• Membrane Journal
• /
• v.24 no.1
• /
• pp.20-30
• /
• 2014

A membrane-coupled sequencing batch reactor (MSBR) was used for the advanced treatment of rural village sewage which is very low C/N ratio. The effect of powdered activated carbon, aeration rate, and external organic material loadings on the treatment efficiency and filtration performance were investigated in sequencing batch reactor, in which a flat-sheet type microfiltration membrane with a pore size of $0.4{\mu}m$ was submerged. At the initial operation (within 54 days) MLSS concentration, and the removal efficiencies of COD, T-N, and T-P were increased with the increase of C/N ratio. After 89 days the removal efficiencies of COD, T-N, and T-P were 97.1%, 75.0%, and 48.3%, respectively. Suspended solid-free effluent was obtained by membrane filtration. The T-P removal was relatively low because of depending on the amount of excess sludge wasting. During the operation of MSBR with powdered activated carbon, the particle size of the sludge reduced by the increase of collision frequency and mixing intensity. In comparison with MSBR without powdered activated carbon, TMP of MSBR with that was significantly elevated.

• Journal of Aquaculture
• /
• v.10 no.3
• /
• pp.261-271
• /
• 1997

Ammonia removal capacities of five submerged filter media, 2~3mm sand, 30~50mm gravel, 20~40mm coral sand, polythylene net, and corrugated plastic plate in a seawater recirculating system were tested. A rotating biological contactor (RBC) was also tested for comparison. Oxygen consumption rates were measured along with the ammonia removal efficiencies. The ammonia concentrations in the system were maintained from 0.052 to 0.904 mg/l (mean 0.338$\pm$0.219 mg/l) and the water temperature was ranged from 19.2 to $21.4^{\circ}C\;(mean 20.2^{\circ}C\pm0.58^{\circ}C$). The 1/2-order kinetic model (Y:g/$m^3$/day) and the mean ammonia removal rates (g/$m^3$/day) of the filter media were : Sand : Y=135.5X0.5-25.1(r2=0.8110), 45.1 Coral sand : Y=125.1X0.5-33.0 (r2=0.7307), 31.8 Polyethylene net : Y=87.4X0.5-20.1 (r2=0.6780), 25.2 Corrugated plastic plate : Y=87.4X0.5-20.1(r2=0.5206), 19.2 Gravel : Y=4307X0.5-5.5 (r2=0.2596), 17.1 RBC : Y=127.6X0.5-33.4 (r2=0.7146), 32.8 where X is the concentration of ammonia. Oxygen consumption rates well corresponded to the ammonia removal capacities of each filter medium, thus the sands showing the highest value (442g/$m^3$/day) followed by coral sands (291.1g/$m^3$/day), polyethylene nets (236.9g/$m^3$/day), gravels (135.6g/$m^3$/day) and corrugated plastic plates (134.2g/$m^3$/day). Oxygen consumption rate of the RBC was unable to measure because of the characteristics of the structure.

• Korean Journal of Environmental Biology
• /
• v.20 no.2
• /
• pp.158-164
• /
• 2002

Some of synthetic chemicals can net as an endocrine disrupting substance in higher animals. Dioxins, DDT, PCBs and bisphenol A (BPA) are classified into endocrine disruptors and aye under a strict control in many countries. This research was designed to compare the clastogenic effects of BPA to those of ionizng radiation to establish the relaltive effectiveness of BPA by means of Tradescantia micronucleus assay. For the uptake of the BPA through the stems, groups of fresh cuttings of Tradescantia BNL 4430 weve placed in BPA solutions of 0 to 4 $\mu$M for 6 hours under continuous aeration. The other groups of the cuttings were irradiated with 0 to 0.5 Gy of gamma- rays. The frequencies of micronucleus showed a positive dose- response relationship in the range of 0 to 0.5 Gy, and a clear concentration-response relationship in the experimental range of BPA concentrations. By comparing the two experimental results, it is possible to estimate the BPA concentration and its equivalent radiation dose for a fixed value of MCN frequency. BPA of $ll.8\mu{M}$ can give rise to 53.3 MCN/100 tetrads, which is the same frequency induced by 25 cGy of gamma- rays. It is of biological importance that clinical symptoms start to develop after a whole body exposure to radiation higher than 25 cGy. The results indicate that the pollen mother cells are an excellent biological end- point for toxicity test of suspected endocrine disrupting chemicals such as bisphenol A, cotylphenol and nonylphenol.

• Journal of the Korean association of regional geographers
• /
• v.6 no.1
• /
• pp.51-68
• /
• 2000

The Sacheon bay region functioned as a strategic place as the bay provided a major sea-route leading to the Kyungnam province. So it is no wonder that a number of castles and walls were located in such an outlying post of strategic importance. In the bay region there are found Sacheon, Gonyang and Seonghwangdang town castles, Yeegu, Seongbangri, Shinbyukdong, Duckgockri, Baekcheondong and Gaksan miltary castles, Seonjinri and Sadung Japanese castles, Kumseonri and Wueolseongri mud walls, Gaksan, Anjeom, Chimzi and Usan beacon-post walls, and Tongyang, Gasan and Jangam warehouse walls(사천읍성, 곤양읍성, 성황당산성, 이구산성, 성방리산성, 신벽동산성, 덕곡리산성, 백천동산성, 각산산성, 사등산성지, 선진리성, 금성리 토성, 월성리 토성지, 각산봉수대성, 안점봉수대성, 침지봉수대성지, 우산봉수대성, 통양창성지, 가산창성지, 장암창성). Castles are, according to their functions, classified into two: town castles and military castles. In the former castles people live permanently, but in the latter people do not. Military castles are occupied only in time of emergence. Beside the two types, two Japanese castles, two old mud walls, four beacon-post walls, and three warehouse-post walls are found in the Sacheon bay region. Castles are also classified into plain castles and mountain castles according to their location. Mud, stone, wood, and brick materials were used for castle and wall building. As the castles and walls of the bay region are precious cultural assets, they should be preserved and protected with much attention. It should be remembered that in the future they can be the most valuable tourist attractions all around.

• Food Science and Preservation
• /
• v.13 no.3
• /
• pp.316-321
• /
• 2006

Disinfection of electrolyzed water (EW) on strawberry by immersion washing and quality changes during storage at $5^{\circ}\C$ was compared with one immersed in chlorine water and not treated. Total count of strawberry washed with EW by immersion in 10 volumes of EW for 20 min was decreased to about 2 log cycle compared to the untreated And rate of microbial growth during storage was lower than ethers. Decaying ratio in strawberry treated with electrolyzed low-alkalinewater (EW-2) showed lower as of 10% level after 5 days of storage compared) to the untreated and the treated with chlorine water (CW). Hardness in the treatment of EW was not changed significantly until 3 days of storage, after then rather increased. Change in surface color of strawberries was observed; L value in the CW treated and the untreated increased whereas it decreased in the treatment of EW. And color difference(${\Delta}E$) during storage was observed the lowest in the untreated until 3 days of storage. The initial value of residual chlorine in the treatment of EW was at the level of $0.04{\sim}0.06ppm$, and $1{\sim}3$ days later showed almost the equal value to level of $0.02{\sim}0.03ppm$ in all treatments. Sensory characteristic during storage was preferable on strawberry washed with EW (EW-1 and EW-2) to the other treatments.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.21 no.4
• /
• pp.269-275
• /
• 1988

Inhibitory effects on bacterial growth by using lysozyme and mixtures of it with other antibacterial substances (sodium hexametaphosphate and sodium pyrophosphate) were investigated against the 7 kinds of hacterial strains isolated from putrefied surumi products. The growth inhibitory concentrations of lysozyme and lysozyme + sodium hexametaphosphate + sodium pyrophosphate against the bacteria were added to kamaboko, imitation crab meat and fried surumi, then viable cell count, pH and VBN were examined during the storage at $30^{\circ}C$ for 7 days. Lysozyme showed growth inhibitions against 6 of 7 isolates and the inhibition effect of mixture of antibacterial substances was multiplied against all the isolates compare with those of its individual use. Growth inhibitory effect of the substances on the bacteria was high in order of lysozyme + sodium pyrophosphate + sodium hexametaphosphate, lysozyme + sodium hexametaphosphate, lysozyme + sodium pyrophosphate and lysozyme. The most effective inhibitory concentration of mixture of the antibacterial substances in kamaboko and imitation crab meat was $0.05\%$ of lysozyme, $0.5\%$ of sodium pyrophosphate and $0.1\%$ sodium hexametaphosphate. But the bacterial growth was slightly inhibited in fried surumi even if the same concentration of the dipped mixture and the effect of the mixture was less than that of $0.2\%$ sorbic acid.

• Membrane Journal
• /
• v.24 no.1
• /
• pp.31-38
• /
• 2014

Rainwater harvesting is a process by which rainwater collected from rooftop or other catchment is purified so that the water can be directly or indirectly used by human beings for beneficial uses. As rainwater is increasingly considered for high quality purposes, membranes have gained an important place in rainwater treatment. It has advantages such as the production of high quality water, small footprint, and affordable energy consumption. Nevertheless, membrane fouling is regarded as a serious problem similar to the cases of water treatment and wastewater reclamation. In this study, we applied microfiltration (MF) membranes for rainwater treatment. In addition, a low pressure ultraviolet (UV) process was also use as a pretreatment to control notonly. To quantify the effect of UV on organic matters, both total organic carbon (TOC) and UV absorbance (UVA) were measured. Moreover, the effect of UV pretreatment on membrane fouling was investigated. Experimental results indicated that the pretreatment of membranes using LPUV was effective to control fouling of MF membranes only when the rainwater was contaminated by algae. This was attributed the reduction and modification of organics after UV treatments. It is likely that the UV/MF process is a promising option for water treatment in decentralized water treatment such as micro water grid systems.

• Journal of fish pathology
• /
• v.18 no.1
• /
• pp.91-97
• /
• 2005

Bio-secure culture of olive flounder Paralichthys olivaceus in the IBK (Intensive Bioproduction Korean) recirculating system with dry pellet was tested for 6 months. The IBK system consists of 12 rearing tanks, 6 sedimentation tanks. 4-sectioned submerged biofilter chamber and channels. The size of each rearing tank was 3m in diameter and 1m in depth. The size of each biofilter chamber was $3.1\times3.3\times2.0$ m (D) and was filled with corrugated plastic plates as a biofilter medium. Total surface area of the biofilter was 3,789.7 $m^2$ Water was circulated by one of two vertical axial pump and circulating rate was about 34 times per day. A UV light sterilizer was used to treat inlet sea water with the flow rate of 4 ton/hr. All fish were treated with 150 ppm formalin 3 times with 5 day interval before stocking. It took 60 days for 'conditioning' the biofilter with the stocking density of 4.5 kg of fish $m^2$. The concentrations of ammonium-nitrogen, nitrite-nitrogen and nitrate-nitrogen in the system remained at the range of 0.096-0.315 mg/L, 0.015-0.504 mg/L, and 2.530-39.517 mg/L, respectively. Water temperature fluctuated from 17.5 to 25.1$^{\circ}C$ and salinity was from 30.1 to 33.5 ppt during rearing period. The fish grew from the average weight of 615.2 g to 1,201.1 g for 180 days. Initial and final fish densities were 8.4 and 15.9$kg/m^2$, Survival rate was 97.1 %. Neither parasites nor noticeable diseases was observed during the raring period even Vibrio spp. were detected from some fish in the system.

• Membrane Journal
• /
• v.26 no.3
• /
• pp.205-211
• /
• 2016

Performance of pyrophyllite-based ceramic membranes newly developed were investigated. Membrane fouling caused by microbial suspensions taken from a full-scaled MBR system at domestic wastewater treatment plant was observed at different airflow rate and distance between each membrane. For the pyrophyllite support, pore size was about $1.0{\mu}m$, but surface coating with $Al_2O_3$ solution decreased the pore size with the reduction of the pure water permeability. With the MLSS taken from the full-scaled MBR system (6 g/L), the fouling rate was decreased by increasing airflow rate under $20L/m^2{\cdot}hr$ of setpoint flux. However, the effectiveness of the airflow rate on the fouling control depends strongly upon the gap between each membrane. At fixed airflow rate, the fouling rate was decreased by increasing the gap between each pyrophyllite membrane. Nevertheless, further increasing the membrane distance from 3.5 to 5.4 cm resulted in higher fouling rate. Similar result was observed with the $Al_2O_3$ coated-pyrophyllite membrane. Nevertheless, the fouling rate was lower with the coated membrane than that observed with the uncoated pyrophyllite support. Regardless of surface coating, the suspended solids were removed almost completely and the surface coating on the pyrophyllite support improved organic rejection with PEG solution (MW : 8000 kDa) tested.

• Membrane Journal
• /
• v.25 no.6
• /
• pp.524-529
• /
• 2015

In this study transmembrane pressure (TMP) was measured with respect to operational time by applying the sinusoidal flux continuous operation (SFCO) for the hollow fiber membrane. The hollow fiber module which has $100cm^2$ of effective area and $0.45{\mu}m$ nominal pore size was submerged in the activated sludge solution of MLSS 5,000 mg/L. The critical permeate flux was measured as $26.6L/m^2{\cdot}hr$ by the method of continuous flux step change. TMPs of the filtration/relaxation (FR), FR with backwashing (FR/BW) and SFCO modes were measured. The SFCO mode was more effective than FR and FR/BW modes below the critical permeate flux such as 15, 20 and $25L/m^2{\cdot}hr$. However, the FR/BW was confirmed as more effectively fouling controlled mode than SFCO mode above the critical permeate flux.