The Initial Research On Natural Attenuation And Sodium Persulfate Oxidation Effects Of BTEX In Groundwater

Natural attenuation and persulfate chemical oxidation to remove BTEX in groundwater are hot experiment methods in recent years.These two methods were initial investigated in this paper.A fuel leak experiment was conducted by using sand tank model.without human intervention,monitoring natural attenuation of BTEX in the sand model.It analyzed the pollutant migration and space-time distribution characteristic emphatically.According to the change of BTEX components and other inorganic ion concentration in the sand tank,BTEX biodegradation were analyzed.By using two different sand column model,the removal effect and influencing factors about non-activation and ferrous ions activation persulfate removing BTEX were studied.The results of natural attenuation experiment show that:?1?Lengthways,BTEX were constantly moving to export.The order of the migration rate of BTEX component is B/T>P,M,O-X>E,The order of retardation factor of BTEX compounds is E>P,M,O-X>B/T.Horizontally,BTEX centered on C,and spread into both sides.Vertically,BTEX is mainly distributed at 45 cm,and in the places deeper,the contaminant concentration lower.?2?Water level rising has promoting effect on the dissolution of BTEX.When the water level is certain,BTEX concentration decreased;when the water level raised,BTEX concentration began to increase.?3?The decrease of BTEX components and dissolved oxygen as well as nitrate content in sand tank shows that BTEX were had biodegradation.?4?Ethanol not only can promote the dissolution of BTEX,but also can hinder the BTEX biodegradation.The results of chemical persulfate oxidation experiments show that:?5?Persulfate was very stable at room temperature.The removal effect of BTEX by non-activation persulfate was worse than by ferrous sulfate ion activation persulfate.When the molar ratio of PS:Fe²⁺:BTEX=100:40:1,the removal efficiency BTEX and its component was highest,among which B is 78.0%,T of 85.9%,E of91.4%,P-X of 95.4%,M-X of 92.5%,O-X of 93.6%.The removal rate of styrene reached 100%.Under the current proportion,the removal rate of benzene was the lowest.?6?when mole ratio of Fe²⁺:BTEX was certain,as the persulfate concentration got higher,BTEX removal effect was better.When the mole ratio of PS:BTEX was bigger than 80:1,the higher the activator concentration of Fe²⁺,the higher the removal rate of BTEX.Ferrous ion concentration was the key factors to determine the amount of residual persulfate.When the pollutant concentration was certain,as ferrous ion concentration was lower,as the residual rate of persulfate was higher;when the ferrous ion concentration was same,and the residual rate of sulfate was same.?7?The oxidation of persulfate inhibits microbial activity.