• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.716-721
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• 2005

The role of an effective microbial species is critical to the successful application of biological processes to remove sulfur compounds. A bacterial strain was isolated from the soil of a malodorous site and identified as Burkholderia spp. This isolate was able to oxidize thiosulfate to sulfate, with simultaneous pH decrease and accumulation of elemental sulfur. The specific growth rate and the sulfate oxidation rate using the thiosulfate basal medium were $0.003 h^{-1}\;and\;3.7 h^{-1}$, respectively. The isolated strain was mixotrophic, and supplementation of $0.2\%$ (w/v) of yeast extract to the thiosulfate-basal medium increased the specific growth rate by 50-fold. However, the rate of sulfate oxidation was more than ten times higher without yeast extract. The isolate grew best at pH 7.0 and $30^{\circ}C$, and the sulfate oxidation rate was the highest at 0.12 M sodium thiosulfate. In an upflow biofilter, the isolated strain was able to degrade $H_2S\;with\;88\%$ efficiency at 8 ppm and 121/h of incoming gas concentration and flow rate, respectively. The cell density at the bottom of the column reached $3.2{\times}10^8$ CFU/(g bead) at a gas flow rate of 121/h.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.655-668
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• 1994

Conventional deodorization filters using soil and compost reach the capacity limitation of deodorization in short period, because its removal mechanism primarily depends on adsorption. Therefore, in this study the experiment was performed on the removal of ammonia which is a strong inorganic malodor, frequently emitted from night soil treatment plants and sewage treatment plants, by seeding activated sludges on the bio-peat containing higher organic contents, water conservation capacity, permeability and lower pressure drop. As a result, in raw peat filter natural ammonia outlet was observed in consequence of pH increase resulted from ammonia ionizing in liquid phase. Ammonia removal mechanism primarily depended on the adsorption onto the anion colloidal substances in peat. In peat bio-filter, theoretical ammonium salts ratio was higher than that of raw peat, resulted from slight pH increase by microorganism activity, however, the experimetal value of ammonia-nitrogen accumulated in bio-peat was lower than that of raw peat because of nitrification by nitrifying bacteria. In the initial reaction period, adsorption was predominant in the ammonia removal mechanism, but nitrification was conspicuous after the middle period. Mass balance of nitrogen was established using experimental data of input $NH_3$ loading, output $NH_3$ loading, $NH_4{^+}$-N, $NO_x$-N, and Org-N. The critical time of unsteady state, which is the maximum activating point of microorganism in bio-filter, was determined using experimental data, and the ammonia adsorption curve was computed using regression analysis. On the basis of the results obtained by above analysis, the delay days for the saturation of adsoption capacity in peat bio-filter was calculated.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.3
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• pp.117-125
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• 2006

A microorganism capable of degrading toluene was isolated from crude oil contaminated soil and identified as Pseudomonas fluorescence. The effects of environmental factors on the degradation of toluene were investigated. The optimum temperature for toluene degradation was $30^{\circ}C$ and the maximum specific cell growth and toluene degradation rates were $0.76hr^{-1}$ and $0.36hr^{-1}$, respectively. Although the wild cells were not able to degrade toluene at $10^{\circ}C$ and $40^{\circ}C$, the cells adapted to toluene at $30^{\circ}C$ degraded 100mg/L of toluene completely at $10^{\circ}C$ and 80% of the toluene at $40^{\circ}C$. The wild cells were not able to degrade more than 200mg/L of toluene but the toluene-adapted cells degraded up to 300mg/L of toluene. Although the optimum pH was 7.0, the degradation rates were not much different in the range of 5.5 to 9.0. When nitrate was used as a nitrogen source instead of ammonium, the adaptation period became longer by 2~10 hours and the cell growth yield became lower by 45%. The toluene degradation rates after adaptation period, however, were almost same in both cases. The observations in this study will be used in the future biofilter design and operation.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.1
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• pp.56-64
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• 2001

Composting of livestock feces is economic and safe process to decrease the possibility of direct leakage of organic pollutants to ecosystem from commercial and environmental point of view. This study was conducted with three different experiments related to composting of livestock feces. The purpose of experiment 1 was to investigate changes of characteristic of compost pile during composting period by low temperature in cold season. To compare composting effect of experimental compost pile and control pile exposed in cold air, experimental compost piles were warmed up by hot air until their temperatures were reached at $35^{\circ}C$. Sawdust, Ricehull and Ricestraw were mixed with livestock feces as bulking agent. The highest temperatures of compost pile during composting period were in sawdust, rice hull, rice straw, and control were $75^{\circ}C$, $76^{\circ}C$, $68^{\circ}C$, $45^{\circ}C$ respectively. Moisture content, pH, C/N and volume of compost were decreased during composting period. Experiment 2 was carried out to study utilization effect of compost by plant. A corn was cultivated for 3 years on fertilized land with compost and chemical fertilizer. The amount of harvest and nutrition value of corn were analyzed. In first year of trial, the amount of harvest of corn on land treated with compost was lower by 20% than that of land treated with chemical fertilizer. In second year, there was no difference in yield of com between compost and chemical fertilizer. In third year, the yield of com on land fertilized with compost was much more than that of land fertilized with chemical fertilizer. The purpose of experiment 3 was to estimate the decrease of malodorous gas originating from livestock feces by bio-filter. Four types of bio-filters filled with saw dust, night soil, fermented compost and leaf mold were manufactured and tested. Each bio-filter achieved 87-95% $NH_3$ removal efficiency. This performance was maintained for 10 days. The highest $NH_3$ removal efficiency was achieved by leaf mold on the first day of operation period. It reduced the concentration of $NH_3$ by about 95%. Night soil and fermented compost showed nearly equal performance of 93 to 94% for 10 days from the beginning of operation. The concentration of hydrogen sulfide and methyl mercaptan originating for compost were equal to or less than $3mg/{\ell}$ and $2mg/{\ell}$, respectively. After passing throughout the bio-filter, hydrogen sulfide and methyl mercaptan were not detected.