Microwave radiometer system for the detection of oil slicks

A major problem of radiometric sensors in the detection of oil spills on the sea is differentiating the oil spill from other objects on the water surface such as rough areas, areas with warm and cold streams, oil-water emulsions, areas with seaweed, etc. A procedure to convert antenna temperatures to brightness temperatures and then to the oil thickness is described. Generally, a calibration procedure at the start of each experiment is needed. In order to develop and test these procedures, a polarization method has been designed for remotely detecting an oil slick. This required building three radiometers operating in the millimeter-wave bands (W, W_a, k_u) as well as associated laboratory test equipment. Experimental results, obtained in the laboratory and in an outdoor test facility, conform well with theoretical computations using an air-oil-water stratified layer model. This new method of microwave radiometry by measuring its polarization contrasts at two orthogonal polarizations is a next step in the development of microwave sensors for detecting oil spills.     

Effectiveness of “Nochar” Solidifier Polymer in Removing Oil from Open Water in Coastal Wetlands

The use of solidifier in oil spill cleanup has been minimal due to lack of practical application method and in situ field testing and evaluation under various coastal and environmental conditions. Solidifiers are dry granular, hydrophobic polymers that react with oil and form a cohesive mass that floats on water. Unlike sorbents, the oil is retained in the solid mass allowing for easy removal. A field test was conducted in coastal Louisiana in which replicated open water enclosures were oiled with South Louisiana Crude. Granular solidifier was spread over oil and the solidified oil was then removed from the plots. Over 70% of the applied oil was recovered. Results demonstrated that solidifier may, under certain conditions, be an option for removing oil from wetlands.     

Biodiesel production using waste frying oil

Waste sunflower frying oil is used in biodiesel production by transesterification using an enzyme as a catalyst in a batch reactor. Various microbial lipases have been used in transesterification reaction to select an optimum lipase. The effects of various parameters such as temperature, methanol:oil ratio, enzyme concentration and solvent on the conversion of methyl ester have been studied. The Pseudomonas fluorescens enzyme yielded the highest conversion. Using the P. fluorescens enzyme, the optimum conditions included a temperature of 45 °C, an enzyme concentration of 5% and a methanol:oil molar ratio 3:1. To avoid an inhibitory effect, the addition of methanol was performed in three stages. The conversion obtained after 24 h of reaction increased from 55.8% to 63.84% because of the stage-wise addition of methanol. The addition of a non-polar solvent result in a higher conversion compared to polar solvents. Transesterification of waste sunflower frying oil under the optimum conditions and single-stage methanol addition was compared to the refined sunflower oil.     

Oil Erosion in an Annular Flume by Seawater of Varying Turbidities: A Critical Bed Shear Stress Approach

Laboratory experiments were conducted in an annular flume using Hibernia crude oil to determine: (1) the critical shear stress (τ_c) necessary to remove stranded oil from a surface by resuspension and (2) the effect of suspended sediment concentrations (SSCs) on the oil erosion processes. Two types of erosion were evident: Type I––solution and erosion of soluble aromatics; and Type II––mass erosion of visible droplets. In particulate free seawater at 13 °C, the Type II erosion threshold τ_cII is 5.0 Pa. This is equivalent to a mean current velocity (U_y) of 0.55 m s⁻¹. At U_y values <0.55 m s⁻¹, Type I erosion occurred as shown by the increase of oil concentrations without visible erosion of the oil surface. Temperature has a strong control on the threshold and rate of oil erosion: the threshold for Type I erosion at 4 °C was higher and erosion rate lower than at 13 °C. No Type II erosion was observed at 4 °C. SSCs also affects the entrainment of oil. Oil erosion was most efficient at moderate SSCs. At very high SSCs, turbulence suppression and drag reduction became effective and oil erosion rate decreased. SSC at 200–250 mg l⁻¹ were observed to give maximum erosion efficiency and is therefore suggested as the optimal concentration for erosion and elimination of heavy crude oil at a water temperature of 13 °C.     

Renewable hydrocarbons through biomass hydropyrolysis process: challenges and opportunities

Considering the current issues of carbon control and the desire to become less dependent on imported oil, the utilization of renewable hydrocarbons for the reduction of CO₂ emission and production of liquid synthetic fuels/chemicals has been proposed by researchers worldwide. Efforts to make chemicals/fuels from renewable resources have escalated over the past few years. Biomass-based renewable hydrocarbons are considered to be one of the sources with the highest potential to contribute to the energy needs of modern society for both developed and developing economies worldwide. Fast pyrolysis is becoming an important thermal route to convert biomass to liquid fuels; however, the raw bio-oils obtained have a number of negative properties such as high acidity, high water content, and variable viscosity over time. To overcome this problem and produce bio-oil of good quality, process of ‘hyropyrolysis’ has been developed. The scope for using pyrolysis under hydrogen pressure and also by process of hydropyrolysis followed by in situ hydroconversion of vapors to give oils with much lower oxygen contents has been reviewed.     

Introduction/Overview to In Situ Burning of Oil Spills

In situ burning is an oil spill response technique or tool that involves the controlled ignition and burning of the oil at or near the spill site on the surface of the water or in a marsh (see Lindau et al., this volume). Although controversial, burning has been shown on several recent occasions to be an appropriate oil spill countermeasure. When used early in a spill before the oil weathers and releases its volatile components, burning can remove oil from the waters surface very efficiently and at very high rates. Removal efficiencies for thick slicks can easily exceed 95% (Advanced In Situ Burn Course, Spiltec, Woodinville, WA, 1997). In situ burning offers a logistically simple, rapid, inexpensive and if controlled a relatively safe means for reducing the environmental impacts of an oil spill. Because burning rapidly changes large quantities of oil into its primary combustion products (water and carbon dioxide), the need for collection, storage, transport and disposal of recovered material is greatly reduced. The use of towed fire containment boom to capture, thicken and isolate a portion of a spill, followed by ignition, is far less complex than the operations involved in mechanical recovery, transfer, storage, treatment and disposal (The Science, Technology, and Effects of Controlled Burning of Oil Spills at Sea, Marine Spill Response Corporation, Washington, DC, 1994).However, there is a limited window-of-opportunity (or time period of effectiveness) to conduct successful burn operations. The type of oil spilled, prevailing meteorological and oceanographic (environmental) conditions and the time it takes for the oil to emulsify define the window (see Buist, this volume and Nordvik et al., this volume). Once spilled, oil begins to form a stable emulsion: when the water content exceeds 25% most slicks are unignitable. In situ burning is being viewed with renewed interest as a response tool in high latitude waters where other techniques may not be possible or advisable due to the physical environment (extreme low temperatures, ice-infested waters), or the remoteness of the impacted area. Additionally, the magnitude of the spill may quickly overwhelm the deployed equipment necessitating the consideration of other techniques in the overall response strategy (The Science, Technology, and Effects of Controlled Burning of Oil Spills at Sea, Marine Spill Response Corporation, Washington, DC, 1994; Proceedings of the In Situ Burning of Oil Spills Workshop. NIST. SP934. MMS. 1998, p. 31; Basics of Oil Spill Cleanup, Lewis Publishers, Washington, DC, 2001, p. 233). This paper brings together the current knowledge on in situ burning and is an effort to gain regulatory acceptance for this promising oil spill response tool.     

Ignition,flame spread and mass burning characteristics of liquid fuels on a water bed

An experimental technique has been developed to study systematically the ignition, flame spread and mass burning characteristics of liquid fuels spilled on a water bed. The final objective of this work is to provide a tool that will serve to assess a fuel's ease of ignition, spread and sustaining a flame, thus, helping to better define the combustion parameters that affect in situ burning of oil spills.     

In situ burning of emulsions R&D in Norway

SINTEF Applied Chemistry has been working in the field of in situ burning since 1988, beginning with the first open water testing of the 3M fire proof boom which took place on Spitsbergen. In recent years, the focus of SINTEF's research activities in this area has been on the burning of emulsions. An experimental programme was initiated by NOFO in 1990 to study the in situ burning of water-in-oil (w/o) emulsions, as part of a wider NOFO programme ‘Oil spill contingency in Northern and Arctic waters’ (ONA). The research conducted under this programme has addressed many areas of in situ burning including:

• &#x02022;• study of processes governing burning emulsions
• &#x02022;• development of ignition techniques for emulsions
• &#x02022;• effect of environmental conditions on burning
• &#x02022;• burning crude oil and emulsions in broken ice
• &#x02022;• uncontained burning of crude oil and emulsions.

     

Value addition of vegetable wastes by solid-state fermentation using Aspergillus niger for use in aquafeed industry

Vegetable waste typically has high moisture content and high levels of protein, vitamins and minerals. Its value as an agricultural feed can be enhanced through solid-state fermentation (SSF). Two experiments were conducted to evaluate the nutritional status of the products derived by SSF of a mixture of dried vegetable waste powder and oil cake mixture (soybean flour, wheat flour, groundnut oil cake and sesame oil cake at 4:3:2:1 ratio) using fungi Aspergillus niger S₁4, a mangrove isolate, and A. niger NCIM 616. Fermentation was carried out for 9 days at 35% moisture level and neutral pH. Significant (p < 0.05) increase in crude protein and amino acids were obtained in both the trials. The crude fat and crude fibre content showed significant reduction at the end of fermentation. Nitrogen free extract (NFE) showed a gradual decrease during the fermentation process. The results of the study suggest that the fermented product obtained on days 6 and 9 in case of A. niger S₁4 and A. niger NCIM 616 respectively contained the highest levels of crude protein.     

A study on the effects of oil fires on fire booms employed during the in situ burning of oil

For over 10 years scientists have studied the effects of in situ burning of oil on air and water quality and potential related health issues. The recent Newfoundland Offshore Burn experiment, conducted by Environment Canada, was the culmination of several years of work. The results of this experiment found that ‘emissions from the in situ oil fire were lower than expected and all compounds and parameters measured were below health concerns at 150 m from the fire’ (The Newfoundland Offshore Burn Experiment—NOBE, Preliminary Results of Emissions Measurement). Polyaromatic Hydrocarbons (PAHs) were found to be lower in the soot generated from the fire than in the starting oil prior to the fire. The conclusion reached was that the environmental benefits resulting from the burning of oil spills far outweigh the potential air pollution caused from the smoke. These findings now open the door on the use of in situ burning of oil as a major tool to be used to mitigate environmental damage from oil spills.As a result of these and other test findings, Region 6 of the Regional Response Team (made up of the U.S. Coast Guard, The Minerals Management Service, The Department of Environmental Quality, The U.S. Environmental Protection Agency, and other state and federal agencies) had pre-approved the use of in situ burning of oil spills for offshore Louisiana and Texas. Other parts of the country and other countries are evaluating the use of in situ burning to combat oil spills. Now that the scientific community has weighed the environmental costs and benefits of in situ burning it is time to address the operational and procedural issues.     

Improved understanding of key elements governing the toxicity of energy ash eluates

Ash from incinerated waste consists mainly of a complex mixture of metals and other inorganic elements and should be classified based on its inherent hazardous effects according to EUs Waste Framework Directive. In a previous study, we classified eight eluates from ash materials from Swedish incineration plants, both chemically and ecotoxicologically (using bacteria, algae, crustacean and fish). Based on measured concentrations in the eluates together with literature acute toxicity data on the crustacean Nitocra spinipes we identified six elements (i.e. Zn, Cu, Pb, Al, K and Ca) potentially responsible for the observed ecotoxicity. However, comparing the used test methods with N. spinipes, the acute test was relatively insensitive to the eluates, whereas the (sub)chronic test (i.e. a partial life cycle test, investigating larval development ratio) was very sensitive. The overall aim of this follow-up study was to verify if the pinpointed elements could be responsible for the observed (sub)chronic toxicity of the eluates. Individual effect levels (i.e. NOEC values) for these six elements were therefore generated using the (sub)chronic test. Our results show that for six of the eight eluates, the observed ecotoxicity can be explained by individual elements not classified as ecotoxic (Al, K and Ca) according to chemical legislation. These elements will not be considered using summation models on elements classified as ecotoxic in solid material for the classification of H-14, but will have significant implications using ecotoxicological test methods for this purpose.     

Overview of the Compensation and Liability Regimes Under the International Oil Pollution Compensation Fund (IOPC)

This paper focuses on the cost recovery issues arising through the operation of the International Oil Pollution Compensation Fund (IOPC) and administrative matters which arose following the Braer and Sea Empress oil tanker pollution incidents in the UK. Each of these oil spills brought very different problems.Any major oil spill will have prolonged economic and social consequences for the communities affected. Membership of the International Oil Pollution Compensation Fund (IOPC Fund) will do much to soften the impact as regards economic damage. However, the operation of the Fund brings difficulties which may not have been considered by the administration prior to the spill. Some of the difficulties are foreseeable.It covers details of the international compensation and liability regimes, it considers a number of administrative consequences and highlights seven lessons that have been learned in the UK in the light of recent experience. These lessons are:

• •Claims may not be paid quickly or in full.
• •Claimants will need advice and government involvement.
• •Action by the government may be needed to complement the IOPC Fund.
• •Governments have to balance their obligations as a member state with the needs of claimants.
• •It is better for claimants to keep matters out of court for as long as possible.
• •Administrative consequences will continue for a long time after the oil has been cleared from the shoreline.
• •Each major oil spill brings different cost recovery problems and will also bring demands ‘to learn the lessons’.

In much the same way as contingency plans are regularly tested, each state party to the regime would be wise, from time to time, to think through the likely scenarios so as to better prepare themselves in the light of experiences elsewhere. The United Kingdom has had rather more experience in recent years than it would have wished!     

Estimating Time Windows for Burning Oil at Sea: Processes and Factors

This paper discusses processes and factors for estimating time period windows of in situ burning of spilled oil at sea. Time-periods of in situ burning of Alaska North Slope (ANS) crude oil are estimated using available data. Three crucial steps are identified. The First Step is to determine the time it takes for the evaporative loss to reach the known or established limitation for evaporation and compare this time-period with estimated time of ignition at the ambient wind and sea temperatures. The Second Step is to determine the water up-take of the spilled oil and compare it with the known or established limitation for water-in-oil content. The Third Step is to determine the necessary heat load from the igniter to bring the surface temperature of the spilled oil to its flash point temperature so that it will burn at the estimated time period for ignition of the slick.     

The effect of biodiesel on the rate of removal and weathering characteristics of crude oil within artificial sand columns

The physical and chemical properties of crude oils differ greatly, and these properties change significantly once oil is spilled into the marine environment as a result of a number of weathering processes. Quantitative information on the weathering of spilled crude is a fundamental requirement for a fuller understanding of the fate and behaviour of oil in the environment. Additionally, such data are also essential for estimating windows-of-opportunities, where specific response methods, technologies, equipment or products are most effective in clean-up operations. In this study, the effects of a relatively low toxicity compound, biodiesel (rape seed oil methyl ester) on the rate of removal and weathering characteristics of crude oil within artificial sand columns are thoroughly investigated using GC/MS techniques. In the absence of the biodiesel, the crude oil exhibits low mobility and a slow rate of microbial degradation within the sediment and as a result, a high degree of persistance. Brent crude oil was subject to a progressive loss of the low molecular weight n-alkanes with respect to time through evaporation and a preferential migration of these fractions through the sediment to depth. The addition of the biodiesel led to greater recovery of oil from the sediment if applied to relatively unweathered crude oil. This was as the result of the crude oil dissolving within the more mobile biodiesel. The negligible concentration of the n-C₁₀ to n-C₂₁ fraction in surface sediment samples suggests a greater solubility of these fractions within the biodiesel and that their subsequent adsorption onto subsurface sediment particles was responsible for their absence from water flushed through the sands. These results suggest that biodiesel may have an active role in the beach clean-up of spilt crude oil.     

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.     

The Social and Political Meaning of the Exxon Valdez Oil Spill

In this paper we argue that the Exxon Valdez oil spill gained so much attention because of its setting in Alaska. Alaska symbolizes for many Americans the wilderness or frontier that has long been part of American thought. At the same time, American national development has largely depended on the discovery and use of the nation’s abundant natural resources. The setting of the Valdez spill in the seemingly pristine waters of Prince William Sound brought the tension between our national identification with wilderness and our national need for further natural resource exploitation into sharp focus. In the aftermath of the spill, a legislative deadlock was passed and the Oil Pollution Act of 1990 was passed. The Valdez accident had longer-term consequences as well, most prominent of which is related to the ongoing debate over whether to open up the coastal plain in the Arctic National Wildlife Refuge to further development.     

Study of Thermal Decomposition Kinetics of Palm Oleic Acid-Based Alkyds and Effect of Oil Length on Thermal Stability

Thermal decomposition kinetics of three palm oleic acid-based alkyds with different oil lengths and having different molecular weights were studied using TGA measurements under non-isothermal conditions. Activation energies were obtained from Kissinger and Ozawa, Flynn and Wall (OFW) methods and subsequently the pre-exponential factor, A, degradation rate constant, k, for all the alkyds were also determined. From kinetic analysis of the thermal decomposition using the OFW method, it was found that degradation of all the alkyds has taken place in more than two stages, corresponding to different mechanisms. As shown from Ozawa and Kissinger methods, the chemical composition of the alkyds influenced the thermal degradation; increasing the phthalic anhydride and glycerol, and decreasing the oleic acid increased the thermal stabilities of the alkyds.     

Computer Modeling of Oil Spill Trajectories With a High Accuracy Method

This paper proposes a high accuracy numerical method to model oil spill trajectories using a particle-tracking algorithm. The Euler method, used to calculate oil trajectories, can give adequate solutions in most open ocean applications. However, this method may not predict accurate particle trajectories in certain highly non-uniform velocity fields near coastal zones or in river problems. Simple numerical experiments show that the Euler method may also introduce artificial numerical dispersion that could lead to overestimation of spill areas. This article proposes a fourth-order Runge–Kutta method with fourth-order velocity interpolation to calculate oil trajectories that minimize these problems. The algorithm is implemented in the OilTrack model to predict oil trajectories following the “Nissos Amorgos” oil spill accident that occurred in the Gulf of Venezuela in 1997. Despite lack of adequate field information, model results compare well with observations in the impacted area.