (variations within operator and between operators) less than 11% compared to above 100% in some cases for the swirling flask.     

Oil Spill Dispersant Effectiveness Protocol. II: Performance of Revised Protocol

The current U.S. Environmental Protection Agency (EPA) protocol for testing the effectiveness of dispersants for use in treating oil spills on the open water, the swirling flask test (SFT), has been found to give widely varying results in the hands of different testing laboratories. Part I addressed the sources of the ambiguities in the EPA SFT and the development of a new test referred to as the baffled flask test (BFT). In this part of the series, further experiments were conducted for estimating the repeatability of three operators in determining the effectiveness of 18 dispersants by both the EPA SFT and the BFT methods. Overall statistical analysis of the results indicated that the coefficient of variation by the BFT was only 7.8% compared to 21.9% for the EPA SFT. The mean percent effectiveness of the EPA SFT was only 19.7% as compared to 64.6% for the BFT. Proposed selection criteria for screening of dispersants for listing on the National Contingency Plan Product Schedule have been developed.     

Effects of Clay Content and Temperature on Crude Oil (Nonvolatile Components) Transport in Unsaturated Soils: Centrifuge Study

Surface soil contamination due to oil spill is one of the major environmental concerns. The extent of the contaminated depth governs the design and installation of remediation method and monitoring system. Physical modeling of oil contaminant in unsaturated soils was conducted using a centrifuge. Preliminary results on effects of clay content and temperature on the contaminant profile near the surface are presented. The experimental results indicate that centrifuge modeling may be a viable method to study the problem of immiscible oil movement in partially water-saturated soils.     

Comparative Absorption of Crude Oil from Fresh and Marine Water Using Recycled Rubber

Crude oil spillage is a major environmental pollution in the Niger–Delta area of Nigeria. The use of recycled rubber from enormous available scrap tires for pollution control of oil-polluted fresh and marine water and the attendant survival of aquatic organisms (fish) in these polluted waters was investigated. The absorption capacity of rubber particles for the oil was the same in both the oil-polluted fresh and marine waters and depended on the rubber particle size and temperature of absorption. The survival time of the fish depended on the amount of rubber added to and the dissolved oxygen (DO) concentration in the oil-polluted waters. The survival time increased from 3.5 to 7.25?h as the rubber to oil ratio was increased from 0.5 to 2.5. At a ratio of 3, the oil film on the water was no longer continuous and the survival time increased to 6,000?h. The survival time increased with the DO concentration in polluted water. In the absence of added rubber particles, the DO concentration decreased within 2?h from 5.27?mg/L to less than 3?mg/L, a value below the limit required for aquatic organism survival.     

Enhancing the Biodegradation of Polycyclic Aromatic Hydrocarbons: Effects of Nonionic Surfactant Addition on Biofilm Function and Structure

The application of surfactants for the bioremediation of sites contaminated with polycyclic aromatic hydrocarbons has been widely reported, because they are known to increase PAH solubility and desorption, thereby enhancing their bioavailability to biofilm microorganisms. The effects of a nonionic surfactant on the biodegradation of PAHs in porous media, as well as the fate of the surfactant, were investigated in this study. Column experiments in the presence of the surfactant showed that the degradation of the two-ring PAH alone was not significantly affected, but that there was a small enhancement of three- and four-ring PAH degradation when they were present as sole substrates and when using Triton X-100. This was due to the higher solubility of the PAHs in the presence of the surfactant. Biofilm seemed to respond well to binary mixtures of phenanthrene–naphthalene and pyrene–naphthalene, with removals of 45.5 and 24.1%, respectively, in the presence of the surfactant; however, higher biodegradations were always achieved by having just PAH mixtures without the surfactant, indicating the importance of cometabolic mechanisms over improved solubilization of PAHs. Optical sections taken using a confocal laser scanning microscope allowed observation of a heterogeneous web-like matrix of biofilm, with diverse biological aggregate structures.     

螺旋板换热器在粗苯贫富油换热的应用

分析了浮头式列管换热器的故障现象及产生原因,提出改造方案,并根据改造后的实际情况将脱苯塔和贫富油换热器部分的贫油工艺进行了合理改进。该项目具有投资少、工艺合理、操作简单、使生产更加稳定、极大地提高了粗苯生产的开工率和收率、减少生产成本等特点。     

韶钢6 m焦炉粗苯一段热贫油余热回收的探讨

基于韶钢6m焦炉粗苯一段热贫油生产现状的分析,通过计算一段热贫油换热器的余热量,同时结合脱硫再生系统再沸器的实际使用情况,就余热利用的可行性进行了探讨,并对余热利用的具体途径提出了工艺改进建议.余热回收的实施,可望对企业经济发展和节能环保产生深远的影响.     

我国油,气长输管道建设及相关行业的发展前景

介绍了我国石油、天然气长输管道敷设的现状及与世界总体水平的比较，分析了今后发展前景及对相关行业的推动作用。     

钢中夹杂物对石油套管螺纹加工性能的影响

在石油套管螺纹加工的过程中,出现断扣问题,为此,对管体进行了气体含量及热酸低倍检验,利用金相显微镜和扫描电镜对其进行微观分析,分析表明,非金属夹杂物是引起断扣的主要原因;同时对夹杂物做了定性分析,找出其来源,并提出相应的改进措施。     

矿山高压供电架空线路防雷措施及效果

矿山高压供电系统的稳定性对矿山企业的生产和安全起着至关重要的作用,而雷电因其突发性和不确定性经常通过高压供电架空线路给矿山用电设备造成巨大影响和损失。为减少因雷电带来的损失,桓仁矿业有限公司对松兰矿、向阳矿的高压供电线路加装了避雷线,在配电室附近安装避雷针等措施。经过几年的实践证明,防雷效果显著。     

油气混烧技术在轧钢加热炉上的应用

介绍了油气混烧节能技术在长钢二轧厂燃油加热炉上的应用;利用低热值的高炉煤气替代部分重油,获得了明显的经济效益和环保效益,具有较好的推广应用价值。     

Effect of Cd(II) on Different Bacterial Species Present in a Single Sludge Activated Sludge Process for Carbon and Nutrient Removal

Heavy metal cadmium(II) was added stepwise into an A2O pilot plant to investigate the toxic effects of Cd(II) on the removal efficiencies, kinetic parameters (yield coefficients and maximum specific growth rates) and reaction rates of carbon, nitrogen and phosphate for the acclimatized heterotrophic and autotrophic bacteria. Results showed that 2?mg/L Cd(II) initially affected the biological reaction of phosphate removal. At Cd(II) 5?mg/L, the efficiencies of total nitrogen removal and nitrification were substantially dropped. At the same time, the yield coefficient and maximum specific growth rate of heterotrophs were significantly decreased from 0.8?g?COD/g?COD and 6.44?day?1 to 0.54?g?COD/g?COD and 4.67?day?1, respectively. And, the denitrification rate was inhibited by about 61%. The inhibition percentages of anaerobic release, anoxic and aerobic uptake rates of phosphate were about 76, 64, and 90%, respectively. When Cd(II) concentration was continually increased up to 35?mg/L, removal efficiency of chemical oxygen demand (COD) was significantly dropped. However, there was no obvious inhibition on the biological reactions of anaerobic ammonification.     

Effects of Ethanol versus MTBE on Benzene, Toluene, Ethylbenzene, and Xylene Natural Attenuation in Aquifer Columns

The increased use of ethanol as a replacement for the gasoline oxygenate, methyl tert-butyl ether (MTBE), may lead to indirect impacts related to natural attenuation of benzene, toluene, ethylbenzene, and the three isomers of xylene (BTEX compounds). Ethanol could enhance dissolved BTEX mobility by exerting a cosolvent effect that decreases sorption-related retardation. This effect, however, is concentration dependent and was not observed when ethanol was added continuously (at 1%) with BTEX to sterile aquifer columns. Nevertheless, a significant decrease in BTEX retardation was observed with 50% ethanol, suggesting that neat ethanol spills in bulk terminals could facilitate the migration of pre-existing contamination. MTBE (25 mg/L influent) was not degraded in biologically active columns, and it did not affect BTEX degradation. Ethanol (2 g/L influent), on the other hand, was degraded rapidly and exerted a high demand for nutrients and electron acceptors that could otherwise have been used for BTEX degradation. Ethanol also increased the microbial concentration near the column inlet by one order of magnitude relative to columns fed BTEX alone or with MTBE. However, 16S-ribosomal ribonucleic acid sequence analyses of dominant denaturing gradient gel electrophoresis bands identified fewer species that are known to degrade BTEX when ethanol was present. Overall, the preferential degradation of ethanol and the accompanying depletion of oxygen and other electron acceptors hindered BTEX biodegradation, which suggests that ethanol could increase the length of BTEX plumes.     

Effects of Flood Flow on Flood Plain Soil and Riparian Vegetation in a Gravel River

Field observations were performed to determine the effects of flood flow on the geometrical and chemical characteristics of flood plain soil and the distribution of riparian vegetation in a gravel river. The results of the observations show a decrease in the amounts of the particulate nutrients in the flood plain soil during fairly large flood, because the fine sands that serve as a nutrient source were removed by the flood flow. Numerical simulations for the transport of suspended sediments were performed by varying the peak discharge of the flood, and the change of the particulate nutrients in flood plain soil was estimated by using the results of the simulations. The numerical analysis predicts the reduction of the particulate nutrients in the flood plain soils well. The particulate nutrients on the flood plains decrease if the discharge exceeds the flood of approximately 2 year return period in the observation area.     

震动膜技术在废矿物油处理再生中的应用研究

对国内外几种废矿物油处置工艺进行了分析比较，发现大部分工艺较难达到节能环保的要求．介绍一种应用广泛、成熟可靠、环保节能的新型废矿物油再生技术——震动膜废油处理工艺．该技术已在香港地区得到广泛使用，具有良好的应用前景。     

贮油区火灾、爆炸危险指数评价法

德兴铜矿露天采区电动轮汽车所用的柴油贮油区存在火灾、爆炸的危险,采用火灾、爆炸危险指数法对露天采区柴油贮油区进行安全评价,以确定露天采区柴油贮油区的安全情况,加强安全检查和安全管理,采取保障设备设施的可靠性并避免人为失误等安全措施。     

08MnNiVR储油罐钢模拟焊接热影响区组织与韧性研究

利用焊接热模拟、示波冲击韧性和光学金相试验,研究了不同焊接热循环对鞍钢08MnNiVR储油罐钢板热影响区组织与性能的影响。试验结果表明,08MnNiVR钢板粗晶区在低热输入时具有很高的韧性且组织以粒状贝氏体为主,随着热输入的增加,组织向块状铁素体和珠光体转变,粗晶区的裂纹扩展功降低,韧性恶化。     

1780mm热轧液压系统油温变化分析与控制

为了提高本钢北营轧钢厂1780mm产线的生产能力,保证生产设备的良性运行,对运行过程中主轧线液压系统油温异常的问题进行了分析。根据各液压系统的不同情况,采取有针对性的改进。改进后,各液压系统的运行油温均得到改善,稳定了系统及相关设备的运行。