• 상하수도학회지
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• 제13권3호
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• pp.91-100
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• 1999

Treatment conditions of DAF(Dissolved Air Flotation) and removal rates of VOCs(Volatile Organic Compounds) in mixed water of H raw water and VOCs were investigated. The used VOCs were benzene, toluene, ethylbenzene, and xylene in aromatic compounds and iso propyl mereaptan, n-butyl mereaptan, dimethyl disulfide, and iso butyl mercaptan in odors. The related parameters include water type, treatment method, clay concentration, pH condition, flocculation time, flotation time, per-cent recycle, water temperature, pressure. The removal rates of VOCs were different on treatment process and water condition. Treatment time was longer, removal rates of VOCs was higher. Water temperature was more important than pressure in DAF parameters. Molecular weight was related with removal rate in several kinds of VOCs were decraesed by competition of each component in II raw water. When algac blooming D water was treated by DAF, TCOD(Total chemical Oxygen Demand) and chorophyll a was removed over 96%.

• 상하수도학회지
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• 제18권2호
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• pp.181-187
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• 2004

The purpose of this study is to investigate the biofilm reactors capable of doing high efficiency treatment. Vertical fluidized bed biofilm reactor(VFBBR) and spiral fluidized bed biofilm reactor(SFBBR) was used for their performence in biodegradation of artificial sewage. The factors influencing the efficiency of those reactors were compared with difference of physical condition. They had same size but different structure to gain access of its unique characteristics. When recycle solution with flow rate of 22 mL/min and artificial sewage with flow rate of 2~10 mL/min were fed into two reactors in aerobic state, the average $COD_{cr}$, removal rate for biodegradation of SFBBR was greater than VFBBR. After reactor feed sewage was constantly maintained as flow rate of 4 mL/min and the recycle solution were changed to 10~32 mL/min respectively, the average $COD_{cr}$ removal rate of artificial sewage in SFBBR was greater than VFBBR. In this experiment for addition of support media into two reactors SFBBR was 4.1% excellent than VFBBR. Above all, SFBBR excelled VFBBR in boidegradation of organic matter in sewage.

• 한국환경과학회지
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• 제27권2호
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• pp.99-107
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• 2018

In order to design the improvement process for T-N removal, the treatment process of Suyoung, Gangbyeon, and Noxan sewage treatment plants (STP) in Busan was anlayzed. Suyoung STP shows a T-N removal efficiency of about 69.8% with MLE(Modified Ludzack ettinger) and A2O+MBR. However, it is necessary to improve the process to maintain over DO of 1 mg/L and is required to install a flow control tank to minimize the rainfall effect. Gangbyun STP shows a about 70.2% T-N removal efficiency with A2O+GFF(gravity fiber filtration). However, in order to improve T-N removal efficiency, it is needed to install MLE process to treat recycle water. Noksan STP shows a T-N removal efficiency of about 71.0% with MLE+Chemical treatment and shows stable T-N concentration in effluent. However, it is required a toxic chemical management process because bad wastewater flows into the STP, also is necessary a process improvement in order to increase internal recycling ratio. Especially, it is required a process improvement to increase HRT of nitrification tank because Suyoung and Gangbyeon STPs shows low nitrification efficiency during winter season.

• 한국환경과학회지
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• 제4권5호
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• pp.509-516
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• 1995

The treatment performances of anaerobic-aerobic activated sludge process were investigated under various operation conditions. The treatment system proposed in this study gave a relatively stable performance against hourly change of the flow rate and showed a satisfactory removal of nitrogen and phosphorus compounds under experimental conditions. The recycle ratio of mixed liquor from aerobic to anaerobic region and peak coefficient primarily controlled the extent of nitrogen removal. The recycle ratio had the optimum values which were determined by the microbial activities of nitrification and denitrification. The behavior of the treatment unit could be simulated by using the kinetic equations and reactor models which considered the treatment units as complete mixing tanks.

• 한국환경과학회지
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• 제4권5호
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• pp.123-123
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• 1995

The treatment performances of anaerobic-aerobic activated sludge process were investigated under various operation conditions. The treatment system proposed in this study gave a relatively stable performance against hourly change of the flow rate and showed a satisfactory removal of nitrogen and phosphorus compounds under experimental conditions. The recycle ratio of mixed liquor from aerobic to anaerobic region and peak coefficient primarily controlled the extent of nitrogen removal. The recycle ratio had the optimum values which were determined by the microbial activities of nitrification and denitrification. The behavior of the treatment unit could be simulated by using the kinetic equations and reactor models which considered the treatment units as complete mixing tanks.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2004년도 학술대회지
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• pp.87-90
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• 2004

Serious problems of the environment protection and resource exhaustion are exhibited. due to the increase of the construction materials and activation of the remodeling, recently. Especially, most of the advanced countries. recycling plan for the waste concrete is vigorously progressing. The purpose of this study is making advances in the recycling of waste concrete material for use as recycled aggregate to make secondary concrete product. Using recycled aggregates form demolished concrete, we manufactured cement bricks to experiment overall performance in Korean Standard and feasible performances. On the recycled cement, in the case of cement : aggregate is 1 : 7 is satisfied with KS F 4004 : dimensions, water absorption, compressive strength of quality of a standard. So we concluded that it has great feasibility to apply these products to construction industry.

• Membrane and Water Treatment
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• 제4권4호
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• pp.251-263
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• 2013

The internal reflux effect on dialysis through the retentate phase of a countercurrently cross-flow rectangular module is investigated. Theoretical analysis of mass transfer in cross-flow devices with or without recycling is analogous to heat transfer in cross-flow heat exchangers. In contrast to a device without reflux, considerable mass transfer is achievable if cross-flow dialyzers are operated with reflux, which provides an increase in fluid velocity, resulting in a reduction in mass-transfer resistance. It is concluded that reflux can enhance mass transfer, especially for large flow rate and feed-concentration operated under high reflux ratio.

• 상하수도학회지
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• 제8권1호
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• pp.9-17
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• 1994

The study of lake pollution problems is often related to the dynamic behavior of phosphorus. Several phosphorus models are available that may be suitable to study these problems. Depending on the the management objectives and data availability, some models may be more appropriate than others. Criteria are defined to help modelers choose the most appropriate total phosphorus models for different lakes. These criteria consider in-lake processes such as sediment feedback, stratification, and algal uptake and recycle.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.41-44
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• 2002

It is unreasonable to calculate the amount of agricultural water use by applying unit demand method, because it is different from other water use due to the return flow and reuse in the recycle of watershed. Data from irrigation pumping station and reservoir were analysed. Factors for water balance are precipitation, evapotranspiration, percolation, runoff, and management loss, etc. Here in the study, the amount of agricultural water was defined in the way of three different categories. First one is "Gross water" including evapotranspiration, percolation, and management loss. Second one is "Agricultural water" including Gross water and effective rainfall. Third one is "Broad water" which is abstracting the return flow from Agricultural water.

• Journal of information and communication convergence engineering
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• 제9권4호
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• pp.375-378
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• 2011

This study is intended to realize an intelligent controller using fuzzy control algorithms in order to recycle energy by recycling the waste water heat discharged by waste water heat collection boilers. Using waste water inflow temperature changes and waste water inflow amount changes as parameters, we present characteristic curves of the number of compressors being operated at fixed speeds and the temperature of hot water being discharged. We propose an intelligent controller that determines the optimum number of compressors being operated at fixed speeds in real time by measuring changes in the temperature and amount of waste water inflows in order to minimize the number of compressors being operated at fixed speeds relative to the waste water load flowing into the waste water heat collection boiler.