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어류양식장 저질개선을 위한 과산화칼슘 투입에 의한 생태 환경변화 관찰
조대철 ( Dae Chul Cho ),배환진 ( Hwan Jin Bae ),권성현 ( Sung Hyun Kwon ) 한국환경과학회 2012 한국환경과학회지 Vol.21 No.10
The aim of this research is to enhance the bottom environment of Geoje fish farm that has been severely contaminated. Treatment of microbial agent and/or calcium oxide significantly changed that environment: in ignition loss, either treatment (25% or 21%)showed better than mixed treatment (13.2%). In COD, the oxygen releasing agent or mixed treatment reduced the index by more than 20%. In T-P and T-N, the effects of CaO2 on them were overwhelming (50% or more) meanwhile that of the microbial agent on them was less than 20%. Also, CaO2 influenced on the microbial flora: Desulfobvibrio thermophilus, a sulfate reducing bacterium decreased in number, considering the increase of pH and rise of redox potential. In contrast, Pseudomonas sp., Pseudoalteromonas sp., Pseudomonas aeruginosa were remarkably dominant over other species with mixed treatment as a PCA analysis confirmed it.
연구논문 : 연안저질 환경 개선을 위한 유용 미생물제제 및 산화제의 사용에 따른 환경변화 및 효율성 관찰
조대철 ( Dae Chul Cho ),배환진 ( Hwan Jin Bae ),이정령 ( Jung Yeol Lee ),권성현 ( Sung Hyun Kwon ) 한국환경과학회 2010 한국환경과학회지 Vol.19 No.11
This study was carried out in order to observe how the bay sediment would be changed with microbial treatments and a chemical oxidant like CaO2. The sediment during the treatments was analyzed in terms of pH, ORP, volatile organics content, COD, AVS, T-N, and T-P. With CaO2 treatment, pH was kept over 9.66 and ORP ranged from +4.70~+46.0, which meant an aerobic state meanwhile with the microbial treatment those were worse. In addition the chemical treatment showed better environmental index values than the microbial one: volatile organics content and COD values in the former were 12.9% and 37.9% while those in the latter were 4.5% and 18.7%, respectively. AVS and T-P were 71.1% and 100% versus 56.5% and 85.8%, respectively. However, the microbial treatment was better for T-N(66% higher). On the other hand, both treatment at a time enhanced all the environmental indices but COD meantime pH and ORP values were lower than with the chemical treatment only. Thus additional input of an oxygen generator like CaO2 could improve the environmental state of a bay sediment where the biological treatment is going on.
생물학적 처리에 따른 갯벌 복원을 위한 현장 적용성 연구
조대철(Cho, Dae-Chul),배환진(Bae, Hwan-Jin),권성현(Kwon, Sung-Hyun) 한국산학기술학회 2012 한국산학기술학회논문지 Vol.13 No.7
현장 갯벌에서의 미생물제제와 CaO<sub>2</sub>처리를 통한 효율성을 관찰하고자 유용미생물 및 미생물과 CaO<sub>2</sub>를 혼합하여 특수 처리한 제제를 100㎡ 크기의 각 처리구에 3.6㎏씩 살포하여 6주간 모니터링 결과, 두 처리구로부터 pH 및 ORP는 평균 pH 7이하, ORP는 초기 값(-178 mV ~ -188 mV)에 비해 –121.06 mV ~ -142.06 mV로 다소 상승하였다. 강열감량과 COD의 경우, 큰 변화가 없었으며 질소와 인 계열은 다소 효과가 있었는데 암모니아는 시간이 경과함에 따라 대조구와 더불어 낮아지는 경향을 보였으며 질산성질소의 경우, CaO<sub>2</sub>와 미생물제제의 혼합처리(11.3%)가 미생물제제 처리(7.3%)보 다 질산염농도가 감소한 이유는 산소발생에 의한 어느 정도의 호기화된 조건에서 질산화반응에 의해 퇴적토의 질산염이 수층으로 용출된 결과로 생각되며 이에 따라 총 질소의 농도도 혼합처리에 의한 감소(6.1%)로 이어진 결과라 판단된다. 마찬가지로 인의 경우에도 초기 농도가 다소 높은 수치(T-P는 0.761 mg/g, PO<sub>4</sub>-P는 0.529 mg/g)를 보였으나 혼합 처리구에 서 T-P는 29%, PO<sub>4</sub>-P는 31.8%의 감소율로 미생물제제보다 인의 용출을 억제시킨 결과로 나타났다. A field test on mud flat remediation was carried out in order to observe the effects of the treatments such as microbial dose and an oxygen releasing compound like CaO<sub>2</sub>. The size of each treatment site was 100 ㎡ and the dosage was 3.6 kg per site. The 6 week monitoring showed that pH on two sites was below 7 and ORP increased from –178∼-188 mV to –121∼-142 mV. In Ignition loss and COD there were no significant changes. Meanwhile nitrogen and phosphorus concentrations changed: ammonia concentration decreased both on control and treatment sites. Nitrate nitrogen decreased more on combined treatment site than on single microbial treatment (11.3% vs. 7.3%) probably because the extra oxygen supplied by CaO<sub>2</sub> formed more oxic environment so that the facilitated nitrification might produce more nitrate but the nitrate would be much rapidly released into the water layer out of the sediment. That also explains the total nitrogen reduction(6.1%). Similarly, T-P and PO<sub>4</sub>-P reduced by 29% and 31.8%, respectively on combined treatment sites, resulting from the phosphorus release effect though the initial concentrations of the two factors were considerably high.
PU매체에 부차한 유류분해 bacteria를 이용한 오염토양 처리
조대철(Cho, Dae-Chul),허남수(Huh, Nam-Soo),권성현(Kwon, Sung-Hyun) 한국산학기술학회 2006 한국산학기술학회논문지 Vol.7 No.3
토양의 생물학적 복원은 산업화로 무차별하게 오염되어 있는 국내 산업단지 주변과 지하수 환경보전을 위한 경제적 도구로 인식되어왔다. 본 연구는 친환경적 생물복원을 위한 기초자료를 얻기 위하여 유류로 오염된 양토에서 Pseudomonas sp. (KCCM 40055)를 접종한 polyurethane 매체환경을 적용, 유류의 성분중 PAH 분해도를 조사하였다. 다공성 매체로서 재현성이 뛰어나며 미생물 부착에 활용되어 온 polyurethane foam을 사용하여 미생물 부착성을 아울러 조사하였다. 사용된 PU중 최저공극 foam인 SR9-35CfG 의 경우 부착률과 PAH분해율이 가장 높았으며 토양함수율 증가에 따라 그 효율이 증가하였다. Bioremediation has been recognized as one of the best tools for hydrocarbon contaminated soil and nearby groundwater which had been heavily polluted in industrial areas. Degradation of PARs in PAR-polluted loam soil were investigated under polyurethane foam environment with adsorbed bacteria Pseudomonas sp. (KCCM 40055) in order to acquire vital data for the environmentally-friendly process and material. macroporous commercial polyurethane foam that is widely used for microbial attachment in such as sewage treatment was selected for experiments. We also examined the microbial adherence upon the media. SR9-35C/G among the PU samples showed the highest degree of attachment and bioconversion. The conversion efficiency increased with moisture content of soil.
A Coop Project-based Business Engineers' Model for Regional Universities Running ABEEK Program
임강빈,조대철,이해각,Yim, Kang-Bin,Cho, Dae-Chul,Lee, Hae-Kag 한국실천공학교육학회 2011 실천공학교육논문지 Vol.3 No.1
This paper suggests a realistic, business engineers' model based on Coop projects run by regional universities or colleges, in which students must meet the guidelines for engineering design that ABEEK requires. Many of current activities such as Coop programs and Internships aimed for engineering majored-undergraduates have notled them either to a satisfactory level of business skill at entrepreneur side, or to their higher chance of employment opportunities. Under the circumstances like this, we need a revised version of Coop activities: for example, launching a project that will be fully supported intrust by both sides, and thus improving students' business skill while they are working on that project. We demonstrate in this study how students have greatly improved their business skill through a model project that was planned by a working group, was successfully carried out on real job positions, and many of the students in the working group were job-offered finally as this new model suggested.
Recombinant Cyanide Hydratases에 의한 시안화물 분해
권성현(Kwon, Sung-Hyun),조대철(Cho, Dae-Chul) 한국산학기술학회 2009 한국산학기술학회논문지 Vol.10 No.6
시안화물을 포름아미드로 변환시키는 nitrilase의 일종인 시안 수화효소 (cyanide hydratase, CHT) 를 진균류인 Neurospora crassa 와 Aspergillus nidulans로부터 유전자 조작을 통하여 His에 태그 또는 언태그된 형태로 대장균에 형질변환시켜 발현하였다. 발현된 효소를 고정 metal affinity chromatography로 정제하였다. 정제된 효소들의 pH 안정성, 동력학적 매개변수의 값을 검토하였다. 실험 결과 N. crassa 의 CHT가 50% 정도 더 넓은 pH 안정 범위를 가졌고 3배 가량 turnover rate도 높았다. 반면 A. nidulans CHT의 Km 값 (효소포화 용량)이 N. crassa CHT보다 더 크게 나타났다. 두 진균류에서 CHT의 유도발현은 질소성분과 상관없이 KCN에 의해 가능하였으며, 생분해 실험결과 N. crassa CHT에 의해 최대 82%/h의 시안분해가 가능하였다. The genes of cyanide hydratase(CHT), a kind of nitrilases whichhydrolyze cyanide to formamide were extracted from N. crassa and A. nidulans, the two fungal strains. The recombinant forms of the CHT originated from N. crassa and A. nidulans were prepared with N-terminal hexahistidine purificationtags or no tags, and expressed in E. coli. The enzymes were purified using immobilized metal affinity chromatography. They were compared according to their pH activity profiles, and kinetic parameters. The N. crassa CHT has the wider pH range of activity above 50% and three-fold higher turnover rate (6.6 x 10⁸ min⁻¹) than the A. nidulans, meanwhile the CHT of A. nidulans has the higher K<sub>m</sub> value. Expression of CHT in both N. crassa and A. nidulans were induced by the presence of KCN, regardless of any presence of nitrogen sources. Max. 82% of KCN was degraded in 60 min for biological degradation tests.