수온과 체중을 고려한 멍게(Helocynthia roretzi)의 여수율

정우건 ( Woo Geon Jeong ),조상만 ( Sang Man Cho ) 한국수산과학회 2013 한국수산과학회지 Vol.46 No.6

In order to understand the co-culture impact of the sea squirt Halocynthia roretzi on the Pacific oyster Crassostrea gigas, we examined the filtration rate of the sea squirt in relation of water temperature (5-25℃) and body weight. The filtration rate increased in relation to body weight and water temperature, indicating a clear positive correlation with the two variables. Due to the clear positive correlation between filtration rates at each temperature groups for acceptable collinearity, each constants at regression equation was further analyzed for a unified model of filtration rate. Therefore the filtration rate of H. roretzi was estimated as: Fr (L/h/animal) = (0.1956+0.0182T)×DW0.7978EXP(-0.0273T) for water temperature in the range of 5-25℃. The estimated filtration rates of H. roretzi were higher than those of C. gigas in the winter season (water temperatures below 16℃) in condition of equal body weight. Our results indicate that H. roretzi may have an advantage over C. gigas in food competition during the winter season when the two species are co-cultured.

모래층의 깊이에 따른 수직 및 수평적 완속여과의 처리효율에 관한 실험적 연구

金憫浩,李弘根 서울大學校保建大學院 1993 國民保健硏究所硏究論叢 Vol.3 No.1

The purpose od this study was to establish acceptable criteria for the design of the vertical slow sand filtration and the horizontal slow sand filtration as units in run area. The treatment efficiencies between vertical slow sand filtration and horizontal slow sand filtration under various conditions were investigated in this study. The main retsults of this study were as follows.. 1. There was no difference in the treatment efficiences or consumed KMnO₄, NH₃-N, NO₃-N, coliform and bacteria between vertical and horizontal filtration. 2. There was no difference in the treatment efficiences or consumed KMnO₄, NH₃-N, NO₃-N, turbidity, coliform and bacteria between vertical and horizontal filtrations with additional chlorination. 3. The treatment efficiencies were inproved in the vertical and horizontal filtrations when chlorination was added. 4. In the vertical and horizontal filtrations with additions, chlorination, the treatment efficiency reduced by depth of sand layer in order of 80cm, 60cm, 45cm. Accordingly, the depth of sand layer must be at least 60cm in simple piped water system. 5. Operating filtration for a long time, the horizontal filtration was more economical than the vertical filtration. When backwashing was operated to remove clogging accumlated on the sand layer, the decline of filtration rate could be prevented . Also, operation can be became for a longer time without sand washing.

Filtration-induced pressure evolution in permeation grouting

Zilong Zhou,Haizhi Zang,Shanyong Wang,Xin Cai,Xueming Du 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.75 No.5

Permeation grouting is of great significance for consolidating geo-materials without disturbing the original geo-structure. To dip into the filtration-induced pressure increment that dominates the grout penetration in permeation grouting, nonlinear filtration coefficients embedded in a convection-filtration model were proposed, in which the volume of cement particles in grout and the deposited particles of skeleton were considered. An experiment was designed to determine the filtration coefficients and verify the model. The filtration coefficients deduced from experimental data were used in simulation, and the modelling results matched well with the experimental ones. The pressure drop revealed in experiments and captured in modelling demonstrated that the surge of inflow pressure lagged behind the stoppage of flow channels. In addition, both the consideration of the particles loss in liquid grout and the number of filtrated particles on pore walls presented an ideal trend in filtration rate, in which the filtration rate first rose rapidly and then reached to a steady plateau. Finally, this observed pressure drop was extended to the grouting design which alters the water to cement (W/C) ratio so as to alleviate the filtration effect. This study offers a novel insight into the filtration behaviour and has a practical meaning to extend penetration distance.

하수 MBR공정에 있어서 막표면 유속과 여과저항

현길수 ( Kil-soo Hyun ) 한국수처리학회(구 한국수처리기술연구회) 2017 한국수처리학회지 Vol.25 No.4

Membrane fouling patterns in membrane bioreactor (MBR) include blockage of membrane pore, gel layer formation and sludge cake deposition on the membrane surface. Stirred dead-cell filtration has been widely used for fundamental studies on membrane fouling caused by soluble and colloidal matter during membrane filtration. In this study, the performance of MBR using a dead-end stirrer cell was carried out to investigate the characteristics of pollutants removal and membrane filtration resistance with hydraulic shear force on the surface of membrane module. Influent water qualities were on average <65 mgCOD/L, <21 mgT-N/L, and <6 mgT-P/L, <4500 mgMLSS/L, respectively. As a result, the membrane biofiltration achieved higher efficiencies of COD and T-P except T-N having lower efficiency <50% regardless of the hydraulic shear force. An increase in the hydraulic shear force resulted in a decrease in both transmembrane pressure (TMP) and total membrane filtration resistance. This suggests that higher hydraulic shear force is needed to improve membrane filtration resistance in operating a long-term filtration of MBR having a suitable permeate flux to enhance nitrogen removal efficiency.

다층 경사기능재료의 제조를 위한 Zr(Y,Ce)$O_2$ TZP/Mullite 현탁액의 가압여과

이상진,박상희,박홍채,전병세 한국세라믹학회 2000 한국세라믹학회지 Vol.37 No.7

Casting behavior of Zr(Y,Ce)O2 TZP/Mullite suspension during pressure filtration was investigated to prepare multi-layered Functionally Gradient Materials(FGM). The dispersion stabilities of each layer suspension were investigated by examination of zeta potential and viscosity. The each suspensions with 20 vol.% solid loading and 100 첸 of viscosity was prepared after fix of the dispersing agent (Sodium hexa-meta phosphate) and the binder (Hydroxyethyl cellulose), and then the cakes were formed at the 2.5 MPa~10.0MPa pressure range. The cake thickness of all suspensions was increased with the square root of time at the constant pressure, and the relations between filtration pressure(P)a nd dehydration rate (Q=dh/dt) showed that the flows of filtrates in the consolidated layers were laminar. The permeabilities were nearly constant during filtration, and kozeny constants(Kc) of the suspensions were 4.8~6.7. These valumes were seen as close to 5, which might be homogeneous particle packing during filtration. On the basis of those data, the multi layered compaction with 9 mm thickness and 52.5% green density was prepared by continuous pressure filtration.

하수처리장 방류수의 여과특성에 관한 연구

이용두,고인범,김현희 제주대학교 해양연구소 1997 해양자원연구소연구보고 Vol.21 No.-

This study was performed to investigated the removal efficiency of BOD and SS from the retreated water of sewage effluent by upflow filtration system. Flow rate of sewage effluent were 80m/day. 150m/day. 200m/day and 300m/day. The removal rate of SS was above 90%. and independent on the flow rate. However. BOD removal rate decreased with the flow rate increase. And removal rate of BOD was 40-60%. In the results of experiment, it was considered that the treated water was possible to use as the graywater because it was suitable to Flush Toilet, Springkle -Water. Cleaning Car. etc.

강변여과용 집수정의 산출유량 예측공식 비교

김승현(Seung-Hyun Kim),곽재혁(Jae-Hyeok Kwak) 대한환경공학회 2018 대한환경공학회지 Vol.40 No.7

강변여과용 집수정의 산출유량 설계에 적용되는 3가지 기법인 Milojevic식, Hantush식 그리고 수치해법을 비교하였다. 가상의 지층에 강변여과용 집수정을 설치하는 경우 이들 기법으로 예상되는 산출유량을 구했으며, 각각 5,972 ㎥/day, 5,286 ㎥/day 그리고 6,600 ㎥/day이었다. 이로부터 Hantush공식이 가장 보수적 예측임을 알 수 있었다. Milojevic과 Hantush공식은 실제 강변여과에서 일어나는 하상폐색을 고려할 수 없는 한계를 가진다. 따라서 하상폐색을 고려한 수치해법을 적용하는 것이 강변여과용 집수정 설계에서 최선의 방법이라 할 수 있을 것이다. In this study, the Milojevic formula, the Hantush formula, and the numerical method, which are the three different methods used to predict the production rate of collector wells in riverbank filtration, were compared. Given a collector well placed in a hypothetical geologic formation, the production rate of the collector predicted by each method was as follows: 5,972 ㎥/day by the Milojevic formula, 5,286 ㎥/day by the Hantush formula, and 6,600 ㎥/day by the numerical method. From these results, the Hantush formula appears to make the safest prediction. However, the Milojevic formula and the Hantush formula cannot take into account the clogging of riverbed which is inevitable in riverbank filtration. Therefore, for now the best method to apply in a collector well design in riverbank filtration is the numerical method with clogging layer included.

Analysis of Changes in the Glomerular Filtration Rate as Measured by the Cockroft-Gault Formula in the Early Period after Percutaneous Nephrolithotomy

Omer Bayrak,Ilker Seckiner,Sakip M. Erturhan,Sedat Mizrak,Ahmet Erbagci 대한비뇨의학회 2012 Investigative and Clinical Urology Vol.53 No.8

Purpose: We aimed to analyze the changes in kidney function during the postoperative early period caused by the application of percutaneous nephrolithotomy (PNL), which is commonly used in kidney stone surgery. Materials and Methods: PNL was performed in 80 patients (48 men, 32 women) with kidney stones. The mean age of the patients was 43.71 years (range, 18 to 71 years). Preoperative and postoperative values for stone size, glomerular filtration rate (GFR), serum creatinine, urea, electrolytes (Na, K, Cl), and Hb were compared in 80 patients in whom PNL surgery was performed. The formula of Cockroft-Gault was used to calculate the GFR during the early postoperative period (72 to 96 hours). Results: Statistically significant decreases after PNL were observed in average stone size (preoperative, 627.75±375.10 mm2; postoperative, 81.70±16.15 mm2), serum urea (preoperative, 38.40±17.26 mg/dl; postoperative, 33.28±16.98 mg/dl), and creatinine (preoperative, 1.03±0.53 mg/dl; postoperative, 0.97±0.55 mg/dl) and an increase was observed in GFR (preoperative, 104.30±37.30 ml/min; postoperative, 112.38±40.1 ml/min). No changes were detected in the serum electrolyte values (Na, K, Cl). Multiple access, operation time, and type of lithotripter did not have any significant effects on the change in the GFR. Conclusions: In light of our results, PNL for kidney stone operations appears to be a reliable and efficient method that provides recovery of kidney functions in the early post-operative period by increasing the GFR and with high stone-free rates. Purpose: We aimed to analyze the changes in kidney function during the postoperative early period caused by the application of percutaneous nephrolithotomy (PNL), which is commonly used in kidney stone surgery. Materials and Methods: PNL was performed in 80 patients (48 men, 32 women) with kidney stones. The mean age of the patients was 43.71 years (range, 18 to 71 years). Preoperative and postoperative values for stone size, glomerular filtration rate (GFR), serum creatinine, urea, electrolytes (Na, K, Cl), and Hb were compared in 80 patients in whom PNL surgery was performed. The formula of Cockroft-Gault was used to calculate the GFR during the early postoperative period (72 to 96 hours). Results: Statistically significant decreases after PNL were observed in average stone size (preoperative, 627.75±375.10 mm2; postoperative, 81.70±16.15 mm2), serum urea (preoperative, 38.40±17.26 mg/dl; postoperative, 33.28±16.98 mg/dl), and creatinine (preoperative, 1.03±0.53 mg/dl; postoperative, 0.97±0.55 mg/dl) and an increase was observed in GFR (preoperative, 104.30±37.30 ml/min; postoperative, 112.38±40.1 ml/min). No changes were detected in the serum electrolyte values (Na, K, Cl). Multiple access, operation time, and type of lithotripter did not have any significant effects on the change in the GFR. Conclusions: In light of our results, PNL for kidney stone operations appears to be a reliable and efficient method that provides recovery of kidney functions in the early post-operative period by increasing the GFR and with high stone-free rates.

실험실 규모의 Tankless 정수처리 시스템의수리학적 안정성 평가에 관한 연구

정우창 ( Woo Chang Jeong ),김관엽 ( Kwan Yeop Kim ) 한국수처리학회 2014 한국수처리학회지 Vol.22 No.6

In this study, the hydraulic stability of lab scale tankless water treatment system was evaluated. This system consists of dummy membrane filtrations, AC filter, backwashing pump, air compressor, supply pump, pressure and flow-rate control valves, water supply tank. The experiments were carried out with 4 cases related to the set-up of pressure, in-going flow-rate and closing status of upper valves of dummy membrane filtration. As the results of experiments, in the case of relatively low preset in-going flow-rate of 10 l/min. the pressure preset from 2.0 bar to 3.0 bar is increased, the flow-rate in the system was stable during the period of experiment but the pressure was very unstable. In the case of the in-going of 20 l/min, the flow-rate and pressure were slightly more stable than the case of the in-going of 10 l/min. In the partially closed case of upper valves of membrane filtrations, the fluid in the system flows with bigger pressure than in the completely opened case.

터널폐수 처리를 위한 여과공정의 최적화 연구

강용태 ( Yong Tae Kang ),송근관 ( Kune Kwan Song ),한상윤 ( Sang Yun Han ),손정호 ( Jeong Ho Sohn ),김연은 ( Yun Eun Kim ),배종환 ( Jong Hwan Bae ) 한국수처리학회 2011 한국수처리학회지 Vol.19 No.3

This experiment used to synthetic of tunneling wastewater with Biocube and fiber media. Filtration efficiency were operated at 0% of the compression rate. In addition, fiber media was changed to 0%, 15%, 30% of compression rate and 300m/day, 500m/day, 1000m/day of Lv in this period. Using of the filtration for treatment of the tunneling wastewater was compared filtration efficiency and backwash cycle of media. For characteristics of filter media, high quality treatment of media investigated compression and change of filtration efficiency. Also, high turbidity of tunneling wastewater examined spiked experiment. Fiber media backwash cycle was 4 times longer than Biocube, The smaller the compression ratio tended to be longer backwash cycle. Except for filtration rate of 1000m/day, removal of turbidity was exceeded 90%.