기존 정수시스템의 전염소 대체처리법에 관한 연구

현길수,최정우,강용태 대한상하수도학회 2000 상하수도학회지 Vol.14 No.4

The prechlorination in the drinking water treatment system have produced chlorination by-products such as trihalomethane(THM). For the improvement of the drinking water treatment efficiencies as well as the control of chlorination by-products, this research was performed to find out an adequate pretreatment process for the Nakdong river water using biological aerated filter (BAF) and ozonation as an alternative of prechlorination. For experimental conditions, ozone dosage and contact time of preozonation ranged from 1 to 2 ㎎/L and from 2 to 5 minutes, respectively. The flow rate of the BAF process ranged from 100 to 120 m/day. Based on the results of this research, the removal rates of preozonation and the BAF processes were 23% and 35% for KMnO_4 consumed, less than 10% and 15% for THM formation potential (THMFP), 40% and 32% for color, 41% and 45% for ABS, and less than 10% and more than 90% for NH_4-N, respectively. Based on above results, the preozonation was effective in reducing color, Fe, and Mn, but not effective on NH_4-N removal. On the other hand, the BAF process was very effective in removing NH_4-N and a little more effective than preozonation in removing ABS, KMnO_4 consumed, and THMFP.

Evaluation of Seasonal Aldehydes Removal from River Water Using Various Processes in a Water Treatment System

현길수 한국수처리학회 2023 한국수처리학회지 Vol.31 No.3

In order to comply with current and anticipated water quality regulations and to control the rising levels of micropollutants in river water, a number of water treatment systems employ ozonation and granular activated carbon (GAC) processes. However, ozonation produces undesirable and harmful disinfection by-products (DBPs) such as aldehydes. In this study, batch and continuous experiments were conducted to investigate the factors influencing the distribution and formation of aldehydes in river water and to investigate the behavior of total aldehydes (TA) in water treatment system processes. The mean influent concentrations of dissolved organic carbon (DOC) and TA were 3.1±0.8 mg/L and 62.6±21.3 ㎍/L, respectively, while TA and bromide levels in the river water increased with a decrease in the water flow rate and temperature. In pre-and post-ozonation processes, the TA concentration increased with a higher ozone dosage and pH. In particular, the concentration of TA with both pre-ozonation and during winter was higher than with post-ozonation and during summer. In the coagulation and sedimentation processes, polyaluminum sulphate organic magnesium (PSOM) coagulation resulted in slightly lower TA removal than polyaluminum silicate sulphate (PASS) coagulation. Both the high removal of turbidity and low pH with different coagulants were achieved in the order of PSOM>PASS>PACl. TA levels were significantly lower at the top of the sand and biological activated-carbon beds.

Evaluation of Bromide removal with Seasonal Level in the Processes of Advanced Water Treatment System

현길수 한국수처리학회 2023 한국수처리학회지 Vol.31 No.5

As the bromide (Br−) containing water is used in drinking water treatment, the most major concern is the formation of brominated disinfection by-products (Br-DBPs). Among them, bromate (BrO3−) has been well proved to be more carcinogenic and mutagenic than other analogues. In this study, batch and continuous experiments were conducted to investigate the factors that influence the seasonal distribution and formation of bromate and bromide in the Nakdong River, which is used as a drinking water source. In addition, the behaviors of bromate and bromide as ozonation by-products (OBPs) in the processes of drinking water treatment systems were investigated. The mean influent concentrations were 3.1±0.7 mg/L for dissolved organic carbon (DOC) and 58.6±31.5 ug/L for bromide. As a result, bromide levels in the Nakdong River increased with decreasing water flow rate and decreasing water temperature. In pre- and post-ozonation, the concentration of OBPs increased with increasing bromide level, ozone dosage, and pH value. In particular, the concentration of OBPs forming in both pre-ozonation and winter was relatively higher than in both post-ozonation and summer. In terms of coagulation and sedimentation, polyaluminum sulfate organic magnesium (PASOM) coagulation resulted in slightly less OBP removal than polyaluminum silicate chloride (PASCl) coagulation. Moreover, bromate was effectively reduced in a three-month-old biological activated carbon filter.

휴믹질과 탁질혼합액처리에 따른 응집.침전이 막여과에 미치는 영향

현길수 한국수처리학회 2023 한국수처리학회지 Vol.31 No.6

. Humic and turbid substances in river water used for drinking can foul membrane filtration. This study explores the effect of coagulation-settler-membrane system on water treatment, specifically with synthetic water containing turbid and humic substances. The experiments involved C-S using a jar test with alum as a coagulant and a multi-layer membrane filtration process using a stirred dead-cell filter. Influent water qualities ranged from turbidity < 30 NTU to CODMn < 20 mg/L. Increasing the alum dose reduced turbidity but did not affect organic matter.Permeate flux decreased with alum dosage in a mixed water, while it did not decreased for settled water. The transmembrane pressure (TMP) build-up of the membrane gradually increased with the alum dose compared to that with no alum dose. The dual-layer microfiltration (DLMF) membrane demonstrated higher removal efficiencies for turbid and organic matter than the single-layer microfiltration (SLMF) membrane. The DLMF membrane slightly outperformed the SLMF membrane in removing turbid and organic matters. The relative permeate flux (J/Jo) and TMP build-up of SLMF membrane was approximate 20% lower than that of DLMF membrane.

응집-분리막시스템 여과시 혼탁수가 막오염에 미치는 영향

현길수 한국수처리학회 2024 한국수처리학회지 Vol.32 No.1

. Humic substances and turbid particles in water sources intended for drinking water can contribute to membrane fouling during membrane filtration processes. This study investigates the effects of filtration characteristics in a coagulation-membrane system on water treatment, particularly using synthetic water containing kaolin (< 60 mg/L) as a colloid and humic acid (< 5 mg/L) as organic matter. Coagulation was performed using a jar test with alum (< 10 gm/L) as a coagulant, followed by a membrane filtration process using a stirred dead-cell filter. The experiments involved increasing the driving pressure and stirring strength at an alum dose of 5 mg/L. The results demonstrated a significant reduction in kaolin levels with increased driving pressure and stirring strength, whereas humic acid remained unaffected. The remaining permeate flux (J/Jo) in the membrane process decreased with increasing driving pressure and decreasing stirring strength. Specifically, at a driving pressure of 30 kPa, J/Jo was 10% lower than that at 50 kPa, whereas at a stirring strength of 100 rpm, J/Jo was 10% higher than that at 50 rpm. Notably, water containing only kaolin exhibited a relatively lower remaining permeate flux than water containing both humic acid and alum with kaolin. The results indicate that both humic acid and alum contribute to particle aggregation in water, but residual alum increases membrane fouling. Therefore, optimal permeate flux can be achieved using lower driving pressure and higher stirring strength at an appropriate coagulant dosage.

Effect of Multi-layer Membrane Configuration on Filtration Efficiency and Resistance in Treating Water

현길수 한국수처리학회 2019 한국수처리학회지 Vol.27 No.2

The objective of this research is to investigate the effect of membrane configuration on filtration efficiency and resistance in treating a synthetic water containing turbid and humic substance. The experiments of coagulation-flocculation/sedimentation(CF/S) process using jar test with alum as coagulant and membrane configuration (single-layer microfiltration (SLMF) and dual-layer microfiltration (DLMF) membranes) using stirred dead-cell filter were carried out. Influent water qualities were in the range of turbidity <110 ntu and CODMn <40 mg/L, respectively. Based on the results, the increase of alum dosage in CF/S/SLMF system decreased considerably turbid matter, but not organic matter, while the build-up of transmembrane pressure (TMP) gradually raised with increase of alum dose compared to that of alum dosage < 2mg/L. Without CF/S process, direct filtration of SLMF membrane using high turbid water (<100ntu) resulted in a considerable decrease of permeate flux. The TMP and resistance build-up of DLMF membrane was approximate 40% lower than that of SLMF membrane, while the efficiencies of DLMF membrane in reducing turbidity and COD achieved slightly higher than that of SLMF membrane.

MBR공정에서 투과속도와 수온이 막오염에 미치는 영향

현길수 한국수처리학회 2024 한국수처리학회지 Vol.32 No.2

. Both permeate flux and water temperature are critical factors that influence aerobic membrane bioreactors (MBR), affecting treatment rates and microbial composition. This experiment assessed the membrane fouling characteristics of aerobic MBRs with varying water temperatures (10-25℃) and permeate fluxes (10-80 L/m2.h). In the membrane filtration process, a dead-end stirred cell with a working volume of 400 mL was used as MBR. The mixed liquid used in this experiment was obtained from an anoxic-selector-aerobic MBR system with a hydraulic retention time of 6 h. As a result, the organic removal efficiency exceeded 80% at permeate fluxes of <10 L/m2h and exceeded 85% at water temperatures of >15℃. The efficiencies of NH4-N and NO3-N removal exceeded 65% and 45%, respectively, at permeate fluxes of <10 L/m2h and water temperatures of >15℃. Regardless of the water temperature, organic and nitrogen reductions at 10 L/m2h were 30% higher than those at 50 L/m2.h. For membrane fouling, the transmembrane pressure (TMP) at permeate fluxes of <10 L/m2.h and water temperatures of <10℃ was approximately 30% lower than that at permeate fluxes of >20 L/m2.h and water temperatures of >15℃. Specifically, TMP at a permeate flux of 10 L/m2.h was two times lower than that at a permeate flux of 30 L/m2.h, indicating that TMP development was affected by permeate flux compared to water temperature.

Treatment of Wastewater with High Organic Loadings Using Granular Sludge in Sequencing Batch Reactor

현길수,이석주,최정우 한국수처리학회 2008 한국수처리학회지 Vol.16 No.1

The objectives of this research to evaluate the effects of aerobic granular sludge SBR on the treatment of the wastewater with high level of organic loadings was to investigate the characteristics of operating conditions of the reactor and the characteristics of organic and nutrient removal with influent loadings. As a results, the pH values increased in the range of 6.8 to 8.5 during a cycle. DO concentrations were in the range of 6-8mg/L and decreased slightly at the initial operating period as a results of initial oxygen consumption due to the removal of considerable amount of organic at initial reaction. Within operating time of two weeks, MLSS concentration ranged from 500 to 4480 mg/L and sludge volume index (SVI) were in the range of 25 to 8 mL/g at steady state. At influent concentrations of 400-700mg COD/L, approximate <30mg TN/L, and <16 mg TP/L, the percentage of organic and nutrient removals were in the range of 45 to 77% for COD, 46.7 to 71.0% for TN, and 67.3 to 74.0% for TP, respectively. It seems that aerobic granulation is not sensitive to the organic loading rate. Although the effect of organic loading rate on the formation of aerobic granules is insignificant, the physical characteristics of aerobic granules depend on the organic loading rate.

논문 / 상수원수의 고도처리를 위한 생물막여와 공법의 처리특성

현길수,김영진 한국수처리학회 1993 한국수처리학회지 Vol.1 No.1

N/A

논문 / 쓰레기 매립지 침출수의 고도처리

현길수 한국수처리학회 1993 한국수처리학회지 Vol.1 No.2

N/A