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임병서 문예운동사 1983 문예운동 Vol.- No.34

지질추출 미세조류 폐기물로부터 바이오 수소 생산 향상을 위한 전처리의 적용

김태훈,임병서,박혜숙,윤여명 대한환경공학회 2019 대한환경공학회지 Vol.41 No.9

Objectives : This study was performed to investigate optimal conditions for fermentative hydrogen production of lipid-extracted microalgae waste (LMW) by single and combined pretreatments. Methods : To produce LMW as a feedstock, the lipids were extracted from Chlorella vulgaris by conventional method and the LMW concentration was controlled at 75 g dry cell weight (dcw)/L. LMW pretreatment was performed by single (alkali, acid, and ultrasonic (U/S)) and combined (alkali+ultrasonic, acid+ultrasonic) pretreatment. For performing dark fermentative hydrogen production, LMW was added on the basis of a solid/liquid ratio (S/L ratio) of 1 : 10 and the heat-treated sludge at 90℃ for 20 min was inoculated in batch reactors. After the batch experiment, microbial community analysis was performed by Next Generation Sequencing (NGS). Results and Discussion : The acid pretreatment showed the greatest influence on the increase of the solubilization rate among three single pretreatment methods. On the other hand, the ultrasonication pretreatment did not lead to increasing the solubilization but showed increased hydrogen production (197 mL H2/g (dcw)) as much as the single acid pretreated methods. The combined pretreatment resulted in the highest 6,880 mg COD/L in the sample pretreated by the acid (1.5% HCl) combined with the single ultrasonic method, but the highest hydrogen production of 237 mL H2/g (dcw) was obtained in the sample pretreated by the acid (1.0% HCl) combined with ultrasonic. However, the alkali combined with ultrasonic combined pretreatment method showed a slight increase in hydrogen production compared to control one. Microbial community analysis revealed that the relative abundance of genera Clostridium was 97.1% in the sample pretreated by combined pretreatment (1.5% HCl+ultrasonic). Conclusions : The improvement of hydrogen production was closely related to the increase of SCOD in both samples employed by single and combined pretreatment. Especially, the application of acid pretreatment method was found to be more effective than alkali pretreatment. Ultrasonic pretreatment, on the other hand, did not result in increased SCOD, but improved hydrogen production. This might be due to that physical structure of LMW was disrupted and became easier biodegradable, even if the solubilization of the substrate did not proceed through the pretreatment of the ultrasonic method. According to the result of NGS analysis, high abundance of Clostridium spp. played the main role in hydrogen production. 목적 : 본 연구는 지질추출 미세조류 폐기물(Lipid-extracted microalgae waste, LMW)을 기질로 이용하여 혐기성 수소 암 발효 생산에서 산, 알칼리, 초음파 단독 전처리 및 병합 전처리를 통해 최적의 조건을 연구했다. 방법 : 기질로 선택한 미세조류는 표준방법을 통해 지질추출을 하여 최종 LMW 농도는 75 g dry cell weight (dcw)/L로고정하였다. LMW 전처리는 알칼리, 산, 초음파(Ultrasonication, U/S), 알칼리+초음파, 산+초음파 병합 방법을 진행하였다. 수소 생산 회분식 반응조 세팅을 위해 LMW는 고상 : 액상 혼합비율(Solid/liquid ratio, S/L ratio)을 1 : 10을기준으로 하였고 열처리된 슬러지(90℃, 20분)를 식종했다. 회분식 실험 후, 유기산 분석과 Next generation sequencing (NGS) 방법을 적용한 미생물 군집 분석을 했다. 결과 및 토의 : 단독 전처리 과정에서 산 전처리가 가용화율 증가에 가장 큰 영향을 미치는 것으로 나타났다. 반면, 초음파 단독 전처리는 가용화율 증가에 큰 영향을 주지 않았지만 산(1.5% HCl) 전처리와 같이 가장 높은 수소 전환율(197 mL H2/g (dcw))을 나타냈다. 병합 전처리의 경우, 산(1.5% HCl)+초음파 전처리 조건에서 가장 높은 6,880 mg COD/L을 보였으나 산(1.0% HCl)+초음파 병합 전처리에서 237 mL H2/g (dcw)의 가장 높은 수소 생산의 결과를보였다. 반면, 알칼리+초음파 병합 전처리 방법은 수소 생산 증가율은 아주 미미했다. 미생물 군집 분석의 결과, 수소 생산 대표 미생물인 Clostridium 속의 상대적 우점도는 대조군에서 91.8%로 가장 낮았던 반면에 산(1.5% HCl)+초음파 병합 전처리가 가장 높은 97.1% 우점도의 결과를 보였다. 결론 : 수소 전환율의 향상은 대부분 단독・병합 전처리 모두 SCOD 증가와 밀접한 관계가 있었으며, 특히 산 전처리 방법의 적용이 알칼리 전처리 적용과 비교하여 효과적임을 확인했다. 반면, 초음파 전처리의 경우 낮은 SCOD 증가에 기인하지 않았지만, 높은 수소 전환율의 결과를 보여주었다. 이는 초음파 전처리를 통해 기질의 완전한 가용화까지 진행되지 않았지만 미생물의 생분해가 쉬운 형태로 전처리가 되어 수소 생산율의 증가에 기인했을 것으로 판단된다. NGS 분석 결과에 따라 Clostridium 속 미생물에 의한 수소 생산이 주가 되었던 것으로 나타났고 이들의 우점도는 수소 생산량과 비례함의 결과를 보였다.

신축건물에서 안구건조증이 작업생산성과 일상활동에 미치는 영향

김효진,박찬정,임병서,김호현 한국안광학회 2014 한국안광학회지 Vol.19 No.3

The study examined dry eye symptoms of occupants in a newly constructed building and its effects ontheir work productivity and general activity. Methods: The study subjects were 33 office workers who spentmore than eight hours per day on average in a new building constructed in the past three months. The indoor airquality of the new building was evaluated by measuring aldehydes, temperature and humidity. The level of dryeye symptoms was classified into normal, mild, moderate and severe by using the Ocular Surface Disease Index(OSDI). The experience of LASIK surgery, use of eye makeup, daily use time of a computer and smart-phone,and average daily working hours were also examined. The Work Limitation Productivity Questionnaire was usedas the questionnaire about work productivity and general activity to measure the impairment level on a ten-pointscale. Results: The concentration variation of formaldehyde in the office was 42.42±6.30 μg/m3. The temperature andhumidity were 26.2±0.70oC and 40±1%, respectively. The respondents with normal, mild, moderate and severedry eye symptoms were 15.2%, 18.2%, 18.2% and 48.5%, respectively. The severity of dry eye symptoms andimpairment of work productivity and general activity demonstrated high correlations of 0.599 and 0.655,respectively (p<0.001). Compared to the normal case, severe dry eye symptoms demonstrated significantly highimpairment of work productivity and interruption of general activity (p<0.001). The case of serious drysymptoms showed the possibilities of having impairment level of work productivity and interruption of generalactivity above three points 3.26 times (p=0.032) and 2.25 times (p=0.045), respectively, higher than that of thenormal case. Conclusions: It was confirmed that dry eye symptoms among office workers in a newly constructedbuilding affects work productivity and general activity. 신축건물 재실자들의 안구건조증을 조사하고, 안구건조증이 작업생산성 및 일상적인 활동에 미치는 영향에대해 알아보았다. 방법: 신축한지 3개월이 지난 건물에서 일 평균 8시간 이상을 근무하는 사무직 근로자 33명을 대상으로 하였다. 실내공기질은 알데하이드류와 온습도를 측정하여 평가하였다. 안구건조증은 Ocular Surface DiseaseIndex(OSDI)를 이용하여 정상, 경도, 중등도 및 중증으로 분류하였고, 라식수술, 눈 화장, 일일 컴퓨터와 스마트폰사용시간, 그리고 일일 평균 근무시간을 조사하였다. 작업생산성과 일상활동 관련 설문은 Work Limitation Productivity설문을 사용하여 손실정도를 10점 척도로 체크하였다. 결과: 사무실의 폼알데하이드 농도는 42.42±6.30 μg/m3 이었고, 온습도는 각각 26.2±0.7oC와 40±1% 였다. 안구건조증은 정상, 경도, 중등도 및 중증이 각각 15.2%, 18.2%, 18.2%,48.5%였다. 안구건조증의 심한 정도와 작업생산성 및 일상적인 활동의 손실 정도는 각각 0.599와 0.655의 높은 상관성을 보였다(p<0.001). 안구건조증이 중증인 경우는 정상에 비해 유의하게 높은 작업생산성 손실과 일상활동 저해를 나타냈다(p<0.001). 안구건조증이 심한 경우는 정상에 비해 작업생산성 손실과 일상활동 저해가 3점 이상일 확률이 각각 3.26배(p=0.032)와 2.25배(p=0.045) 높았다. 결론: 신축건물 사무직 근로자들의 안구건조증은 작업생산성과 일상적인 활동에 영향을 미치는 것을 확인할 수 있었다.

식종슬러지 종류에 따른 이산화탄소 이용 바이오메탄 생산 비교

김태훈(Tae-Hoon Kim),임병서(Byung-Seo Lim),이승주(Sung-Ju Yi),윤광수(Gwang-Sue Yun),안병규(Byung-Kyu Ahn),미치드마(Michidmaa Enkhtsog),윤여명(Yeo-Myeong Yun) 유기성자원학회 2020 유기물자원화 Vol.28 No.1

본 연구는 초기 식종슬러지 종류별 CO₂의 생물학적 바이오메탄 생산 적용 가능성을 비교를 위해 국내 혐기성 소화조로부터 획득한 식종미생물을 종류에 따라 Specific methanogenic activity (SMA) test를 수행한 결과이다. 36일간의 실험 결과 CH₄ yield는 2,434-2,051mL CH₄/g COD의 범위를 얻었고 생산된 가스 내 CH₄ 분압은 맥주공장과 음식물류 폐기물 식종슬러지에서 가장 높은 89.3-91.9% CH₄ 분포를 보인 반면 하수슬러지 식종슬러지로부터 가장 낮은 효율을 나타냈다. 반응조의 CH₄ production rate/CO₂ consumption rate 비교를 통해 CH₄전환 속도 및 CO₂소비율의 간접적 물질 수지 비교가 가능했으며 SMA test 실험 기간 중 반응조 내 아세트산의 농도의 검출이 확인되었다. 이는 식종슬러지 내부의 잔류 유기물들의 분해, 식종미생물의 사멸 및 이들의 분해, Homoacetogenic bacteria의 활성에 의해 반응조 내 Metabolic pathway가 부분적으로 Hydrogenotrophic methanogenesis 단계에서 Acetoclasctic methanogenesis로의 변환됨에 따른 결과로 사료된다. The aims of this study were to compare the biomethanation of CO₂ through specific methanogenic activity(SMA) test which was inoculated with four different types of mixed microbial culture obtained from full-scale anaerobic digestion (AD) plants. The experimental results showed that CH₄ conversion was the highest in the samples inoculated by seed sludge taken from ADs of food waste and brewery; under this condition, the produced biomethane contains 89.3-91.9% of CH₄. Meanwhile, the lowest level was obtained in the sample from sewage sludge. The measured ratio of CH₄ production rate to CO₂ consumption rate in all reactors was higher than the theoretical value (1) in the middle of the period and soon dropped to 0.7-0.8. It might be due to changed metabolic pathways in the reactor by the degradation of residual organic matter and the increased activity of homoacetogenic bacteria.

조류(algae)에 의한 카드뮴 흡착 특성

신택수,연익준,이상우,임병서,박상찬,김광렬 한국폐기물자원순환학회 2007 한국폐기물자원순환학회지 Vol.24 No.6

Chlorella pyrenoidosa에 의한 납 흡,탈착시 고정화 방법의 영향

신택수(Taek Soo Shin),임병서(Byung Seo Lim),이상우(Sang Woo Lee),류권걸(Kwon Gul Rhu),정선기(Seon Ki Jeong),김광렬(Kwang Yul Kim) 大韓環境工學會 2009 대한환경공학회지 Vol.31 No.8

본 연구는 조류 Chlorella pyrenoidosa에 의한 Pb 흡착시 고정화 방법이 흡착특성에 미치는 영향에 관한 것으로, 고정화는 Ca-alginate, Κ-carrageenan, and polyacrylamide를 이용하여 실시하였다. 연구결과, 고정화에 따라 흡착평형 도달시간의 지연이 나타났으며, Pb의 최대 흡착능(mg/g)은 중금속 농도와 pH가 높을수록, 고정체 투입량이 적을수록 높게 나타났다. 고정화 방법별 흡착능은 Ca-alginate로 고정화한 경우 가장 높은 흡착능을 나타낸 반면, 흡착량이 pH에 가장 민감하게 영향을 받았다. Pb 흡착현상은 Freundlich 등온흡착식에 의해 잘 해석되었고, 흡착속도는 2차 모형식을 따르는 것으로 나타났다. FT-IR분석으로 Chlorella pyrenoidosa에 의한 Pb의 생물흡착 메커니즘이 주로 carbo-acid와 amide 그룹에 Pb가 결합되어 일어남을 알 수 있었다. 흡착된 Pb의 탈착은 탈착제 농도가 높을수록 탈착 효율도 높았다. 실험에 사용되어진 여러 탈착제(NTA, HCl, EDTA, H₂SO₄, NA₂CO₃)중 Ca-alginate과 Κ-carrageenan로 고정화한 경우 NTA가 가장 높게 나타났으며, polyacrylamide로 고정한 경우 EDTA를 사용한 경우 가장 효과적인 것으로 나타났다. 고정화 방법별 최대 탈착효율은 각각 90.0, 83.0, 80.0% 이었다. In this studies, the adsorption test using Chlorella pyrenoidosa was conducted to examine the effect of Pb adsorption according to various immobilized methods such as Ca-alginate, K-carrageenan, and Polyacrylamide. From the results, the duration to need to reach adsorption equilibrium was delayed according to the immobilization. And, the higher adsorption capacity of immobilized Chlorella pyrenoidosa was represented in the higher concentration of Pb, the smaller amount of immobilizing agent, and the higher pH of solution. The maximum adsorption capacity of Pb was shown in the adsorption test using Chlorella pyrenoidosa immobilized with Ca-alginate even though it was sensitive pH. The adsorption results properly represented with Freundlich isotherm equations. And, pseudo second-order chemisorption kinetic rate equation was applicable to all the biosorption data over the entire time range. The FT-IR analysis showed that the mechanism involved in biosorption of Pb by Chlorella pyrenoidosa was mainly attributed to Pb binding of carbo-acid and amide group. Adsorbed Pb on immobilized Chlorella prenoidosa was easily desorbed in the higher concentration of desorbents(NTA, HCl, EDTA, H₂SO₄, NA₂CO₃). Among the several desorbents, NTA showed the maximum desoption capacities of Pb from Chlorella pyrenoidosa immobilized with Ca-alginate and K-carrageenan and EDTA was the most effective in Chlorella pyrenoidosa immobilized with polyacrylamide. The desoprtion efficiency in the optimum condition was 90.0, 83.0, and 80.0%, respectively.

사업장별 소음발생원에 따른 소음 주파수 특성

최현일 ( Hyeon-il Choi ),임병서 ( Byung-seo Lim ),연익준 ( Ik-jun Yeon ) 한국환경기술학회 2014 한국환경기술학회지 Vol.15 No.3

본 연구에서는 2011~2012년 총 2년에 걸쳐서 주거 시설 내에 위치하는 50개 사업장을 대상으로 현장을 방문하여 소음 발생 현황에 대한 조사와 측정을 하고 소음 발생장치나 기계류의 종류에 대하여 분류하여 사업장내 존재하고 있는 소음저감 시설에 대한 현황을 조사 및 측정하여 분석하였으며, 이에 대한 연구의 결론은 다음과 같다. 제조사업장의 경우 소음에 의한 피해는 주로 주간에 발생하고 있었으며 소음을 발생하는 설비는 송풍기, 압축기, 절단기, 분쇄기 및 성형기가 주요 소음원이었다. 소음도는 81.2∼106.2 dB(A)이었으며 주요 주파수 대역은 1 kHz 대역이 가장 많이 나타나고 있다. 가공 사업장 역시 주간에 주로 소음피해가 발생하고 있었으며 소음도는 77.1∼98.0 dB(A)로 주요 주파수 대역은 2 kHz 이상 대역이 가장 많이 나타나고 있었고, 인쇄사업장은 24시간 작업이 이루어지는 경우가 많아서 야간에 소음민원이 주로 발생하고 있었으며 소음도는 78.0∼92.1 dB(A)로 주요 주파수 대역은 2 kHz 대역이 가장 많이 나타나고 있었다. 운송 사업장에서 발생되는 소음은 화물트럭의 대기 중 엔진소음과 작업소음으로 소음도는 74.2∼83.7 dB(A)로 주요 주파수 대역은 1 kHz 이하 대역이었으며, 판매 사업장소음도는 67.1∼86.0 dB(A)로 주요 주파수 대역은 1 kHz 이하 대역이 가장 많이 나타나고 있다. This study analyzes the variety of noise sources and characterizes levels and factors for the noise from factories. Noise levels in working environments were measured in 50 different industrial workplaces from 2011 to 2012. The measurement industrial workplaces were divided into six categories : manufacturing company, processing plant, printing company, transportation businesses, businesses for sales and others. Noise measurement was performed according to the standardized environment pollution test with a 1/1 and 1/3 octave analyzer. The legal standards are based on neighborhood noise caused by facilities and noise exposure limits for factory workers. As a result, most of the sites exhibited noise levels higher than the permissible noise regulation standard. The major noise sources were found to be fan, press, cutting machine and outdoor unit cooler. The measurement results show 81.2~106.2 dB(A) with a main frequency band of 1 kHz in manufacturing companies, 77.1~98 dB(A) with 2 kHz in processing plants, 78~92.1 dB(A) with 2 kHz in printing companies, 74.2~83.7 dB(A) with less than 1kHz in transportation businesses, 67.1~86 dB(A) with less than 1kHz in businesses for sales, and 74.8~97.2 dB(A) with 500 Hz in other sites.

혐기성소화 공정에서의 황 환원균의 선택적 배양을 위한 연구

김태훈 ( Tae-hoon Kim ),( Michal Sposob ),임병서 ( Byung-seo Lim ),윤여명 ( Yeo-myeong Yun ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 한국폐기물자원순환학회 춘계학술발표논문집 Vol.2019 No.-

The anaerobic sulfidogenic reactors are a promising option for the sulfur presence reduction in feedstock prior the regular anaerobic digestion. In sulfidogenic operation the sulfate reducing bacteria (SRB) reduce sulfate (SO₄ ^2-) to H2S that is released to the gas phase. In this process the organic carbon as electron donor is required as for methanogenesis. The objective of this study was to enrich SRB presence and stop the methanogenic activity in the methane generating granular sludge by testing 4 different enrichment strategies, that included: acid (0.1 N HCl), alkali (0.2 N KOH), heat and starvation. After 14 days of incubation, the highest SO₄ ^2- removal was achieved by starved granules reaching 92.0% and was followed by heat pretreated granules (76.0%), non-pretreated granules (64.2%) and alkali pretreated granules (36.6%). The lowest SO₄ ^2- removal was reached by acid pretreated granules (22.6%). In terms of COD removal, non-pretreated granules removed the highest COD part (93.0%), while acid, heat and starved granules reached lower COD removal that was 49.2, 42.0 and 37.2%, respectively. The lower COD removal, suggests the methanogenesis inhibition. Due to low COD removal and the highest SO₄ ^2- reduction, starvation was found to be the most effective strategy for selectively enhancing the SRB activity. This pretreatment method seems to be suitable prior the continuous operation in sulfidogenic reactors using the methanogenic seed sludge.

도시 생활폐기물의 발열량 특성과 폐열회수량 예측

이성희,이원재,이민희,연익준,윤상규,임병서 한국폐기물자원순환학회(구 한국폐기물학회) 2012 한국폐기물자원순환학회 추계학술발표논문집 Vol.2012 No.-

House-plant placement for indoor air purification and health benefits on asthmatics

임영욱,양지연,이재영,박정원,김관진,임병서,이건우,이시은,신동천,임영욱 환경독성보건학회 2014 환경독성보건학회지 Vol.29 No.-

Objectives Some plants were placed in indoor locations frequented by asthmatics inorder to evaluate the quality of indoor air and examine the health benefits to asthmatics. Methods The present study classified the participants into two groups: households ofcontinuation and households of withdrawal by a quasi-experimental design. The householdsof continuation spent the two observation terms with indoor plants, whereas thehouseholds of withdrawal passed the former observation terms with indoor plants andwent through the latter observation term without any indoor plants. Results The household of continuation showed a continual decrease in the indoor concentrationsof volatile organic compounds (VOCs) during the entire observation period,but the household of withdrawal performed an increase in the indoor concentrations ofVOCs, except formaldehyde and toluene during the latter observation term after the decreaseduring the former observation term. Peak expiratory flow rate (PEFR) increased inthe households of continuation with the value of 13.9 L/min in the morning and 20.6 L/min in the evening, but decreased in the households of withdrawal with the value of -24.7L/min in the morning and -30.2 L/min in the evening in the first experimental season. Allof the households exhibited a decrease in the value of PEFR in the second experimentalseason. Conclusions Limitations to the generalizability of findings regarding the presence ofplants indoors can be seen as a more general expression of such a benefit of human-environmentrelations.