• Journal of Environmental Science International
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• v.4 no.2
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• pp.215-222
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• 1995

Thiokncillus neapolitanus R-10 isolated from sludge of night soil, showed an oxidizing activity on several malodorous sulfur compounds. The microbe successfully utilized hydrogen sulfide(H2S), methy mercaptan(MM), dimethyl sulfide(DMS) and dimethyldisulfide(DMDS) during the batch culture reaction, of which H2S was rather rapidly oxidized. To examine the ability for removal of malodorous sulfur compounds, various concentrations of sulfide substrates were supplemented separately to basal medium and their responses were investigated. As the concentration of sulfide was increased, growth was accelerated within three days of cultivation. 2.5mM was the most favorable substrate concentration of sulfide added for all cases tested. However, when the concentration of sulfur compounds were raised over 4M, they behaved as a growth inhibitor.

• Journal of Environmental Science International
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• v.4 no.3
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• pp.295-301
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• 1995

Continuous deodorization of malodorous sulfur compounds by Thiobaillus neapolitanusts R-10 immobilized onto a polypropylene pellet was studied using a column reactor at 30$^{\circ}$C. The maximum amounts of immobilized cells was 5.3 gall polypropylene with 5$\times$7.5mm in pellet size, and the amounts of immobilized cells in the higher part of the column was as twice as in the lower part. The optimum pH and temperature for removal of dimethyl sulfide were 6.0 and 30$^{\circ}$C, respectively. When 5-20 ${mu}ell$/l of hydrogen sulfide and methylmercaptan were employed 98% of removal efficiency were achieved. In contrast, lower concentrations of dimethyl sulfide and dimethyldisulfide should be supplied to meet satisfactory deodorization efficiency. The immobilized cell column was successfully operated for the deodorization of mixture of sulfur compounds over 15 days without significant loss of initial activity achieving high efficiency.

• Journal of Environmental Science International
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• v.4 no.3
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• pp.143-143
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• 1995

• Journal of environmental and Sanitary engineering
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• v.14 no.4
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• pp.117-123
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• 1999

The analytical instrument method was applied to analyze malodorous sulfur compounds emitted from industrial fields. Six factories and two sites which release malodorous substances into ambient air were selected to determine the level of hydrogen sulfide($H_2S$), methylmercaptan(MeSH), dimethyl sulfide($Me_2S$), and dimethyl disulfide($Me_2S_2$) using automated thermal desorption system (STD400) and GC-FPD in summer and fall seasons of 1999. The Air sampler for ATD400 uses a small pump to draw sample and a mass flow controller to adjust sample amount without using a dilution apparatus. The trap temperature of ATD400 reached to $-80^{\circ}$ by supplying liquid nitrogen and $H_2S$ can be analyzed under this condition. The recovery rates of $H_2S$, MeSH, $Me_2S$, and $Me_2S_2$ of odorous sulfur compounds standard were shown 98.2%, 93.6%, 98.2%, 99.4% respectively. The concentrations of $Me_2S$ at outside boundary of G market, L factory, and J factory were 0.018ppm, 0.021ppm, 0.032ppm in summer, respectively. The concentration of $H_2S$ at Nanjido landfill was 1.167ppm in summer, but that of $H_2S$ was not detected in fall because of soil covering. The concentration of H2S and $Me_2S_2$ at inside of Chonggye stream were 0.564ppm and 1.045ppm in summer, while those of H2S and Me2S2 were 0.285ppm and 0.465ppm in fall, respectively.

• Journal of Environmental Health Sciences
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• v.40 no.6
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• pp.477-483
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• 2014

Objectives: This study was carried out to investigate the characteristics of odors emitted from sewage in a sanitary sewer and its outlets. Methods: The concentration of mal-odorous sulfur was analyzed by gas chromatograph, and odor intensity was estimated by an on-site sensory test. Odor intensity calculated from instrumental analysis results was compared with odor intensity observed at field. Results: As a results, the concentration of $H_2S$ ranged from 2.4 ppb to 5,889 ppb (average 703 ppb), while $CH_3SH$, $(CH_3)_2S$, and $(CH_3)_2S_2$ showed from 10 ppb to 554 ppb (average 119 ppb) and from 20 ppb to 332 ppb (average 70 ppb) and from 2.7 ppb to 8.1 ppb (average 5 ppb) individually. Average odor intensity observed in the field was degree three. Odor intensity calculated from sulfur compound concentration was confirmed as similar to the observed odor intensity because the coefficient of variance between the observed and the calculated intensities was less than one. Conclusion: It was expected that the results of this study will be helpful to design a deodorizing device to reduce odor emissions from sewerage facilities in the future.

• Journal of Environmental Science International
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• v.22 no.1
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• pp.109-117
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• 2013

The removal characteristics of composite odor and malodorous substances using 33 biofilters in sewage treatment facilities were investigated. The geometry mean values of composite odor and odor quotient were reduced by 52.7% and 59.2% at the outlet of the biofilters, respectively. The removal efficiencies of the biofiltes for the composite odor and odor quotient show a significant difference statistically(p=0.000<0.05). The median value of odor quotient of sulfur compounds was reduced by 69.1% at the outlet of the biofilter and the odor quotient of the sulfur compound at the inlet and outlet of the biofilter shows a significant difference statistically(p=0.000<0.05); on the other hand, those of the $NH_3$ and trimethylamine, aldehydes, VOCs and alcohols, organic acids do not.

• International Journal of Oral Biology
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• v.44 no.1
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• pp.27-29
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• 2019

Halitosis is a very common disease that affects the majority of the population and is characterized by unpleasant odor during expiration. Anaerobic bacteria produce a range of malodorous substances including volatile sulfur compounds. To reduce oral malodor, the amount of oral microorganisms should be managed through brushing, scraping, and use of antibacterial agents. In this study, a mouthwash containing 0.05% cetylpyridinium chloride was tested on 22 candidates with oral malodor for two weeks to confirm oral malodor reduction through the use of antibacterial mouthwashes. Volatile sulfur compound measurements were significantly lower after using the mouthwash than before using it; thus, the mouthwash effectively reduced oral malodor.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.1
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• pp.77-85
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• 2004

In this study, the concentrations of reduced S compounds (including hydrogen sulfide (H$_2$S); methyl mercaptan ($CH_3$SH); dimethyl sulfide (($CH_3$)$_2$S); carbon disulfide (CS$_2$); and dimethyl disulfide (($CH_3$)$_2$S$_2$) were determined from landfill gas (LFG) in three municipal landfill sites in the two cities of Gwang Ju (GJ) and Jeju (JJ), Korea. The S gas concentrations measured in these landfill sites were found to be dominated by H$_2$S with its mean concentration of 850 ppm from 10 LFG samples. Both absolute and relative dominance of H$_2$S was seen to be significant in most LFG samples, except those collected from very old and inactive landfills. Unlike the pattern of H$_2$S, other S gases were typically observed at much reduced concentration levels (a few ppm or less) as follows: DMS (3.5); $CH_3$SH (1.3); CS$_2$(1.2); and DMDS (0.02 ppm). If compared equally in mass concentration unit (mg m$^{-3}$ ), H$_2$S generally explained far above 90% of all S gas masses determined concurrently. Moreover, as its mass concentration commonly exceeds those of the major aromatic VOC components in LFG (like benzene and toluene), it appeared to be one of the most dominant gaseous components emitted as LFG in a quantitative sense.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.965-974
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• 2009

This study evaluated the degradation efficiency of malodorous sulfurized-organic compounds by utilizing N- and Sdoped titanium dioxide under visible-light irradiation, and examined the catalyst deactivation and regeneration. Catalyst surface was characterized by employing Fourier-Transform-Infrared-Red (FTIR) spectra. The visible-light-driven photocatalysis techniques were able to efficiently degrade low-level dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) with degradation efficiencies exceeding 97%, whereas they were not effective regarding the removal of high-level DMS and DMDS, with degradation efficiencies of 84 and 23% within 5 hrs of photocatalytic processes. As compared with DMS, DMDS which containes one more sulfur element revealed quick catalyst deactivation. Catalyst deactivation was confirmed by the equality between input and output concentrations of DMD or DMDS, the obsevation of no $CO_2$ generation during a photocatalytic process, and the FTIR spectrum peaks related with sulfur ion compounds, which are major byproducts formed on catalyst surfaces. The mineralization efficiency of DMS at 8 ppm, which was a peak value during a photocatalytic process, was calculated as 144%, exceeding 100%. The catalyst regenerated by high-temperature calcination exhibited higher catalyst recovery efficiency (53 and 58% for DMDS and DMS, respectively) as compared with dry-air and humid-air regeneration processes. However, even the calcined method was unable to totally regenerate deactivated catalysts.

• 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.