Source identification and characterization of the accumulating non-biodegradable organics in Korean reservoirs

Kim, Sungwon,Hong, Seungkwan,Kim, Geonha,Sohn, Jinsik,Choi, Euiso Elsevier 2008 Journal of environmental management Vol.88 No.4

<P><B>Abstract</B></P><P>An increase in the chemical oxygen demand (COD) has been noticed in most Korean reservoirs. Therefore, this research systematically investigated the causes of organic accumulation. Samples of soil affecting the quality of water of reservoirs were collected at various sources and analyzed for their organic characteristics. The COD to biochemical oxygen demand (BOD) ratio was used as the key parameter in the evaluation of non-biodegradable (NBD) organic accumulation in the reservoirs. Soil samples containing plant roots were agitated, with the supernatant showing COD/BOD ratios of less than 2.8, while those of the composted tree leaves were greater than 5.0, suggesting that humic substances produced in forest areas are a major cause of NBD organic accumulation in reservoirs. In addition, the organic fractionation of the leachate from leaching tests showed that of the various types of hydrophobic natural organic matter (NOM), the larger molecular weight humic acid makes a greater contribution than fulvic acid to the increase in the NBD COD in Korean reservoirs.</P>

Molecular Epidemiology of Ciprofloxacin-Resistant Escherichia coli Isolated from Community-Acquired Urinary Tract Infections in Korea

Kim Bongyoung,Seo Mi-Ran,Kim Jieun,Kim Yeonjae,Wie Seong-Heon,기모란,Cho Yong Kyun,Lim Seungkwan,Lee Jin Seo,Kwon Ki Tae,이혁,Cheong Hee Jin,Park Dae Won,Ryu Seong Yeol,Chung Moon-Hyun,Pai Hyunjoo 대한감염학회 2020 Infection and Chemotherapy Vol.52 No.2

Background: Escherichia coli is the predominant causative pathogen for community-acquired urinary tract infections (UTIs), and the increase in fluoroquinolone-resistant E. coli is of great concern in Korea. The objectives of this study were to investigate the genotypic characteristics and molecular epidemiology of ciprofloxacin-resistant (CIP-R) E. coli isolated from community-acquired UTIs in Korea. Materials and Methods: E. coli samples isolated from the blood or urine were collected from patients with community-acquired acute pyelonephritis aged 15 years and more who were admitted to 12 Korean hospitals from 1st April 2010 to 29th February 2012. Phylogenetic typing, multilocus sequence typing, and molecular characterization of β-lactamase and plasmidmediated quinolone resistance determinants were performed for CIP-R E. coli isolates. Results: A total of 569 E. coli isolates were collected, and 122 (21.4%) isolates were CIP-R isolates. The most prevalent sequence type (ST) was ST131 (28.7%, 35/122), followed by ST393 (14.7%, 18/122), ST1193 (13.1%, 16/122), ST38 (9.0%, 11/122), and ST405 (8.2%, 10/122). The antimicrobial resistance rates of ST131 to cefepime (22.9%, 8/35), ST38 to gentamicin (100%, 11/11), and ST405 to cefotaxime (66.7%, 6/9) were significantly higher than the resistance rates of all other STs combined. Notably, 40% (4/10) of ST405 clones produced extendedspectrum β-lactamases and were co-resistant to trimethoprim/sulfamethoxazole. aac(6′)-1b-cr (20%, 7/35) and CTX-M-14 (40%, 4/10) were more frequently observed in ST131 and ST405 compared with other clones, respectively. Conclusions: Among the CIP-R uropathogenic E. coli isolates in this study, ST131, ST38, and ST405 were specifically associated with antimicrobial resistance.

Osmotically enhanced dewatering-reverse osmosis (OED-RO) hybrid system: Implications for shale gas produced water treatment

Kim, Jungwon,Kim, Jungbin,Kim, Junghyun,Hong, Seungkwan Elsevier 2018 Journal of membrane science Vol.554 No.-

<P><B>Abstract</B></P> <P>Managing shale gas produced water (SGPW) is one of the greatest challenges for shale gas industry due to its high salinity and water volume. Osmotically enhanced dewatering (OED) has great potential for treating SGPW because of its higher water recovery and lower energy consumption. This study systematically investigated the effects of operating conditions on OED performance through numerical simulation of membrane modules. The simulation results first showed that OED achieved higher water recovery over forward osmosis (FO) due to less internal concentration polarization (ICP). Water recovery could be higher with decreasing feed flow fraction, increasing normalized membrane area, and increasing hydraulic driving force fraction. It was also demonstrated that OED-RO hybrid process was able to yield more water with similar energy efficiency as one-stage RO, for SGPW of 28.5 g/L total dissolved solids (TDS) under realistic conditions considering inefficiency associated with pump and energy recovery device (ERD). Lastly, to validate our findings, OED experiments were performed with pre-treated real SGPW as a feed solution, and exhibited good agreement with the simulation results. Specifically, water recovery was achieved up to 67% with a high rejection rate of over 97% for most ions at a hydraulic pressure of 30 bar. Our modeled and experimental observations suggest that the OED-RO process can be an energy-efficient process in concentrating high salinity wastewater.</P> <P><B>Highlights</B></P> <P> <UL> <LI> OED process at module-scale was simulated for treating SGPW with high salinity. </LI> <LI> OED exhibited higher water recovery over FO due to less ICP. </LI> <LI> OED-RO yielded more water with the similar energy efficiency as one-stage RO. </LI> <LI> OED was able to extract water up to 67% from real SGPW with a pressure of 30 bar. </LI> <LI> SGPW treatment by OED-RO agreed well with the simulation results. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Analysis of an osmotically-enhanced dewatering process for the treatment of highly saline (waste)waters

Kim, Jungwon,Kim, David Inhyuk,Hong, Seungkwan Elsevier 2018 Journal of membrane science Vol.548 No.-

<P><B>Abstract</B></P> <P>The dewatering of highly saline (waste)waters by typical osmotic membranes, such as reverse osmosis (RO) or forward osmosis (FO), was significantly improved by a novel process in which an osmotic pressure gradient across the membrane is eliminated or reduced by increasing osmotic pressure in the permeate side. In this work, the concept of an osmotically enhanced dewatering (OED) process was fundamentally analyzed via conceptual modeling and verified experimentally under various hydraulic and osmotic pressure conditions. No or less osmotic gradient across the membrane resulted in higher water recovery than RO. Larger water flux was also produced than FO because the loss of osmotic driving force by internal concentration polarization (ICP) was greatly reduced. For instance, a series of experiments demonstrated that water flux of 1.2 LMH was obtained at low hydraulic pressure of 15bar when a feed of 2.4M NaCl was dewatered by the OED process. In addition, membrane characteristics (A, B, S) were optimized by modeling, and further examined experimentally using typical NF and FO membranes. Lastly, less reverse solute diffusion ensured a product of high quality after dewatering, suggesting that this process can be applied to not only highly saline shale gas produced water treatment, but also protein and pharmaceutical enrichment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An osmotically enhanced dewatering was newly proposed for highly saline waters. </LI> <LI> Feed osmotic pressure was offset by increasing osmotic pressure in permeate side. </LI> <LI> No osmotic gradient across the membrane resulted in higher water recovery than RO. </LI> <LI> Less reverse solute diffusion ensured a product of high quality after dewatering. </LI> <LI> Membrane characteristics (A, B, S) were examined and optimized for OED process. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

E 모빌리티 안전사고 감소를 위한 서비스 시나리오 및 제품 디자인 연구 : 서비스디자인 프로세스를 중심으로

SeungKwan Kim,HyunJeong Kim,Hyunsung Park 한국서비스디자인학회 2020 서비스디자인융합연구 Vol.4 No.1

Evaluation of ethanol as draw solute for forward osmosis (FO) process of highly saline (waste)water

Kim, Jungwon,Kim, Junghyun,Lim, Jihun,Hong, Seungkwan Elsevier 2019 Desalination Vol.456 No.-

<P><B>Abstract</B></P> <P>In the study, ethanol was evaluated for its potential as a draw solution in forward osmosis (FO) in terms of performance for treating highly saline (waste)waters and energy requirements for regeneration. When compared to NH<SUB>4</SUB>HCO<SUB>3</SUB> (a thermolytic draw solution) ethanol exhibited significantly higher osmotic pressure and significantly easier regeneration. In FO experiments using commercial TFC FO membranes, the ethanol draw solution exhibited a water flux comparable to that of NH<SUB>4</SUB>HCO<SUB>3</SUB> at equivalent osmotic pressure albeit a relatively high reverse solute flux (RSF) due to its volatility. The modeling prediction based on membrane transport properties obtained from the FO experiments revealed the critical role of the ethanol permeability of the membrane in the overall FO performance, thereby suggesting the necessity of a higher water-ethanol selective membranes for the extensive application of the ethanol draw solution for the treatment of highly saline wastewater. Easy-regeneration of the ethanol draw solution was also demonstrated based on experimental results obtained using laboratory scale vacuum distillation at room temperature and exergy analysis of the integrated system. The results indicated that the regeneration process required an estimated 8.8 kWh/m<SUP>3</SUP>, thereby supporting the feasibility of ethanol as a potent draw solution for FO application of highly saline waters.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ethanol as a draw solution in FO was investigated for treating high saline water. </LI> <LI> High osmotic pressure and easy-separability of ethanol were experimentally verified. </LI> <LI> Reduced RSF of ethanol was predicted to be critical to improving FO performance. </LI> <LI> The ethanol was easily reconcentrated by vacuum distillation with low energy. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Recovery of water and minerals from shale gas produced water by membrane distillation crystallization

Kim, Junghyun,Kim, Jungwon,Hong, Seungkwan Elsevier 2018 Water research Vol.129 No.-

<P><B>Abstract</B></P> <P>Shale gas produced water (SGPW) treatment imposes greater technical challenges because of its high concentration of various contaminants. Membrane distillation crystallization (MDC) has a great potential to manage SGPW since it is capable of recovering both water and minerals at high rates, up to near a zero liquid discharge (ZLD) condition. To evaluate the feasibility of MDC for SGPW treatment, MDC performance indicators, such as water recovery rate, solid production rate (SPR) and specific energy consumption (SEC), were systematically investigated, to our knowledge for the first time, by using actual SGPW from Eagle Ford Shale (USA). The main operating parameters including feed cross-flow velocity (CFV) and crystallization temperature (T<SUB>Cr</SUB>) were optimized by performing a series of MDC experiments. The results reported that water and minerals were effectively recovered with 84% of recovery rate and 2.72 kg/m<SUP>2</SUP>day of SPR under respective optimal operating conditions. Furthermore, the scale mechanism was firstly identified as limiting factor for MDC performance degradation. Lastly, SEC of MDC was estimated to be as low as 28.2 kWh/m<SUP>3</SUP> under ideal optimal operating conditions. Our experimental observations demonstrated that MDC could sustainably and effectively recover water and mineral with low energy consumption from SGPW by optimizing operating condition.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MDC was newly proposed for shale gas produced water (SGPW) management. </LI> <LI> MDC could effectively recover both water and minerals from SGPW. </LI> <LI> T<SUB>Cr</SUB> and CFV were optimized for water and solid production as well as energy consumption. </LI> <LI> Mineral recovery including CaCO<SUB>3</SUB>, NaCl from SGPW was accelerated at low T<SUB>Cr</SUB>. </LI> <LI> Crystal particle transfer and secondary nucleation at high CFV caused scaling in MD. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Application of membrane distillation crystallization (MDC) process for shale gas produced water (SGPW) treatment with zero liquid discharge (ZLD)

Junghyun Kim,Jungwon Kim,Seungkwan Hong 대한환경공학회 2015 대한환경공학회 학술발표논문집 Vol.2015 No.10

관광 레포츠용 E 모빌리티 서비스의 이용패턴 연구 및 제안 : 제주도 지역 관광을 중심으로

HyunJeong Kim,SeungKwan Kim,Hyunsung Park 한국서비스디자인학회 2020 서비스디자인융합연구 Vol.4 No.1

과산화수소/에탄올 단일추진제 추력기 연소 시험

백승관(Seungkwan Baek),정우석(Woosuk Jung),김주원(JuWon Kim),김예현(Yehyun Kim),정준영(Junyeong Jeong),권세진(Sejin Kwon) 한국추진공학회 2018 한국추진공학회 학술대회논문집 Vol.2018 No.12