• Journal of Microbiology and Biotechnology
• /
• v.31 no.6
• /
• pp.803-814
• /
• 2021

A pilot-scale biocover was constructed at a sanitary landfill and the mitigation of methane and odor compounds was compared between the summer and non-summer seasons. The average inlet methane concentrations were 22.0%, 16.3%, and 31.3%, and the outlet concentrations were 0.1%, 0.1%, and 0.2% during winter, spring, and summer, respectively. The odor removal efficiency was 98.0% during summer, compared to 96.6% and 99.6% during winter and spring, respectively. No deterioration in methane and odor removal performance was observed even when the internal temperature of the biocover increased to more than 40℃ at midday during summer. During summer, the packing material simultaneously degraded methane and dimethyl sulfide (DMS) under both moderately thermophilic (40-50℃) and mesophilic conditions (30℃). Hyphomicrobium and Brevibacillus, which can degrade methane and DMS at 40℃ and 50℃, were isolated. The diversity of the bacterial community in the biocover during summer did not decrease significantly compared to other seasons. The thermophilic environment of the biocover during summer promoted the growth of thermotolerant and thermophilic bacterial populations. In particular, the major methane-oxidizing species were Methylocaldum spp. during summer and Methylobacter spp. during the non-summer seasons. The performance of the biocover remained stable under moderately thermophilic conditions due to the replacement of the main species and the maintenance of bacterial diversity. The information obtained in this study could be used to design biological processes for methane and odor removal during summer and/or in subtropical countries.

• Journal of Korea Water Resources Association
• /
• v.30 no.3
• /
• pp.235-245
• /
• 1997

A pilot scale study for removing odor and trihalomethane formation potential (THMFP) was investigated in the standard water treatment plant equipped with ozone oxidation and granular activated carbon (GAC) adsorption processes. The removal efficiency of dissolved organic carbon (DOC) in the pilot scale standard water treatment process (PSWTP) was about 25%, however, no more removal in the ozone oxidation process. On a GAC after 30 days operation, DOC removal efficiency was about 75%. Odor removal efficiency was about 30% in PSWTP, 60% in ozone oxidation, and almost complete in well as DOC. Mid-1 and 2 that showed breakthrough in odor inducing material as well as DOC. Mid-1 and 2 chlorination was able to reduce trihalomethanes (THM) by 25% compared to prechloringation, while postchlorination alone could reduce them by 30%.

• KIEAE Journal
• /
• v.9 no.1
• /
• pp.47-53
• /
• 2009

To know the effect of smells from eco-friend and existing interior construction materials to human response, EEG of subjects' were measured. EEG signals were measured from 8 electrodes according to the international 10-20 system (Fp1, Fp2, F3, F4, Fc3, Fc4, P3, P4) from 10 healthy subjects in seven odor construction material. Followings are results. When stimuli of smell were suggested, non-stimuli pattern of ${\alpha}$-wave is largely in right occipitallobe part and rare in frontallobe part respectively. In case of eco-friend materials' smell, there is a activation of EEG in right occipitallobe part for every stimuli. But in case of eco-friend paint and Hwang-to, ${\alpha}$-wave is appeared in most part of brain even in frontallobe part. Especially for wet cedar case, activation of brain is very positive in right occipitallobe part and in frontallobe part. When comparing the normalized sensitivity of ${\beta}$-wave which appears in negative response, the preference ratio order is like this. Normal paint ${\rightarrow}$ MDF ${\rightarrow}$ Eco-friend paint ${\rightarrow}$ Gypsum board ${\rightarrow}$ Cedar ${\rightarrow}$ Wet cedar ${\rightarrow}$ Hwang-to.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.27 no.2
• /
• pp.55-62
• /
• 2021

This study aims to reduce the rancid odor generated during the fermentation process of kimchi by inserting zinc oxide (ZnO) into an inorganic porous material with a high surface area to decompose or adsorb the fermentation odor. ZnO activated by the presence of moisture exhibits decomposition of rancid odors. Mixed with Titanium dioxide (TiO₂), a photocatalyst. To manufacture the packaging liner used in this study, NaOH, ZnCl₂, and TiO₂ powder were placed in a tank with diatomite and water. The sludge obtained via a hydrothermal ultrasonication synthesis was sintered in an oven. After being pin-milled and melt-blended, the powders were mixed with linear low-density polyethylene (L-LDPE) to make a masterbatch (M/B), which was further used to manufacture liners. A gas detector (GasTiger 2000) was used to investigate the total amount of sulfur compounds during fermentation and determine the reduction rate of the odor-causing compounds. The packaging liner cross-section and surface were investigated using a scanning electron microscope-energy dispersive X-ray spectrometer (SEM-EDS) to observe the adsorption of sulfur compounds. A variety of sulfur compounds associated with the perceived unpleasant odor of kimchi were analyzed using gas chromatography-mass spectrometry (GC-MS). For the analyses, kimchi was homogenized at room temperature and divided into several sample dishes. The performance of the liner was evaluated by comparing the total area of the GC-MS signals of major off-flavor sulfur compounds during the five days of fermentation at 20℃. As a result, Nano-grade inorganic compound liners reduced the sulfur content by 67 % on average, compared to ordinary polyethylene (PE) foam liners. Afterwards SEM-EDS was used to analyze the sulfur content adsorbed by the liners. The findings of this study strongly suggest that decomposition and adsorption of the odor-generating compounds occur more effectively in the newly-developed inorganic nanocomposite liners.

• Korean Journal of Food Science and Technology
• /
• v.19 no.2
• /
• pp.157-163
• /
• 1987

Changes in the odor components of Sergia Lucens during fermentation were studied by simultaneous distillation and extraction method. Forty seven components were identified by GC and GC-MS. Major cooked odor components of raw material were alkyl pyrazines and thialdine. Alkyl pyrazines, furfuryl alcohol, isoamyl alcohol and sulfide compounds, such as dimethylsulfide and dimethyltrisulfide increased during the period of fermentation. On the other hand, thialdine content decreased as the period of fermentation was extended. Sensory evaluation of cooked Sergia Lucens odor was carried out by GC-sniff analysis. The odors of GC effluents at the sniffing port were sniffed in order to find out the key compound of cooked Sergia Lucens odor components. The results of the GC-sniff analysis indicated that 2,5-dimethylpyrazine, 2,6-dimethylpyrazine and 2,3-dimethylpyrazine had dried or roast shrimp-like odor and thialdin had dried small sardine-like odor. The result showed that pyrazines and thialdine could play an important role in the formation of cooked Sergia Lucens odor.

• The Korean Journal of Ceramics
• /
• v.6 no.3
• /
• pp.304-308
• /
• 2000

WO$_3$/SnO$_2$ceramics has been suggested as an effective sensing material for monitoring offensive odor or pollutant gases. This work was focussed on improving long-term stability, which has been a principal problem generally taking place in SnO$_2$semiconductor gas sensor. Miniaturized thick film gas sensors were fabricated by screen printing technique. Two types of sensor materials, W doped SnO$_2$and WO$_3$mixed SnO$_2$, were comparatively investigated on those long-term stability and sensitivites to several gases. Small amount of W doping(0.1 mol%) into SnO$_2$largely improved the long-term stability. The W(0.1 mol%) doped SnO$_2$gas sensor had higher sensitivities to both acetone and alcohol compared with WO$_3$(5 wt%) mixed SnO$_2$gas sensor. On the contrary, WO$_3$(5 wt%) mixed SnO$_2$gas sensor showed more superior sensitivity to cigarette smoke due to larger W content.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.4 no.3
• /
• pp.236-241
• /
• 2003

산업체 발생 VOC를 효과적으로 처리하는 Biofilter 시스템을 고안하였다. 재질과 다공성이 다른 3기의 시스템으로부터 황화수소, 벤젠, 톨루엔, 크실렌의 단일성분과 복합성분계의 성능을 고찰하였다 저 pH Biofilter(pH 2-3)의 장기운전이 가능하였고 벤젠의 경우 경쟁적 저해를 나타내었으나 일정기간의 순응 이후 혼합처리시 양호한 처리능력을 보여주었다.

• Journal of Animal Environmental Science
• /
• v.9 no.2
• /
• pp.93-102
• /
• 2003

This study designed and constructed an experimental column far adhesion efficiency test and conducted experiment to investigate the offensive odor adhesion efficiency of filter bed materials. The offensive odor adhesion experiment was conducted using mixture of high physical adhesion efficiency material, and the fixity of deodorization microorganism of selected filter bed material was tested using ammonia exclude microorganism A4-­2 and sulfur oxidation microorganism S5­-5.2 those were cultured at the Agricultural Chemical Department of Chungnam National University, and deodorization efficiency of selected filter bed material mixture was tested. Following are summary of these tests results. 1. Amount of elimination of the offensive odor gas of ammonia and hydrogen sulfide per unit volume was 0.054 and 0.016$\ell/\textrm{cm}^3$ in rice hull, 0.01 and 0.004 $\ell/\textrm{cm}^3$ in rice straw 0.158 and 0.01 $\ell/\textrm{cm}^3$ in coconut, 0.014 and 0.02$\ell/\textrm{cm}^3$ perlite, 0.004 and 0.003$\ell/\textrm{cm}^3$ in high road ball, and 0.112 and 0.015 $\ell/\textrm{cm}^3$ in chaff of pine, respectively. 2. Amount of elimination of offensive odor gas of ammonia and hydrogen sulfide per unit volume was 0.045 and 0.014$\ell/\textrm{cm}^3$ in mixture 1, 0.079 and 0.016$\ell/\textrm{cm}^3$ in mixture 2, 0.123 and 0.017 $\ell/\textrm{cm}^3$ in mixture 3, 0.031 and 0.015$\ell/\textrm{cm}^3$ in mixture 4, 0.055 and 0.016$\ell/\textrm{cm}^3$ in mixture 5, and 0.111 and 0.020$\ell/\textrm{cm}^3$ in mixture 6, respectively. 3. The offensive odor elimination microorganism inoculated to mixture of chaff of pine(70%) and perlite(30%) showed the elimination efficiency of 99.06% and 96.61% against the ammonia and hydrogen sulfide, respectively, during 24 hours period.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1997.04a
• /
• pp.99-102
• /
• 1997

An electronic nose system is an instrument designed far mimicking human olfactory system. It consists generally of gas (odor) sensor array corresponding to olfactory receptors of human nose and artificial neural network pattern recognition technique based on human biological odor sensing mechanism. Considerable attempts to develop the electronic nose system have been made far applications in the fields of floods, drinks, cosmetics, environment monitoring, etc. A portable electronic nose system has been fabricated by using oxide semiconductor gas sensor array and pattern recognition technique such as principal component analysis (PCA) and back propagation artificial neural network The sensor array consists of six thick film gas sensors whose sensing layers are Pd-doped WO$_3$ Pt-doped SnO$_2$ TiO$_2$-Sb$_2$O$_3$-Pd-doped SnO$_2$ TiO$_2$-Sb$_2$O$_{5}$-Pd-doped SnO$_2$+Pd filter layer, A1$_2$O$_3$-doped ZnO and PdCl$_2$-doped SnO$_2$. As an application the system has been used to identify CO/HC car exhausting gases and the identification has been successfully demonstrated.d.

• Agricultural and Biosystems Engineering
• /
• v.3 no.2
• /
• pp.59-64
• /
• 2002

Odor generated during composting of livestock manure is mainly due to ammonia emission. Biofiltration is a desirable method to control composting odor. This study was conducted to analyze the efficiency of using fresh compost as a biofilter. A mixture of cattle manure and recycled compost was composted in a bin equipped with a suction-type blower. The exhaust gas was filtered through the fresh compost. Residence time was controlled by the flow rate of exhaust gas and the depth of filtering materials. At the aeration rate of 30 L/min(experiment I), ammonia reduction rate varied from 100% to -15% for biofilter A(residence time 56.5 s) and almost 100% for biofilter B(residence time 113 s). At the aeration rate of 30 L/min, the cumulative ammonia reduction rate was 80.5% for biofilter A and 99.9% for biofilter B. At the aeration rate of 50 L/min(experiment II), the lowest reduction rate showed a negative value of -350% on the 8th and 9th day for biofilter A(residence time 33.9 5), and 50% on the loth day for biofilter B(residence time 67.8s). At the aeration rate of 50 L/min, the cumulative ammonia reduction rate was 82.5% fur biofilter A and 97.4% for biofilter B. Filtering efficiency was influenced by residence time. The moisture content(MC) and total nitrogen(T-N) of the filtering material were increased by absorbing moisture and ammonia included in the exhaust gas, while pH was decreased and total carbon(T-C) remained unchanged during the filtering operation.