• 한국물환경학회지
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• 제16권4호
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• pp.501-512
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• 2000

This study was carried out to develop the new process for RBC process which is capable of nutrient removal and to obtain its design parameters for Sludge Settling Type Rotating Biological Contactors by comparing RBC with RBC combined with HBR (Hanmee Bio-Reactor). To achieve more than 90% of organic removal efficiency, organic loading rate less than $6.0g\;BOD/m^2/d$ is recommended. Nitrification rate was about 90% at $6.0g\;BOD/m^2/d$. TN removal efficiency of RBC+HBR was higher than those of RBC1 and RBC2. TN removal efficiency at condition of $5.0g\;BOD/m^2/d$ was about 60% in RBC1. When BOD loading rate was $6.0g\;BOD/m^2/d$. TN removal efficiencies in RBC2 and RBC+HBR were about 70%, 80%, respectively. TP removal efficiency was more than about 67% for RBC1, about 63% for RBC2 and about 71 % for RBC+HBR at the same loading rate. From the blank experiment to observe removal efficiency in the first stage, it can be known that COD removal efficiency was about 30% and suspend solids settling rate was about 45%. It was proved that RBC+HBR is much better in sludge dewatering than RBC.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권6호
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• pp.102-111
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• 2012

Fine suspended solids generated effluence from treatment process of mine drainage could destroy environment as the aesthetic landscapes, and depreciate water quality. Therefore, the purpose of this research is focused on process development applied the actual field for controlling fine suspended solids and heavy metals, and so lab-scale test was performed for inducement of basic data. The mine drainage used in this research was sampled in H mine located Jeongseon-gun, Gangwon-do. Concentration of suspended solid, arsenic, iron and manganese was exceeded the standard of contaminant limitation for the clean water, and particle size of suspended solid was less than 10 m as fine particle. Although hydraulic retention time of mine drainage for effective settling was required more than 6 hours, hydraulic retention time would be increased in winter season when the settling efficiency could be reduced because of viscosity decreasing. Moreover, installed inclination plate helped to increase settling efficiency of suspended solid about 48 %. Filtering media that was the most effective removal of suspended solids and heavy metal was decided granular activated carbon of 1~2 mm was the optimal size.

• 한국물환경학회지
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• 제31권3호
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• pp.328-333
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• 2015

In this study, Mg-Sericite was used as a flocculant to harvest freshwater microalgae, Chlorella. vulgaris. Mg-Sericite separated successfully >95% of the C. vulgaris at the following optimal parameters: Mg/Si mol ratio 1.25 to 1.50, mixing time of 20 min and settling time of 20 min. The harvesting efficiency was pH dependent. The highest harvesting efficiency ($99{\pm}0.3%$) was obtained at Mg/Si mol ratio 1.5 and pH 9 to 11. These results indicated that a biopolymer, Mg-Sericite, can be a promising flocculant due to its high efficiency, low dose requirements, short mixing and settling times. This harvesting method is helpful to lower the production cost of algae for biodiesel.

• 유기물자원화
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• 제14권1호
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• pp.151-159
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• 2006

런던협약의 영향으로 슬러지 처리의 중요성이 대두되고 있는 실정이므로 본 연구는 슬러지 처리에 대한 개선방안의 제시를 목적으로 유기성 폐수 및 하수처리장 슬러지를 대상으로 JAR test 및 교반장치를 부착한 침강 column을 이용하여 응집효율이 침강특성에 미치는 영향에 대한 실험을 실시하였으며 다음과 같은 결과를 얻었다. 최적의 침강효율을 얻기 위한 최소의 응집제 투여농도는 200mg/L의 경우로 나타났으며. 200mg/L 이상으로 PAC가 투여될 경우 각각의 임계슬러지 영역의 크기에서는 큰 변화가 없는 것으로 나타났다. 따라서 200mg/L로 투여되었을 때의 Clarification Rate(CR)은 임계슬러지 침강높이 비율이 0.4로 나타났으므로 CR = (Ho-Ht) / Ho = 1-0.4=0.6 로 산정되었다. MLSS농도가 높아질수록 슬러지 계면 침강속도는 감소하였으나 MLSS농도가 1,000mg/l 이상으로 증가하면 오히려 침강속도는 증가하는 것으로 나타났다. 이는 슬러지 농도가 1,000mg/l 이상으로 증가하게 되면 압밀침전영역으로 전이되어 상호작용에 의한 응집에 영향을 미치게 됨으로써 오히려 floc 형성에 긍정적인 영향을 미치기 때문이다. 슬러지 응집계면의 침강속도는 유기폐수 활성슬러지의 평균 침강속도 $4.25{\times}10^{-3}/min$보다 하수처리장 슬러지의 평균 침강속도가 $28.66{\times}10^{-3}/min$로 6.7배 높은 것으로 나타났다. 유기성 폐수 활성슬러지는 PAC의 투여량이 200mg/l 이하일 때는 침강속도 증가율보다 CR의 증가율이 더 컸으나 200mg/l 이상일 때는 CR의 증가율보다 침강속도 증가율이 더 커졌음을 알 수 있었다. 그러나 하수슬러지의 경우는 PAC 투여량이 증가함에 따라 CR의 변화율에는 차이가 적었으나 침강속도는 200m/l 이상일 때 차이가 급격히 증가하였다. 따라서 응집제 투여효과는 상등수의 SS제거율 효과보다는 MLSS의 침강속도에 더 큰 영향을 미치는 것을 알 수 있다.

• 한국물환경학회지
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• 제26권2호
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• pp.215-224
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• 2010

This study was carried out to estimate effects of sediment reduction with net type sediment settling pond at highland agricultural areas. Flow and sediment monitoring system with rainfall gauge were installed at the study area for real-time monitoring and analysis. It was found that amount and intensity of rainfall events strongly affect sediment yield from the study area. With net type sediment settling pond, it was expected that approximately 61% of sediment could be removed. The correlation between heavy metals and SS were analyzed in this study. $R^2$ values were 0.644, 0.876, 0.945, and 0.928 for Fe, Mn, Al, and Si, respectively. This results indicate that heavy metals also could be removed with net type sediment settling pond. As shown in this study, the sediment settling pond will be an efficient sediment reduction facility at highland agricultural areas. For maximum reduction efficiencies of sediment and other pollutants at agricultural fields, simplified sediment settling pond should be designed and implemented.

• 상하수도학회지
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• 제23권6호
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• pp.719-726
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• 2009

One of the alternative runoff management measures is on-site runoff mitigation, such as rainwater retention tank and infiltration facilities especially the latter that is possible to manage simultaneously runoff quality and quantity as a perspective of water-cycle. This study was conducted to develop a particle separator, inclined-pipe settling system, that could improve particle removal efficiency of road runoff as a pre-treatment device of stormwater infiltration. Solid particles larger than $100{\mu}m$ are separated by simple sedimentation; however, the significant amount of pollutants with a diameter less than $100{\mu}m$ remain in suspension. Without any treatment in that case of the runoff into infiltrate, groundwater would be deteriorated and also infiltration rate would be decreased by clogging. Therefore, we suggest optimal design parameters (inclined angle, pipe length, and surface loading rate) of inclined-pipe settling system which can be designed to effectively remove particles diameter smaller then $70{\mu}m$. Thus, the results showed TSS removal efficiency more than 80% with a particle diameter between $20{\mu}m$ and $70{\mu}m$, 100% above particle diameter $70{\mu}m$ for the inflow rate $0.018 m^3/m^2{\cdot}hr$ with pipe inclined at angle $15^{\circ}$.

• 한국환경보건학회지
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• 제35권5호
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• pp.411-416
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• 2009

This study was initiated to improve the cooling water quality by chemical coagulation and sedimentation in steel mills. Due to the inefficient flocculation in the settling tanks of blast furnace cooling water systems, the solid particles in the cooling water overflow accumulate and clog the cooling system. To protect the cooling water system from such fouling, proper flocculants must be continuously used. Laboratory tests were performed for the indirect cooling water system of a plate mill. The batch test in the gas scrubbing cooling water system of a blast furnace showed that the proposed coagulant was more effective for the improvement of coagulation and sedimentation than the existing one. During the tests, cationic flocculants were more effective than use of only an anionic flocculant. The suggested combination of anionic and cationic flocculants can probably improve the turbidity removal efficiency of the cooling water. Proper control of the overflow rate by the designed residence time would help turbidity removal efficiency in the settling tank. In addition, the settling can be enhanced by adopting rapid and slow mixing alternatively. Scale problems in blast furnace cooling water system were reduced to some extent by efficient settling.

• 전기전자학회논문지
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• 제22권2호
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• pp.384-392
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• 2018

다중출력 LDO 레귤레이터는 다양한 공급 전압이 필요한 임베디드 시스템에서 변환 효율을 개선할 수 있는 방안이 된다. 다중 출력을 위한 시분할 구조에서 LDO의 피드백 인자가 작아지면 정착시간이 길어져서 리플 전압이 커진다. 제안하는 토폴로지에서는 기준 전압을 가변하여 일정한 피드백 인자를 구현함으로써 정착시간과 리플 특성을 개선한다. $0.35{\mu}m$ 표준 CMOS 공정으로 설계한 4 채널 프로토타입의 시뮬레이션 결과 제안하는 구조는 피드백 인자가 0.4 이하인 기존 회로보다 정착시간과 리플 특성이 2배 이상 개선되는 것을 입증하였다.

• 해양환경안전학회지
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• 제26권7호
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• pp.858-863
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• 2020

본 연구에서는 활성탄소를 이용하여 해양환경으로 유출된 침강 HNS를 현장에서 대응하기 위한 기술 개발을 목적으로, 활용 가능한 활성탄소의 조건을 검토하고 예상 소요량을 산출하였다. 입자 크기별 7종의 활성탄소들을 대상으로 침강 속도를 측정하였고, 침강 HNS로 분류된 클로로포름(CHCl3)에 대한 흡착용량을 실험실 규모 실험(lab-scale test)으로 측정하였다. 또한 7종 활성탄소들에 대하여 유해물질함량과 용출 실험을 실시하여 용출된 유해물질 함량을 정량 분석하였다. 평균 침강속도(Mean particle-settling velocity)는 0.5~8 cm/sec의 범위로 8-20 mesh 경우를 제외하고 입자의 크기가 클수록 침강속도가 빨랐으며, 클로로포름에 대한 흡착효율은 대체로 입자가 작을수록 표면적이 넓어져 증가되었다. 또한 현장 투입 후 2차 오염가능성 확인을 위한 유해물질함량과 용출 실험 실험에서 >100 mesh의 활성탄소는 전함량분석결과가 아연(Zn)과 비소(As)가 수처리제기준보다 높고, 용출실험결과에서도 크롬(Cr), 아연(Zn), 비소(As)가 다른 활성탄소에 비해 높은 농도로 용출되었다. 흡착효율, 침강속도, 유해성분 용출량 등을 종합적으로 고려하여 현장 처리 적용 가능한 활성탄소는 20-60, 20-40, 2mm&down mesh 이었으며, 흡착용량을 최우선으로 판단하여 투입물량을 계산하면 최소 현장 투입 물량은 각각 0.82, 0.90, 1.28 ton/㎘ 이다.

• 한국산업융합학회 논문집
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• 제11권3호
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• pp.107-111
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• 2008

Usually, flow mediation earth and settling pond etc. of processing plant to handle water or wastewater. Mediation is the wastewater that flowed past settling pond than material of heavy particles, water weight colloid particles that big solids are removed but are suspensibility material settlement exclusion impossible. So, we need flocculation and coagulation action to remove materials from this colloid state. Flocculation and coagulation by addition of chemical agents forms floc settle size. That is, shorten the sedimentation time and quality of processing water because promoting sedimentation doing to do fines or suspended solids and colloid can materials large size and also, flocculation to annex efficiency of filtration augment. Therefore, I executed this research to prove that COD efficiency for wastewater by using inorganic coagulant.