• KSBB Journal
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• 제20권5호
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• pp.341-344
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• 2005

섬유상 담체를 이용한 2단 소형 바이오필터를 이용한 악취가스 처리공정의 운전조건을 확립하기 위하여 BTX를 처리대상 물질로 바이오필터를 연속적으로 운전하여 섬유상 바이오필터 담체에 악취가스 처리용 미생물을 부착시킨 결과 우수한 부착된 생물막을 형성하여 높은 처리효율 $93\%$를 얻을 수 있었다. 또한, 악취 유입 농도 400 ppm 미만에서 체류시간 10 sec일 때 1단 반응기에서 $76\%$ 정도 제거율을 보이다가 2단 반응기에서 약 $93\%$의 제거율을 나타내었다. 그러나 체류시간이 15 sec 이상인 경우에는 제거효율이 $97\%$ 이상 유지되었다.

• 한국산학기술학회논문지
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• 제8권2호
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• pp.372-379
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• 2007

전로슬래그는 폐수 중에 함유된 인산염을 고형물 형태로 제거하는데 유용하게 사용될 수 있다 본 연구는 전로슬래그를 이용하는데 있어서 폐수의 초기 조건에 따라 전로슬래그로 인한 폐수의 pH, 알칼리도 그리고 양이온 용출변화에 따른 인산염 제거 등에 관하여 연구하였다. 실험대상 폐수의 pH를 0.5 단위로 7.0부터 8.5까지 다른 초기조건에서 폐수의 pH는 10시간 내에 급격하게 pH 11이상까지 상승하였다. 알칼리도는 pH보다는 급격하게 상승하지는 않았지만 반응시간 10 시간이 경과한 후 꾸준하게 상승하였다. 인산염 제거는 pH상승, 알칼리도 상승과 함께 반응시간 10시간까지 급격하게 제거되다가 서서히 제거되는 양상을 보였다. 반응시간 27시간 경과 후 그리고 36 시간 경과 후 전로슬래그에 함유된 마그네슘 이온 용출 농도를 측정한 결과 2.0 mg/L과 4.3 mg/L 수준까지 지속적으로 용출 되었다. 본 실험 결과 전로슬래그에 함유된 마그네슘이 용출되었기 때문에 물속에 암모니아가 존재한다면 인산염과 함께 스트루바이트 형태의 결정체로 인이 제거될 수 있음을 확인하였다.

• 보존과학연구
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• 통권17호
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• pp.20-38
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• 1996

Horse armour from Dohang-ri site had been retained its original form and all iron metal fragments of armour were very completely corroded without remaining metal core. Horse armour excavated is archaeologically very important, Also it should be maintained the original form. So, only moderate treatments such as brushing and consolidation techniques were performed. The processes for the conservation is as follows : 1) preliminary investigation, 2)removal of chlorides and corrosion products, 3) consolidation with 40% ParaloidNAD-10, 4) joining and restoration

• Environmental Engineering Research
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• 제11권2호
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• pp.84-90
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• 2006

UV-catalytic oxidation technique was applied for the treatment of bio-refractory character of the leachate, which is generally present in the form of adsorbable organic halogens (AOX). Destruction of AOX was likely to be governed by pH adjustment, quantitative measurement of oxidants, and the selection of oxidation model type. Peroxide induced degradation ($UV/H_2O_2$) facilitated the chemical oxidation of organic halides in acidic medium, however, the system showed least AOX removal efficiency than the other two systems. Increased dosage of hydrogen peroxide (from 0.5 time to 1.0 time concentration) even did not contribute to a significant increase in the removal rate of AOX. In ozone induced degradation system ($UV/O_3$), alkaline medium (pH 10) favored the removal of AOX and the removal rate was found 11% higher than the rate at pH 3. Since efficiency of the $UV/O_3$ increases with the increase of pH, therefore, more OH-radicals were available for the destruction of organic halides. UV-light with the combination of both ozone and hydrogen peroxide ($UV/H_2O_2$ 0.5 time/$O_3$ 25 mg/min) showed the highest removal rate of AOX and the removal efficiency was found 26% higher than the removal efficiency of $UV/O_3$. The system $UV/H2O_2/O_3$ got the economic preference over the other two systems since lower dose of hydrogen peroxide and relatively shorter reaction time were found enough to get the highest AOX removal rate.

• 한국환경보건학회지
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• 제31권2호
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• pp.99-106
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• 2005

The removals of organic matter, nitrogen and phosphate in wastewater were investigated with Sequencing Batch Reactor (SBR). Glucose and sodium acetate were Used for organic carbon source so as to know nutrient removal efficiency in proportion to MLSS concentration. In the case of glucose, the COD removal rate was $74\%,\;41\%\;and\;66\%$ in MLSS 5000, 3000 and 1000, respectively. On equal terms, the BOD was $57\%,\;21\%\;and\;38\%$, the T-N was $24\%,\;13\%\;and\;44\%$, and the T-P was $12\%,\;21\%\;and\;33\%$. As a result, the removal rate of organic materials showed the finest remove when MLSS was 5000, but the nutrient removal rate appeared as was best when MLSS was 1000. In the case of sodium acetate, the COD removal rate was $83\%,\;81\%\;and\;86\%$ in MLSS 5000, 3000 and 1000, respectively. On equal terms, the BOD was appeared by $76\%,\;82\%\;and\;92\%$, the T-N $57\%,\;42\%\;and\;78\%$, and the T-P $48\%,\;52\%\;and\;38\%$. As a result, organic and T-N removal rates were best when MLSS was 1000. But, the T-P removal rates were best when MLSS was 3000. Glucose was shown fast removal in reaction beginning, but screened by more efficient thing though sodium acetate removes organic matter, nitrogen and phosphate. Form of floc was ideal in all reactors regardless of carbon source and MLSS concentration. And its diameter was about $200\~500{\mu}m$.

• 한국환경과학회지
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• 제8권2호
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• pp.227-231
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• 1999

This study was conducted to investigate the removal characteristics of $PO_4^{3-}-P$ contained in livestock wastewater using waste concrete. With small particle size, increased dosage and temperature of water, $PO_4^{3-}-P$ was well removed by waste concrete.$PO_4^{3-}-P$ was removed by adsorption reaction in low pH of the primary phase, but the crystallization reaction predominated for increasing pH with passed time. As a result of adapting the adsorption isotherm equation, $PO_4^{3-}-P$ removal was more affected by the crystallization reaction than the adsorption reaction. In the SEM micrograph, there was no evident change on the waste concreter surface. Particle size was plate-phase before reaction but appeared a dense form to progress in the crystallization reaction.

• 한국공작기계학회논문집
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• 제12권2호
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• pp.1-8
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• 2003

Conventionally used linear or circular interpolator is undesirable for the precision machining of 3D free-form surface as the following reason: the transmission errors due to the huge number of data, discontinuity of segmentation, unsmooth motion speed. To this regard, modern CNC machine tools are designed with the function of machining arbitrary parametric curves. However, these systems don't consider the adaptive federate, which dominates the quality of the machining process. This paper proposes a NURBS interpolator for the constant material removal rate. That is accomplished by the variable federate using curvature of curve. The curvature-compensated feederate system has important Potential applications in ensuring part accuracy and protecting cutting tool. The simulated result show it can be applicable to the real machining.

• 산업기술연구
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• 제16권
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• pp.5-11
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• 1996

While the enhanced biological phosphorus removal(EBPR), in anaerobic/aerobic condition, was known to remove phosphorus by means of metabolism of poly-P microorganisms, the phosphorus removed could be released in the form of ortho-P in the aerobic fixed biofilm reactor. This study was initiated to investigate the cause of ortho-P release in the aerobic fixed biofilm reactor. The resutls indicated that the phosphorus release was caused by autooxidation. The synthesis and release of phosphrous were related to the ORP and the boundary value for the phase change was about 170mV. In the synthesis phase, the phosphorus removal rate per COD removed was $0.023mgP_{syn}/mgCOD_{rem}$. The phosprous contents of the microorganism were 4.3 ~ 6.0% on a dry weight basis.

• 상하수도학회지
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• 제25권5호
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• pp.651-658
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• 2011

Nitrate is a common contaminant in industrial wastewater and ground water. The maximum contaminant level set by EPA for nitrate of 10 mg/L as N. In this study, nitrate was removed using bipolar ZVI packed bed electrolytic cell that maximized the contact area between each electrode and contaminants under 600 V. Also this study investigates the simultaneously deals with removal of ammonia by operating air stripping tower. In addition to the air stripping also helped to precipitate iron ions to the form of iron oxides. Bipolar ZVI packed bed electrolytic cell was also effective in removing coliform by electrical power. In the continuous experiments for the simulated wastewater (initial nitrate for 25 mg/L as N), maximum 96.3% removal of nitrate was achieved in the applied 600 V at the flow rate of 6 mL/min.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 추계학술발표대회 논문집
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• pp.249-252
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• 2000

To overcome problems of excavation technology far repairing or replacing underground buried pipes which are worn out or damaged, various trenchless repair-reinforcement technologies have been invented. But these trenchless technologies also have many problems in the aspect of economy and convenience of operation. In this research, the repair-reinforcement process using RTM (Resin Transfer Molding) which can solve problems of present trenchless technologies was developed. The resin wetting and void removal during RTM process to form large composite structures inside of buried pipes were experimentally investigated. From the experiment, it was found that the new technology had advantage over conventional methods by employing appropriate process parameters and void removal vents.