• 대한환경공학회지
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• 제30권2호
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• pp.168-174
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• 2008

본 논문에서는 하수처리장의 자동 계측 제어 시스템을 구축함에 있어 제한 요소로 작용되는 2차 침전조의 침전 상태를 자동으로 진단하기 위해 이미지 분석 기법을 적용한 On-line SVI(Sludge Volume Index) analyzer를 이용하였다. 침전 상태를 알아보기 위해 카메라로 촬영한 디지털 이미지로부터 RGB(Red-Green-Blue) 프로파일을 얻었으며, 이를 통해 상등수와 슬러지층의 경계를 자동으로 감지할 수 있는 SV30 감지 알고리즘을 제안하였다. 개발된 SV30 감지 알고리즘은 벌킹, 핀플럭과 같은 침전 문제 발생 시에도 신뢰성 있는 감지능을 보여주었다. 또한 본 논문에서는 상등수 부분의 RGB 값과 실제 운전자에 의해 측정된 탁도 값 사이의 상관관계를 통하여, 탁도 추정 모델을 제안하였다.

• 한국환경과학회지
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• 제25권3호
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• pp.439-446
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• 2016

Domestic sewerage treatment plant is operated by activated sludge method and its modified method by using microorganism. In most cases, a method of using microorganism is directly controlled by the operator based on individual judgment through factors of DO, pH and ORP. In addition, under aerobic condition in bioreactor, energy consumption including excessive air injection is learned to be somewhat plenty. In order to solve this problem, in most of the process, improvement of internal recycling and activated environmental factor of microorganism were researched extensively. However, as factors are changed depending on various conditions, it is not sufficient as an indicator of judgment. As such, a research on operation of bioreactor that measures metabolic change in short time by directly measuring activated condition of microorganism using NADH fluorometer is required in reality.It is considered that the method like this could supplement problem of energy consumption being occurred in the existing treatment method and operational optimization of bioreactor would be enabled by controlling optimal air volume. Therefore, in this study, in order to obtain optimal operational indicator of bioreactor, proper air volume control test was performed and through batch test and site evaluation, possibility of NADH sensor being utilized as operational control indicator of bioreactor is intended to be analyzed. In order to compare with measured value, DO, ORP that are operational control indicator of existing bioreactor were used. As MLSS concentration was increased through batch test, NADH value was increased and site evaluation also showed similar tendency to batch test. Resultantly, it could be confirmed that changing level of NADH fluorometer was a sensor that could measure bioreactor condition effectively and optimized scale of bioreactor is considered to be utilized.

• 한국해양환경ㆍ에너지학회지
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• 제9권2호
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• pp.72-78
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• 2006

혐기성 소화조의 단면적/용량 비를 일정하게 한 상태에서 반응조 직경만을 달리한 반응조에 유기물 부하율에 따른 소화조 운전효율을 평가하였다. $0.4\;kg\;COD/m^3{\cdot}d$의 낮은 유기물 부하율에서는 반응조 직경에 관계없이 높은 처리 효율을 나타내어 반응조 형상에 따른 처리효율 차이는 없었다. $6\;kg\;COD/m^3{\cdot}d$의 유기물 부하율에서는 반응조 직경에 따라 전혀 다른 처리효율이 관측되었다. 즉, 직경 6.4 cm 반응조에서는 휘발성산의 축적과 낮은 COD 제거효율이 관측되었으나 직경 3 cm 반응조에서는 높은 COD 제거효율이 관측되었고 휘발성산의 축적도 일어나지 않았다. 이러한 차이가 나타나게 된 이유는 직경이 작은 반응조의 경우에는 생성된 가스의 부상에 의해 슬러지층의 유동화가 원활하게 일어난데 반해 직경이 큰 반응조의 경우에는 그렇지 못한 것이라고 판단된다. $20\;kg\;COD/m^3{\cdot}d$의 높은 유기물 부하율에서는 반응조 직경과는 관계없이 극히 낮은 처리효율을 나타내어 높은 유기물 부하에서는 반응조 형상과 처리효율과는 관계가 없는 것으로 나타났다. 따라서 혐기성 소화조의 효율적인 start-up은 슬러지층의 유동화가 중요한 인자이며 동일 단면적/용량 비에서 반응조 직경이 작을수록 유리한 것으로 나타나 반응조 형상도 반응조 운전효율에 큰 영향을 미치는 것으로 나타났다.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제1권2호
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• pp.125-136
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• 1997

Digestion of a municipal wastewater sludge by the anaerobic sequencing batch reactor(ASBR) was investigated to evaluate the performance of the ASBR process at a critical condition of high-solids-content feed. The reactors were operated at an HRT of 10 days with an equivalent loading rate of 0.8-1.5 gVS/L/d at $35^{\circ}C.$ The main conclusions drawn from this study were as follows: 1. Digestion of a municipal wastewater sludge was possible using the ASBR in spite of high concentration of settleable solids in the sludge. The ASBRS with 3- and 4-day cycle period showed almost identical high digestion performances. 2. No adverse effect on digestion stability was observed in the ASBRS in spite of withdrawal and replenishment of $30\%\;or\;40\%$ of liquid contents. A conventional anaerobic digester could be easily converted to the ASBR without any stability problem. 3. Flotation thickening occurred in thicken step of the ASBRS throughout steady state, and floating bed volume at the end of thicken period occupied about $70\%$ of the working volume of the reactor. Efficiency of flotation thickening in the ASBRS could be comparable to that of additional gravity thickening of a completely mixed digester. 4. Solids were accumulated rapidly in the ASBR during start-up period. Solids concentrations in the ASBRS were 2.6 times higher than that in the completely mixed control reactor at steady state. Dehydrogenase activity had a strong correlation with the solids concentration. Dehydrogenase activity of the digested sludge in the ASBR was 2.9 times higher than that of the sludge in the control reactor, and about 25 times higher than that of the subnatant in the ASBR. 5. Remarkable increase in equivalent gas production of $52\%$ was observed at the ASBRS compared with the control reactor in spite of similar Quality of clarified effluent from the ASBRS and control reactor. The increase in gas production from the ASBRS was believed to be combined results of accumulation of microorganisms, higher driving force applied, and additional long-term degradation of organics continuously accumulated.

• 청정기술
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• 제18권4호
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• pp.398-403
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• 2012

폐수로부터 안정적이며 경제적으로 질소 성분을 제거하기 위하여 선택적 질산화와 슬러지 그래뉼화를 파일럿 규모의 공기 유동 연속회분반응기(sequencing batch reactor, SBR)에서 수행하였다. 연속회분반응기 유입 암모니아 부하가 1.0 kg ${NH_4}^+-N/m^3{\cdot}d$까지는 거의 100%에 가까운 높은 질산화율을 보였고, 1.0~2.0 kg ${NH_4}^+-N/m^3{\cdot}d$에서는 거의 90%, 2.0 kg ${NH_4}^+-N/m^3{\cdot}d$ 이상에서는 질산화율이 90% 아래로 떨어짐을 확인할 수 있었다. 암모니아 저해와 용존산소 제한에 의한 아질산 산화균의 선택적 저해는 폐수 질산화에서 아질산 축적을 유도할 수 있다. 본 실험에서 연속회분반응기의 pH를 8.0 이상으로 그리고 용존산소를 1.5 mg/L 이하로 유지했을 때 모두 0.95 이상의 아질산 비율을 얻었다. 또한 공기 유동 연속회분반응기의 침전시간을 5분으로 짧게 유지하여 침전성이 좋지 않은 슬러지를 반응기에서 배제하고 침전성이 좋은 슬러지를 선택적으로 배양하였다. 그 결과 슬러지 침전성이 향상되면서 그래뉼 형성이 촉진되었으며 슬러지 침강계수(sludge volume index, SVI)는 60일 이후부터 75 이하로 안정되게 유지되었다.

• 한국재료학회지
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• 제34권7호
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• pp.370-376
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• 2024

In this study, we report significant improvements in lithium-ion battery anodes cost and performance, by fabricating nano porous silicon (Si) particles from Si wafer sludge using the metal-assisted chemical etching (MACE) process. To solve the problem of volume expansion of Si during alloying/de-alloying with lithium ions, a layer was formed through nitric acid treatment, and Ag particles were removed at the same time. This layer acts as a core-shell structure that suppresses Si volume expansion. Additionally, the specific surface area of Si increased by controlling the etching time, which corresponds to the volume expansion of Si, showing a synergistic effect with the core-shell. This development not only contributes to the development of high-capacity anode materials, but also highlights the possibility of reducing manufacturing costs by utilizing waste Si wafer sludge. In addition, this method enhances the capacity retention rate of lithium-ion batteries by up to 38 %, marking a significant step forward in performance improvements.

• 한국환경과학회지
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• 제6권6호
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• pp.671-678
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• 1997

This study was conducted to use oyster shell as media for biological wastewater treatment. The comparison between the removal efficiencies of the activated sludge and the submerged biofilm process with oyster shell media (5% of reactor volume) for domestic sewage treatment was made. The contaminant removal efficiencies of the submerged process were higher than that of the activated sludge process. And the removal efficiencies of the submerged biofilm process with oyster shell media of 10% and 18% were Investigated at various loading rate. The removal efficiencies of 10% were higher than that of the 18% during the experimental period. The effluent concentration from the sub- merged bloom process using oyster shell media was prediceted by the Stover-Kincannon model.

• 환경위생공학
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• 제11권2호
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• pp.1-7
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• 1996

The behavior of total organic carbon (TOC) and phosphate were observed for 15 days with immobilized activated sludge using polyacrylamide (PAA) by sequencing batch reactor (SBR). In the preparation of immobilized sludge by PAA, it was found that suitable acrylamide concentration for actual wastewater treatment was to be 15% through the batch test. When SBR system was operated in the repeated aerobic and anaerobic conditions, TOC removal efficiency was 92%. The uptake rate of phosphate was increased from 1.78 mg-P/g cell/hr on the 5th day of acclimation to 2.5 mg-P/g cell/hr on the 15th day of acclimation. And the total phosphorus content in PAA bead was increased from 40 mg-P/g cell on the 1st day of operation to 55 mg-P/g cell on the 15th day of operation. From this study, lowering the volume of aeration tank was possible when PAA bead was used in wastewater treatment and long operation was also possible without the settler.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 창립총회 및 춘계학술발표회
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• pp.11-14
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• 2000

Wastewater sludge and composted food wastes were examined as the alternatives of a landfill cover for soils to eliminate the emission of VOCs. The benefit of these alternatives is in their high sorption capacity, which is 5 to 50 times higher than natural soils. After sorption is finished, biodegradation is an important mechanism in decrease of VOCs concentration. In order to investigate appropriate VOCs degradation condition, biodegradation batch experiment is being conducted with isolated strain X9-c. Both benzene and TCE were degraded only in soil with 12%(water volume/sorbent volumn) water condition. When the water condition varied from 12 to 48% in compost, optimum water conditions of composted food waste was 36%.

• KSBB Journal
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• 제16권2호
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• pp.183-187
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• 2001

The biological activities of wastewater and sludge taken from the wastewater treatment process of Hyangnam pharmaceutic factories in Hwaseong, Kyeonggi-Do was measured using a respirometer. Oxygen uptake rate (OUR) was used as a tool for measuring biological activity. OUR was measured for varying amounts of sludge and organic chemicals in wastewater, and its toxicity was evaluated. Maximum OUR was observed as 61, 75, and 89 mg O$_2$/L/hr when sludge was added as 3, 5, and 10% of total volume, respectively. When the concentration of organic chemicals was changed to 1,486, 337, and 164 mg COD/L, maximum OUR was 53, 13, 8 mg O$_2$/L/hr, respectively. The toxicity test results showed that there seemed that there seemed to be no observable toxic effect on microbes in pharmaceutic wastewater.