Environmental and Plant Engineering Research Institute

Goyang, South Korea

Environmental and Plant Engineering Research Institute

Goyang, South Korea
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Lee S.,Environmental and Plant Engineering Research Institute | Ahn C.H.,Environmental and Plant Engineering Research Institute | Song H.M.,Environmental and Plant Engineering Research Institute | Park J.R.,Environmental and Plant Engineering Research Institute | Joo J.C.,Hanbat National University
Water (Switzerland) | Year: 2017

The aim of this study was to evaluate the newly-developed juvenile fish shelter (JFS) for its ability to increase prey survival and to improve species diversity in a freshwater ecosystem. An experiment was performed in an outdoor large-scale mesocosm three times from 2011 to 2012 by comparing the responses to adjustment as a function of the volume of JFS in the control and experimental groups. Analysis results of the environmental monitoring over three periods indicated only minor differences in the physicochemical characteristics of the water quality and phyto- and zoo-plankton biomass, thereby enabling a comparative analysis of the feeding ecology. However, the water temperature exhibited large fluctuations, ranging from 16.4 to 27.6 °C, and high water temperature conditions (Period 1, 25.6 ± 2.0 °C) enhanced the predation activity of the piscivorous fish Coreoperca herzi (C. herzi, size 89 ± 4 mm). Statistically, the survival rates of the prey fish, Rhynchocypris oxycephalus (R. oxycephalus, size 29 ± 1 mm), with JFSs were greater by 35.9%-46.7%, and improved as the patch volume of JFS increased. Based on both experimental observations and statistical analysis, the JFS developed in this study could reduce the chances of predator-prey encounters, minimize prey vulnerability, and thereby increase prey survival rates. © 2017 by the authors.

Lee C.-K.,Hanyang University | Lee C.-K.,Research South, Inc. | Park C.,Hanyang University | Choi J.-S.,Environmental and Plant Engineering Research Institute | Kim J.-O.,Hanyang University
Water Science and Technology | Year: 2017

A pilot-scale pressured hollow-fiber microfiltration (MF) process as pretreatment for the reverse osmosis process was studied and operated under various conditions to assess the relative influence of backwashing, chemical enhanced backwashing (CEB), and bag filter application. The pilot plant process consisted of backwashing but without the CEB or the bag filter as the first step of the research. As the second step of the research, the impact of the backwashing on permeability recovery was assessed at different intervals followed by the influence of CEB on flowrate recovery. Results from operating the pilot-scale hollow-fiber membrane modules for more than 1 year have demonstrated that the appropriate pore size of bag filters was 25-50 μm and the optimized backwashing process was every 30 minutes with 25 mg/L of NaOCl, and CEB with an interval of 10 cycles with the use of 100 mg/L NaOCl. © IWA Publishing 2017.

Kim C.-K.,Environmental and Plant Engineering Research Institute | Yoon J.-Y.,Hanyang University
Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering | Year: 2017

Passive micromixers are one of the parts used for the mixing of two or more fluids in micro-electro-mechanical system devices, and they have been developed for various types. Fluid mixing in microscale devices is essential in microfluidic applications; however, it is difficult to mix fluids in microchannels due to the slowness of the molecular diffusion process at the microscale. In this study, optimization of the groove shape geometries of a micromixer using response surface design was performed, and the mixing performance was investigated through a numerical analysis applied with the passive scalar method. The most useful parameters were determined to be the geometric parameters of optimization, such as groove depth, groove length, distance between grooves, and groove angle. Response surface design, a design of experiments technique, was applied to the optimization procedure. The mixing index and pressure drop are important factors for evaluating the micromixer performance. Through the response surface design, this study aims to affect the groove shape of a passive micromixer. Consequently, it was concluded that the groove length and distance between grooves improved the mixing performance and decreased the pressure drop. In addition, optimal models were proposed for the passive micromixer. © IMechE 2015.

Kim D.,Konkuk University | Lee K.,Environmental and Plant Engineering Research Institute | Park K.Y.,Konkuk University
Journal of Industrial and Engineering Chemistry | Year: 2016

In this study, hydrothermal carbonization of the main lignocellulosic components was investigated as a method of renewable solid biofuel production from biomass. Hydrothermal carbonization of cellulose, xylan, and lignin was experimentally conducted between 150 °C and 280 °C, and the chemical and fuel properties of the resulting biochars were investigated. The properties of each of the three biomass components were greatly improved by hydrothermal carbonization and were similar to coal-like fuel substances; an increase in fixed carbon and carbon contents was also observed. Furthermore, by assessing carbon recovery and energetic retention efficiency, we could establish the optimum condition for hydrothermal carbonization of biomass to produce energy. The C/O and C/H ratios of all of the obtained biochars were decreased and found to be similar to those of lignite and sub-bituminous coal. The calorific values of the biochars were between 23–26 MJ/kg at a reaction temperature of 220 °C. The results of this study indicate that hydrothermal carbonization can be used as an effective method to generate highly energy-efficient renewable fuel resources from biomass. © 2016 The Korean Society of Industrial and Engineering Chemistry

Ki S.J.,Gwangju Institute of Science and Technology | Lee S.W.,Environmental and Plant Engineering Research Institute | Kim J.H.,Gwangju Institute of Science and Technology
Desalination and Water Treatment | Year: 2015

Statistical models play an important role in elucidating the dynamic behaviors of surface water quality, given limited data on a large scale. In this study, we examine alternative approaches to develop regression models that predict fecal coliform (FC) concentrations in a river using different methods for selecting important variables provided by a self-organizing map (SOM). The raw data used as input to the SOM included 11 water quality, 6 meteorological, and 7 land use parameters that were monitored along the Yeongsan River in Korea on various time scales (from daily to half a decade) during 1996–2008. In both test and validation data sets, (multiple) regressions using backward elimination were compared against regression models via forced entry, which included a set of ranked variables simultaneously based on four indices in the SOM (i.e. structuring index, relative importance, cluster description, and Spearman’s rank correlation). Results showed that the SOM effectively illustrated the complex relationship between FC and the remaining variables in the entire data set. This relationship was seen more clearly in homogeneous clusters, indicating that the regression models became more robust in each subdivided group. While the original backward elimination model (R2 = 0.66) had much better performance than the models with four indices (R2 = 0.40–0.45) in the test data set, its performance (R2 = 0.42) was quite comparable to the relative importance model (R2 = 0.38) in the validation data set. Based on this preliminary study, we recommend further investigation of these indices for a reliable regression analysis, as the t values currently used for the variable selection in regressions provide only a locally optimal solution for the final model. The proposed methodology, if verified successfully, would be useful in developing early warning models that control mortality or disease rates of fishes in high-density aquafarms via water quality. © 2015 Balaban Desalination Publications. All rights reserved.

Shafique M.,Korean University of Science and Technology | Lee D.,Korean University of Science and Technology | Kim R.,Korean University of Science and Technology | Kim R.,Environmental and Plant Engineering Research Institute
International Journal of Control and Automation | Year: 2016

This study evaluated performance for runoffmanagement of the Blue roof and Green blue roof comparing monitoring data measured at two low impact development (LID) facilities and control roof in Seoul metropolitan area. From the results these two roofs proved as suitable stormwater management practices in urban areas. For this purposes, Blue roof and Green-blue roof were installed at Seoul City Hall Annex Seosomun and Cheong-un middle school respectively. The data used for this study were collected during the actual storm events of more than 30 mm/hr and 60 mm/hr rainfall intensity in July and September 2014 at green blue roof and blue roof. During different actual storm events, rainfall runoffoutflow was measured from blue roof was 0.45 l/s as compared to common roof where outflow was 1.55 l/s. While on the other hand, the outflow from green blue roof was 0.1 l/s to as compared to control roof where the runoffoutflow was 0.3 l/s. Results also indicated the peak flow reduction in both types of roofs. From the results, it was found that Green blue roof is capable of handling effectively long duration rain events than blue roof. However, the blue roof is inexpensive than green blue roof and suitable option for retrofitting in urban areas. These results also revealed that Blue roof and Green blue roof could be applied to urban buildings as the suitable management practices for rainfall runoffmanagement in urban areas. At the end, from theoretical analysis some suggestions are also made which could be apply for the more safe sustainable drainage system of an urban area. © 2016 SERSC.

Shafique M.,Korean University of Science and Technology | Kim R.,Korean University of Science and Technology | Kim R.,Environmental and Plant Engineering Research Institute
Ecological Chemistry and Engineering S | Year: 2015

A low impact development (LID) is an alternative land development approach for managing stormwater that has been recommended instead of the traditional stormwater design. The main purpose of LID is to reduce the impact of development on water related problems through the use of stormwater management practices that infiltrate, evaporate, or harvest and use stormwater on the site where it falls. In recent years, more research has been carried out on the individual practice of LID such as bioretention, pervious pavements, rain garden and grassed swales. Nowadays LID practices have been successfully used to manage stormwater runoff, improve water quality, protect the environmental and hydrological aspects of the developed areas. Bioretention cells have been effectively used in retaining large volumes of runoff and pollutants on site. Pervious pavements have been extremely effective practice in infiltrating stormwater runoff as early as possible as rain fall on site and store a large quantity of water. Nowadays, sand ditch a new water harvesting technique is used that significantly reduces runoff and sediment losses and increases infiltration and soil loss. This paper highlights evidence in the literature regarding the beneficial uses of LID practices and encourage to adopt these practices for environmental friendly construction and sustainable development in the world. © 2015 Muhammad Shafique et al., published by De Gruyter Open 2015.

Kim S.Y.,Environmental and Plant Engineering Research Institute | Yoon Y.H.,Environmental and Plant Engineering Research Institute | Kim K.S.,Environmental and Plant Engineering Research Institute | Kim K.S.,Korea Advanced Institute of Science and Technology
International Journal of Environmental Science and Technology | Year: 2016

An activated carbon-impregnated cellulose filter was fabricated, and the capacity to remove dust and volatile organic compounds was evaluated in a laboratory. The adsorption capacities for benzene, toluene, ethyl benzene and m-xylene gases were compared by an adsorption isotherm test conducted as a preliminary test, showing that m-xylene and benzene were the most and least favorable for adsorption onto activated carbon, respectively. Cellulose filters were made with four levels of activated carbon contents, and dust removal was performed with all of the filters showing 99 % and higher efficiencies stable with a small variation during the experiment. Activated carbon content of 5 g in the unit filter area (125 g/m2) was found optimum for benzene, toluene, ethylbenzene and m-xylene removal, as it appeared that higher than 5 g activated carbon content was unnecessary for the improvement of its capacity. With increasing benzene, toluene, ethylbenzene and m-xylene loading, the highest removal rates were determined as 0.33–0.37 mg/cm2 s for as short as 0.0046 s of air filter residence time. The rapid removal was possible because of the high surface area of the activated carbon-impregnated cellulose filter provided by powdered activated carbon, which is distinguished from the granular form in conventional activated carbon towers. As fixed within a cellulose scaffolding structure, the powdered activated carbon performed excellent benzene, toluene, ethylbenzene, and m-xylene adsorption (98.9–100 %), and at the same time, particular matters were removed in average 99.7 % efficiency after being filtered through the cellulose filter sheet. © 2016, Islamic Azad University (IAU).

Shin H.,Environmental and Plant Engineering Research Institute | Han S.,Environmental and Plant Engineering Research Institute | Hwang H.,Environmental and Plant Engineering Research Institute
Desalination and Water Treatment | Year: 2016

The operation and management of social infrastructures can create significant headaches for municipal governments. Sewer systems are no exception, and prioritizing plans and strategies for asset management is usually adopted as a cost-effective solution. The condition assessment, which is an important element of asset management, provides current information about the condition of municipal facilities. Condition assessments were first used by Water Research Centre (WRc) in the UK, the country with the longest history of sewer management, and are now widely used in many countries. Korea uses the condition assessment protocol developed by the Ministry of Environment (MOE), but as this protocol does not fully reflect the underground environment in Korea, the assessments and judgments are ambiguous. The sewer condition assessment and rehabilitation decision-making (SCARD) program developed by this study is based on the MOE protocol with the defect items, score, and condition grading system modified in consideration of the type of buried pipelines in Korea. To compare the assessment results produced by these two protocols, a closed-circuit television inspection was performed on 11 km of sewer pipeline in the sampled area in P city. The inspection indicated that SCARD set a higher score of structural defects common to both protocols for items that affect the collapse mechanism (fracture, damage, etc.). The amount of pipeline that received a grade of five for internal condition rating of identified structure defects was 45% with the MOE protocol, which was much higher than the 0.6% given with SCARD. This result showed that there was a big difference between the two protocols in condition grade evaluations of structural defects. In the future, the findings of this study can be used to develop an objective protocol reflecting actual sewer pipeline conditions. © 2016 Balaban Desalination Publications. All rights reserved.

Kim K.-S.,Environmental and Plant Engineering Research Institute | Kim K.-S.,Korea Advanced Institute of Science and Technology | Kim S.,Environmental and Plant Engineering Research Institute | Jun T.H.,Korea Advanced Institute of Science and Technology
Water, Air, and Soil Pollution | Year: 2015

The dust removal performance of two types of modified electrode electrostatic precipitator systems was evaluated and compared with that of a conventional aluminum plate electrode using laboratory-scale experiments. In the novel electrode systems, the electrode surface was coated with activated carbon using a mixed slurry containing carbon black, polyvinyl acetate, and methanol. The modification of the electrode surface improved dust precipitation by increasing the specific capacitance of the electrode. The modification also lowered the electrode's resistance and increased its specific surface area. The optimum electrode spacing and electric voltage supply were determined using batch-type tests. In addition, dielectric insulators were applied as a partition between the oppositely charged electrodes equipped with the modified electrode plates. Multi-layered office paper cut to the same size as the electrodes was used as an insulating material. The addition of the insulator resulted in excellent improvement in the dust removal performance by minimizing the back-corona discharge phenomenon as well as doubling the dust collecting surface. Continuous dust removal tests with the three electrode systems revealed that whereas the conventional aluminum electrode exhibited 54 % dust removal, the activated carbon (AC)-coated system showed 85 % and AC-coated + insulator system showed 90 % and higher dust removal efficiency. © 2015 Springer International Publishing Switzerland.

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