• Journal of Korean Society of Water and Wastewater
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• v.18 no.6
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• pp.715-723
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• 2004

The quantity of residuals generated from water treatment plants depends upon the raw water quality, dosage of chemicals used, performance of the treatment process, method of sludge removal, efficiency of sedimentation, and backwashing frequency. Sludge production by the physical separation of SS occurs under quiescent conditions in the primary clarifier, where suspended solids are allowed to settle and to consolidate on the clarifier bottom. Raw primary sludge results when the settled solids are hydraulically removed from the tank. The relative solid and liquid fractions of a slurry are most commonly described by the solids concentration, expressed as mg/L or percent solids. The purpose of the present investigation is to estimate a suitability on the design capacities of residuals treatment facilities by the quantity of dewatered sludge generated from water treatment plants.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.284-285
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• 2000

분산된 공기 기포에 의해 고형물을 제거하는 포말분리법은 30 $\mu\textrm{m}$이하의 미세 입자와 용존 고형물을 매우 효율적이면서도 경제적으로 운전을 할 수 있고 연속 운전이 가능하며 역세척이 필요 없다는 장점을 지니고 있다((Clarke and Wilson. 1983). 현재 사용되고 있는 포말분리장치는 공기의 공급방식과 유체과 공기의 접촉방향에 따라 항류 공기구동식(counter current air driven type, CCAD), 고속 폭기식(high speed aeration type, HSA), 벤튜리식(venturi type) 등이 있으나 현재까지 우리나라에서 연구되어 오고있는 포말분리 장치는 공기구동 방식이 전부이다. (중략)

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.250-250
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• 2015

ASR(Aquifer Storage Recharge) 또는 ASTR(Aquifer Storage Transfer Recharge)과 같은 직접적인 지하수 인공함양기법은 대수층을 활용하여 수자원을 공급하고 관리하기 위한 적극적인 방안으로 고려될 수 있다. 그러나 하천 수와 같은 지표수를 주입할 경우 부유물질 그리고 생물학적 및 화학적 물질 등에 의해 주입정 내 스크린 부분에서 폐색이 발생할 수 있으며, 이로 인해 인공함양 시설의 운영에 있어 부정적인 영향을 미칠 수 있다. 주입정 내 폐색을 저감시키기 위해서는 주기적인 주입정 역세척과 같은 방법이 적용될 수 있다. 본 연구에서는 물리적인 폐색을 발생시키는 부유물질이 포함되어 있는 지표수를 주입할 경우 주입정 내에서의 부유물질의 거동을 수치적 기법을 통해 모의 및 분석을 수행하였다. 본 모의에서는 부유물질을 구성하는 입자들은 세 가지 서로 다른 비중(0.8, 1.3, 1.5)을 가지며, 각각의 경우에 대해 입자분포는 정규분포를 통해 발생시켰다. 비중이 서로 다른 부유입자들은 동시에 주입정 내로 주입된다고 가정하였다. 모의는 비정상상태 조건으로 수행되었으며, 시간에 따라 변화되는 주입정 내 부유물질의 거동에 대해 분석하였다.

• Journal of Korean Society of Transportation
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• v.23 no.8 s.86
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• pp.19-29
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• 2005

The purpose of this study is to categorize subway station areas in Seoul by rail use characteristic. Most studies have categorized rail-oriented areas, based on land use patterns or/and urban spatial structure in Korea as well as the United States. However, the land use pattern of a subway station area tends to form by the real use of subway users since the latter plays an important role in forming the former. Therefore, the study is expected to contribute to the planning and policy of subway station areas in Seoul by analyzing characteristics of rail use. To achieve the purpose, the study uses a factor analysis for rail use, in terms of time of the day and day of the week. and then conducted a multidimensional scaling method to identify a relation of the real pattern to land use pattern. The results find that the Seoul subway station areas are categorized into residential, commercial and recreational, and office-centered ones. Furthermore, unlike the results of previous studies, the study identifies that many station areas have the mixed characteristics of economic activities. That is, they form more than a centered function such as residential and commercial, residential and office, commercial and office, residential, commercial and office. In addition, the study identifies that there is a close connection between rail use and land one. In short, identification of these mixed characteristics for subway station areas is expected to contribute to developing the planning and development method of TOD in Korea.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.3
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• pp.230-236
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• 2016

Economic growth has increased the living standards around the world. Water pollution, in particular, is a public relations issue because it poses a direct threat to everyone's lives. As of recently, the production of taste and odor (T&O) compounds has been a common problem in the water industry. The adsorption process using granular activated carbon (GAC) has been the most widely used process. The objectives of this study were to evaluate the microorganisms before and after the backwashing of GAC and to identify the species of the microorganisms found. Five dominants microorganisms were confirmed after the microfiltration process from backwashing of GAC, and the dominant bacterial species were found to be ${\beta}$-proteobacterium species, Porphyrobacter donghaensis, Polaromonas rhizophaerae, Hydrogenophaga species, and Pseudonocardia species. However, when UV treatment after microfiltration was performed, Hydrogenophaga species and Psedonocardia species were eliminated. Herein, I conclude that the UV treatment post microfiltration process is more efficient than microfiltration process alone. The findings of this study may provide useful information regarding the management of microfiltration process.

• Membrane Journal
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• v.18 no.4
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• pp.325-335
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• 2008

In this study, we used multi-channels ceramic membrane having larger permeate volume per unit time rather than tubular membrane. The hybrid process for advanced drinking water treatment was composed of granular activated carbons (GAC) packing between module inside and outside of multi-channels microfiltration membrane. Instead of natural organic matters (NOM) and fine inorganic particles in natural water source, modified solution was prepared with humic acid and kaolin. Kaolin concentration was fixed at 30mg/L and humic acid was changed as $2{\sim}10\;mg/L$ to inspect effect of organic matters. As a result, both resistance of membrane fouling ($R_f$) and permeate flux (J) were highly influenced by concentration of humic acid. Also, in result of water-back-flushing period (FT) effect, the shorter FT was the more effective to reduce membrane fouling and to enhance permeate flux because of frequent water-back-flushing. However, the optimal FT condition was 8 min when operating costs were considered. Then, the hybrid process using multi-channels ceramic membrane and GAC was applied to lake water treatment. As a result, average treatment efficiencies in our experiment using the hybrid process were 98.02% for turbidity, 75.64% for $UV_{254}$ absorbance, 7.18% for TDS and 84.73% for $COD_{Mn}$.

• Membrane Journal
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• v.22 no.5
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• pp.359-368
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• 2012

For hybrid water treatment of high turbidity water, we used the hybrid module that was composed of photocatalyst packing between tubular membrane outside and module inside. Photocatalyst was PP (polypropylene) bead coated with $TiO_2$ powder by CVD (chemical vapor deposition) process. Water back-flushing of 10 sec was performed per every period of 10 min to minimize membrane fouling for modified solution was prepared with humic acid and kaolin. Resistance of membrane fouling ($R_f$) decreased as humic acid concentration changed from 10 mg/L to 2 mg/L, and finally the highest total permeate volume ($V_T$) could be obtained at 2 mg/L, which was the same with the previous results. Then, treatment efficiencies of turbidity and humic acid were above 98.9% and 88.7%, respectively. As results of treatment portions of UF, UF + $TiO_2$, and UF + $TiO_2$ + UV processes, turbidity was treated little by photocatalyst adsorption, and photo-oxidation. However, treatment portions of humic acid by adsorption and photo-oxidation were 2.5% and 12.3%, respectively. Compared with the previous results, treatment portions of humic acid by adsorption and photo-oxidation were different depending on membrane material and pore size. As simplified the process, the membrane fouling resistance after 180 minutes' operation ($R_{f,180}$) increased and the final permeate flux decreased a little.

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

• Membrane Journal
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• v.31 no.5
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• pp.343-350
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• 2021

In this study the suction pressure was measured with respect to operational time by submersing the multi-bore capillary membrane module in membrane bioreactor(MBR). The hexagonal shape capillary module which has the nominal pore size of 0.2 ㎛, outer diameter of 6.4 or 4.2 mm was immersed in MLSS 8,000 mg/L active sludge aqueous solution, and confirmed changes with respect to permeation flux and air flow rate. It was operated by the filtration/relaxation(FR), FR with backwashing(FR/BW), and sinusoidal flux continuous operation(SFCO) modes. The suction pressure for the SFCO and FR modes was lower at 30 and 50 L/m²·hr, respectively. In addition, the suction pressure of the module with a small outer diameter was relatively low. The suction pressure of a large outer diameter was greatly increased, but it could be reduced by more than 40% by backwashing.

• Journal of Navigation and Port Research
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• v.30 no.3 s.109
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• pp.241-245
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• 2006

Displayed result that handle particle contaminant and hydrospace organism included a number of ballast that is happened in ship using automatic back washing filter. Reason that removes first contaminant that is included in number of ballast is that heighten processing effectof after processing processof the filter. Another advantage is to drop off the solids with controlling revolution of drum screen in pretreatment filtration process. The fact that it is easy to attach and detach a several type of screen for getting the expected water quality is another advantage. Filter rotation speed of filtration filter could be expose by 35mmHg more than 60 rpm and filter consecutively filtration pressure is 40.5mmHg in 20 rpm and 40 rpm are 36.6mmHg. Filtration system removal aquatic organism over $70{\mu}min$ ballast water. This study shows that the filtration treatment system has a potential for the treatment of ballast water.