• Environmental Engineering Research
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• 제23권2호
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• pp.195-204
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• 2018

A pilot scale study was conducted on a down-flow hanging sponge (DHS) reactor installed at a sewage treatment plant in Banda Aceh, Indonesia for treatment of desludging septic tank wastewater. Raw wastewater with an average biochemical oxygen demand (BOD) and total suspended solids of 139 mg/L and 191 mg/L, respectively, was pumped into the reactor. Two different hydraulic retention times (HRTs, 3 h and 4 h) were investigated, equivalent to organic loadings of 1.11 and $0.78kg\;BOD/m^3/d$, respectively. The average BOD concentration in the final effluent was 46 and 26 mg/L at HRTs of 3 and 4 h, respectively. The concentration of retained sludge along the reactor height was 10.2-18.7 g VSS/L-sponge, and the sludge activities were 0.24-0.32 and 0.04-0.40 mg/g VSS/h for heterotrophs and nitrification, respectively. Values of water hold-up volume, dispersion coefficient, and number of tank in-series found from tracer studies of clean sponge and biomass-loaded sponge confirmed that growth of retained sludge on the sponge module improved hydraulic performance of the reactor. Adoption of the DHS reactor by this Indonesian sewage treatment plant would enhance the role of the current desludging septic tank wastewater treatment system.

• 환경위생공학
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• 제23권3호
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• pp.39-46
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• 2008

In order to study the estimate of $CH_4$ emission factors in the municipal wastewater treatment plants, the active sludge process, 5-stage process, Denipho process, and SBR process were investigated. When active sludge process, 5-stage process, and Denipho process were used in wastewater treatment plant, the $CH_4$ emission factors were 2.88, 1.61, and 0.57 g-$CH_4/kg$-BOD, respectively. On the other hand, in the case of SBR process, it was 4.14 g-$CH_4/kg$-BOD. These results indicate that SBR process was effective for $CH_4$ emission in municipal wastewater treatment plants. Using the above processes, the methane emission factor and amount of waste water sludge were $4.78m^3/t$ and $12,204,506m^3/yr$, respectively. The remove of BOD was a range of $93.91{\sim}98.63%$.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.526-531
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• 2000

Application of electrodewatering (EDW) to mechanical dewatering system was studied to decrease water content in the sludge generated from waste water treatment process. Experiments realized the reduction of water content in the sewage sludge. EDW enhancing the conventional filtration by an electric field is an emerging technology with the potential to improve dewatering. In this study, a piston filter press was constructed, the digested sludges were dewatered by EDW under conditions of DC electric field and constant pressure in the piston filter press. Constant electric field from $0{\sim}120\;V/cm$ and constant pressure $98.1{\sim}392.4\;kPa$ were used. The results showed that as electric field was increased the dewatering rates increased and as pressure was increased the dewatering rates decreased. Also as polymer was added the dewatering rates increased. This experiments produced final sludge cake with water content of 60 wt% using EDW, compared with 80 wt% using pressure filtration alone.

• Applied Biological Chemistry
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• 제41권2호
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• pp.181-186
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• 1998

하수처리 운전이 슬러지 특성에 미치는 영향을 실제규모 하수처리장에서 수행하였으며 하수 슬러지 특성변화가 퇴비화 원료로 이용될 경우 그 영향을 조사, 분석하였다. 천안 하수처리장은 가동 초기 1년동안 정상적으로 운전되고 있으며 유출수는 방류수 수질기준을 만족하고 있으나 유입유량의 증가로 인하여 처리장 증설이 시급하다. 슬러지 탈수시설인 Belt press의 용량부족으로 하수처리장 내 비휘발성 고형물이 순환, 농축되어 활성 슬러지 MLSS 증가와 이에 따라 F/M비가 감소되게 운전하는 결과를 초래하고 있으며 이러한 상태로 하수처리장이 장기간 운전될 경우 하수처리 시설의 효율저하가 우려된다. 하수 슬러지의 수분함량은 79.5%, 유기물 함량은 11.6 %, C/N비는 6.1이었으며 중금속으로 As 1.8 mg/kg, Cd 27 mg/kg, Hg <0.1 mg/kg, Pb 54 mg/kg, T-Cr 370 mg/kg과 Cu 1,100 mg/kg이 검출되었다.하수 슬러지는 퇴비화 적정조건을 만족할 수 있는 원료로서 사용되기 위하여 수분함량, 유기물 함량 그리고 C/N비의 조절이 필요하며 이를 위한 첨가제/팽화제의 첨가가 필수적이다. 하수처리장 유입수에 함유된 중금속은 대부분 하수 슬러지에 농축되며 퇴비화 원료로 사용될 경우 부산물비료로서 규격기준에 적합하지 않을 뿐만아니라 토양오염이 우려되므로 유입수의 중금속 발생원을 추적, 제거하는 방안이 검토되어야 한다.

• 세라미스트
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• 제14권2호
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• pp.7-14
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• 2011

This paper has investigated physicochemical properties and conventional and environmental-friendly treatment methods of paper mill sludge to emphasize the importance and necessity of the sludge recycling. The paper mill sludge generally shows high contents of calcium and water, and is mostly discharged by landfill after incineration process rather than being recycled due to technical or economical problems. In recent years, however, several possible methods for recycling the paper mill sludge have been suggested for its sustainable process as follows; compost, raw material for the construction and paper industry, new energy source for reducing fossil fuel use and raw material of activated carbon for treating paper mill wastewater. Thus the authors suggest that practical recycling technologies of the paper mill sludge must be developed for substantiality in the paper industry through comprehending physicochemical compositions and generation status of the sludge and actively performing various related studies. Furthermore, this investigation could be used as preliminary information for the study on recycled paper development using paper mill sludge incineration ash.

• Membrane and Water Treatment
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• 제9권1호
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• pp.33-42
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• 2018

Microscopic examination of the activated sludge and morphological characterization of the flocs provides detailed information about the treatment process. The aim of this study is to investigate the morphological parameters of flocs obtained from a thermophilic jet loop membrane bioreactor (JLMBR) in different sludge retention times (SRTs), considering EPS and SMP concentration, hydrophobicity, zeta potential. The results showed that irregularity decreased with the increasing SRT. The compactness value was calculated to be less than 1 for all SRTs. However, the sludge had a more compact structure when the SRT increased. Zeta potential increased whereas hydrophobicity and floc size reduced, with increasing SRT. Furthermore, 2-D porosity calculated using the hole ratio was higher at greater SRTs. Hence, there was a significant correlation between the results obtained using the imaging technique and operation conditions of thermophilic JLMBR.

• 한국막학회:학술대회논문집
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• 한국막학회 1998년도 추계 총회 및 학술발표회
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• pp.150-152
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• 1998

Now the lack of water is serious problem all over the world because of the growth of population and expansion of industrial activities. So wastewater recycle and reuse is essential in many countries. One of the most popular wastewater treatment processes is conventional activated sludge system. In spite of significant degree of treatment rate the biological process has some operational difficulties and capital disadvantages. In conventional activated sludge process, sludge settling condition is getting worse in case of sludge bulking, it is common that overall process fails due to wash-out of biomass causing low concentration of MLSS in the aeration tank. Because of the absence of claifier the membrane bioreactor(MBR) process is less affected by such problems.

• 상하수도학회지
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• 제20권1호
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• pp.128-137
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• 2006

This study aims at developing the practical technology in the treatment of box-mill wastewater using the aerobic co-metabolism principle. The conventional activated sludge method exhibited the removal efficiency of $TBOD_5$ and $TCOD_{Mn}$ as 30~50% and 40~50%, respectively. Color was rather increased by 30~130% because the conventional treatment under the aerobic condition did not induce the conversion of molecular structure of dyeing agents. Meanwhile, when the aerobic co-metabolism principle was applied to the same wastewater, the removal efficiency of $TBOD_5$ and $TCOD_{Mn}$ were obtained as 92~97% and 90~94%, respectively. In particular, color was significantly reduced down to 65~85%. The enhancement of treatment efficiency was ascribed to occur not only that the non-degradables were converted to the second substrates, but also that the enzyme activity was increased as MLVSS was kept 3000mg/l or more with the first substrates injected.

• 상하수도학회지
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• 제21권3호
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• pp.279-285
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• 2007

Toxicity evaluations using oxygen uptake rate (OUR) on activated sludge process were investigated. On toxicity evaluations of heavy metals, all toxicants in experiments decreased OUR with respect to the concentrations of the toxicants, while high toxicities with cyanide and mercury were observed respectively. On toxicity evaluations of composite heavy metals, composite toxicities had similar results as to the total sum of each toxicants that presents accurate toxicity evaluation using OUR. From these results, it is concluded that activated sludge is effective indicator for toxicity evaluation on wastewater of biological treatment plants.

• 한국환경과학회지
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• 제23권1호
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• pp.97-104
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• 2014

The sludge flotation/thickening apparatus equipped a micro-bubble generating pump was used to investigate micro-bubble generating properties on operational parameters. We evaluated micro-bubble generating properties as results to be operated the apparatus by operational parameters which are pump discharge pressure, air/water ratio(A/W ratio), air flow rate, and water flow rate. Micro-bubble generating efficiencies in pumps without recycling flow and with 50% of recycling flow was found to be very efficient on optimum A/W ratio from 1.06 to 3.62% and optimum A/W ratio from 1.05 to 4.06%, respectively. In condition of 3.6% of A/W ratio, we showed that the apparatus could be generated 36,000 ppm of micro-bubble concentration to be optimum treatment efficiency in sludge thickening process.