A comparison of standard test methods for determining the laboratory effectiveness of oil spill dispersants: their benefits and drawbacks

A comparison of two standard test methods for determining the laboratory effectiveness of oil spill dispersants — ASTM F2059-17 «Standard Test Method for Laboratory Oil Spill Dispersant Effectiveness Using the Swirling Flask» and ASTM F3251-17 «Standard Test Method for Laboratory Oil Spill Dispersant Effectiveness Using the Baffled Flask» — is presented in this article. It is underlined that ASTM F2059-17 and ASTM F3251-17 are almost identical from the methodological and technical points of view. The main differences lie in specific design features of the applied test vessels and mixing energies created inside them. It is reasonably established that ASTM F2059-17 can be defined as a low-energy, but ASTM F3251-17 — as a high-energy laboratory test method. The specific examples of application of the test methods for determining the effectiveness of commercially available dispersants are given. It is also concluded that both test methods are necessary to apply for a correct understanding of the dispersant effectiveness. Herewith, the results obtained according to ASTM F2059-17 should be conditionally considered as the lower limit and those according to ASTM F3251-17 — the upper limit of effectiveness of the dispersant. Moreover, the use of gas chromatography with flame ionization detection (GC-FID) is emphasized to be sometimes impossible as a recommended in both ASTM F2059-17 and ASTM F3251-17 method for analyzing the oil extracts obtained during the test. The UV spectrophotometry is proposed instead of GC-FID as an alternative. However, its application is possible only after mandatory optimization of the measurement parameters for each specific oil.

Новая судовая система как способ обеспечения экологической безопасности в условиях арктического шельфа

Работа посвящена теме устранения загрязнения акватории морей нефтепродуктами в условиях сложной ледовой обстановки. Приведены различные способы очистки водных пространств от нефти и нефтепродуктов, дан сравнительный анализ их особенностей и недостатков. Описана проблема очистки водоемов от нефтепродуктов при наличии колотого и сплошного льда. Предложена новая технология использования сорбента в таких специфических условиях. Представлена сконструированная авторами установка, которая подключается к стандартным судовым системам и позволяет без их затратной модернизации эффективно бороться с нефтеразливами в низкотемпературных широтах. Ключевые слова: новая технология использования сорбента, арктический шельф, боновые заграждения, разлив нефти, диспергенты, сорбент, пульпа, струйный смеситель : This work is focused on the problem of eliminating the pollution of the seawater with oil products in difficult ice conditions. Various methods of cleaning water spaces areas from oil and oil products are presented, and a comparative analysis of their features and disadvantages is given. The problem of cleaning water bodies from oil products in the presence of crushed and solid ice is described. A new technology for using the sorbent in such specific conditions has been proposed. An installation designed by the authors is presented, which is connected to standard ship systems allows to effectively deal with oil spills in low-temperature latitudes with no need for high-cost modernization. Keywords: Arctic shelf, booms, oil spill, dispersants, sorbent, pulp, jet mixer

Comparative Bioremediation Potentials of Pseudomonas aeruginosa KX828570 and Bacillus megaterium KY085976 on Polluted Terrestrial Soil Treated with Oil Spill dispersant

Aim: To assess the bioremediation potential of Pseudomonas aeruginosa and Bacillus megaterium on oil spill dispersant polluted terrestrial soil. Study Design: The study employs experimental design, statistical analysis of data and interpretation. Place and Duration of the Study: Polluted Terrestrial Soil (Ts) samples were collected from Kegbara-Dere community in Gokana Local Government Area of Rivers State with sterile shovel from three different spots at the same location and put in black polythene bags and transported to the microbiological laboratory within 24 hours for physicochemical and microbiological analyses. Oil spill dispersant (OSD/LT and OSD/Seacare) were obtained from Baker and Hughes Nigeria Limited in Rivers state, Nigeria. Methodology: Standard microbiological procedures were used to enumerate, isolate and identify the bacterial isolates. Pseudomonas aeruginosa and Bacillus megaterium in oil spill dispersants contaminated soil were monitored over a period of 1, 7, 14, 21 and 28 days respectively for their bioremediation potentials. Results: The presence of Pseudomonas aeruginosa (Pa) or Bacillus megaterium(Bm) in oil spill dispersant polluted soils enhanced decrease in Total Hydrocarbon Content (THC) of the soil. THC for control soil reduced from 18348.68 mg/kg to 9111.84 mg/kg; TS+OSD/LT+Bm, 18348.68 to 7092.11 mg/kg; TS+OSD/LT+Pa, 18348.68 to 6263.16(mg/kg); TS+OSD/LT+Bm+Pa, 18348.68 to 2473.68 mg/kg; TS+OSD/SC+Bm, 18348.68 to 6421.05 mg/kg; TS+OSD/SC+Pa, 18348.68 to 5618.42 mg/kg; TS+OSD/SC+Bm+Pa, 18348.68 to 5835.53 mg/kg, between the first (day 1 ) and last day ( day 28). The percentage (%) bioremediation rate of polluted soil was as follows: control (TS(CRTL) 50.3%, TS+OSD/LT+Bm 61.3%, OSD/LT+Pa 65.9%, and OSD/LT+Bm+Pa 86.5% Whereas, TS+OSD/Seacare+Bm had 65.0%, OSD/Seacare+Pa 69.4%, OSD/Seacare+Bm+Pa 68.2% respectively. The highest percentages of THC in this study were from soil samples treated with oil spill dispersant and organisms while the least was observed in treatments without oil spill dispersant and organism. This suggests that microorganisms are more abundant in oil spill dispersant polluted soils than unpolluted soils. Conclusion: From this study, it was observed that bioremediation of dispersant polluted environments could be achieved by stimulation of native microorganisms such as Pseudomonas aeruginosa KX828570 and Bacillus megaterium KY085976 and this would be cost effective in the clean-up strategy for such pollutants.