디젤 오염토양에서 오존산화에 의한 토양미생물의 사멸과 재성장

Abstract

Field soil contaminated with diesel fuel was collected, and the soil was treated from 0 to 900minutes by in-situ ozonation. The treated soil samples were incubated with supplying oxygen during the 9weeks to investigate the characteristics of microbial regrowth, damaged by ozone. A rapid decrease of total petroleum hydrocarbons (TPH) within 60minutes of ozone injection was observed and then TPH concentration decreased asymptotically with ozonation time because of the instantaneous ozone demand of soil matrix and heterogenous distribution of TPH. Indigenous microbes (heterotrophic, alkane-degrading and phenanthrene-degrading bacteria) were very sensitive to ozone. The numbers of heterotrophic, alkane-degrading, and phenanthrene-degrading bacteria were reduced from 108 to 104, 107 to 103, and 106CFU/g soil to below detection limit after 900minutes of ozonation, respectively. The population of heterotrophic bacteria for the soil sample ozonated for 900minutes remained nearly unchanged during the 9weeks of incubation, but the concentrations of the microbes showed about an order of magnitude increase in the other soils reacted with ozone for 30, 60, 180 and 300 minutes. However, reduced number of heterotrophic microbes by ozonation was not significantly recovered during the incubation period even with supplying oxygen.