• Design & Manufacturing
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• 제14권2호
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• pp.28-33
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• 2020

Recently, as the income level and quality of life have improved, the desire for a pleasant environment has increased, and a deodorization plan is required through thorough prevention and diffusion of odorous substances in waste treatment facilities recognized as hateful facilities, appropriate collection, and selection of the right prevention facilities. In this study, a waste disposal facility was modeled and computerized analysis for odor and ventilation analysis was conducted. Numerical analysis of the waste treatment facility was performed at the size of the actual plant. CATIA V5 R16 for numerical model generation and ANSYS FLUENT V.13 for general purpose flow analysis were used as analysis tools. The average air-age of the internal was 329 seconds, and the air-flow velocity was 0.384m/s. The odor diffusion analysis inside the underground pump room showed congestion-free air circulation through streamline distribution and air-age distribution. This satisfies the ASHRAE criteria. In addition, the results of diffusion analysis of odorous substances such as ammonia, hydrogen sulfide, methyl mercaptan and dimethyl sulfide were all expected to satisfy the regulatory standards. Particularly in the case of the waste loading area, the air-flow velocity was 0.297m/s, and the result of meeting the regulatory standards with 0.167ppm of ammonia, 0.00548ppm of hydrogen sulfide, 0.003ppm of methyl mercaptan, and 0.003ppm of dimethyl sulfide was found.

• 한국식품과학회지
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• 제34권6호
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• pp.1123-1126
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• 2002

김치를 $25^{\circ}C$에서 4일간 숙성시킨 후, pH와 관능성을 관찰하고 몇가지 주요한 휘발성냄새성분의 변화를 관찰하였다. pH는 가열에 의하여 거의 변화가 없었다. 전반적인 기호도는 가열된 시료, 특히 40분 가열시료의 기호도수치가 높았으며 3시료 사이에 유의적인 차이를 보였다(p<0.05). 산미, 맛, 냄새, 조직감의 경우도 전반적인 기호도와 유사한 경향을 보였으나, 형태의 경우는 3시료 사이에 차이가 없었다. 휘발성 냄새성분의 결과를 보면 reference(비가열시료)는 allyl mercaptan, methyl allyl sulfide, dimethyl disulfide, diallyl sulfide, diallyl disulfide와 같은 5종의 황함유성분과 ethanol이 검출되었는데, $100^{\circ}C/10$분시료는 ethanol과 methyl allyl sulfide만 검출되고 그 함량도 reference에 비하여 현저하게 감소하였으며, $100^{\circ}C/40$분 시료는 $100^{\circ}C/10$분 시료와 비교하여 ethanol의 함량은 현저히 감소하고 methyl allyl sulfide의 함량은 거의 변화가 없었다.

• Bulletin of the Korean Chemical Society
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• 제15권10호
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• pp.873-881
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• 1994

The approximate rate and stoichiometry of the reaction of excess diisobutylaluminum hydride-dimethyl sulfide complex($DIBAH-SMe_2$) with organic compounds containing representative functional group under standardized conditions (toluene, $0{\circ}C$) were examined in order to define the reducing characterstics of the reagent and to compare the reducing power with DIBAH itself. In general, the reducing action of the complex is similar to that of DIBAH. However, the reducing power of the complex is weaker than that of DIBAH. All of the active hydrogen compounds including alcohols, amines, and thiols evolve hydrogen slowly. Aldehydes and ketones are reduced readily and quantitatively to give the corresponding alcohols. However, $DIBAH-SMe_2$ reduces carboxylic acids at a faster rate than DIBAH alone to the corresponding alcohols with a partial evolution of hydrogen. Similarly, acid chlorides, esters, and epoxides are readily reduced to the corresponding alcohols, but the reduction rate is much slower than that of DIBAH alone. Both primary aliphatic and aromatic amides examined evolve 1 equiv of hydrogen rapidly and are reduced slowly to the amines. Tertiary amides readily utilize 2 equiv of hydride for reduction. Nitriles consume 1 equiv of hydride rapidly but further hydride uptake is quite slow. Nitro compounds, azobenzene, and azoxybenzene are reduced moderately. Cyclohexanone oxime liberates ca. 0.8 equiv of hydrogen rapidly and is reduced to the N-hydroxylamine stage. Phenyl isocyanate is rapidly reduced to the imine stage, but further hydride uptake is quite sluggish. Pyridine reacts at a moderate rate with an uptake of one hydride in 48 h, while pyridine N-oxide reacts rapidly with consumption of 2 equiv of hydride for reduction in 6h. Similarly, disulfides and sulfoxide are readily reduced, whereas sulfide, sulfone, and sulfonic acid are inert to this reagent under these reaction conditions.

• 환경영향평가
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• 제21권3호
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• pp.353-365
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• 2012

This study is understanding characteristics and analyzing contributions of the odor causing compounds of complex-odor & major specified odor materials, and contribution analysis, caused pre-treatment facilities(input and storage) and post-treatment facilities(heating and drying). The target of this study is feeds-production-facilities, located in Seoul. The averaged complex-odor compounds on the boundary line is 21 times higher, and it is 15 times higher than emission standards. In cracking&collection(pre-treatment facilities), the concentration of compounds is 4,881 times, 2,080 times in drying, and 1,442 times in putting&storing facilities. Ammonia occupies the largest portion of the results of monitoring specified odor compounds in input&storage facilities, followed Acetaldehyde > Hydrogen sulfide > Methyl mercaptan. In cracking&collection, Ammonia also occupies most of odor compounds, followed Methyl mercaptan > Acetaldehyde > Dimethyl disulfide > Dimethyl sulfide > Hydrogen sulfide. Acetaldehyde > Methyl mercaptan in drying facilities. On the boundary line, however, the concentration of specified odor compounds stays below emission standards. The result of contribution analysis is that methyl mercaptan has the highest contribution in input & storage, as well as cracking&collection facilities, followed Acetaldehyde > Hydrogen sulfide > Dimethyl sulfide > Dimethyl disulfide. In the drying facilities, the contribution shows Methyl mercaptan > Acetaldehyde > i-Valeraldehyde and Butyraldehyde. Therefore, to decrease odor in foodwaste treatment facilities, proper prevention facilities need to be installed and operated, according to characteristics of individual odor compounds, based on monitored data.

• 한국환경과학회지
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• 제4권2호
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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.

• 한국식품영양학회지
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• 제13권4호
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• pp.334-341
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• 2000

해조류에서 생합성되는 3급 함황화합물인 DMPT를 창자파래로부터 추출하기 위하여 시료의 상태, 용매 의 극성, 초음파 처리, boiling 및 autoclaving 처리에 의한 추출조건을 검토하였다. 용매추출, 초음파 처리후 용매추출, 열수추출 및 가압 열수추출법을 이용하여 창자파래로부터 DMPT를 추출한 결과, 초음파 처리후 가압 열수처리한 경우가 가장 효과적이었고, 다음으로는 초음파 처리후 열수 처리하는 방법이었다. 창자파래로부터 DMPT를 추출 해내는 최적조건으로 분말시료에 물과 acetone (2:1, v/v)의 혼합용매를 15배량 가하여 초음파 처리 후 121$^{\circ}C$에서 60분간 autoclaving하는 방법으로서, 이 때 추출된 DMPT 함량은 시료 g당 311.200ng이었다. 창자파래에서 추출한 DMPT 수용액을 조제하여 온도별로 저장시킬 때 DMPT 분해에 의한 DMS의 발생량은 저장온도에 비례하여 증가되었지만 저온에서는 매우 낮은 분해율을 나타내었다. DMPT 1mg을 저장하였을 때의 잔존율은 6$0^{\circ}C$ 저장의 경우78.5%로 고온에서는 다소 불안정하였으나 $0^{\circ}C$에서는 DMPT의 잔존율이 99.8%로 매우 높게 나타났다. 창자파래에서 추출한 DMPT 수용액을 3$0^{\circ}C$에서 방치하였을 때 pH가 5 이하의 산성영역에서는 DM-PT의 분해가 거의 일어나지 않았으나 pH가 올라감에 따라서 분해가 서서히 일어나기 시작하여 pH 9.5에 이르러서는 DMS의 양이 급속하게 증가하였다.

• 한국대기환경학회지
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• 제20권1호
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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.

• 환경영향평가
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• 제21권5호
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• pp.695-705
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• 2012

The purpose of this study is to investigate concentration level and characteristics of malodour substances generated from landfill site in C city. Also, it is tried to predict distribution of concentration level using ISCST3 model around landfill site. From the results, it can be confirmed that twelfth-class malodour substances such as ammonia, methyl mercaptan, hydrogen sulfide, dimethyl sulfate, dimethyl disulfate, toluene, acetaldehyde, styrene, propionaldehyde, butylaldehyde, n-Valeraldehyde, xylene were generated from landfill site. The levels of the malodour substances were lower than that of permeable concentration regulated by odor control law in Korea. However, the concentration of malodour substances including methyl mercaptan, hydrogen sulfide, acetaldehyde, and propionaldehyde exceeded threshold limit value(TLV). It was seemed that these substances caused the problem of offensive odor around circumstance of landfill. The concentration of malodour substances was higher in slant than in upper part of landfill. The concentrations of malodour substances measured at night time were shown higher level than those at night time because atmospheric condition was stable at night time. It showed that the concentration of malodour substances were higher in spring. The results of atmospheric diffusion model predicted that tolerance limit level of hydrogen sulfide and methyl mercaptan was detected within nearly 5km from the boundary of landfill.

• International Journal of Oral Biology
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• 제39권1호
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• pp.35-40
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• 2014

Halitosis is caused by consumption of certain foods or drinks and production of volatile sulfur compounds (VSCs) by periodontopathogens. VSCs-related halitosis is not easily removed using mechanical or chemical therapies such as dental floss, plaque control and mouth rinse. Lactobacillus are known to be probiotics and stimulate immune systems of human. Furthermore, L. casei ATCC 334 and L. rhamnosus GG have an effect on protection of dental caries in vitro studies. The aim of this study was to investigate effect of Lactobacillus on halitosis by Fusobacterium nucleatum- and Porphyromonas gingivalis-producing VSCs and to analyze inhibitory mechanism. The periodontopathogens were cultivated in the presence or the absence Lactobacillus, and the level of VSCs was measured by gas chromatograph. For analysis of inhibitory mechanisms, the susceptibility assay of the spent culture medium of Lactobacillus against F. nucleatum and P. gingivalis was investigated. Also, the spent culture medium of Lactobacillus and periodontopathogens were mixed, and the emission of VSCs from the spent culture medium was measured by gas chromatograph. L. casei and L. rhamnosus significantly reduced production of VSCs. L. casei and L. rhamnosus exhibited strong antibacterial activity against F. nucleatum and P. gingivalis. The spent culture medium of L. casei inhibited to emit gaseous hydrogen sulfide, methyl mercaptan and dimethyl sulfide from the spent culture medium of periodontopathogens. However, the spent medium of L. rhamnosus repressed only dimethyl sulfide. L. casei ATCC 334 may improve halitosis by growth inhibition of periodontopathogens and reduction of VSCs emission.

• 통합자연과학논문집
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• 제8권2호
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• pp.128-134
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• 2015

This paper focuses on the applicability of a continuous monitoring method on trace sulfur compounds in the ambient air by TD and GC/PFPD. The target compounds for monitoring include H2S(hydrogen sulfide), Methyl mercaptan, Dimethyl Sulfide, and Dimethyl disulfide. The result of QA/QC on monitoring instruments satisfies all the standards of Odor Measurement and Analysis Method, showing that the reproductivity of the compounds by concentration is within 10%, linearity is above 0.98 of a correlation efficient, method detection limit is 0.16 ppb by MM standard, and recovery rate is over 70%. Monitoring was conducted for two years from March 2006 to February 2008. As a result of the monitoring, the average concentration of H2S was 0.08 ppb, with the maximum concentration at 16.15 ppb. The result indicates that it is reasonable to do continuous monitoring as there appears a spontaneous event of high concentration by the condition of the site during monitoring odor-causing substances. Therefore, it is suggested that the continuous monitoring method used in this paper is appropriate to identify the characteristics of sudden occurrence and concentration variations of sulfur compounds.