The Release?Migration Of Oil In Oil Polluted Sandy Beach And The Formation Of OSAs

Under the action of the tidal wave marine oil spill migrate to the beach,seriously affected the ecological environment and landscape of the beach.The beach oil pollutants will migrate to the deep sand,and may cause persistent pollution.The sediment reset method is exposed on the surface of buried beach body deep oil,through the coastal hydrodynamic action,the oil released from the beach body and interact with particles to form OSAs(Oil-SPM Aggregations),to remove pollutants from oil sands.In depth understanding of the migration and release of oil pollutants in the sandy beach,it is of great significance to study the mechanism of OSAs formation and its influence factors,and to repair the oil contaminated sands.Firstly,through the experimental study on the release of the conical flask in the process of weathering oil sand and sand fresh oil and effects of environmental factors on the release of oil,and then through the longitudinal migration of sand column experiments of oil sand and oil sand weathering fresh oil,influence factors and release process;In the end of the experiment,the simulation of the formation of OSAs of different pollution intensity of weathered sand and fresh oil is carried out.The main conclusions are obtained:(1)Weathered oil sand reach the release balance cost 240 min,equilibrium emission is 2.40mg/g,while the newly oil polluted sand reached the equilibrium time costs 210 min,equilibrium emission is 2.75mg/g,both the two release process are in line with Lagergren pseudo first order kinetic model release.(2)Weak acidic environment conducive to the release of oil,the rise of pH will result in reducing of the release.when the temperature range from 0-35?,higher temperatures favor the release of oil in the oil sand.The larger the oscillation frequency,oil sand reach the oil release balance needs less time,and the greater the corresponding balance emissions.oil sand of different particle size,the higher the initial oil content of gravel,the greater the release rate of oil sand.Smaller the particle size,the greater of the release rate.while salinity have little effect on oilrelease.(3)Sand column experiment,the effluent oil concentration were tested at different depths of sand column increases with the increase of time,eventually reach equilibrium.Upon reaching equilibrium,sand column contained newly polluted oil sand effluent oil concentration was significantly higher than the stable value of weathered oil sand column,oil sand recently pollution release oil easier.(4)High head height and pollution intensity is conducive to oil release;high concentration of oil sand of different water depths in simulated tidal conditions,water conditions and continuous low tide movement shortened the concentration of oil and water stable time.The thickness of the oil sand,sand on the residual oil content is higher that is not conducive to the release of oil.In the run earlier stage,filling sand oil and water concentration order of different particle size is 28 mesh sand gravel sand >48 mesh >100 mesh sand gravel sand,show that the larger particle size,release more oil well,The original sand sand filled between oil and water concentration between 28 mesh and 48 mesh sand sand.After stop water,oil and water concentration of the stable range of the order of 28 mesh >48 mesh >100 mesh > sand.The original sand,28 sand,oil sand release 48 mesh and 100 mesh sand corresponding to 2.44,0.77,2.06 and 4.49mg/L,the release amount of raw sand,in addition to 28 sand,sand particle size,the greater the amount of the release of oil sand,gravel particle size of oil release 48 oil sand to the minimum that is only 0.77mg/g.(5)Higher pollution intensity weathered oil contaminated sand,forming a larger number of OSAs,and OSAs' s morphogenesis mostly irregular.The newly polluted sand with pollution intensity of 4.79mg/ g formed less OSAs.But when the pollution intensity are 11.43 and 16.29mg/ g,there are more OSAs formed,with oil droplets and more irregular shapes.(6)There are larger changes after plowing through sand from different depths of the column filled with weathered oil sand and newly oil polluted sand.Weathered sand release rate was more than 50%,up to 85.97%;recently oil polluted sand column,in 10 cm release amount of up to 2.89mg/g,the other half depth oil sand release itself close to the oil content of oil,the release amount was more than 40%,upto 84.7%.The sediment reset technique has better effect for the removal of oil sand.The pollution intensity of weathering sand and similar oil pollution of fresh sand,the number of fresh pollution sand forming OSAs and intensity was significantly higher than that of weathered sand.Oil dispersant containing fresh oil sand is beneficial to the formation of OSAs.