Research on evaluation and optimization of soil and groundwater remediation technology

在污染场地进行土壤和地下水修复时，污染物的去除速率随着时间的推移而下降。因此，使用单一修复技术，虽然成本增加，但去除效果并没有提高。为了有效地清理受污染的土壤和地下水，有必要选择和结合合适的技术。为此，重要的是要了解污染物在地下的迁移。本研究的目的是根据污染物在地下的迁移特征，阐明高效、经济地清理受污染的土壤和地下水的程序。1999年和2000年，我们对现有的土壤和地下水修复技术进行了分类和整理，并通过现场试验对就地喷气进行了评价。原位空气喷射技术作为一种净化土壤和地下水中挥发性有机化合物污染的技术而受到人们的关注。此外，还对茶园附近地下水硝态氮污染情况进行了调查。2001年，在现场试验和室内试验的基础上，对现场空气喷射的最佳使用方法进行了研究。另一方面，化肥用量的减少对地下水中硝态氮浓度的降低有较大的影响，反应障对地下水中硝态氮的分解和去除是有效的。因此，反应屏障与减量施肥相结合是目前地下水硝态氮污染最有效的修复技术。

When soil and groundwater remediation is carried out in the contaminated site, the rate of removal of contaminants falls with progress of time. Therefore, using single remediation technology, the effect of removal does not go up although cost increases. In order to clean up the contaminated soil and groundwater efficiently, it is necessary to select and combine the suitable technologies. For that purpose, it is important to understand the migration of contaminants in subsurface. The purpose of this research is to clarify the procedure to clean up the contaminated soil and groundwater efficiently and economically based on the characteristics of migration of contaminants in subsurface. It focuses on volatile organic compounds and nitrate nitrogen as contaminants this time.In 1999 and 2000, we classified and arranged the existing soil and groundwater remediation technologies and evaluated the in situ air sparging through the field trial. In situ air sparging attracts attention as technology which cleans up soil and groundwater contaminated with the volatile organic compounds. In addition, we investigated the groundwater contamination with nitrate nitrogen near tea plantation area. In 2001, the optimal employment method of in situ air sparging was examined based on the field trial and laboratory experiment. On the other hand, it was cleared that the reduction in fertilizer application had great influenced on the decrease of the concentration of nitrate nitrogen in groundwater and the reactive barrier is effective to decompose and remove the nitrate nitrogen in groundwater. As a result, the reactive barrier coupled with the reduction of fertilizer application is the most effective remediation technology for groundwater contamination with nitrate nitrogen at present.