• Analytical Science and Technology
• /
• v.19 no.3
• /
• pp.244-254
• /
• 2006

Flame retardants are added to prevent catching fire and to slow down the burning process. PBDEs are known to affect thyroid hormones and hormone disruption. The aim of this study was to propose a manual for determination of PBDEs, and investigate the accumulation of PBDEs(BDE-28, 47, 99, 100, 153, 154 and 183) in fish&shellfish and human milk samples. Pre-treatment for PBDEs determination, alkali digestion and L-L(Liquid-Liquid) extraction method could be applied to fish and shellfish. When Multi-layer column was used for cleaning up the sample, 50 mL of hexane and 100 mL of hexane:dichloromethane(9:1) solutions were used for pre- and post-elution, respectively. Activated-carbon column was optimized by a 100 mL of hexane:dichloromethane(3:1). The result of fish, highest concentration was detected in flatfish, 890 pg/g(wet weight). The other side, lowest concentration was detected in pollack, 40 pg/g(wet weight). The result of breast milk, PBDEs was detected 2,580 and 3,600 pg/g(lipid weight) from breast milk of Seoul and Juju, respectively. BDE-153 and 183 were not detected in all samples. There was no difference in PBDEs level was not difference between first and second delivery. In this study, we could find that PBDEs level in Korea is lower than other countries.

• Journal of Korean Society of Environmental Engineers
• /
• v.36 no.8
• /
• pp.561-569
• /
• 2014

This study was carried out to get the characteristics of anaerobic digestion for chemical/biological sludge produced from municipal sewage treatment plant for phosphorus. Anaerobic mesophilic batch tests showed that the ultimate biodegradability of waste activated sludge showed 31%, PACl sludge 24%, Alum sludge 26%, respectively. At the S/I 1.0, 75% of total biodegradable volatile solids (TBVS) of waste activated sludge was degraded with an initial rapid decay coefficient, k1 of $0.1129day^{-1}$ and 74% of TBVS of PACl sludge with k1 of $0.0998day^{-1}$, and 76% of TBVS of Alum sludge with k1 of $0.1091day^{-1}$ for 20 days. During the operation of SCFMRs, the 3 reactor (Control, PACl, Alum) pH maintained 6.7~7.0 and the reactor alkalinity maintained 1,800~ 2,200 mg/L as $CaCO_3$. The average biogas production rates of SCFMRs fed with PACl sludge and Alum sludge were 0.089 v/v-d and 0.091 v/v-d, respectively, which was 27~28% lower than that of the control (0.124 v/v-d) at an HRT (hydraulic retention times) of 20 days. And the methane content during the operation ranged 70~76% in 3 reactor. The average TVS removal efficiency of SCFMRs fed with PACl sludge and Alum sludge were 19.6% and 19.9%, respectively, at an HRT of 20 days, which showed 4% lower than that of the control (23.8%). The average BVS removal efficiency of SCFMRs fed with PACl sludge and Alum sludge were 25.8% and 26.9%, respectively, at an HRT of 20 days, which was 8~9% lower than that of the control (34.5%).

• Journal of the Korea Organic Resources Recycling Association
• /
• v.1 no.1
• /
• pp.103-113
• /
• 1993

Every year, over $3.37{\times}10^7$ ton of municipal solid waste is generated in Korea, of which about 28% is organic food waste from restaurant, dining halls and households etc. Methane conversion of the food waste by anaerobic digestion could be a viable approach for energy recovery as well as safe disposal of the waste. However, as food waste is composed of highmolecular complex polymers such as cellulose, lignin and protein, anaerobic digestion of food waste has not been efficient in terms of volumetric loading rate, solid retention time and extent of anaerobic degradation. In this research, the improved anaerobic degradation of food waste was attemped by applying rumen microorganisms to anaerobic digestion. Acidification efficiency of food waste by rumen microorganisms was compared with that of conventional acidogenesis. And optimum acidification conditions by rumen microorganisms were also determined. For the experiments, anaerobic batch reactors of 600 mL was fed with the processed (dried and milled) food waste obtained from a restaurant. Ultimate volatile fatty acid (VFA) yield produced by rumen microorganisms was about 8.4 meq VFA/g volatile solid (VS) that is 95% of the theoretical value. This yield was not much different from that of conventional acidogenesis, but hydrolysis rate was about twice faster. Cumulative VFA concentration increased from 66 meq/L to 480 meq/L, when the initial TS was increased from 1% to 15%. But VFA yield at 15% TS was half of that at 1% TS. This inhibition on the acidification might be caused by the rapid drop of pH and higher concentration of nonionized VFA. Optimal pH and temperature range for the acidification were about 6.0~7.5 and $35{\sim}45^{\circ}C$, respectively.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.11a
• /
• pp.152.1-152.1
• /
• 2010

매립지에서 유기물의 분해로 발생되는 매립가스는 악취 등으로 인한 대기오염뿐만 아니라 온난화지수가 21인 메탄이 약 50vol% 이상 포함되어 있어 지구온난화에 큰 영향을 미친다. 하지만 매립가스를 에너지원으로 활용하면 대기오염저감, 지구온난화 감소, 대체에너지원 확보뿐만 아니라 CDM사업 등과 연계하여 부가수익창출이 가능하다. 현재 국내에는 약 242개의 폐기물매립지가 있는데, 이중 매립가스를 활용하는 곳은 단지 14개소로 개별 경제성이 있는 대형매립지에서만 자원화시설을 설치하여 운영 중이며 그 외 매립지에서는 매립가스를 소각 또는 단순 대기 방출하여 대기오염유발과 동시에 대체에너지원 미활용으로 국가차원에서 큰 손실이므로 이를 활용할 수 있는 기술개발이 시급하다. 현재 매립가스 에너지화 기술로는 매립가스 열량에 따라 가스엔진, 가스터진, 증기터빈을 이용하는데 국내에서는 수분제거와 같은 간단한 처리 과정을 거친 후, 정제 없이 사용한다. 그런데 매립가스 구성 성분 중 일부 미량가스($H_2S$ 등)는 부식성이 높아 실제 공정에서 큰 문제점으로 작용하게 되므로 전처리공정이 반드시 필요하다. 본 연구에서는 중소규모 매립지에서 발생하는 매립가스를 중심적환장으로 이송하여 경제성을 가지는 에너지원으로 활용할 수 있는 기술개발을 목표로 하이드레이트 기술을 활용함에 있어 전처리 기초연구를 수행하였다. 매립가스 구성성분 중 대표적 악취물질인 메르캅탄과 부식성 물질인 황화수소의 전처리 기술로서 활성탄 흡착방법을 이용하여 외부에서 관찰이 가능하고 흡착탑을 2단으로 구성하여 활성탄 흡착탑을 제작하였다. 대상가스는 일반적으로 매립가스에 포함되어 있는 성분으로 제작하여 사용하였고 흡착탑 전 후 가스의 성분분석은 LMSxi를 이용하였다. 실험결과 활성탄의 상태, 접촉시간, 흡착탑의 구성에 따라 50~80%의 제거효율을 보였으며 이는 활성탄 흡착탑을 매립가스 에너지화의 전처리 시설로 사용될 경우 각각의 변수들에 대해 정확한 공정설계가 필요하다고 할 수 있다.

• Journal of the Korean GEO-environmental Society
• /
• v.1 no.1
• /
• pp.13-18
• /
• 2000

The purposes of this study are the analysis of landfill gases(LFGs) in old open dumping landfill site near middle city and offer the useful data for reusing the landfill site as the residental, commercial and other purposes. The concentration of $CO_2$ and $CH_4$ were lower as 8.28 vol% and 1,247 ppm but the concentrations of $NH_3$ and $H_2S$ were 7 times and 12 times higher than TLV-TWA standard. The concentration of $CH_4$ and other gases were lower than the ACGIH criterion. As the result of the environmental assessment on the open dumping landfill, if appears that this landfill is maturation phase and the formation of LFGs is reduced. If the treatment facility of $NH_3$ and $H_2S$ gases is prepared, it can be safely used as this landfill site.

• Journal of the Korean Wood Science and Technology
• /
• v.17 no.2
• /
• pp.13-19
• /
• 1989

Two different quartz types of gasification reactor were used for pyrolysis and gasification of sawdust, ricestraw, ricehusk and municipal wastes which contain only cellulosics., operating at 1 atmospheric and vacuum pressure respectively. Also a stainless steel autoclave gasification reactor was used which is possible to use up to 100 atmospheric pressures and $800^{\circ}C$ of reaction temperature to complete pyrolysis and gasification reaction. The catalysts used in this reaction w- ere $K_2CO_3$, $Na_2CO_3$, Ni and Ni-$K_2CO_3$ as CO-Catalyst. The product gas mixtures were identified to be CO, $CO_2$, $C_3H_3$, $CH_4$ and $CH_3CHO$ etc. by Gas Chromatography and Mass Spectrometry. The pressurized gasification reaction shows significant increase in terms of methane composition and yield of product gases, comparing with those from unpressurized gasification reactions. The total volume of product gas mixtures amounts to 1600-1800ml per1gof waste of waste lignocellulosics or municipal waste, and the metane content of the gas mixtures reached to 40%, when $800^{\circ}C$ of reaction temperature and 100 atmospheric pressures with Ni-$K_2CO_3$ as CO-catalyst in the pressurized gasification reaction were used. This results show that the product gas mixtures containing 40% of methane call be used for alternative enegy source.

• Resources Recycling
• /
• v.15 no.1 s.69
• /
• pp.66-73
• /
• 2006

The effects of operation conditions, such as bed temperature, temperature rising rate, particle size, moisture content and so on, on thermo-chemical conversion of waste wood have been determined in a micro fixed bed gasifier. The samples were waste wood-chips such as pine, oak, acacia and ginkgo. The thinning timbers used as reactants in the experiments had $35wt\%$ moisture content, $0.5wt\%$ ash content and 4,550 kcal/kg heating value on a dry basis. A typical product distribution was a $40wt\%$ liquid, $20wt\%$ solid, and $40wt\%$ dry syngas. The syngas concentration was affected by operation conditions and average syngas concentration was $H_2:40vol\%,\;CO:30vol\%,\;CH_4:10vol\%$.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.6
• /
• pp.614-619
• /
• 2005

The activated carbon fibers of different surface area and pore structures were modified by carbon deposition from the pyrolysis of benzene, in an attempt to obtain carbon molecular sieves of high adsorption capacity and selectivity for the separation of $CO_2/CH_4$ gas mixtures. The ACFs molecular sieves prepared from different temperature and time were tested by the static adsorption of $CO_2$ and $CH_4$ gas, and their pore structures were characterized by the $N_2$ adsorption isotherms. We are able to prepare ACF molecular sieve with good selectivity for $CO_2/CH_4$ separation and showing acceptable adsorption capacities from the change of porosity by carbon deposition of pyrolyzed benzene.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.13 no.4
• /
• pp.269-275
• /
• 1993

The performance of Upflow Anaerobic Sludge Blanket(UASB) reactor for treatment of corn starch wastewater was investigated using continuous and batch experiment. Results showed that the corn starch wastewater had different characteristics in terms of biodegradability and methane potential, depending on the manufacturing precess. COD removal efficiencies were maintained over 70% up to the loading rate of 3.2 kg $COD/m^3{\cdot}day$ and the maximum gas production rate was about 55 l/day, equivalent to 3.5 l/day per liter of reactor volume, at the loading rate of 8.4 kg $COD/m^3{\cdot}day$. In the anaerobic serum bottle test(SBT) carried out along with continuous operation, the sludge activity was found to increase from 0.03 to 0.53 g $COD-CH_4/g\;VSS{\cdot}day$ as granular sludges were developed in 130 days operation. SBT gave valuable informations on the characteristics of wastewaters to be treated as well as on the sludge activity. The overall morphological characteristics of granular sludges cultivated on corn starch wastewaters were similar to those cultivated on various organic industrial wastewaters such as distillery and sugar.

• Journal of the Korean Wood Science and Technology
• /
• v.37 no.1
• /
• pp.114-120
• /
• 2009

The bark of Populus alba ${\times}$ glandulosa was collected, air-dried and extracted with 70% aqueous acetone. Then it was successively partitioned with n-hexane, $CH_2Cl_2$, EtOAc and $H_2O$. Repeated Sephadex LH-20 column chromatography and preparative TLC on the EtOAc soluble fraction gave a grandidentatin isomer. The structure was elucidated as grandidentatin A (cis-2-hydroxycyclohexyl 6-O-p-coumaroyl-${\beta}$-D-glucopyranoside) on the basis of spectroscopic evidences such as $^1H$-NMR, $^{13}C$-NMR, 2D-NMR and MALDI TOF-MS spectrum followed by acid hydrolysis. Grandidentatin A was identified here for the first time in Populus alba ${\times}$ glandulosa bark, and to the bset of our knowledge it has not been reported in any other literature.