• Journal of Korean Society of Environmental Engineers
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• v.39 no.10
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• pp.556-560
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• 2017

This research carried out to evaluate the disadvantage of pre-chlorination and the effect of polyamine as coagulant aids for treating the blooming water with Microcystis sp.. Pre-chlorination on blooming water makes the colony of Microcystis sp. to the smaller size. Coagulation with polyamine advanced treatment efficiency not only turbidity but also particulate matters especially less then $5{\mu}m$ size for the blooming water compared with using alum alone. Particle count was more sensitive than turbidity on water quality management of settlement and filtrate.

• Membrane Journal
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• v.19 no.3
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• pp.203-211
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• 2009

In this study, we used the hybrid module that was composed of granular activated carbons (GAC) packing between module inside and outside of tubular ceramic microfiltration membrane for advanced drinking water treatment. Instead of natural organic matters (NOM) and fine inorganic particles in natural water source, modified solution was prepared with humic acid and kaolin. $N_2$-back-flushing of 10 sec was performed per every period of 10 min to minimize membrane fouling and to improve permeate flux (J). As a result, resistance of membrane fouling ($R_f$) decreased and J increased as concentration of humic acid changed from 10 mg/L to 2 mg/L step by step, and finally the highest total permeate volume ($V_T$) could be obtained at 2 mg/L. Then, treatment efficiencies of turbidity and $UV_{254}$ absorbance were excellent above 99.36% and 97.19%, respectively, but that of $UV_{254}$ absorbance for only microfiltration without GAC at 10 mg/L of humic acid was decreased a little as 90.84%.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.8
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• pp.579-587
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• 2014

Various kinds of micro organic pollutants have frequently been detected from a water system. Therefore, it is considered to be very important part in the drinking water treatment system. And the research about removal process and processing efficiency have been being conducted briskly. In this study, the removal efficiency was evaluated using advanced water treatment process and nanofiltration process. The removal efficiency of nanofiltration process was very different according to physical and chemical characteristics of materials. The molecular weight of cutoff was the most influential factor in the removal efficiency. And when pKa value was higher than pH of raw water or Log Kow value was below 2, the removal efficiency of material was decreased. In case of oxidation reaction, the bigger the molecular weight of material was and the more hydrophobic a material was, the less oxidation reaction occurred. And the removal efficiency was decreased. Most unoxidized materials were removed by absorption. And the more actively oxidation reaction occurred by $H_2O_2$, the more absorption reaction increased.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1285-1294
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• 2000

In this study, we investigated the possibility of the elimination of suspended solid and the factors affecting effluent water quality, and the amount of treated water, using the SS removal equipment adapted capillary-syphon phenomenon. Treated water quantity decreased as the accumulation time and the increase of head of capillary syphon, whereas the effluent water quality was improved. At coagulant dosage 0, 0.45, $1.82mg/{\ell}$ (as $Al^{+3}$) and limiting flux $107{\ell}/m/day$. turbidity of treated water was 2, 1, 0.5 NTU in each case. During operating period 15~17 days, the amount of washing water was just used 0.5~0.7% of the amount of treating water. So it is expected that coagulation & sedimentation and rapid filtration process can be replaced with the SS removal equipment adapted capillary-syphon phenomenon in water purification process.

• Journal of Life Science
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• v.17 no.10
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• pp.1374-1380
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• 2007

The development of polymerase chain reaction (PCR) technology has the potential to solve for isolating pathogenic microorganisms from environmental samples than traditional plate counting methods. We have been detected pathogenic bacteria from raw water and water treatment process in Busan metropolitan city by PCR method. According to the result of survey from July 2004 to October 2005, 80 out of 92(87.0%) were positive for bacterial pathogens in raw water samples and positive rate of Shigella spp., Yersinia spp., Salmonella spp. and Legionella spp. were 46.2%, 40.7%, 17.6% and 9.9%, respectively. Pathogenic bacteria in raw water was mainly distributed through the lately Autumn to the winter and more highly detected Maeri than Mulgum region. During the period of survey in water treatment process, Shigella spp. was highly detected but all of bacterial pathogens were entirely removed after in post-ozonation step. These suggest that waters supplied in Busan metropolitan city may be safe against the pathogenic bacteria.

• Membrane Journal
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• v.25 no.6
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• pp.503-514
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• 2015

In this study, water purification system without coagulant was consisted of F/A and membrane to produce purified water which only uses physical treatment without coagulant. Because the use of coagulant has a possibility remaining of hazardous aluminum with our health. Especially, the Filtralite was reviewed the possibility to remove turbidity and organic material. It was found that the turbidity removal rate of Filtralite was 83~84%. It show that Filtralite has similar efficiency to sand-filter. But Filtralite has higher 50% removal rate of organic material than sand-filter due to well-developed pore on the surface of it. So, Filtralite could be used to substitute the sand-filter for the F/A process due to higher removal rate. And also coupled with activated carbon in F/A process, TMP was increased by TOC value. To prevent increasing TMP, media that has outstanding organic adsorption ability should be used.

• Journal of Korea Water Resources Association
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• v.57 no.3
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• pp.151-164
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• 2024

In water treatment plants supplying potable water, the management of chlorine concentration in water treatment processes involving pre-chlorination or intermediate chlorination requires process control. To address this, research has been conducted on water quality prediction techniques utilizing AI technology. This study developed an AI-based predictive model for automating the process control of chlorine disinfection, targeting the prediction of residual chlorine concentration downstream of sedimentation basins in water treatment processes. The AI-based model, which learns from past water quality observation data to predict future water quality, offers a simpler and more efficient approach compared to complex physicochemical and biological water quality models. The model was tested by predicting the residual chlorine concentration downstream of the sedimentation basins at Plant, using multiple regression models and AI-based models like Random Forest and LSTM, and the results were compared. For optimal prediction of residual chlorine concentration, the input-output structure of the AI model included the residual chlorine concentration upstream of the sedimentation basin, turbidity, pH, water temperature, electrical conductivity, inflow of raw water, alkalinity, NH₃, etc. as independent variables, and the desired residual chlorine concentration of the effluent from the sedimentation basin as the dependent variable. The independent variables were selected from observable data at the water treatment plant, which are influential on the residual chlorine concentration downstream of the sedimentation basin. The analysis showed that, for Plant, the model based on Random Forest had the lowest error compared to multiple regression models, neural network models, model trees, and other Random Forest models. The optimal predicted residual chlorine concentration downstream of the sedimentation basin presented in this study is expected to enable real-time control of chlorine dosing in previous treatment stages, thereby enhancing water treatment efficiency and reducing chemical costs.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.168-168
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• 2016

BDD(Boron Doped Diamond) 전극은 전위창이 넓고, 다른 불용성 전극에 비해 산소발생과전압이 높아 물을 전기화학적인 방법으로 처리하는 영역에 있어 매우 효과적일 뿐만 아니라, 전통적인 불용성 전극에 비해 전극 표면에서 수산화 라디칼(-OH)과 오존(O3)의 발생량이 월등히 높아 수처리용 전극으로서의 유용성이 매우 높다. 따라서 BDD 전극을 수처리용 전극에 사용하는 경우 수산화 라디칼(-OH)과 오존(O3), 과산화수소(H2O2) 등과 같은 산화제의 생성은 물론이고, 염소(Cl2)가 포함되어 있는 전해액에서는 차아염소산(HOCl)이나 차아염소산이온(OCl-)과 같은 강력한 산화제가 발생되어 전기화학적 폐수처리, 전기화학적 정수처리, 선박평형수 처리 등의 분야에 널리 활용될 수 있다. 본 연구에서는 상온 및 상압에서 운전이 가능하고 난분해성 오염물질 제거 효과가 뛰어난 전기화학적 고도산화공정(Electrochemical Advanced Oxidation Process, EAOP)에 적합한 대면적의 BDD 전극을 개발하고 자 하였다. 이러한 BDD 전극의 성막 방법으로는 필라멘트 가열 CVD, 마이크로파 플라즈마 CVD, DC 플라즈마 CVD 등이 널리 알려져 있는데 최근에는 설비의 투자비가 비교적 저렴하고, 대면적의 기판처리가 용의한 필라멘트 가열 화학기상증착법(Hot Filament Chemical Vapor Deposition, HFCVD)이 상업적으로 각광을 받고 있다. 따라서 본 연구에서는 HFCVD 방법을 이용하여 반응 가스의 투입비율, BDD 박막의 두께, 기판의 재질 등에 따른 여러 가지 성막 조건들을 검토하여 $100{\times}100mm$ 이상의 대면적 BDD 전극을 개발하였다. Fig. 1은 본 연구를 통하여 얻어진 BDD 전극의 표면 및 단면 SEM이다.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.6
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• pp.663-669
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• 2005

The aim of this study was to investigate the ozone decay pattern for the effective application of ozone in drinking water treatment. In order to measure the ozone decomposition in water, ozone measuring instrument was developed with flow injection analysis (FIA) method. From the result of continuous residual ozone concentration in water, it was confirmed that the ozone decay pattern was divided with instantaneous ozone demand(I.D) and pseudo first-order rate($k_c$) phases, which were influenced by the variation of ozone dose. The empirical model obtained from I.D and $k_c$ values enabled us to predict the residual ozone concentration according to the reaction time, showing the high correlation between model and experimental values. The concentration of OH radical and $R__{ct}$ could be indirectly measured by OH radical probe compound. In both I.D and $k_c$ phases, the production pattern of OH radical could be observed, which was also affected by the variation of ozone dose. Finally, it was confirmed that the ozone consumption rate was varied according to the each drinking water treatment process and seasoning. Therefore, the optimum position and dosage of ozone have to be selected by considering various factors.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.1
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• pp.58-63
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• 2009

Dissolved air flotation (DAF) process is generally considered more effective than sedimentation process in raw water containing algae, humus materials, and low density particles. This study presents the treatment efficiencies by the coagulation and flocculation conditions at a drinking water treatment plant using a laboratory tester and the full scale DAF pump system. The full scale DAF pump system (F-DAF) in this study had a capacity of 5,000 $m^3$/d and a hydraulic surface loading of 10 m/hr. F-DAF in D drinking water treatment plant was continuously operated to determine the operational performance and pretreatment (mixing and coagulation) conditions. Results in the laboratory experiment showed that the optimum coagulant (PSO-M) doses required to 2.7~4.5 mL/$m^3$/NTU with raw water turbidity from 13.8 NTU to 56.3 NTU. F-DAF in the optimum coagulant dosage could be operated in effluent turbidity of 1 NTU or below for a month.