A Review of the Status of Advanced Technologies for the Detection of Oil in and with Ice

Remote sensors for application to oil in ice and oil with ice are assessed. Radio-frequency methods to detect oil in ice depend on the difference in dielectric properties between oil and water. Freshwater ice is relatively transparent to frequencies below about 200 MHz. Despite extensive theoretical studies, there is a lack of experimental evidence to support the notion that radio-frequency methods have potential.Acoustic methods for the detection of oil in ice show promise. Regular metal inspection equipment is capable of detecting oil layers under ice. Oil propagates shear waves and detection methods based on this unique property are capable of identifying oil in ice. One unit has been built and tested in the field based on this principle.Oil with ice detection is a well developed technology. A common sensor is an infrared camera or an IR/UV (infrared/ultraviolet) system. The inherent weaknesses include the inability to discriminate oil on beaches, among weeds or debris. The laser fluorosensor is a most useful instrument because of its unique ability to identify oil on backgrounds that include water, soil, ice and snow. It is the only sensor that can positively discriminate oil on most backgrounds. Radar offers the only potential for large area searches and foul weather remote sensing, however, there is little potential to detect oil in the immediate vicinity of ice. A major weakness of radar is that it is limited to operation over seas with winds of about 2–8 m/s.Equipment operating in the visible region of the spectrum, such as cameras and scanners, is useful for documentation or providing a basis for the overlay of other data. It is not useful beyond this because oil shows no spectral characteristics in the visible region that can be used to discriminate oil.     

Review of oil spill remote sensing

Airborne and space-borne sensors are reviewed and evaluated in terms of their usefulness in responding to oil spills. Recent developments and trends in sensor technology are illustrated with specific examples. The discussion of the sensors is divided into two main categories, namely active and passive. Active sensors are those that provide their own source of illumination or excitation, whereas passive sensors rely on illumination from a secondary source. A common passive sensor is an infrared camera or an IR/UV (infrared/ultraviolet) system. The inherent weaknesses include the inability to discriminate oil on beaches, among seaweeds or debris. Among active sensors, the laser fluorosensor is a most useful instrument because of its unique capability to identify oil on backgrounds that include water, soil, ice and snow. It is the only sensor that can positively discriminate oil on most backgrounds. Disadvantages include the large size, weight and high cost. Radar offers the only potential for large area searches and foul weather remote sensing. Radar is costly, requires a dedicated aircraft, and is prone to many interferences. Equipment that measures relative slick thickness is still under development. Passive microwave has been studied for several years, but many commercial instruments lack sufficient spatial resolution to be practical, operational instruments. A laser-acoustic instrument, which provides the only technology to measure absolute oil thickness, is under development. Equipment operating in the visible region of the spectrum, such as cameras and scanners, is useful for documentation or providing a basis for the overlay of other data. It is not useful beyond this because oil shows no spectral characteristics in the visible region which can be used to discriminate oil.     

Laser fluorosensor overflights of the Santa Barbara oil seeps

The Emergencies Science Division of Environment Canada recently participated in a series of remote sensing flights over the naturally occurring oil seeps off Santa Barbara, California. During these flights the laser environmental airborne fluorosensor was operated to test its ability to detect oil in an actual marine environment. This joint project was sponsored by the United States Minerals Management Service and the Emergencies Science Division of Environment Canada. The Santa Barbara area of the California coastline contains numerous gas and petroleum deposits, which are slowly released from faults under the water and rise to the surface in the form of gas, oil and tar. In and around several of these seeps are kelp beds that release biogenic material, which can be mistaken for petroleum oil by certain remote sensors and human observers. This biogenic oil does not fluoresce when irradiated with ultraviolet light since it contains none of the aromatic compounds necessary to absorb the ultraviolet light and return fluorescence. The laser environmental airborne fluorosensor is, therefore, able to discriminate between this non-fluorescing oil and petroleum oils, which fluoresce with characteristic spectral signatures and intensities. High-resolution colour reconnaissance camera images and down-looking video images were collected concurrently with the fluorescence data for documentation purposes. Fluorescence data were collected at 100 Hz and correlated in real-time against reference spectra characteristic of light refined, crude and heavy oils. Maps of oil detection locations were produced in flight and printed in the aircraft. This paper will present details of the overflights and post-flight analysis of the fluorescence data using the Pearson correlation coefficient.     

油气生产过程中放空燃烧气的检测与回收利用现状

本文对油气生产中放空燃烧气的检测方法进行了总结,并对国内外放空气回收利用的主要技术进行了比较分析。指出:利用遥感监测数据计算放空燃烧气量具有较好的应用前景,但需同地面常规实测数据结合,改进反演算法,以减少不确定性;采用油气混输、天然气发电、压缩天然气（CNG）、液化天然气（LNG）、液态产品转化等回收利用手段将显著减少放空燃烧气带来的温室气体排放。     

Recovery of the Irving Whale oil barge: Overflights with the laser environmental airborne fluorosensor

In the summer of 1996 the oil barge, Irving Whale, was successfully raised from the depths of the St Lawrence River with the majority of its cargo of bunker C fuel oil intact. As part of the recovery effort, the Emergencies Science Division of Environment Canada performed airborne remote sensing flights over the site of the barge prior to, during and following the lift procedure. The primary sensor employed during these remote sensing flights was the laser environmental airborne fluorosensor (LEAF). Additional equipment on board Environment Canada's DC-3 aircraft included an RC-10 colour mapping camera and two down-looking video cameras.In the days leading up to the lifting of the Irving Whale, the LEAF system detected bunker C fuel oil on the surface of the gulf in close proximity to the location of the sunken barge. This oil was believed to have been dislodged from beneath structures on the top of the barge during inspections, welding and other preparations in advance of the lift. On the actual day of the lift, 30 July, greatly increased amounts of bunker fuel were detected. During each overflight, the real-time LEAF system produced timely, concise map-based oil contamination information in hard-copy form. The locations of the visibly thick and recoverable oil were radioed to spill response personnel on the surface and promptly recovered by booming and skimming operations. In addition, the LEAF system found extremely thin, sub-sheen levels of oil over the majority of the southern Gulf of St Lawrence on the day of the lift. The extent of this coverage was greatly reduced the following day (presumably due to further spreading) and essentially eliminated by 1 August. The LEAF system on the DC-3 continued to monitor the Irving Whale as it was transported to Halifax, Nova Scotia on the deck of the submersible vessel Boabarge 10. During transit no oil which could be attributed to the Irving Whale was detected, apart from a small residual amount at the lift site.     

Three-Dimensional Ground-Based Measurements of Urban Air Quality to Evaluate Satellite Derived Interpretations for Urban Air Pollution

Urban air quality and meteorological measurements were carried out in the region of Brescia (Italy) simultaneously to the acquisition of satellite data during winter and summer smog conditions in 1999. The main objectives of the campaigns were: delivery of data for the validation of air pollution interpretations based on satellite imagery, and determination of the aerosol optical thickness in spectral ranges similar to those used by satellites. During the winter campaign the ground-based network was complemented by local stations and by SODAR, DOAS, and FTIR remote sensing measurements. Size distributions of aerosol particles up to 4,000 m a.s.l. were measured by means of an ultra-light aircraft, which was also equipped with meteorological sensors and an ozone sensor. During the summer campaign an interference filter actinometer, an integrating nephelometer and an ozone LIDAR were operated additionally. The satellite images acquired and processed were taken from SPOT. Optical thickness retrieved from interference filter actinometer measurements were compared with the retrievals from the satellite imagery in the same spectral intervals. It is concluded that remaining aerosols in the reference image yield an off-set in the satellite retrieval data and that information about the vertical structure of the boundary layer is very important.     

The technology windows-of-opportunity for marine oil spill response as related to oil weathering and operations

This paper identifies and estimates time periods as ‘windows-of-opportunity’ where specific response methods, technologies, equipment, or products are more effective in clean-up operations for several oils. These windows have been estimated utilizing oil weathering and technology performance data as tools to optimize effectiveness in marine oil spill response decision-making. The windows will also provide data for action or no-action alternatives. Crude oils and oil products differ greatly in physical and chemical properties, and these properties tend to change significantly during and after a spill with oil aging (weathering). Such properties have a direct bearing on oil recovery operations, influencing the selection of response methods and technologies applicable for clean up, including their effectiveness and capacity, which can influence the time and cost of operations and the effects on natural resources.The changes and variations in physical and chemical properties over time can be modeled using data from weathering studies of specific oils. When combined with performance data for various equipment and materials, tested over a range of weathering stages of oils, windows-of-opportunity can be estimated for spill response decision-making. Under experimental conditions discussed in this paper, windows-of-opportunity have been identified and estimated for four oils (for which data are available) under a given set of representative environmental conditions. These ‘generic’ windows have been delineated for the general categories of spill response namely: (1) dispersants, (2) in situ burning, (3) booms, (4) skimmers, (5) sorbents, and (6) oil-water separators. To estimate windows-of-opportunity for the above technologies (except booms), the IKU Oil Weathering Model was utilized to predict relationships—with 5 m s⁻¹ wind speed and seawater temperatures of 15°C.The window-of-opportunity for the dispersant (Corexit 9527^®) with Alaska North Slope (ANS) oil was estimated from laboratory data to be the first 26 h. A period of ‘reduced’ dispersibility, was estimated to last from 26–120 h. The oil was considered to be no longer dispersible if treated for the first time after 120 h. The most effective time window for dispersing Bonnic Light was 0–2 h, the time period of reduced dispersibility was 2–4 h, and after 4 h the oil was estimated to be no longer dispersible. These windows-of-opportunity are based on the most effective use of a dispersant estimated from laboratory dispersant effectiveness studies using fresh and weathered oils. Laboratory dispersant effectiveness data cannot be directly utilized to predict dispersant performance during spill response, however, laboratory results are of value for estimating viscosity and pour point limitations and for guiding the selection of an appropriate product during contingency planning and response. In addition, the window of opportunity for a dispersant may be lengthened if the dispersant contains an emulsion breaking agent or multiple applications of dispersant are utilized. Therefore, a long-term emulsion breaking effect may increase the effectiveness of a dispersant and lengthen the window-of-opportunity.The window-of-opportunity of in situ burning (based upon time required for an oil to form an emulsion with 50% water content) was estimated to be approximately 0–36 h for ANS oil and 0–1 h for Bonnie Light oil after being spilled. The estimation of windows-of-opportunity for offshore booms is constrained by the fact that many booms available on the market undergo submergence at speeds of less than 2 knots. The data suggest that booms with buoyancy to weight ratios less than 8:1 may submerge at speeds within the envelope in which they could be expected to operate. This submergence is an indication of poor wave conformance, caused by reduction of freeboard and reserve net buoyancy within the range of operation. The windows-of-opportunity for two selected skimming principles (disk and brush), were estimated using modeled oil viscosity data for BCF 17 and BCF 24 in combination with experimental performance data developed as a function of viscosity. These windows were estimated to be within 3–10 h (disk skimmer) and after 10 h (brush skimmer) for BCF 17. Whereas for BCF 24, it is within 2–3 d (disk skimmer) and after 3 d (brush skimmer).For sorbents, an upper viscosity limit for an effective and practical use has in studies been found to be approximately 15,000 cP, which is the viscosity range of some Bunker C oils. Using viscosity data for the relative heavy oils, BCF 17 and BCF 24 (API gravity 17 and 24), the time windows for a sorbent (polyamine flakes) was estimated to be 0–4 and 0–10 d, respectively. With BCF 24, the effectiveness of polyamine flakes, was reduced to 50% after 36 h, although it continued to adsorb for up to 10 d. For BCF 17, the effectiveness of polyamine flakes was reduced to 50% after 12 h, although it continued to adsorb for up to 4 d. The windows-of-opportunity for several centrifuged separators based upon the time period to close the density gap between weathered oils and seawater to less than 0.025 g ml⁻¹ (which is expected to be an end-point for effective use of centrifugal separation technology), were estimated to be 0–18 (ANS) and 0–24 h (Bonnie Light) after the spill. Utilizing the windows-of-opportunity concept, the combined information from a dynamic oil weathering model and a performance technology data base can become a decision-making tool; identifying and defining the windows of effectiveness of different response methods and equipment under given environmental conditions. Specific research and development needs are identified as related to further delineation of windows-of-opportunity.     

Waste gasification vs. conventional Waste-to-Energy: a comparative evaluation of two commercial technologies

A number of waste gasification technologies are currently proposed as an alternative to conventional Waste-to-Energy (WtE) plants. Assessing their potential is made difficult by the scarce operating experience and the fragmentary data available. After defining a conceptual framework to classify and assess waste gasification technologies, this paper compares two of the proposed technologies with conventional WtE plants. Performances are evaluated by proprietary software developed at Politecnico di Milano and compared on the basis of a coherent set of assumptions. Since the two gasification technologies are configured as “two-step oxidation” processes, their energy performances are very similar to those of conventional plants. The potential benefits that may justify their adoption relate to material recovery and operation/emission control: recovery of metals in non-oxidized form; collection of ashes in inert, vitrified form; combustion control; lower generation of some pollutants.     

Description of a field experiment to measure leachate formation from oil shale wastes

This paper describes an experimental program that measured the formation of leachate from wastes expected from a mining operation on the Rundle oil shale resource in north-eastern Australia. The experiment, located in a remote situation at the proposed disposal site, consisted of eight lysimeters, a weather station and instruments to monitor the processes occurring within the lysimeters. The paper also presents measurements of meteorological processes and moisture movement observed within the waste materials. The information obtained was used in the development of a predictive mathematical model to explain leachate formation and movement (to be presented elsewhere).     

The Svalbard Intertidal Zone: A Concept for the Use of GIS in Applied Oil Sensitivity,Vulnerability and Impact Analyses

Historical oil spills have shown that environmental damage on the seashore can be measured by acute mortality of single species and destabilisation of the communities. The biota, however, has the potential to recover over some period of time. Applied to the understanding of the fate of oil and population and community dynamics, the impact can be described by the function of the following two factors: the immediate extent and the duration of damage. A simple and robust mathematical model is developed to describe this process in the Svalbard intertidal. Based on the integral of key biological and physical factors, i.e., community specific sensitivity, oil accumulation and retention capacity of the substrate, ice-cover and wave exposure, the model is implemented by a Geographical Information System (GIS) for characterisation of the habitat’s sensitivity and vulnerability. Geomorphologic maps and georeferenced biological data are used as input. Digital maps of intertidal zone are compiled, indicating the shoreline sensitivity and vulnerability in terms of coastal segments and grid aggregations. Selected results have been used in the national assessment programme of oil development in the Barents Sea for priorities in environmental impact assessments and risk analyses as well as oil spill contingency planning.     

Oil and water separation in marine oil spill clean-up operations

This paper discusses the changes in spilled oil properties over time and how these changes affect differential density separation. It presents methods to improve differential density, and operational effectiveness when oil-water separation is incorporated in a recovery system. Separators function because of the difference in density between oil and seawater. As an oil weathers this difference decreases, because the oil density increases as the lighter components evaporate. The density also increases as the oil incorporates water droplets to form a water-in-oil emulsion. These changes occur simultaneously during weathering and reduce the effectiveness of separators. Today, the state-of-the-art technologies have limited capabilities for separating spilled marine oil that has weathered.For separation of emulsified water in an emulsion, the viscosity of the oil will have a significant impact on drag forces, reducing the effect of gravity or centrifugal separation. Since water content in an emulsion greatly increases the clean up volume (which can contain as much as two to five times as much water as the volume of recovered oil), it is equally important to remove water from an emulsion as to remove free water recovered owing to low skimmer effectiveness. Removal of both free water and water from an emulsion, has the potential to increase effective skimming time, recovery effectiveness and capacity, and facilitate waste handling and disposal. Therefore, effective oil and water separation in marine oil spill clean-up operations may be a more critical process than credited because it can mean that fewer resources are needed to clean up an oil spill with subsequent effects on capital investment and basic stand-by and operating costs for a spill response organization.A large increase in continuous skimming time and recovery has been demonstrated for total water (free and emulsified water) separation. Assuming a 200 m³ storage tank, 100 m³ h⁻¹ skimmer capacity, 25% skimmer effectiveness, and 80% water content in the emulsion, the time of continuous operation (before discharge of oil residue is needed), increases from 2 to 40 h and recovery of oil residue from 10 to 200 m³.Use of emulsion breakers to enhance and accelerate the separation process may, in some cases, be a rapid and cost effective method to separate crude oil emulsions. Decrease of water content in an emulsion, by heating or use of emulsion breakers and subsequent reduction in viscosity, may improve pumpability, reduce transfer and discharge time, and can reduce oily waste handling, and disposal costs by a factor of 10. However, effective use of emulsion breakers is dependant on the effectiveness of the product, oil properties, application methods and time of application after a spill.     

Development of Quantitative Methods For Spill Response Planning: A Trajectory Analysis Planner

In planning for response to oil spills, a great deal of information must be assimilated. Typically, geophysical flow patterns, ocean turbulence, complex chemical processes, ecological setting, fisheries activities, economics of land use, and engineering constraints on response equipment all need to be considered. This presents a formidable analysis problem. It can be shown, however, that if an appropriate set of evaluation data is available, an objective function and appropriate constraints can be formulated. From these equations, the response problem can be cast in terms of game theory or decision analysis and an optimal solution can be obtained using common scarce-resource allocation methods. The optimal solution obtained by this procedure maximizes the expected return over all possible implementations of a given set of response options. While considering the development of an optimal spill response, it is useful to consider whether (in the absence of complete data) implementing some subset of these methods is possible to provide relevant and useful information for the spill planning process, even though it may fall short of a statistically optimal solution. In this work we introduce a trajectory analysis planning (TAP) methodology that can provide a cohesive framework for integrating physical transport processes, environmental sensitivity of regional sites, and potential response options. This trajectory analysis planning methodology can be shown to implement a significant part of the game theory analysis and provide `minimum regret' strategy advice, without actually carrying out the optimization procedures.     

Review of state of the art methods for measuring water in landfills

In recent years several types of sensors and measurement techniques have been developed for measuring the moisture content, water saturation, or the volumetric water content of landfilled wastes. In this work, we review several of the most promising techniques. The basic principles behind each technique are discussed and field applications of the techniques are presented, including cost estimates. For several sensors, previously unpublished data are given. Neutron probes, electrical resistivity (impedance) sensors, time domain reflectometry (TDR) sensors, and the partitioning gas tracer technique (PGTT) were field tested with results compared to gravimetric measurements or estimates of the volumetric water content or moisture content. Neutron probes were not able to accurately measure the volumetric water content, but could track changes in moisture conditions. Electrical resistivity and TDR sensors tended to provide biased estimates, with instrument-determined moisture contents larger than independent estimates. While the PGTT resulted in relatively accurate measurements, electrical resistivity and TDR sensors provide more rapid results and are better suited for tracking infiltration fronts. Fiber optic sensors and electrical resistivity tomography hold promise for measuring water distributions in situ, particularly during infiltration events, but have not been tested with independent measurements to quantify their accuracy. Additional work is recommended to advance the development of some of these instruments and to acquire an improved understanding of liquid movement in landfills by application of the most promising techniques in the field.     

Remote sensing systems considerations and user requirements for oil spill surveillance

New communications technology coupled with using GIS and GPS technology gives an opportunity to bridge the gap from the sensor-equipped aircraft to the user of the information. Finally, remote sensing information can be delivered in a form that is tailored to the needs of the end user. The challenge today is to keep to simple systems that make sense operationally rather than try to integrate every new technology.     

Biodegradation Behavior of Some Vegetable Oil-Based Polymers

The potential biodegradability of several vegetable oil-based polymers was assessed by respirometry in soil for 60–100 days at temperatures of 30–58°C. Films of soybean oil and linseed oil which were oxidatively polymerized (Co catalyst) on a kraft paper support were 90%–100% mineralized to CO₂ after 70 days at 30°C. Mineralization of polymerized tung oil to CO₂ was much slower than soy or linseed oils. Mineralization of epoxy resins made from epoxidized soybean oil (ESO) and aliphatic dicarboxylic acids was rapid while mineralization of similar resins made with a triacid (citric) was slower. There was no significant degradation of polyamine/ESO resins after 100 days at 58°C. Mineralization of the available carbon in vegetable oil polyurethanes and cationically polymerized ESO was less than 7.5% after 70 days at 30°C and 25 days at 55°C compared to 100% for soybean oil. From these results, it appears that triglycerides highly cross-linked with non-degradable linkages are not biodegradable to a significant extent while triglycerides cross-linked with hydrolysable bonds such as esters remain biodegradable.     

Dynamic modelling of oil boom failure using computational fluid dynamics

The common response to an oil spill on water is to contain the oil with booms and recover it with skimming devices. In some situations, however, the booms cannot hold the oil and the oil will escape underneath the boom due to hydrodynamic forces. Computational fluid dynamics (CFD) is a powerful modelling tool combining fluid dynamics and computer technology. We have utilized a commercial CFD program, Fluent, to simulate the oil-water flow around a boom. The studies accurately model channel experiments conducted in recent years. The studies show that the flow patterns around booms are modified by the presence of oil and, therefore, suggest that towing and wave-conformity tests of booms will not be meaningful unless they are undertaken with the presence of oil.     

Odour management and treatment technologies: an overview

There is a large variety of options available for the effective treatment of odorous emissions. The most important physical, chemical and biological treatment processes are shortly described and their favourable applications, as well as their limits, are highlighted. But for a sustainable solution of an industrial odour problem, there is more involved than just the installation of a waste gas treatment system. This article focuses on a general and systematic approach towards extensive odour management. First of all, an odour assessment should be worked out where all actual and potential odour emission sources are recorded and characterised. A special focus should be set on fugitive emissions, which may have an enormous impact on the overall odour problem. They need to be captured before they can be supplied to a treatment system. According to the composition and condition of the waste gases, an appropriate treatment system must be selected. For this purpose, test systems have been developed and are presented in this article.     

Australia’s Tyranny of Distance in Oil Spill Response

In view of the quantity of oil spilled, smaller spills generally receive less attention than headline grabbing incidents such as the “Amoco Cadiz”, “Exxon Valdez”, “Braer” and “Sea Empress”. The latter incidents involve the loss of significant quantities of oil, the establishment of relatively complex spill response management structures and the involvement of significant numbers of personnel and equipment. As such, large spills from tankers have the potential to create problem areas, for example in establishing and maintaining effective communications, logistics and resource management systems.In general terms spill response personnel are well aware that large spills come complete with significant operational and administrative problems, however what may not be so well recognised is that smaller spills also have the potential to present response personnel with their own unique problems.One of the major problems to be overcome when responding to spills in Australia is the “tyranny of distance”. In quite a few responses, Australian oil spill response managers have had to move personnel and equipment thousands of kilometres to provide an effective outcome. This paper outlines a range of problems that have been encountered by Australian personnel over the years. These include health and safety, communications, logistics and equipment issues.For the purpose of this paper a “smaller” spill has been defined as one involving a discharge of less than 1000 tonnes of oil.     

Oil Spill Contingency and Response (OSCAR) Analysis in Support of Environmental Impact Assessment Offshore Namibia

The work reported here encompasses analyses of specific potential spill scenarios for oil exploration activity planned offshore of Namibia. The analyses are carried out with the SINTEF Oil Spill Contingency and Response (OSCAR) 3-dimensional model system. A spill scenario using 150 m³ of marine diesel demonstrates the rapidity with which such a spill will dissipate naturally, even in light winds. Vertical and horizontal mixing bring subsurface hydrocarbon concentrations to background levels within a few days. A hypothetical 10 day blowout scenario releasing 11,000 bbl per day of light crude oil is investigated in terms of the potential for delivering oil to selected bird and marine mammal areas along the Namibian coast. Worst case scenarios are selected to investigate the potential mitigating effects of planned oil spill response actions. Mechanical recovery significantly reduces, and in some cases eliminates, potential environmental consequences of these worst case scenarios. Dispersant application from fixed wing aircraft further reduces the potential surface effects. The analysis supplies an objective basis for net environmental analysis of the planned response strategies.