Feasibility of micro-organisms in soil bioremediation and dust control

Detrimental impacts of dust caused by mine tailings have yielded to several studies on the efficiency of different soil stabilizers. Bacterial stabilization has been recognized as a reality within recent decades, where bacteria could get adhesion to the grains and stabilize the soil particles. However, these bacteria are prone to be destroyed while exposed to the normal environmental conditions. In this study, the effects of microcapsules containing two types of bacterial freeze-dried spores (B.Subtilis Natto LMG 19457 and B.ESH) have been investigated on the mine tailing stability in terms of two parts. The first part of the study is dedicated to the fabrication of microcapsules within the two bacteria and identification of the characteristics of these microcapsules to set the time of microcapsules break and release in the soil. The urea-formaldehyde microcapsules containing tung oil were synthesized using microencapsulation method and at the following, the bacterial spores of B.Subtilis Natto LMG 19457 and B.ESH which had the high durability and the capability to grow in the silicon oil, were added to the microcapsules. The microcapsules effect on MT specimens and the viability of encapsulated spores were determined. The characteristics of the capsules were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermo-gravimetric thermal analysis (TGA). In the second part, wind tunnel tests were conducted to study the effects of microorganism stabilizers on mine tailings. The results indicated that the dust erosion reduced from 16% - using water as a stabilizer- to the 0.2% while using microcapsules containing B.Subtilis Natto LMG 19457 and 0.8% while using microcapsules containing ESH. The results showed the high efficiency of microcapsules containing bacteria in stabilizing the MTs. This phenomenon was proved by SEM imaging in which the voids were bounded significantly while using the bacteria.