Ferronickel Slag Performance from Reclamation Area in Pomalaa, Southeast Sulawesi, Indonesia

This study aimed to assess the differences of characteristics between the new ferronickel slag generated from the production of nickel and the slag which had been used as a material reclamation. The Toxicity Characteristic Leaching Procedure (TCLP) test was conducted on ferronickel slag to determine the concentration of heavy metals leaching. Then, the tests of X-Ray Diffraction (XRD), Scanning Electron Microscopic (SEM) and Energy-Dispersive X-Ray Spectroscopy (EDX) are also conducted on the ferronickel slag samples. The results of TCLP test show that the new ferronickel slag samples contain Fe (158, 6775 ppm), Cr (0.64465 ppm), and Pb (0.0219 ppm), and that the ferronickel slag has been used as a reclamation material containing Fe (3.94 ppm) and Cr (2.91 ppm). The result of EDX test shows that the slag sample from the reclamation area contains higher Ni concentration than the new slag sample. Slag that has been used for reclamation contains high SiO2 and Mg2(SiO6). The XRD analysis result shows that the highest elements in the slag are Si and Mg with 18.94% and 15.83% respectively. The dominant mineral in the slag is forsterite (Mg 1.784 FeSiO4 0216) by 41% and the rest is magnesium silicate (Mg2(SiO6)).

Isolation and Screening of Rhizobacteria from Scirpus Grossus Plant after Lead （Pb） Exposure

Phytoremediation is one of method which can be applied to remediate the contaminated environment. In most cases, microorganisms bacteria and fungi, living in the rhizosphere closely associated with plants, may contribute to mobilize metal ions by increasing the bioavailable fraction. Some studies have evidenced that heavy metal-resistant bacteria can enhance metal uptake by hyperaccumulator plants. Lead-resistant bacteria which could help to increase the lead uptake by Scirpus grossus was isolated and screened. The samples were taken from plant roots after being exposed in a range finding test by spiking analytical grade of Pb（NO3）2 solution in variation of Pb concentrations. The results of rhizobacteria isolation showed that there were several colonies having resistance to grow and survive in contaminated environment even the host plant had withered. Only a few of rhizobacteria colonies were affected by high concentrations of lead exposure during screening test. The screening test was conducted by growing the isolated colonies on plates containing tryptic soy agar （TSA） medium containing of 200, 400 and 600 mg/L Pb solution including the plate with only TSA media without any lead exposure acting as a control medium, and incubating them at 30℃ for 72 hours. Isolation of bacteria from rhizosphere had found 47 colonies including several colonies from the withered plants. These all 47 colonies then become 28 after characterization by using color and colony morphology, followed by Gram stain, catalase, oxidase and motility test. The screening test of lead resistant bacteria colonies resulted 3 groups which is scored high, medium and low. The screened colonies will then be used for further study.