• 상하수도학회지
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• 제22권3호
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• pp.329-336
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• 2008

The pilot study was conducted to evaluate the applicability of air flotation(AF) processes combined with biological nutrient removal(BNR) for the retrofitting of conventional wastewater treatment facilities. The BNR system was operated in pre-denitrification and intermittent aeration; developed ceramic membrane diffusers were installed to separate the solid-liquid of activated sludge at the bottom of a flotation tank. Before performing a pilot scale study, the size distribution of microbubbles generated by silica or alumina-based ceramic membrane diffusers was tested to identify the ability of solid-liquid separation. According to the experimental results, the separation and thickening efficiency of the alumina-based ceramic membrane diffuser was higher than the silica-based ceramic membrane diffuser. In a $100m^3/d$ pilot plant, thickened and return sludge concentration was measured to be higher than 15,000mg SS/L, therefore, the MLSS in the bioreactor was maintained at over 3,000mg SS/L. The effluent quality of the AF-BNR process was 4.2mg/L, 3.7mg/L, 10.6mg/L and 1.6mg/L for $BOD_5$, SS, T-N and T-P, respectively. Lastly, it was revealed that the unit treatment cost by flotation process is lower than about $1won/m^3$ compared to a gravity sedimentation process.

• 한국물환경학회지
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• 제20권6호
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• pp.647-651
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• 2004

In this study, some of bacterial growth kinetic parameters were delineated and evaluated for the biological nutrient removal processes such as the $A^2/O$, 4stage-BNR, Intermittent Cycle Extended Aeration System(ICEAS) and Intermittently Aerated Cylindrical Oxidation Ditch(IACOD) processes. $Y_H$ values for the ICEAS process ranged from 0.71 to 0.74, and were higher than those for the other processes. It seems to indicated that organic carbons uptaked by microorganism were more used up for cell synthesis rather than for energy components in the ICEAS process. $b_H$ for the ICEAS and IACOD processes were lower than those for $A^2/O$ and 4stage-BNR processes. The $\mu_{max{\cdot}A}$ for the ICEAS was higher than those for the other processes, which indicated that desirable operating conditions for nitrifying bacteria's growth were established.

• The Journal of Korean Physical Therapy
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• 제23권3호
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• pp.37-42
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• 2011

Purpose: The principal objective of this study was to evaluate the power output of ultrasound in Korean clinics and compare the value with Korean and global standards. Methods: A total of 69 units were measured for ultrasound power output. The normal range of power output level was ${\pm}30%$ of the output set according to KFDA standards. Device model, manufacturer, ERA, and BNR were obtained via simple questionnaires. A portable ultrasound power meter was used for output measurement. Results: 37 machines, with reported ERA values, were assessed for power output per unit area. Of these machines, 13 (37.14%) were considered to be compliant with US FDA standards at 0.5, 1.0, 1.5, $20W/cm^2$ and 18 (51.43%) were considered within KFDA standards. The remainder of the machines were outside the standard error and evidenced irregular output levels, even though most of them were the same model. Conclusion: Appropriate ultrasound intensity is incredibly important for safety and effective use. Therefore, the KFDA standards regarding ultrasound may require revision in light of global standards, including BNR and ERA additionally, attention should be paid to regular calibration for safe use in clinical practice.

• Membrane and Water Treatment
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• 제3권2호
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• pp.133-140
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• 2012

The overall performance of BNR-MBR, so-called Anoxic-Anaerobic-Aerobic Membrane Bioreactor ($A^3$-MBR), developed for nutrient removal was studied to determine the efficiencies and mechanisms under different solid retention time (SRT). The reactor was fed by synthetic high-rise building wastewater with a COD:N:P ratio of 100:10:2.5. The results showed that TKN, TN and phosphorus removal by the system was higher than 95%, 93% and 80%, respectively. Nitrogen removal in the system was related to the simultaneous nitrification-denitrification (SND) reaction which removed all nitrogen forms in aerobic condition. SND reaction in the system occurred because of the large floc size formation. Phosphorus removal in the system related to the high phosphorus content in bacterial cells and the little effects of nitrate nitrogen on phosphorus release in the anaerobic condition. Therefore, high quality of treated effluent could be achieved with the $A^3$-MBR system for various water reuse purposes.

• 대한환경공학회지
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• 제32권1호
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• pp.97-104
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• 2010

현재 강화된 방류수 수질 기준에 발맞춰 질소 인 제거를 포함한 고도처리 공정을 건설 중이거나 기존 표준활성슬러지 공정에서 고도처리공정으로의 개선이 추진되어지고 있다. 그러나 다양한 고도처리공정의 적용을 검토함에 있어 제거 효율 측면에서의 단순 평가만이 사용되고 있다. 따라서 고도처리공정 적용 시 제거 효율 뿐 아니라 슬러지 생산, 포기 비용 등을 복합적으로 평가할 수 있는 방법이 필요하였다. 따라서 본 연구에서는 표준활성슬러지 공정으로 운영 중인 S 하수처리장을 Biological nutrient removal(BNR) 공정으로 개선할 경우를 가정한 대안 공정 평가 방법을 제안하였다. 시간적, 비용적 장점을 가지며 객관적인 평가 기준으로 대두되고 있는 수학적 모델을 이용한 시뮬레이션을 통해 대안 공정으로 선정된 Anaerobic/anoxic/oxic ($A^2$/O), Virginia initiative plant (VIP), Daewoo nutrient removal (DNR) 공정에 대해 평가하였다. 시뮬레이션 결과를 바탕으로 공정의 처리 성능 뿐 아니라 슬러지 생산량 및 에너지 효율을 포함한 5가지 성능 지수들을 적용함으로써 개별 항목간의 비교 평가가 가능하였으며, 최적 공정을 제시하기 위한 객관적 판단과정을 퍼지 추론을 통하여 구현하였다.

• 대한환경공학회지
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• 제22권1호
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• pp.121-132
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• 2000

TCODcr 380mg/L이며 TKN이 65mg/L, TP 12mg/L가량인 도시하수의 질소, 인 제거를 위하여 $13{\sim}28^{\circ}C$에서 선단무산소조를 설치한 영양소제거공정(Bio-NET)을 $10m^3/d$ 규모의 pilot plant를 설치하여 내부반송율과 SRT를 변화시켜 운전하여 질소, 인 제거 특성을 살펴 보고 이를 시뮬레이션 프로그램을 이용하여 모사한 결과를 상호 비교하였다. SS, CODcr의 경우 각각 94%, 87%의 제거효율을 안정적으로 보였으며, 질소의 경우 52%~89%로 평균 75%의 제거효율을 보였다. 또한 인의 경우 안정적으로 평균 90% 이상의 높은 제거효율을 보여주었다. 또한 선단무산소조에서는 유입수내에 높은 $COD/NO_3-N$가 유지되어 비탈질속도는 평균 9.04mgN/gMv/hr로 분석되었다. 인의 거동은 유입수의 SCOD부하에 의해 큰 영향을 받는 것으로 나타났으며 비인용출속도는 평균 6.25mgP/gMv/hr를 보였다. 혐기조에서 비인용출속도는 평균 1.0mgP/gMv/hr를 보였고 폭기조에서 비질산화속도는 평균 2.9mgN/gMv/hr로 분석되었다. GPS-X 프로그램을 이용하여 모델의 내부인자 중 종속영양미생물군의 최대비중식속도, 인의 용출에 관련된 Short Chain Fatty Acid(SCFA) limit, 인의 섭취와 관련된 COD 이용당 인용출량을 반응조 특성에 맞게 보정하여 시뮬레이션을 실시한 결과와 pilot plant 실측치가 유사한 것으로 나타났다.

• 한국물환경학회지
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• 제22권3호
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• pp.451-455
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• 2006

Heterotrophic biomass yield coefficients, $Y_H$, for aerobic, anoxic and anaerobic reactors were successfully estimated for the two wastewater treatment plants, where one plant was operating in the $A^2/O$ process and the other was operating in the 4-stage BNR process. The estimation of $Y_H$ was undertaken by plotting the biomass COD concentrations versus the soluble COD concentrations in order to calculate the ${\Delta}biomass$ COD/ ${\Delta}soluble$ COD in each batch reactor. The batch reactors employed in this study were fed by filtered influent and mixed liquors in the ratio of 10:1, and operated in the aerobic, anoxic and anaerobic conditions, which represented the actual operating conditions for the $A^2/O$ and 4-stage BNR process. The average $Y_H$ values of the aerobic, anoxic and anaerobic reactor for the $A^2/O$ process were 0.52, 0.41 and 0.18 mg COD/mg COD, respectively, and those for the 4-stage BNR process were 0.58, 0.40 and 0.20 mg COD/mg COD, respectively. The average ratio of the $Y_H$ for aerobic reactors to those for the anoxic reactors were about 1:0.79 for the $A^2/O$ process, and about 1:0.69 for the 4-stage BNR process. The experimental method for anoxic and anaerobic $Y_H$ estimation shown in this study has turned out to be simple and efficient in its practical application.

• 대한환경공학회지
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• 제22권6호
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• pp.1093-1101
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• 2000

본연구의 목적은 국내의 기존 하 폐수처리장에 생물막을 적용하여 BNR공정으로 전환 및 개조하거나 생물막 공법을 적용한 BNR공정을 3차 처리로 적용할 수 있는 새로운 공정을 개발하는 데 있다. 우리 나라 하수의 $SCOD_{cr}/T-N(NH_4{^+}-N+NOx-N) $ 비는 다른 나라에 비하여 상대적으로 낮기 때문에 완전한 탈질화를 얻기 위해서는 외부탄소원을 반드시 공급해야만 한다. 본 연구에서의 $SCOD_{cr}/NH_4{^+}-N$비는 2.49이었으며, 실험기간 동안 유입수 $NH_4{^+}-N$농도는 25에서 37 mg/L로 변화되었다. 하수처리시 질소제거능을 향상시키기 위하여 R-1(무산소/중간침전조/호기성/무산소/호기성)과 R-2(호기성/중간침전조/무산소/무산소/호기성)의 생물막을 이용하는 두 공정을 적용하였다. 외부탄소원을 투여하지 않은 조건에서 $NH_4{^+}-N$와 T-N의 유출수질과 제거효율은 R-1공정이 R-2공정에 비하여 하수로부터 질소제거에 보다 적절한 것으로 평가되었다. 무산소 반응조의 $SCOD_{cr}/NOx-N$비와 T-N제거효율을 고려하였을 때, R-1공정이 원하수내 유기물질의 분배에 있어서 더 효과적인 것으로 사료되었다. R-1 공정과 R-2공정에서 1 g의 $NH_4{^+}-N$를 제거하는데 요구되는 알칼리도는 R-1과 R-2 각각 5.18과 5.76(g $CaCO_3/g$ removed $NH_4{^+}-N$)이었으며, 이는 활성슬러지 BNR공정에 비하여 낮았다.

• Bio news
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• 2호
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• pp.31-32
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• 2003

• 환경정보
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• 제21권9_10호
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• pp.38-48
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• 1999