• Resources Recycling
• /
• v.17 no.2
• /
• pp.3-15
• /
• 2008

Different toxic wastes are disposed of in our surroundings and these will ultimately threaten the existence of living organisms. Biohydrometallurgy, which includes the processes of bioleaching and bioremediation through the activities of microorganisms such as bacterial or fungal species, is a technology that has the potential to overcome many environmental problems at a reasonable economic cost. Bioleaching were carried out for dissolution of metals from different materials using most important metal mobilizing bacteria such as Thiobacillus ferrooxidans, Thiobacillus thiooxidans and Laptospirillum ferrooxidans. According to the reaction, bioleaching is parted as direct and indirect mechanism. In direct mechanism the bacteria oxidize the sulphides minerals by accepting electron and producing sulphuric acid in leaching media for their growth and metabolism. In other hand the indirect bioleaching is demonstrated as the oxidation of sulphides mineral by the oxidant like $Fe^{3+}$ produced by the iron oxidizing bacteria. Through this process, substantial amount of metal can be recovered from low-grade ores, concentrates, industrial wastes like sludge, tailings, fly ash, slag, electronic scrap, spent batteries and spent catalysts. This may be alternative technology to solve the high deposition of waste, which moves toward a healthy environment and green world.

• Korean Chemical Engineering Research
• /
• v.51 no.5
• /
• pp.568-574
• /
• 2013

A semi-pilot biofilter packed with media with immobilized Thiobacillus sp. IW and return sludge, was operated under various operating conditions in order to treat malodorous waste air containing both hydrogen sulfide and ammonia which are major air pollutants emitted from composting factories and many publicly owned treatment works (POTW). At the incipient and middle stages of a semi-pilot biofilter operation, the hydrogen sulfide-removal efficiency behaves regardless of an inlet-load of ammonia. However, the ammonia-removal efficiency decreased as an inlet-load of hydrogen sulfide increased. Nevertheless, at the final stage of the semi-pilot biofilter operation, the ammonia-removal efficiency was not affected by the increase of hydrogen sulfide-inlet load. It is attributed to that a serious acidification of semi-pilot biofilter-media did not occur due to continuous injection of buffer solution at the final stage of the semi-pilot biofilter operation. When both hydrogen sulfide and ammonia contained in malodorous waste air were treated simultaneously by semi-pilot biofilter, the maximum elimination capacities of hydrogen sulfide and ammonia turned out to be ca. 58 and $30g/m^3/h$, respectively. These maximum elimination capacities were estimated to be ca. 39 and 46% less than those for lab-scaled biofilter-separate elimination of hydrogen sulfide and ammonia, respectively. Thus, for the simultaneous biofilter-treatment of hydrogen sulfide and ammonia, the maximum elimination capacity of ammonia decreased by 7% more than that of hydrogen sulfide.

• KSBB Journal
• /
• v.16 no.4
• /
• pp.389-397
• /
• 2001

The effect of sludge digestion on the leaching efficiency of heavy metals from sludge by bioleaching with Thiobacillus thiooxidans MET was investigated. The used sludges were a non- and anaerobically digested. The leaching efficiency of heavy metals was strongly dependent on the pH of the sludge solution rather than the sludge condition and stolid concentration. The lower the pH the more heavy metal was leached from 3.0 of pH. The sequent orders of leaching heavy metals were Zn, Cu, and Cr. Although the buffering capacity of non-digested sludge was similar to anaerobically digested sludge, the pH decrease rate of the anaerobically digested sludge solution was faster than that of the non-digested sludge solution due to the higher sulfur oxidation rate of T. thiooxidans MET in the anaerobically digested sludge. The amount of leached heavy metals from the anaerobically digested sludge showed higher than that of non-digested sludge at the same pH value. This result might be caused by the difference of the insoluble metal types, which were contained in the sludge. An increase in sludge solids concentration decreased the leaching efficiency of heavy metals in the range of solids concentration 10 g/L to 70 g/L. The optimum ratio of S° to sludge stolid was 0.1 in both the sludge. The bioleaching process of heavy metals with T. thiooxidans MET showed the disinfecting effect over 90% as well as the reduction effect in sludge weight of 20%.

• Korean Journal of Soil Science and Fertilizer
• /
• v.39 no.6
• /
• pp.409-414
• /
• 2006

Sulfur-oxidizing bacteria were enumerated and isolated from a steady-state anaerobic master culture reactor (MCR) operated for over six months under a semi-continuous mode and nitrate-limiting conditions using thiosulfate as an electron donor. Most are Gram-negative bacteria, which have sizes up to 12 m. Strains AD1 and AD2 were isolated from the plate count agar (PCA), and strains BD1 and BD2 from the solid thiosulfate/nitrate medium. Based on the morphological, physiological, FAME and 16S rDNA sequence analyses, the two dominant strains, AD1 and AD2, were identified as Paracoccus denitrificans and Paracoccus versutus (formerly Thiobacillus versutus), respectively. From the physiological results, glucose was assimilated by both strains AD1 and AD2. Heterotrophic growth of strains AD1 and AD2 could be a more efficient way of obtaining a greater amount of biomass for use as an inoculum. Even though facultative autotrophic bacteria grow under heterotrophic conditions, autotrophic denitrification would not be reduced.

• Journal of the Korean GEO-environmental Society
• /
• v.8 no.4
• /
• pp.41-45
• /
• 2007

It is very important that selection of packing media with large surface area, high limited back pressure in biofilter. The object of this study is the isolation of sulfur-oxidizing bacteria and the removal of hydrogen sulfide in biofilter by media. This investigation led to the following results: 1) we isolated Thiobacillus sp. IW. at an abandoned coal mine in Hwasun, Jeonnam Province. 2) The inorganic media showed better results than the organic media from experiments looking at removal characteristics and changes in pressure drop using various media. 3) Among the inorganic media, fibril and PU media showed best performance.

• Korean Chemical Engineering Research
• /
• v.52 no.2
• /
• pp.240-246
• /
• 2014

A semi-pilot biofilter inoculated with the microbes consortium of Bacillus cereus DAH-1056 and Arthrobacter sp. KDE-0311 was operated under various operating conditions in order to treat malodorous waste air containing both hydrogen sulfide and ammonia. When both hydrogen sulfide and ammonia contained in malodorous waste air were treated simultaneously by semi-pilot biofilter inoculated with Thiobacillus sp. IW and return-sludge, the removal efficiencies of hydrogen sulfide and ammonia were ca. 80% and ca. 50%, respectively. On the other hand, in this study, the removal efficiencies of hydrogen sulfide and ammonia were ca. 90% and ca. 60%, respectively. Therefore, the removal efficiencies of hydrogen sulfide and ammonia were enhanced by ca. 13% and 20%, respectively, compared to the semipilot biofilter inoculated with Thiobacillus sp. IW and return-sludge. In addition, in this study, the maximum elimination capacities of hydrogen sulfide and ammonia were enhanced by ca. 15% ($8g/m^3/h$) and 10~17% ($3{\sim}5g/m^3/h$), respectively. In this study, it was observed either that in case of even a same inlet load of hydrogen sulfide, a higher concentration of hydrogen sulfide causes more difficulties in treating ammonia containing in waste air than a lower one, or that in case of even a same inlet load of ammonia, a lower concentration of ammonia results in higher removal efficienciy and elimination capacity than a higher one. Even though hydrogen sulfide and ammonia were treated simultaneously by a biofilter in this study, the maximum elimination capacity of hydrogen sulfide in this study exceeded or was similar to that in previous study of biofilter treating only hydrogen sulfide. In addition, this study showed the higher maximum elimination capacity of ammonia than other previous investigation of biofilter treating hydrogen sulfide and ammonia simultaneously.

• Journal of Soil and Groundwater Environment
• /
• v.11 no.2
• /
• pp.38-44
• /
• 2006

Two sulfur-based column reactors inoculated with a bacterial consortium containing autotrophic denitrifiers were operated for 100 and 500 days, respectively and nitrate removal efficiency and the adaptation of microbial communities in the columns were monitored with column depths and time. For better understanding the adaptation phenomenon, molecular techniques including 16S rDNA sequencing and DGGE analysis were employed. Although both columns showed about 99% of nitrate removal efficiency heterotrophic denitrifiers such as Cenibacterium arsenioxidans and Geothrix fermentans were found to a significant portion at the initial stage of the 100-day reactor operation. However, as operation time increased, an autotrophic denitrifier Thiobacillus denitrificans became a dominant bacterial species throughout the column. A similar trend was also observed in the 500-day column. In addition, nitrate removal efficiencies were different with column depths and thus bacterial species with different metabolic activities were found at the corresponding depths. Especially, T. denitrificans was successfully adapted and colonized at the bottom parts of the columns where most nitrate was reduced.

• 한국생물공학회:학술대회논문집
• /
• 2003.10a
• /
• pp.462-462
• /
• 2003

• Korean Journal of Microbiology
• /
• v.11 no.3
• /
• pp.109-114
• /
• 1973

It is well known that the ornithine-containing lipids were separated and identified from the other lipids of Rhodopseudomonas spheroides, Rhodospirillum, and Thiobacillus thiooxidans. An ornithine-containing lipid that lacks phosphorus and glycerol has been observed in Ferrobacillus ferrooxidans which was isolated from dalsung copper mine in Korea. The aminolipid was extracted from F.ferrooxidans and furthr purified by thin layer chromatography, and the product was identified as an ornithine-containing lipid by paper and liquid chromatography respectively.

• Journal of Environmental Science International
• /
• v.10 no.4
• /
• pp.287-292
• /
• 2001

A packed bed of volcanic rock was used as deodorizing material to remove hydrogen sulfide($H_2$S) from air in a laboratory-scale column, and was inoculated with Thiobacillus sp. as $H_2S$ oxidizer. The effects of volcanic rock particle size distribution on system pressure drop were examined. Various tests have been conducted to evaluate the effect of $H_2S$ inlet concentration and CBCT(Empty Bed Contact Time) on $H_2S$ elimination. The pressure drop for particles of size range from 5.6 to 10 mm was 14 mm$H_2S$/m at a representative gas velocity of 0.25m/s. Biofilter using scoria and Thiobacillus sp. could get the stable removal efficiencies more than 99.9% under $H_2S$ inlet concentrations in the range from 30 to 1,100ppm at a constant gas flow rate of $15.2{\ell}$/min. $H_2S$ removal efficiencies greater than 99% were observed as long as EBCT was longer than 8sec at the 250ppm of $H_2S$ inlet concentration. When EBCT was reduced to 5.5 sec, $H_2S$ removal efficiency decreased by about 12 percent. The maximum $H_2S$ elimination capacity was determined to be 269g-$H_2S/m^3{\cdot}hr$.