• 한국대기환경학회지
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• 제34권4호
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• pp.554-566
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• 2018

The rice husk contains nutrients which can be easily utilized by microorganisms, and also has a water retaining ability, which played a crucial part in enabling it to become a biofilter media. In this study, we evaluated the applicability of rice husk pellet bio-scrubber as a microbiological carrier. The pelletization experiment of rice husk as a biological media was performed using PVA and EVA binder. Also, the feasibility tests of rice husk as a biological media for odor removal were carried out in order to know whether rice-husk contains useful components as a media for microbiological growth or not. Lastly, a combined test for odor gas absorption and biological oxidation was conducted using a lab scale bio-filter set-up packed with rice-husk pellets as wet-scrubber. The major components of the rice husk were carbon, hydrogen, nitrogen, and oxygen, while carbon acted as the main ingredient which comprised up to 23.00%. The C : N : P ratio was calculated as 45 : 1 : 2. Oxygen uptake rate, yield and decay rate of the rice husk eluent was calculated to be $0.0049mgO_2/L/sec$, 0.24 mgSS/mgCOD and 0.004 respectively. The most stable form of rice husk pellets was produced when the weight of the rice husk, EVAc, PVAc, and distilled water was 10 : 2 : 0.2 : 10. The prepared rice husk pellets had an apparent density of 368 g/L and a porosity of 59.00% upon filling. Dry rice husks showed high adsorption capacity for ammonia gas but low adsorption capacity for hydrogen sulfide. The bio-filter odor removal column filled with rice husk pellets showed more than 99.50% removal efficiency for NH3 and H2S gas. Through the analysis of circulation water, the prime removal mechanism is assumed to be the dissolution by water, microbial nitrification, and sulfation. Finally, it was confirmed that the microorganisms could survive well on the rice husk pellets, which provided them a stable supply of nutrients for their activity in this long-term experiment. This adequate supply of nutrients from the rice husk enabled high removal efficiency by the microorganisms.

• KSBB Journal
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• 제24권5호
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• pp.420-424
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• 2009

악취방지법의 시행으로 악취의 규제가 강화됨에 따라 축산 시설에서 발생하는 악취의 주요 원인 물질인 암모니아와 황화수소를 신속하고 간단한 방법으로 검지할 수 있는 방법으로 화학적 방법을 이용한 가스 검지관을 개발하였다. 악취물질의 농도를 변색길리를 통하여 알 수 있도록 발색반응 메카니즘을 규명하고 이를 정량화 하여 유리관에 충전하여 암모니아와 황화수소 검지관을 제작하였다. 암모니아 검지관은 선형성 및 재현성 평가에서 99.6%의 선형성을 나타내었으며, 검지환경에 따라서 민감한 경향을 나타내었으나, 암모니아 가스에 대한 동일한 경향성을 나타내었다. 또한 황화수소 검지관은 99.7%의 선형성을 나타내었으며, 동일한 시료를 이용한 반복 평가에서 95% 이상의 재현성을 나타내었다.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2011년도 제45차 학술발표회
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• pp.7-7
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• 2011

Poly(ethylene terephthalate)(PET) is one of the most widely used materials in textile industry. It can have a low cost, silk-like handle, and excellent mechanical properties. Low thermal stability of PET had been a common problem limiting its high temperature application. The polyester have been known to have the disadvantage of degradation under ionized irradiation compared to crosslikable polymers such as polyethylene, polypropylene and polystylene. To improve thermal stability of PET, the PET films were photocrosslinked by UV irradiation. A hydrogen-abstractable photoinitiator was used to photocrosslink of PET by continuous UV irradiation. Photoinitiator addition increased the gel fraction. The photocrosslinking was attributed to the recombination of PET radicals generated upon UV irradiation, which was enhanced by the hydrogen abstraction of the PET polymer chains by the added photoinitiator. Also the crosslinked PET showed higher thermal stability and mechanical strength with increasing UV energy. Polyester type films such as poly(ethylene naphthalate)(PEN) and poly(butylene terephthalte)(PBT) were also increased the gel fraction and improved thermal stability and mechanical properties by UV irradiation.

• 한국수소및신에너지학회논문집
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• 제13권1호
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• pp.52-64
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• 2002

유기성 폐기물을 이용하여 생물학적 수소생산 통합화 시스템 연구를 수행하였다. 통합화 시스템은 유기성폐기물의 전처리, 2단계 혐기발효 및 광합성 배양으로 구성된 생물학적 수소생산 공정, 초임계수 가스화 공정, 생산된 가스의 저장, 분리 및 연료전지를 이용한 전력 생산으로 구성되었다. 실험에 사용된 유기성 폐자원은 식품공장 폐수, 과일폐기물, 하수슬러지이며, 전처리는 폐기물에 따라 열처리 및 물리적 처리를 하였으며, 전처리된 시료는 생물학적 수소생산 공정에 직접 적용되었다. Clostridium butyricum 및 메탄 생성조에서 발생하는 하수슬러지중의 미생물 복합체는 수소생산 혐기 발효공정에 사용되었으며, 광합성 수소생산 미생물인 홍색 비유황 세균은 광합성 배양에 사용되었다. 생물학적 공정에서 발생하는 미생물 슬러지는 초임계수 가스화 공정으로 수소를 발생하였으며, 슬러지 중의 COD를 저하시켰다. 생물학적 공정 및 초임계수 가스화 공정에서 발생하는 수소는 가스탱크에 가입상태로 저장한 후, 95%순도로 분리하였으며, 정제된 수소는 연료전지에 연결하여 전력 생산을 하였다.

• Journal of Applied Biological Chemistry
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• 제54권3호
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• pp.214-217
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• 2011

바나나, 오렌지 및 파인애플을 대상으로 시안화수소 처리후 잔류 특성을 평가하여 과실류에 대한 메틸브로마이드 대체 훈증제 개발 가능성을 조사하였다. 메틸브로마이드 훈증소독시 3일차에서 잔류량이 오렌지와 바나나에서는 1 mg/kg 미만 수준으로 나타났고, 파인애플의 경우에도 1 mg/kg을 조금 상회하는 수준으로 잔류허용 기준치 50 mg/kg을 훨씬 하회하고 있어 메틸브로마이드 잔류로 인한 독성문제는 우려할 수준이 아닌 것으로 평가되었다. 시안화수소 훈증소독의 경우 3일차에서 오렌지 50-60%, 바나나 70-80% 그리고 파인애플 50% 정도 분해 소실된 것으로 나타나, 잔류허용 기준치 5 mg/kg을 하회하는 1 mg/kg 미만 수준으로 나타났다. 이는 향후 메틸브로마이드 대체 훈증제로서 시안화수소의 사용이 가능함을 뒷받침하는 유용한 결과로 판단된다.

• 대한환경공학회지
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• 제36권10호
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• pp.672-678
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• 2014

본 연구는 음식물 쓰레기 내 질소농도에 따른 발효과정에서 수소생성 특성과 미생물의 군집변화를 살펴보았다. 음식물 쓰레기 내 질소의 함량이 200 mg/L일 때 가장 높은 수소생산 효율을 보여주었으며, 이 때 수소생산율은 83.43 mL/g dry wt biomass/hr이였다. 질소의 함량이 600 mg/L 이상이 되면 수소생산이 저해되는 것으로 나타났으며 수소생산량과 B/A ratio (Butric acid/Acetic acid)의 비례적 상관관계는 관찰되지 않았다. 16S rDNA의 PCR-DGGE결과 대부분 군집은 Clostridium sp. 미생물로 규명되었으며 수소생성에 기여도가 큰 미생물은 Enterococcus faecium partial, Klebsiella pneumoniae strain ND6, Enterobacter sp. NCCP-231, 그리고 Clostridium algidicarnis strain E107 등으로 판명되었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.465-469
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• 2006

Two mesophilic trickling bed bioreactors filled with two different types of media, hydrophilic- and hydrophobic-cubes, were designed and tested for hydrogen production via anaerobic fermentation of sucrose. Each reactor consisted of a column packed with polymeric cubes and inoculated with heat-treated sludge obtained from anaerobic digestion tank. A defined medium containing sucrose was fed with changing flow rate into the capped reactor, hydraulic retention time and recycle rate. Hydrogen concentrations in gas-phase were constant, averaging 40% for all conditions tested. Hydrogen production rates increased up to $10.5 L{\cdot};h^{-1}{\cdot}L^{-1}$ of reactor when influent sucrose concentrations and recycle rates were varied. Hydrophobic media provided higher value of hydrogen production rate than hydrophilic media at the same operation conditions. No methane was detected when the reactor was under a normal operation. The major fermentation by-products in the liquid effluent of the both trickling biofilters were acetate and butyrate. The reactor filled with hydrophilic media became clogged with biomass and bio gas, requiring manual cleaning of the system, while no clogging occurred in the reactor with hydrophobic media. In order to make long-term operation of the reactor filled with hydrophilic media feasible, biofilm accumulation inside the media in the reactor with hydrophilic media and biogas produced from the reactor will need to be controlled through some process such as periodical backwashing or gas-purging. These tests using trickling bed biofilter with hydrophobic media demonstrate the feasibility of the process to produce hydrogen gas in a trickle-bed type of reactor. A likely application of this reactor technology could be hydrogen gas recovery from pre-treatment of high carbohydrate-containing wastewaters.

• Ocean and Polar Research
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• 제39권4호
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• pp.269-277
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• 2017

Medium compositions for the hyperthermophilic archaeon, Thermococcus onnurineus NA1 was statistically optimized to enhance formate-driven hydrogen ($H_2$) production by using response surface methodology. From the Plackett-Burman design-based experiment, it was confirmed that among the minor components of medium such as KCl, $MgSO_4$, $NH_4Cl$, Cystein-HCl, trace elements, Fe-EDTA and $CaCl_2$, the trace elements were screened as the only positively effective components with respect to $H_2$ production. Subsequently, the optimal concentrations of the trace elements and the major components of a medium such as NaCl, yeast extract and sodium formate were determined from the five-level central composite design (CCD)-based experiment. The resulting quadratic model predicted the maximum $H_2$ production of 46.6 mmol/L in serum bottle and it was validated experimentally using the optimal medium initially supplemented with 26.70 g/L of NaCl, 9.81 g/L of sodium formate, 3.50 g/L of yeast extract and 4.59 mL/L of trace elements. From the duplicate batch cultivations in the fermentor using the optimized medium, the a maximum $H_2$ production rate up to 71.8 mmol/L/h could be obtained, which was a 65% enhanced value compared with that obtained using the control medium, showing the high efficiency of the optimized medium.

• 한국산학기술학회논문지
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• 제16권12호
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• pp.8665-8672
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• 2015

본 연구에서는 하수처리장의 소화슬러지(digest sludge)를 대상으로 악취제거 및 유기물제거에 대한 타당성을 검토하고자 BIO-CLOD를 넣은 반응조와 넣지 않은 반응조에 대하여 24시간, 48시간, 72시간 후 ammonia, methyl mercaptan(MMC) 및 $H_2S$에 대해서 측정하였다. BIO-CLOD를 침적시킨 반응조(BIO-CLOD)에서 24시간 내에 ammonia는 48%인 것에 비해 $H_2S$와 MMC는 98%이상의 높은 제거율을 보인 반면에 BIO-CLOD를 침적시키지 않은 반응조(Non BIO-CLOD)에서는 24시간 내에 ammonia가 45%, $H_2S$는 71%, MMC는 84%로서 악취제거 가능성을 보였다. 암모니아 농도는 시간이 지남에 따라 감소하면서 질산성질소농도는 증가하는 질산화 현상을 보였으며, 소화슬러지내의 유황계 악취성분들이 호기성 미생물들에 의해 산화 분해되어 용액 중의 황산염농도를 증가시키는 데는 BIO-CLOD효과가 있었음을 알 수 있었으며, 황산염농도증가와 대기중의 $H_2S$ 제거율간에는 상관관계가 있음을 알수 있었다. 반응조 유출수에서 유기물의 감소는 짧은 시간 내에서는 BIO-CLOD가 영향을 주지 않았으며, HRT 12시간과 HRT 24시간으로 운전하였을 때 경제적인 면에서 HRT 12시간을 고려해야 할 것으로 판단되었다.

• 한국수소및신에너지학회논문집
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• 제26권6호
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• pp.609-628
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• 2015

Thie study presents the biomass-derived jet (bio-jet) fuel production technologies for greenhouse gas (GHG) reduction in aviation sector. The aviation sector is responsible for the 2% of the world anthropogenic $CO_2$ emissions and the 10% of the fuel consumption: airlines' costs for fuel reach 30% of operating costs. In addition, the aviation traffic is expected to double within 15 years from 2012, while fuel consumption and $CO_2$ emissions should double in 25 years. Biojet fuels have been claimed to be one of the most promising and strategic solutions to mitigate aviation emissions. This jet fuel, additionally, must meet ASTM International specifications and potentially be a100% drop-in replacement for current petroleum jet fuel. In this study, the current technologies for producing renewable jet fuels, categorized by alcohols-to-jet, oil-to-jet, syngas-to-jet, and sugar-to-jet pathways are reviewed for process, economic analysis and life cycle assessment (LCA) on conversion pathways to bio-jet fuel.