• Proceedings of the Membrane Society of Korea Conference
• /
• 2000.07b
• /
• pp.15-41
• /
• 2000

• Proceedings of the Membrane Society of Korea Conference
• /
• 2000.07b
• /
• pp.141-171
• /
• 2000

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.51 no.1
• /
• pp.94-101
• /
• 2015

The heat treatment machine based on immersion was developed to reduce temperature difference during netting process and appraised it performance compared current heat treatment machine using high pressure. It was also reviewed the optimum heat treatment procedures for PBSAT monofilament net in accordance with the immersion time and temperature. The procedure was based on physical measurement such as breaking load, elongation and angle of the mesh for PBSAT monofilament. The water temperature gap of the treatment machine based on immersion was less than $1^{\circ}C$. and the energy consumption was also increased in high temperature condition. It was identified that the optimum temperature was $75^{\circ}C$ and its optimum processing time was between 15 minutes and 20 minutes to get qualified physical properties.

• Journal of Korean Society of Water and Wastewater
• /
• v.22 no.1
• /
• pp.79-86
• /
• 2008

In Korea, most of the drinking water treatment relied upon the availability of the surface water, of which the raw water quality varied significantly by season and location. Therefore, the comparison of two operation modes (Pressurized type and Submerged type membrane system) must be estimated before the long-term establishment of two systems. In this study, two pilot-scale microfiltration systems with the capacity of $50m^3/day$ were installed and operated in two different modes, and the applicability of the system was determined based on the results such as the TMP (Trans-Membrane Pressure) and flux. For quantitatively comparing the two systems, a new concept, DRF (Differential Resistance Fraction) was introduced. The accumulated sum of the permeate after each cycle of chemical cleaning was also used as a tool for the system comparison.

• Journal of Environmental Health Sciences
• /
• v.23 no.3
• /
• pp.85-90
• /
• 1997

The objective of this study was to investigate biodegradation of TPA(terephthalic acid) and EG (ethylene glycol), treatment efficiency of polyester weight loss wastewater and microbial characteristics by aerated submerged biolfilm(ASB) p.rocess. In a batch reactor, pH increased from 7.0 to 8. 5 in the biodegradation of TPA. Whereas, in case of EG, decreased from 7.0 to 5.2. COD concentration rapidly decreased within 24hr in the biodegradation of TPA and EG. COD removal velocity constant(k) were 0.065-0.088 hr$^{-1}$. The biodegradation velocity of TPA was 1.4 times faster than that of EG. The ratio of suspended biomass to the total biomass in the reactor was 18.3-33.3%, increased as a high ratio of EG content. Biofilm thickness, biofilm dry density and attached biomass were 346-432 $\mu$m, 41.8-61.9 mg/cm$^3$, 1.45-2.67 mg/cm$^2$, respectively. There values increased as a high ratio of TPA content. In the hydraulic retention time of 36 hr, organic loading rate of 4 kgCOD/m$^3\cdot$ day and packing ratio of 70%, the effluent concentrations of TCOD, SCOD in a continuous flow reator were 1,388 mg/l, 147 mg/l and removal efficiencies were 77%, 97.6%, respectively.

• Journal of environmental and Sanitary engineering
• /
• v.23 no.3
• /
• pp.23-30
• /
• 2008

This study was carried out to get efficient of nutrient removal effects on the treatment of paper making wastewater using submerged biological film process. The concentration of average BOD at raw wastewater was $324mg/{\ell}$ and COD was $435mg/{\ell}$. The average BOD of effluent was maintained $24.2mg/{\ell}$ and average COD was $37mg/{\ell}$. The concentration of average T-N at raw wastewater was $16.5mg/{\ell}$ and T-P was $1.2mg/{\ell}$. The average T-P of effluent was maintained $2.3mg/{\ell}$ and average T-P was $0.08mg/{\ell}$. The concentration of average SS at influent wastewater was $263mg/{\ell}$. The average SS of effluent was maintained $28.2mg/{\ell}$. The result of this experiment was wastage sludge did generated and the removal efficiency of nutrients were kept equilibrium.

• Ocean and Polar Research
• /
• v.22 no.1
• /
• pp.45-56
• /
• 2000

Hydrodynamic mixing characteristics of submerged effluent discharges into Masan Bay were investigated by both field observations and numerical model simulations. CORMIX model, a length-scale mixing model, was adopted to obtain the near-field dilution and wastefield characteristics of the effluent discharges into Masan Bay. Model predictions of the near-field dilution rates were in a good agreement with field observations in summer and winter seasons. Seasonal variations in the dilution rates showed that the highest dilution rate was obtained in winter while the lowest dilution rate was in summer. As the effluent discharges are increased with the treatment capacity expansion to be completed by 2011, the dilution rates are expected to be much reduced and the near-field stability of the wastefields will become unstable due to the increased effluent discharges.

• Korean Journal of Organic Agriculture
• /
• v.21 no.3
• /
• pp.403-411
• /
• 2013

This study was performed to examine whether it is possible to promote rice growth by midsummer drainage without damage of golden apple snails in environment-friendly rice farming. The effect of drainage on the life of snails was examined in a greenhouse before the filed experiment. Spats (young shells) of snails survived 100% at 12 days after drainage, and 93.3% at 15 days after drainage. The midsized shells survived 100% at 9 days, 93.3% at 12 days, and 86.6% at 15 days after drainage. In the field experiment, 10-days drainage did not affect the snail population and there was no significant difference of weeding activity of snails between the midsummer drainage treatment and the continuous submerged treatment. The plant height and the effective tiller number in the midsummer drainage treatment were higher than those of the continuous submerged treatment. The rice yield of midsummer drainage plot was 511kg/10a, which was 66kg/10a higher than 445kg/10a of continuous submerged plot. In conclusion, midsummer drainage could increase rice growth and yield without damage of golden apple snails in the environment-friendly rice farming.

• Journal of Korean Society on Water Environment
• /
• v.25 no.1
• /
• pp.120-124
• /
• 2009

This study was performed to investigate the application of submerged membrane bioreactor (MBR) system for biological nutrient removal of municipal wastewater. MBR bioreactor consists of four reactors such as anaerobic, stabilization, anoxic and submerged membrane aerobic reactors with two internal recycles. The hydraulic retention time (HRT), sludge retention time (SRT) and flux were 6.2 hr, 34.1 days and $19.6L/m^2/hr$ (LMH), respectively. As a result of operation, the removal efficiency of $COD_{Cr}$, SS, TN and TP were 94.3%, 99.9%, 69.4%, and 74.6%, respectively. There was no significant effect of microbial activity after the maintenance cleaning using 200 mg/L of NaOCl. Membrane filtration for the treatment of municipal wastewater was performed for longer than 9 months without chemical recovery cleaning.

• Computational Structural Engineering
• /
• v.9 no.3
• /
• pp.125-134
• /
• 1996

The base-isolation of building, as appeared in many studies, has shown remarkable performance in seismic response attenuation of the internal system as well as the building structure itself. But for the case that the internal system is submerged and hence subject to a considerable hydrodynamic effect, the seismic response of the system due to the base-isolation of building can be greater than the case that they are in air. This paper presents the dynamic analysis of a submerged internal system on base-isolated building to show such an example. The results show that an additional treatment is required to reduce the adverse effects on the seismic response of such a system when the building is base-isolated, and that the system response can be reduced to some extent by an appropriate control of fluid gap between the system and the building structure.