Ishii Kazuei, Furuichi Toru
Laboratory of Sound Material-Cycle Systems Planning, Graduate School of Engineering, Hokkaido University, N 13, W8, Kita-ku, Sapporo, 060-8628, Hokkaido, Japan.
J Hazard Mater. 2007 Sep 30;148(3):693-700. doi: 10.1016/j.jhazmat.2007.03.032. Epub 2007 Mar 16.
We developed a conceptual feasible design of bioreactor system for treatment of dioxin-contaminated soils that uses the dioxin-degrading fungus Pseudallescheria boydii (P. boydii) we had isolated. The dioxin-degradation conditions in bioreactor treatment was established by clarifying the inhibiting factors for the growth of P. boydii using both real contaminated and laboratory prepared soils mixed with fly ash. In addition, ethanol extraction process as post-treatment methods for the remaining dioxins, and the sterilization conditions of P. boydii, i.e., a weakly pathogenic fungus, in the residue was investigated. The better growth conditions of P. boydii were found to be chloride ion concentration of less than 10 g/L and a pH of less than 9. Under these conditions, 7310 pg-TEQ/g of the soil was treated to 2860 pg-TEQ/g by the bioreactor process, and the dioxin concentration was further decreased to 580 pg-TEQ/g by ethanol extraction, resulting to total removal ratio of 92%. Furthermore, development of an effective sterilization method for living P. boydii in the residue increased the applicability of our bioreactor system for practical use in dioxin-contaminated sites.
我们利用分离出的二恶英降解真菌博伊德假阿利什霉（P. boydii），开发了一种用于处理二恶英污染土壤的生物反应器系统的概念性可行设计。通过使用实际污染土壤和与粉煤灰混合的实验室制备土壤，阐明抑制博伊德假阿利什霉生长的因素，确定了生物反应器处理中的二恶英降解条件。此外，研究了乙醇萃取工艺作为残留二恶英的后处理方法，以及博伊德假阿利什霉（一种弱致病性真菌）在残渣中的灭菌条件。发现博伊德假阿利什霉的较佳生长条件为氯离子浓度低于10 g/L，pH值低于9。在此条件下，生物反应器工艺将土壤中二恶英含量从7310 pg-TEQ/g处理至2860 pg-TEQ/g，经乙醇萃取后二恶英浓度进一步降至580 pg-TEQ/g，总去除率达92%。此外，开发一种有效的方法对残渣中存活的博伊德假阿利什霉进行灭菌，提高了我们的生物反应器系统在二恶英污染场地实际应用中的适用性。
