| Summary: | 碩士 === 國立臺灣大學 === 生物環境系統工程學研究所 === 104 === The method of in-situ bioremediation has been widely used to treat the groundwater polluted by chlorinated organic compounds. This method by gravity flow is commonly used, so that the substrates or nutrients will settle and diffuse freely. However, it is difficult to confirm whether the substrates are distributed effectively and evenly in the areas to be treated.
Therefore, in this research, a method of permeation grouting which has been often used in geotechnical engineering to improve the soil was applied to inject substrate. With the self-designed high speed vortex colloidal mixer and air compressor system, 3 kinds of commercial substrate (EOS, HRC and EcoClean) is permeably injected into 7 kinds of different soil column-shaped specimens (Soil A(D50=0.51mm)、Soil B(D50=0.45mm)、Soil C(D50=0.30mm)、Soil D(D50=0.27mm)、Soil E(D50=0.25mm)、Soil F(D50=0.01mm) and Soil G(D50=0.05mm)),and the indexes of the permeability and persistence will be used to evaluate the applicability of these 3 kinds substrate.
The permeability results are as follows. For the specimens of Soil A, the targeted heights of permeation grouting was reached for the 3 kinds of substrates. As for the specimens of Soil B, Soil C and Soil D, only EcoClean could reach the targeted heights; however, HRC and EOS could not reach the targeted heights. For the specimens of Soil E, HRC, EOS and EcoClean can only be grouted to 48(cm), 42(cm) and 43(cm), respectively. For the specimens of Soil F and Soil G, those 3 kinds substrate are completely unable to be grouted.
The results of persistence showed that the retention rates of the substrates, in decreasing order, were HRC, EOS and EcoClean. As for the specimen of Soil E, the persistence of 3 kinds substrate are more than 94%, and the persistence in decreasing order, were EOS, EOS and EcoClean.
Generally speaking, it is found that the permeability and persistence is affected by not only the properties of substrate, but also the D10 of the soil. The R2 of D10 between the permeability and the persistence are 0.96 and 0.78, respectively. Therefore, the D10 of soil may be used to assess the goutability. For the soils with particle size distribution similar to that of Soils A, B, C and D, HRC is suggested to be used. As for the Soils with particle size distribution similar to that of Soils E, F and G, because of low permeability, it is suggested to increase dilution ratio and injection pressure to improve the permeation in the future.
|
|---|
