• Journal of Soil and Groundwater Environment
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• v.19 no.4
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• pp.62-69
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• 2014

In the results of monitoring nitrate concentration in more than 8,000 groundwater wells around agro-livestock, the average and maximum nitrate concentration was 9.4 mg/L and 101.2 mg/L, respectively. Since about 31% of the monitoring wells was exceed the quality standard for drinking water, nitrate control such as remediation or source regulation is required to conserve safe-groundwater in South Korea. Typical nitrate-treatment technologies include ion exchange, reverse osmosis, and biological denitrification. Among the treatment methods, biological denitrification by indigenous microorganism has environmental and economic advantages for the complete elimination of nitrate because of lower operating costs compared to other methods. Major mechanism of the process is microbial reduction of nitrate to nitrite and nitrogen gas. Three functional genes (nosZ, nirK, nirS) that encode for the enzyme involved in the pathway. In this work, we tried to develop simple process to determine possibility of natural denitrification reaction by monitoring the functional gene. For the work, the functional genes in nitrate-contaminated groundwater were monitored by using PCR with specific target primers. In the result, functional genes (nosZ and nirK) encoding denitrification enzymes were detected in the groundwater samples. This method can help to determine the possibility of natural-nitrate degradation in target groundwater wells without multiplex experimental process. In addition, for field-remediation application we selected nitrate-contaminated site where 200~600 mg/L of nitrate is continuously detected. To determine the possibility of nitrate-degradation by stimulated-natural attenuation, groundwater was sampled in two different wells of the site and nitrate concentration of the samples was 300 mg/L and 616 mg/L, respectively. Fumarate for different C/N ratio was added into microcosm bottles containing the groundwater to examine denitrification rate depending on carbon concentration. In the result, once 1.5 times more than amount of fumarate stoichiometry required was added, the 616 mg/L of nitrate and 300 mg/L of nitrate were completely degraded in 8 days and 30 days. The nitrite, byproduct of denitrification process, was also completely degraded during the experimental period.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.755-758
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• 2005

This paper describes the novel immunoassay sensing system for a portable clinical diagnosis system. It consists of a bead cage reactor and a CMOS integrated biosensor. It showed the simple and easy antibody coating method on beads by flow-through avidin biotin complex technology in a microfluidic device. It showed just 90 nL sample consumption and good result for the application of alpha feto protein. The bead cage reactor has the role of the antibody coating, antigen binding and enzyme linking for the electrochemical sensing method. The CMOS biosensor consists of ISFET (ion selective field effect transistor) biosensor and temperature sensor for detecting pH that is the byproduct of enzyme reaction. The sensitivity is 8 $kHz/^{\circ}C$ in a temperature sensor and 33 mV/pH in a pH sensor. After filling the 15 um polystyrene beads in bead cage, antibody flowed and reacted to beads. Subsequently, the biotinylated antigen flowed and bound to the antibody and GOD (glucose oxidase)-avidin conjugate flowed and reacted to the biotin of the biotinylated antigen. After this reaction process, glucose solution flowed and reacted to the GOD on beads. The hydrogen was generated by glucose-GOD reaction. And it was detected by the pH sensor.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.32-32
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• 2017

2012년부터 도입된 "신재생에너지 의무할당제(RPS)"로 인하여 500MW이상의 설비 용량을 갖춘 발전소의 경우 총발전량에서 일정 비율을 신재생에너지로 공급하여야 한다. 이러한 신재생에너지 중 농업부산물은 목질계 바이오매스의 한 종류로 '탄소중립(Carbon Neutral)' 연료이며 기존 화석연료와 혼소로 활용 할 수 있는 장점을 지니고 있다. 그러나 낮은 발열량, 운송 및 저장비용, 일정하지 않은 연소특성의 문제로 인하여 대부분 노지에 방치되거나 버려지고 있다. 이러한 버려지는 농업부산물을 효율적으로 활용하기 위한 방법 중 하나로 반탄화(Torrefacation) 처리가 대두되고 있다. 반탄화 처리 시, 발열량이 증대되며, 저장과 이송에서의 이점을 갖게 된다. 그러나, 반탄화는 공정 과정중 질량손실에 따른 에너지 총량의 감소한다는 단점을 가지고 있다. 이에 본 연구에서는 효율적인 반탄화공정을 위한 질량감소모델을 제시 하고자한다. 승온 속도(heating rate)를 $7.5^{\circ}C/min$, $15^{\circ}C/min$, $22.5^{\circ}C/min$의 조건에서의 열중량분석 결과를 토대로 속도모델식(Arrhenius method, Ingraham & Marrier method 등)을 적용하여, 반응속도상수를 도출하였다. 이 반응속도상수를 이용하여 질량감소 모델을 정립하였고, 이를 실험결과와 비교, 검증하였다.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.6
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• pp.653-658
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• 2008

The bacteria responsible for the reduction of ammonia concentration in a food-wastewater treatment facility were isolated and their characteristics were analyzed. The isolated bacteria were closely related to the bacteria belonging to genus Citrobacter, Enterobacter, Buttiauxella, Shigella, and Aeromonas, which were found in gut of animals, indicating the isolated bacteria may come from the butchery-byproduct of pigs which is the main component of wastewater. When we monitored the concentration of nitrite and nitrate in the process, it was relatively constant, indicating the isolated bacteria reduce ammonia concentration through ammonia assimilation. Based on the removal efficiency of ammonia by the isolated bacteria, we concluded that they play a role in the reduction of odorous compounds.

• KIEAE Journal
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• v.5 no.1
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• pp.3-10
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• 2005

Indoor air quality (IAQ) is recognized as a byproduct of industrialization that took place in the 20th century. The great attention to IAQ has been gained since 1980s, and led to numerous research studies that have mainly made in the developed countries. As the development of residential environment in Korea enters in the process of qualitative growth, IAQ has viewed as one of the core issues in the society, and research in relation to IAQ has been implemented until now in the fields of engineering and medical science. It is widely known that the sources and effects of indoor air pollution have been various, and IAQ research with multidisciplinary approaches is required. Nevertheless, few research embedded into a socio-behavioral approach to identifying interventive measures of residents and analyzing their choices is made. The purpose of this study is to examine the use of an interactive measure of residents in apartments that is air purification with phytoncide available in the market, and to investigate their self-reported effects of the air purifying substance on sick building syndrome symptoms. This study utilizes a field experiment design with pre-test and post-test, and the experiment is conducted in a natural field setting. A total of 87 test subjects from 32 households with already sick building syndrome are drawn via internet, and the participation is solely voluntary. The participants receive and use the air purifying substance, and are asked to use it continuously for two weeks and identify their self-reported symptoms of before- and after-use. The research findings indicate that air purification using phytoncide is effective to alleviate their symptoms in relation to sick building syndrome. Also it is noted that the participants report that the use of the air purification causes the positive impacts on their daily life. Further research is needed that compares the group with only humidifier and evaluates the mid-term and long-term use of the air purification and its effects.

• Journal of the Society of Naval Architects of Korea
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• v.39 no.1
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• pp.61-72
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• 2002

The flaring system of FPSO burns out the byproduct natural gas. The thermal loading due to radiative heat of flaring gas leads to undesirable thermal-stresses on itself. Nowadays it needs to understand the amount of thermal loading of flaring system since the requirement for the safety of the flaring system. However, few studies have been performed on the thermal environment and radiative heat flux on the FPSO flaring system. Present study suggests a procedure to model the thermal environment and a FEA process to analyze the temperature distribution and thermal stresses of FPSO flaring system. In order to get the temperature distribution, the radiative heat conditions and convective heat conditions are included in the heat transfer analysis. By making the use of temperature obtained through heat transfer analysis, the thermal stress analyses are performed. The results of the present study can be used to design the flaring system and determine the heat shield in the flaring system.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.2
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• pp.58-66
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• 2012

Brewers grain is a byproduct of beer brewing and consists primarily of grain husks, pericarp, and fragments of endosperm. Although this material is consumed by animals and used as fertilizer, a large amount of brewers grain is simply discarded. Therefore, new methods for utilizing this fibrous resource should be pursued. In this study, we examined the potential utilization of brewers grain as an additive in the paperboard industry by determining the chemical composition of brewers grain and the physical properties of brewers grain powders after grinding with two types of grinders. We found that brewers grain had a lower holocellulose content and higher lignin content and intermediate ash content when compared to other biomass materials, and did not contain any contaminants that would interfere with the papermaking process. Particles had a higher fiber length, less fiber width, and narrower shape factor distribution when ground by a blender type grinder than by a pin crusher type grinder. The blender type grinder was concluded to make regular brewers grain particles appropriate for papermaking.

• Journal of the Korea Concrete Institute
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• v.21 no.6
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• pp.729-735
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• 2009

In this study, it is experimentally verified a feasibility of the wasted phosphogypsum ($CaSO_4/H_2O$) that is a byproduct from the phosphoric acid process of manufacturing fertilizers can be applied as an admixture in slag cement. For the test, phosphogypsum is modified as dihydrate, hemihydrate, type III anhydrite, and type II anhydrite, and then chemical characteristics and mechanical properties of various slag cements containing above mentioned gypsum materials were analyzed. The test results show that the gypsum made at high temperature has better quality with decrease of water-soluble phosphoric acid ($S-P_2O_5$) which has an effect on the quality of cement. And type II anhydrite shows superior quality in terms of drying shrinkage and the compressive strength of cement paste with hemihydrate at 56 days is higher than other gypsum material.

• KSBB Journal
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• v.29 no.3
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• pp.165-178
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• 2014

Statistical medium optimization has been carried out for the production of succinic acid in anaerobic fermentations of Actinobacillus succinogenes. Succinic acid utilized as a precursor of many industrially important chemicals is a fourcarbon dicarboxylic acid, biosynthesized as one of the fermentation products of anaerobic metabolism by A. succinogenes. Through OFAT (one factor at a time) experiments, corn steep liquor (CSL), a very cheap agricultural byproduct, was found to have significant effects on enhanced production of succinic acid, when supplemented along with yeast extract. Hence, using these factors including glucose as a carbon/energy source, interactive effects were investigated through $2^n$ full factorial design (FFD) experiments, showing that the concentration of each component (i.e., glucose, yeast extract and CSL) should be higher. Further statistical experiments were conducted along the steepest ascent path, followed by response surface method (RSM) in order to find out optimal concentrations of each constituent. Consequently, optimized concentrations of glucose, yeast extract and CSL were observed to be 180 g/L, 15.08 g/L and 20.75 g/L respectively (10 g/L of $NaHCO_3$ and 100 g/L of $MgCO_3$ to be supplemented as bicarbonate suppliers), with the estimated production level of succinic acid to be 92.9 g/L (about 3.5 fold higher productivity as compared to the initial medium). Notably, the RSM-estimated production level was almost similar to the amount of succinic acid (92.9 g/L vs. 89.1 g/L) produced through the actual fermentation process performed using the statistically optimized production medium.

• Korean Chemical Engineering Research
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• v.46 no.2
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• pp.369-375
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• 2008

To achieve zero-emission, one of the main goals of an eco-industrial park (EIP), it is needed to develop an effective water exchange network. The network includes various subsystems and decision making processes, which make the modeling process extremely complicated. Agent-based modeling was used to simulate water exchange network in an EIP. Firm agents were created based on the behavior pattern of firms, and an agent-based model (ABM) was made with the agents, showing the growth of the exchange network. An existing steel and iron making industrial park was chosen as a case study, and the ABM model shows eco-efficient behavior with a decreased environmental cost. Water reuse network based on the ABM model results in 35% decrease of the fresh water supply and 50% reduction of the wastewater generation in EIP. A case study shows that agent-based model can be a powerful tool in modeling and designing complex eco-industrial parks, especially when a part of the system needs to be changed.