Environmental friendly remediation and recycling method for contaminated soil by combination of Bioleaching and Bioremediation

针对污染土壤的修复和资源的增值进行了基础试验。具体而言，对突尼斯共和国斯法克斯市系统磷酸农用化肥厂排放的硫酸污染的堆积物进行中和，提取资源石膏（CaSO4）。浮选法是一种矿山工艺，可用于提取高纯白石膏。添加硫酸铝作为浮选絮凝剂，成功地提高了石膏的回收率。通过对石膏细度的检测，确定其细度达到了可以作为水泥缓凝剂的细度。根据污染物的硫酸，残留物是一种pH1.8左右的强酸。用强酸溶液冲洗残渣，用碳酸钙中和。从100g残渣样品中得到的酸水溶液中加入约3g的钙碳，可使其ph变为6，并可中和。此外，还考察了微生物的中和作用的可能性。以三种产氨杆菌为研究对象，分别为：delmer根霉、黑曲霉和MJKC25。首先，在残渣100 g中加入精馏水100 ml的一株进行过滤，种植，将上述芽孢杆菌施用于包括顶水在内的LB琼脂培养基中，观察其生长情况。通过pH指示剂甲基红由红色变为黄色，证实了各细菌在强酸中的活性和中和作用。当初始pH为4.9 ~ 6.3时，在4天左右的时间内pH升高到7或8，证实了中和作用。另一方面，当初始pH接近3时，几乎无法证实中和。结果表明，对于pH≤5的污水，该菌可以对上述废水中的残渣进行中和处理

A basic experiment was executed aiming at remediation of the polluted soil and valorization for the resource. Concretely, the piling up residue polluted with the sulfuric acid exhausted by the system phosphoric acid agricultural fertilizer factory in the Sfax city of Republic of Tunisia is neutralized and gypsum (CaSO4) that is the resource is extracted. The flotation method that was the mine technology was able to be used to take out high purity White gypsum. It succeeded in the improvement of the collection rate of gypsum by addition of the sulfuric acid aluminum as the flocculent of the flotation. When the gypsum fineness was examined, it was confirmed to reach the fineness that was able to be used as a setting retarder of cement.The residue is a strong acid of about pH1.8 according to the sulfuric acid of the contaminant. A strong acid solution that washed the residue executed neutralizing with calcium carbonate. It became pH6 and possible to neutralize by adding the calcium carbon … More ate of about 3g to aqueous acids obtained from the residue sample 100g.In addition, the possibility of neutralizing by the action of the microorganism was examined. Three kinds of bacilli that generated ammonia, Rhizopus delmer, Aspergillus niger, and MJKC25 were used. First of all, the one that refinement water 100 ml was added to the residue 100 g was filtered, it planted, the above-mentioned bacillus was applied to the LB agar medium including the top water, and it observed it. Living and the neutralizing action of each bacterium in the strong acid were confirmed from the change of the color of methylic red of the pH indicator into yellow from red. When the initial pH is from 4.9 to 6.3, the neutralizing action was confirmed from the rise of the pH to 7 or 8 at the period about the four day. On the other hand, neutralizing was able hardly to be confirmed when the initial pH was near 3. It was verified that the neutralizing processing by the bacillus was possible from the residue in the above-mentioned for the drain of pH 5 or more Less