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

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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