| Facing the growing problem of groundwater polluted by organic, the groundwater remediation technology got more and more people's attention. The bio-sparging technology has been fully concerned with its advantages of low-cost, high-efficiency and in-situ operation. There had been a lot of successful bio-sparging fields application in foreign countries.But little was known about the material removal mechanism of bio-sparging. In our country the research of the bio-sparging technology is in the initial stage. The laboratory research on the bio-sparging is less and the field tests are short.The groundwater in our country is scarce resources relatively. Under the condition of the environmental issues have become increasingly prominent, it's very necessary to develop high-efficient and low-cost environment remediation program. In the areas of groundwater pollution remediation, the bio-sparging remediation technology has great advantages, which dominate used widely. Benzene as the feature components, the paper investigated the effect and the main factors of bio-spaging through microbiology experiment, sand column experiment, radius of influence experimental and sandbox experiment.In the microbiology experiment, the paper mainly researched on high efficiency bacteria domesticated, the influence of biodegradation and microbiology identification. The research domesticated three high efficiency psychrotrophs, which belong to Flavobacterium. Pseudomonas and Bacillus. The degradability of the three mixed bacteria is better than any single strain. Under the optimum conditions of pH=7.5,DO>4mg/L and adding nitrogen and phosphorus, the degradation could reach 87.6% in 18 davs.In the sand column experiment, the paper mainly researched the migration of microbiology, inorganic salt, benzene and the treating effect of bio-sparging. The results showed that the different medium conditions have greater impact on the migration of microbiology and benzene and the treating effect of bio-sparging than the migration of inorganic salt. The larger of average particle size of medium, the migration of microorganisms and benzene is stronger, but the worse the treatment effect of BS.In the radius of influence experimental, the paper measured the radius of influence of gas using Electrical Resistance Tomography (ERT) innovatively, which achieved good experimental result. The result showed that the radius of influence of BS had related with the type of the medium. As the average particle size of medium was smaller, the radius of influence of BS becomes uneven irregular distribution by the symmetrical distribution. In the medium sand and coarse sand, the process of BS created irregular gas channel, which the gas of BS overflow. The site of small size medium is not suitable for aeration.In the sandbox experiment, the paper mainly researched the migration of benzene, the treating effect of BS and the corresponding changes of DO, pH in the sand box. The result showed that the migration of benzene had related with the type of the medium. The organic compounds had migrated fast when the medium had a large permeability coefficient. As the permeability coefficient became small, the migration of organic compounds gradually slowed down. The treating effect of BS had related with the type of the medium in the BS progress of layered medium. The degradation of organic compounds was faster in the medium with large permeability coefficient. The DO and pH had correspondingly changed with the BS process. The DO changed greatly. The rapid reduction of DO affected BS process through reducing the degradation rate of organic compounds. The change of pH had related with microbial metabolites in the sandbox. The decrease of pH was caused by the hydrolysis acidification pretreatment of organic, identifying the process of facultative and anaerobic cause of DO inadequate in the sandbox.
|
PDF Full Text Request