• Membrane Journal
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• v.23 no.1
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• pp.61-69
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• 2013

The effect of humic acid (HA), and the roles of microfiltration (MF), PES (polyethersulfone) beads adsorption, and photo-oxidation were investigated in hybrid process of ceramic MF and PES beads loaded with titanium dioxide ($TiO_2$) photocatalyst for advanced drinking water treatment. Those were compared and studied in viewpoints of membrane fouling resistance ($R_f$), permeate flux (J), and total permeate volume ($V_T$). Because membrane fouling increased dramatically as decreasing HA, $R_f$ increased and J decreased, and finally $V_T$ was the highest at 2 mg/L HA. In the experiment to investigate the roles of photo-oxidation and adsorption at humic acid 4 mg/L and 6 mg/L. In both conditions, $R_f$ was the lowest and $V_T$ was the highest in MF + $TiO_2$ + UV process. The average treatment efficiencies of turbidity and dissolved organic matters were the highest in MF + $TiO_2$ + UV process, too.

• The Korean Journal of Pain
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• v.32 no.3
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• pp.178-186
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• 2019

Background: Epidural steroid injections (ESIs) have been widely used in managing spinal pain. Dexamethasone has recently emerged as a useful drug in this setting, relative to particulate steroids, although the associated systemic effects have not been fully elucidated. This study aimed to investigate the incidences and types of systemic effects after fluoroscopically guided ESI with dexamethasone. Methods: This retrospective study included 888 ESIs with dexamethasone (fluoroscopically guided at the cervical and lumbosacral levels) performed on 825 patients during January to June 2017. Data regarding systemic effects were collected via telephone interviews using a standardized questionnaire at 2 weeks after the procedure. Data on patient demographic, clinical, and procedural characteristics were collected and analyzed to identify factors that were associated with systemic effects. All statistical analyses were performed using the chi-squared test. Results: Among the 825 patients, 40 patients (4.8%) experienced systemic effects during the 2-week follow-up period. The most common systemic effect was facial flushing (12 patients, 1.5%), which was followed by urticaria (7 patients, 0.8%) and insomnia (7 patients, 0.8%). A history of spine surgery was significantly associated with the occurrence of systemic effects (P = 0.036). Systemic effects were significantly more common for injections at the cervical level than at the lumbar level (P = 0.019). Conclusions: Approximately 4.8% of the patients who underwent ESI with dexamethasone experienced minor and transient systemic effects. These effects were more common in patients who had undergone a previous spine surgery or received a cervical ESI.

• Journal of Korean Society on Water Environment
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• v.27 no.5
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• pp.634-645
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• 2011

A newly developed rainwater harvesting (RWH) system reliability model is evaluated for roof area of buildings in Haeundae District of Busan. RWH system is used to supply water for toilet flushing, back garden irrigation, and air cooling. This model is portable because it is based on a non-parametric precipitation generation algorithm using a markov chain. Precipitation occurrence is simulated using transition probabilities derived for each day of the year based on the historical probability of wet and dry day state changes. Precipitation amounts are selected from a matrix of historical values within a moving 30 day window that is centered on the target day. Then, the reliability of RWH system is determined for catchment area and tank volume ranges using synthetic precipitation data. As a result, the synthetic rainfall data well reproduced the characteristics of precipitation in Busan. Also the reliabilities of RWH system for each of demands were computed to high values. Furthermore, for study area using the RWH system, reduction efficiencies for rooftop runoff inputs to the sewer system and potable water demand are evaluated for 23%, 53%, respectively.

• Membrane Journal
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• v.19 no.1
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• pp.34-46
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• 2009

Effect of backflushing on the membrane fouling for polyethylene capillary membranes was examined by measuring the flux of $Al_2O_3$ colloidal suspensions through the cross flow microfiltration. In the comparison of with and without the application of backflushing, the hydraulic resistance to permeate flow of the suspension was less with backfluslng, but the Increasing rate in permeate resistance was higher. Regardless of backflushing, the cake filtration was dominant at the initial period of filtration with backflushing, being followed by the pore blocking. And at steady state, the fouling mechanism is almost governed by the cake filtration model. On the contrary, the pore blocking preceded the cake filtration in the initial stage of the original membrane before backflushing. And irrespective of backflushing, the ratio of cake filtration to total fouling increased, compared with that fur before backflushing. For the membrane with $0.24{\mu}m$ pore size, the permeate resistance was higher than that of $0.34{\mu}m$ pore size membrane. but the ratio of cake filtration was smaller than that of large pore membrane. In comparing the ratio of each fouling component to the total fouling for the case with backflushing pore blocking was 7.8% and cake filtration was 92.2%. for the case without backflushing, total fouling was composed of 9.6% pore blocking and 90.4% cake filtration.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.6
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• pp.689-699
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• 2003

This study was to examine characteristics of treating toluene vapor, which gets to be problematic due to its harmful carcinogenicity and mass generation from various sources, through a biological treatment facility which is environment-friendly and adopts a high-efficient and low-cost clean technology. In order to identify whether Alnus Firma Fruit (AFF) can be used as a media for a bioreactor, its utility and basic operating factors, a study was conducted on pressure drop, supply of nutrient substances and retention time which are operating factors of a biofilter, and eliminating characteristics were compared between AFF and the conventional biological activatedcarbon (BAC) widely used as filter media. In the case of AFF, the initial microbial deposits was 2.3${\times}$10$^{7}$ CFU/g dry AFF, which represents the initial microbial density higher than the case of BAC showing 5.5${\times}$10$^{6}$ CFU/g dry BAC And it took about 2 weeks to acclimate until its eliminating rate got to be increased over 90%. As a result of comparing pressure loss taking place with the lapse of time between BAC and AFF, after 130 days passed at SV 25h$^{-1}$ , BAC showed that its eliminating efficiency had a tendency to drop greatly due to a great pressure loss (0.53\longrightarrow54.7 mm$H_2O$/m) caused by an excess of biomass as accumulated. On the other hand. AFF showed that the pressure drop was 0.53 mm$H_2O$/m, about 2 times as much as the initial pressure loss of 0.4 mm$H_2O$/m, which represents no great change in the pressure loss, and its eliminating efficiency was also shown to be continuously high. Therefore, when AFF was used as a filler for a biological treatment facility, a biological filter enabling improvement of the purifying efficiency to be promoted could be provided, and moreover, the pressure loss was so small that the filler replacement cycle or the back flushing cycle could be extended. So, even in terms of the operating cost, it was identified to be an economical filler When an inorganic material was used as a filler, the biofilters performance acted sensitively on whether nutrient substances were supplied or not. In the case of AFF with low adsorptivity, addition of ethyl-alcohol increased the solubility of toluene, and consequently, biodegradation got to be actively made by microbes, and thus, its eliminating rate could be increased. As the flow velocity and the inflow concentration got to be more increased, its eliminating rate got to be lower, and particularly, an increase in the flow velocity made its eliminating rate drop more greatly than an increase in the concentration.

• Membrane Journal
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• v.9 no.3
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• pp.178-184
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• 1999

A periodic backflushing was performed to reduce the membrane fouling of ultrafiltration for wastewater, and the effect and the optimum condition were investigated in this study. The alumina¬ceramic tubular membrane with pore size of 0.02${\mu}m$ was used for the wastewater treated by coagulation and sedimentation from two paper plants, of which A plant made toilet paper by recycling milk paper cartons and B plant recycled corrugated cardboards. And the effect of periodic backflushing to membrane fouling and quality of permeate were studied with a constant backflushing time of 3 sec. As results of measuring SS, TDS, and COD of source and permeate, the rejection rate of SS showed the highest value at the backflushing period of 15 see, which was the shortest time in these experiments, in case of waste¬water discharged from A plant. However, the rejection rate of COD had the highest value at the period of 30 sec for wastewater from both A and B plant. Then, the rejection rate of TDS was almost same at 30 and 60 sec for A plant wastewater, and the highest at 60 see for B plant. The effect of periodic back¬flushing to membrane fouling was investigated by change of permeate flux according to operating time. The permeate flux decreased slowly at the operation with backflushing, and was higher compared with that without backflushing in both case of A and B wastewater. But, the optimum period with the highest flux of A wastewater was different from that of B, because SS and COD of A was higher than those of Band TDS of B was higher than that of A.