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We have shown that Bacillus cereus is dominating the bacterial population at three polluted oil-industry sites where weather and soil conditions are extreme in terms of temperature, UV-radiation and salinity. A minor part of the bacterial population includes a strain of Bacillus sonorensis and Pseudomonas stuztzeri. Six bacterial isolates were characterized by MALDI-TOF mass spectrometry. The identity of Bacillus sonorensis was also confirmed by ribotyping using molecular techniques. The extreme conditions result in the limited bacterial diversity at the present sites. Our results indicate that the bacteria have sustained because of their ability to degrade low, medium and high molecular weight hydrocarbons in diesel which were removed by up to 89%, 61% and 92%, respectively by Bacillus sonorensis. Bacillus cereus isolates were less effective, but all showed high activity on high molecular weight hydrocarbons. The study is based on growth tolerance to high diesel toxicity and removal of the three ranges of hydrocarbons. Each isolate showed higher hydrocarbon removal efficiencies when applied separately in biopiles in fresh soil compared to weathered soil. Almost 88% and 25% of the diesel range organics and 23% and 83% of the polyaromatic hydrocarbons were removed from the weathered soil versus the clean, respectively, by Bacillus sonorensis. Such efficiencies were obtained with growth stimulation by addition of nitrogen and phosphorus sources and with Tween-80 as a surfactant. The results are key in an application context, since it is clear that overcoming the recalcitrance of weathered hydrocarbon contaminations to biodegradation is a central issue in for example the Arabian Gulf. Moreover the results emphasize that bioaugmentation/biostimulation with bacteria originally adapted to the site conditions is the way forward since endogenous or exogenous hydrocarbon-degrading bacteria generally are not appropriate for applications that involve weathered hydrocarbon spills.

The primary aim of this research was to identify the physicochemical properties of the oil and water-in-oil (W/O) emulsions used during a NOFO Oil-on-Water field trials that reduced the performance of the skimmers recovery efficacy during the trials. Extensive studies were performed at SINTEF laboratories with the residues of oil topped (i.e. evaporative loss of crude oil components by distillation process at large scale) for the field trial and compared it with different residues of oil topped by bench scale laboratory procedures. In order to obtain a sufficient stable W/O emulsion for the field trial, bunker fuel oil (IFO380) and various concentrations of an emulsifier (Paramul®) were also added to the residues of oil topped on large scale and investigated through interfacial tension, contact angle, droplet adhesion and “dip and withdraw” tests. The investigations revealed that the addition of an emulsifier lowered the interfacial tension of oil residues, which consequently reduced the adherence properties of the oil and emulsions to the surface of the skimmer material. Too high concentration of an emulsifier (>0,5%) also had a negative effect on the stability of W/O emulsion.

SINTEF har siden åttitallet foretatt forvitringsstudier på en rekke oljetyper (både norske og utenlandske). Hovedmålsettingen med disse forvitringsstudiene har vært å predikere oljenes forvitringsegenskaper dvs. hvordan de oppfører seg på sjøen ved et eventuelt oljesøl (fordamping, emulgering, naturlig dispergering etc). Det ble i perioden 1997-99 utført et multivariabelt korrelasjonsstudie for Statoil av oljers sammensetting (Crude Assay (CA) data) og forvitringsegenskaper (data fra laboratoriestudier) som var generert hos SINTEF fram til 1997 (19 utvalgte oljetyper). En modell som beregner de input-data som SINTEFs Oil Weathering Model (OWM) trenger for å predikere oljens forvitringsegenskaper når forvitringsdata fra laboratoriet ikke er tilgjengelig, er etablert. Denne modellen ble også utvidet med et kalibreringssett bestående av 58 oljer gjennom et prosjekt finansiert av Statoil i 2005. Prosjektet beskrevet i denne rapporten har styrket modellen og gjort den mere generell, dvs gjeldene for en større gruppe av oljer ved å utvide kalibreringssettet til 141 oljer inkludert rafineriprodukter. Dette gjør at forvitringsegenskaper også for bunkersoljer kan predikeres basert på enkle parametre (viskositet, voks/asfalten, tetthet, stivnepunkt og kokepunktsprofilen). For å forbedre denne muligheten til å bruke SINTEF OWM direkte har dette prosjektet fokusert på: 1. Inkludere flere oljetyper/forvitringsstudier for å få flere oljer (totalt 141) i de enkelte klassene 2. Dele oljene inn i klasser (med/uten stivnepunktsproblemer, raffineriprodukter, meget voks/asfaltenrike) og predikere egenskapene innbyrdes i de enkelte klassene 3. Brukergrensesnitt med "warning messages" som gjør at modellen ikke kan brukes utenfor det området den er kalibrert for, samt angir forventet kvalitet på prediksjonene og "guiding messages" som hjelper brukeren å forstå hvordan CA-dataene kan brukes optimalt. 4. Det er ikke mulig å predikere forvitringsegenskaper basert på CA data fra lette raffeneriprodukter og kondensater. 5. Ny funksjonalitet "Find model oil" som rangerer oljer i oljedatabasen etter likhet med oppgitte CA data. Modernisation and updating of SINTEF Oil Weathering Model (OWM} - Extending and recalibration of the Crude Assay (CA) module in SINTEF OWM Statoil; Norwegian Coastal Association

In case of oil spills due to disasters, one of the environmental concerns is the oil trajectories and spatial distribution. To meet these new challenges, spill response plans need to be upgraded. An important component of such a plan would be models able to simulate the behaviour of oil in terms of trajectories and spatial distribution, if accidentally released, in deep water. All these models need to be calibrated with independent observations. The aim of the present paper is to demonstrate that significant support to oil slick monitoring can be obtained by the synergistic use of oil drift models and remote sensing observations. Based on transport properties and weathering processes, oil drift models can indeed predict the fate of spilled oil under the action of water current velocity and wind in terms of oil position, concentration and thickness distribution. The oil spill event that occurred on 31 May 2003 in the Baltic Sea offshore the Swedish and Danish coasts is considered a case study with the aim of producing three-dimensional models of sea circulation and oil contaminant transport. The High-Resolution Limited Area Model (HIRLAM) is used for atmospheric forcing. The results of the numerical modelling of current speed and water surface elevation data are validated by measurements carried out in Kalmarsund, Simrishamn and Kungsholmsfort stations over a period of 18 days and 17 h. The oil spill model uses the current field obtained from a circulation model. Near-infrared (NIR) satellite images were compared with numerical simulations. The simulation was able to predict both the oil spill trajectories of the observed slick and thickness distribution. Therefore, this work shows how oil drift modelling and remotely sensed data can provide the right synergy to reproduce the timing and transport of the oil and to get reliable estimates of thicknesses of spilled oil to prepare an emergency plan and to assess the magnitude of risk involved in case of oil spills due to disaster.

This dataset reports petroleum hydrocarbon data and oxygen concentration data for laboratory experiments conducted to assess the relation between (aerobic) biodegradation of light crude oil, present of dispersants and presence of suspended solids (e.g clay). Experiments were conducted with no dispersant, and with dispersant to oil ratios of 1:20 and 1:100, using either weathered or crude oil and were tested in duplicate. Replicates were sampled 10 times over approximately two months for analysis of total petroleum hydrocarbons. Oxygen consumption was measured in experiments testing crude oil at different dispersant to oil ratios with the addition of bacterial cultures of Psuedodemonas putida and Rhodococcus qingshengii TUHH-12 over a period of 36 days.

A module, MEUN (Módulo de Envejecimiento Universidad Nacional), that describes the processes that occur due to the interaction, also known as weathering, of the crude in an oil spill with the atmosphere and the ocean, was developed. This module, couples individual sub-models available in the literature used to describe the evaporation, emulsification, dispersion and spreading processes that characterize the first week after an ocean oil spill. MEUN predicts as well the variation in density and viscosity over time as a result of the weathering processes. All sub-model constants were adapted to the specific requirements of Colombian crudes, particularly to Cusiana (API 43.2) and Vasconia (API 20.7). While the first one represents light crudes, the second one is an example of heavier oils. These two crudes have high production and require marine transport. To evaluate MEUN predictions, experiments were carried out for evaporation and emulsification processes at conditions similar to those observed during an oil spill in the Colombian Caribbean Sea. In the case of the evaporation experiments, a wind tunnel of 3.0 m and a circular cross section of 30 cm in diameter was adapted to measure the weight loss of crude oil while varying the wind velocity between 3 m/s and 8 m/s. The emulsification process was simulated using the rotating-cylinder method, a standard in the weathering community. The emulsification experiments evaluated the effect of temperature (ranging from 22°C to 30°C) as well as the degree of evaporation of the crude oil in the rate and extent of emulsification. Variations in density and viscosity as a result of evaporation and emulsication were also measured. The evaporation results showed a strong dependence of evaporation rate with wind velocity, particularly for Cusiana. This behavior is not predicted by the state-of-the-art models used by the oil spill community. MEUN included a new correlation for the mass transfer coefficient that correctly predicts the evaporation process of Cusiana. Furthermore, the experiments revealed that Cusiana increases the pour point because of evaporation from 0°C for fresh oil up to 30°C when the evaporated fraction is 48%. When the oil temperature is below the pour point, something rather possible even at the relative high temperatures of the Colombian Caribbean Sea given the significant increase in pour point because of evaporation, the evaporation rate significantly decreases to virtually zero. This effect was included in MEUN. Vasconia presents the typical behavior for oil emulsification described in the literature as it forms an emulsion with a water content of 70-90% that becomes more stable as the evaporated fraction increases and the temperature decreases. Contrary, Cusiana only forms an emulsion when the temperature is below the pour point. The final version of MEUN reproduces these emulsification behaviors for Cusiana and Vasconia. When compared to well-established weathering software, such as ADIOS, MEUN gives predictions that are closer to the experimental behavior, particularly for Cusiana, as it considers the effect of pour point and predicts a combination of evaporation and dispersión considerably higher than that predicted by MEUN (100% vs 50% of the spilled amount, respectively, 30 hours after the spill). Resumen: Se desarrolló un módulo, MEUN (Módulo de Envejecimiento Universidad Nacional) que describe los procesos que ocurren debido a la interacción, del crudo en un derrame con la atmósfera y el océano también conocido como envejecimiento. Este modelo acopla sub-modelos disponibles en la literatura para describir los procesos de evaporación, emulsificación, dispersión y esparcimiento que caracterizan la primera semana después de un derrame de crudo en el océano. MEUN predice también la variación en la densidad y la viscosidad a través del tiempo como resultado de los procesos de envejecimiento. Las constantes de los sub-modelos fueron adaptadas a los requerimientos específicos de crudos Colombianos, Particularmente para Cusiana (°API 43.2) y Vasconia (°API 20.7). Mientras que el primero representa los crudos livianos, el segundo es un ejemplo de un crudo más pesado. Estos dos crudos tienen alta producción y requieren transporte marítimo. Para evaluar la predicción de MEUN, se desarrollaron experimentos para los procesos de evaporación y emulsificación en condiciones similares a las observadas en un derrame de crudo en el mar Caribe Colombiano. En el caso de los experimentos de evaporación, un túnel de viento de 3.0 m de largo y una sección transversal circular de 30 cm de diámetro fue adaptado para medir la pérdida de peso de crudo mientras se varia la velocidad del viento entre 3 m/s y 8m/s. El proceso de emulsificación fue simulado usando el método de cilindro rotatorio, un método estándar en la comunidad del envejecimiento de crudos. Los experimentos de Emulsificación evaluaron el efecto de la temperatura (variando de 22°C a 30°C) y el del grado de evaporación del crudo en la velocidad y el grado de emulsificación. Las variaciones en la densidad y la viscosidad como resultado de la evaporación y la emulsificación fueron también medidas. Los resultados de evaporación mostraron una fuerte dependencia de la velocidad de evaporación con la velocidad del viento, particularmente para Cusiana. Este comportamiento no es predicho por los modelos del estado del arte usados por la comunidad de derrames de hidrocarburos. Por esto, MEUN incluye una nueva correlación para el coeficiente de transferencia de masa que predice correctamente el proceso de evaporación para Cusiana. Más aun, los experimentos revelaron que el punto de fluidez del crudo Cusiana se incrementa debido a la evaporación desde 0°C para el crudo original hasta 30°C cuando la fracción evaporada es 48 %. Cuando la temperatura del crudo está por debajo del punto de fluidez, algo que es posible incluso con las relativamente altas temperaturas del mar caribe Colombiano debido al incremento significativo del pour point con la evaporación, la velocidad de evaporación disminuye significativamente hasta alcanzar el valor de cero. Este efecto fue incluido en MEUN. Vasconia presenta el típico comportamiento de emulsificación de crudos descrito en la literatura ya que forma una emulsión con un contenido de agua de 70-90% que se convierte más estable a medida que la fracción evaporada aumenta y la temperatura disminuye. Contrariamente, Cusiana solo forma una emulsión cuando la temperatura este por debajo del punto de fluidez. La versión final de MEUN reproduce estos comportamientos de emulsificación de Cusiana y Vasconia. Al ser comparado con software de envejecimiento reconocidos como ADIOS, las predicciones de MEUN son más cercanas al comportamiento experimental, particularmente para Cusiana, ya que considera el efecto del punto de fluidez y predice una combinación de evaporación y dispersión considerablemente mayor que la predicha por MEUN (100% vs 50% de la cantidad derramada, respectivamente, 30 horas después del derrame) Maestría

This paper describes details of an oil spill model, OILTRANS, developed by the authors. The model is an off-line particle-transport model coupled to the most up to date operational met-ocean model forecasts. Formulations for the dominant oil fate processes of spreading, advection, diffusion, evaporation, emulsification and dispersion have been encoded, providing the model with the ability to accurately predict the horizontal movement of surface oil slick, the vertical entrainment of oil into the water column and the mass balance of spilled oil. The application of the OILTRANS model to an accidental release during a ship-to-ship fuel transfer in the Celtic Sea in February 2009 is presented to validate the system. Comparisons with aerial observations of the oil slick at the time of the incident, and subsequent model simulations, indicate that the OILTRANS model is capable of accurately predicting the transport and fate of the oil slick.

วารสารวิทยาศาสตร์และเทคโนโลยี, 26, 7, 1107-1115