• Journal of the Korean Society of Hazard Mitigation
• /
• v.11 no.2
• /
• pp.81-86
• /
• 2011

Without a special mineral resources in Korea, such as petrochemical industries, electronics and automotive industries to supply the basic material, but remains a key industry locations. Gongjeongsang dealing with hazardous materials, such as a fire or explosion hazard, and from this site sangjonhae safety regulations to protect human and material disaster prevention activities are focused. However, depending on the actual implementation of standardized safety regulations as necessary if not originally intended, proper objectivity and reliability of safety regulations, as well as impaired resulting in a waste of public and private administrative power and petrochemical industries and the competitiveness of the entire drop factor will. Accordingly, this study petrochemical plant is applied to a representative safety regulations, items for their safety are needed and these regulations as being implemented that was identified, according to a study, some of the need for regulation and implementation both in terms of reliability was low.

• Journal of Convergence for Information Technology
• /
• v.11 no.4
• /
• pp.122-129
• /
• 2021

As the total organic carbon (TOC) becomes a new water quality standard as an organic matter (OM) index for public sewage treatment facilities (PSTFs) in Korea from 2021, a comparison study needs to be conducted by examining the correlation between TOC and the existing OM indices (DOC, BOD5, CODMn, CODCr). 500 PSTFs were categorized by process configuration and capacity, and correlation between OM indices in influent and effluent was analyzed. The CODMn/TOC showed higher correlation than other OM indices. This results can be used to basic data for various research associated with TOC.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.28 no.4
• /
• pp.69-75
• /
• 2020

This study was conducted to improve the solid-liquid separation efficiency of clarifiers. To do so, the study did a bio-flocculation experiment simply by controlling the stirring speed (rpm) and baffle angle of a clarifier on a lab scale, but without using a coagulant. For the purpose of the experiment, the feed wall of a clarifier was so improved that a baffle could be installed on the clarifier. Then, it was ensured to change its stirring speed (to 0.0rpm, 0.6rpm, and 1.2rpm), with the angle fixed at 10°. As a result, it was found that concentration efficiency increased by 2.0%, and effluent removal efficiency (SS concentration) by 7.8%, at a stirring speed of 0.6ppm. This indicates the bio-coagulation efficiency of sludge increased with changing stirring speeds. Then, the baffle angle of the sedimentation unit was changed to analyze how the changed baffle angle would affect the sedimentation of sludge. As a result, it was found that the compression of sludge interface was very effective at a baffle angle of 20°. It is hoped that these experimental findings will be useful in improving the sedimentation efficiency of circular clarifiers.

• Journal of the Korean Geotechnical Society
• /
• v.22 no.5
• /
• pp.27-37
• /
• 2006

Cemented Sand and Gravel (C.S.G) method has become increasingly popular in Japan and throughout the world as a construction method and material. This method is favorably used for cofferdam and large dam because a quarry and aggregate plant facility can be diminished. Also, this method can reduce construction cost, work duration and destruction of environment. In this paper, a methodology for C.S.G mix design based on so-called soil mechanics approach is proposed for trapezoid-shaped dam. The methodology consists of selection of a suitable aggregate, introduction of compaction method, processing to prepare standard specimens, and determination of mix portions. Also, unconfined compressive strength tests and large triaxial compression tests are performed. From the results of the test, correlation equation among strength, elastic modulus and unit cement is proposed.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2021.06a
• /
• pp.21-21
• /
• 2021

효과적인 하천의 유지 및 관리를 위해서는 준설과 각종 수리시설물 영향에 의한 하상변화 양상을 파악하는 것이 필수적이다. 일반적으로 하상변화 분석을 위해서는 하도지형, 하상재료, 유사량 등 현장계측자료가 요구되지만, 대하천 주요 지점이나 정기조사가 이루어지는 일부 지점이 아니라면 하상변화 분석을 위한 현장계측자료가 부족한 실정이다. 따라서 하천을 효율적으로 관리하고 운영하기 위해서는 장래 하상변화 양상을 분석하는데 필요한 충분한 공간적 해상도를 가지는 지형정보와 하상재료 및 유사량 계측자료가 필요하며, 이를 기반으로 중기 및 장기 하상변화를 예측하고 그에 따른 하천관리계획을 수립하게 된다. 본 연구에서는 하도지형 현황자료의 공간해상도가 하상변화의 양적 규모 평가에 미치는 영향을 평가해보고자 한다. 현행 낙동강과 같은 대하천 하도의 하상변동 관련된 조사 및 연구 분석에는 500 m 간격을 기준으로 설정된 기준상의 측선 자료를 이용한다. 본 연구방법으로는 기존 측선을 이용하여 산정된 체적하상변동량과 기준 측선 사이 구간에 대해 측정된 보조측선에 대한 지형정보를 함께 활용하여 산정한 체적하상변동량을 비교함으로써, 하도지형자료의 해상도에 따른 체적변동량 산정결과의 차이와 영향을 평가하였다. 비교를 통해 기존 측선기준 하상변동량 산정치가 실체 하상변동량과 큰 차이를 보일 수 있음을 확인하였다. 따라서 효과적인 하천의 유지 및 관리와 계획 수립을 위해서는 보다 높은 공간해상도의 하도지형자료를 기반으로 한 하상변동 평가 및 분석의 정확도 제고가 필요한 것으로 판단된다. 향후 본 연구 성과를 장래의 하상변화조사의 기초자료로 활용시 상기의 문제점(자료 품질, 추정 자료 사용 등)을 해결하여 모의의 정확성과 정밀성을 제고할 수 있을 것으로 기대되는 바이다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.390-390
• /
• 2022

도시 생활용수 수요는 생활 수준 향상, 도시화 등으로 지속적 증가 추세에 있으며, 최근 기후변화, 시설 노후화, 도시화, 그리고 수질 오염 등의 문제들에 직면해 있다. 이는 물 부족을 심화시켜 현행 상수도시스템에서 한정적인 수자원을 배분하는데 어려움을 가중시킨다. 이를 해결하기 위해 스마트워터그리드 기술이 상수도시스템에 도입이 되면서 지능형 상수도 계량기를 이용한 개별 소비자들의 물 소비량 자료를 보다 정밀하게 실시간으로 모니터링 할 수 있게 되었다. 실시간 실측을 바탕으로 한 물 소비량 자료는 미래 용수 수요 예측과 수운영 관리에 도움을 줄 수 있다. 한편 생활용수는 용도 또는 요금 부과 기준에 따라 가정용, 업무용, 영업용, 욕탕용, 그리고 공업용으로 분류할 수 있다. 미국과 호주 등에서는 용도 분류에 따른 모니터링 강화로 절수 방안을 개발하여 물 부족에 대비하고 있다. 우리나라도 비 가정용수(가정용수를 제외한 용수들)를 체계적으로 분류하기 위한 선행 연구들이 이뤄졌으나 분류체계가 표준화되지 않았는데, 이는 용도에 따른 개별 소비자들의 소비 특성 분석이 충분히 선행되지 않았기 때문이며, 아직까지 많은 지자체에서 물 소비량을 월 단위로 인력검침 하는데 의존하고 있어, 충분한 물 소비량 자료가 부족했기 때문이다. 본 연구에서는 영종도 112 블록에 구축된 스마트워터그리드 파일롯플랜트 527개 개별 소비자들로부터 2018년 1월 1일부터 2020년 1월 1일까지 1시간단위로 수집된 물 소비량 자료를 이용하여, 개별 소비자들의 일평균 첨두 소비량과 발생 시간, 관경, 요일, 계절에 따른 물 수요 특성 분석을 수행했다. 이 때 수집된 자료의 결측치 및 오측치를 보정하여 자료의 신뢰성을 높이고자 했다. 분석결과는 용도별 물 수요 특성을 보다 잘 이해할 수 있게 도와주며, 비가정용수의 용도별 분류에 기초자료로 사용될 수 있을 것이라 사료된다.

• Journal of the Korean Geotechnical Society
• /
• v.40 no.3
• /
• pp.19-31
• /
• 2024

In Korea, driven piles are generally penetrated up to weathered rock or harder strata. Friction piles have been used to some extent in the southwest coastal area with deep soils; however, friction piles are not extensively due to uncertainties about construction quality. The embedded pile construction method is primarily used due to noise and vibration complaints. However, in Southeast Asian countries (e.g., Cambodia, Myanmar, and Vietnam), where soft sediments are deep, the driven pile method is commonly used due to its economic advantages. Construction companies are increasingly entering overseas construction markets, e.g., Southeast Asia; thus, it is necessary to understand the behavior of driven friction piles in the soil and improve on-site engineering management to gain market competitiveness in these countries. In this study, the bearing capacity of friction piles driven into clayey coastal soils in Vietnam with time-dependent characteristics was evaluated based on the dynamic and static pile load tests. Based on the results, a modified Danish formula is proposed for on-site quality management.

• Membrane Journal
• /
• v.24 no.2
• /
• pp.142-150
• /
• 2014

This paper is to develop the process suitable for the advanced treatment of liquid fertilizer from the livestock night soil treatment facility (biogas plant). Nanofiltration (NF) and reverse osmosis (RO) process was used, respectively, for the advanced treatment of liquid fertilizer. And membrane bioreactor (MBR) with and without biomedia were tested, respectively, for the pretreatment. It was found that almost T-N of the liquid fertilizer was composed of ammoniacal nitrogen. Transmembrane pressure of MBR with biomedia increased slowly during the operation time, while that of MBR without biomedia increased rapidly at the initial time. But there was no difference observed in the removal efficiencies of COD, T-N, and T-P irrespective of the dosage of biomedia. When the liquid fertilizer was pretreated by MBR with biomedia, the removal efficiencies of COD, T-N, and T-P were 99.8, 86.5%, and 99.8% by NF, and 99.9, 86.8%, and 99.8% by RO, respectively. Compared with the effluent quality standards of the livestock night soil treatment facility, the water quality treated by MBR and NF/RO process met the standard for COD and T-P, but exceeded the permitted standard for T-N. In order to meet the effluent quality standard for T-N, it is necessary to change the MBR operation cycle or to add the secondary treatment by NF/RO.

• Journal of Energy Engineering
• /
• v.14 no.2 s.42
• /
• pp.159-166
• /
• 2005

In Korea, although the generation of waste plastic has been increasing, the rate of recycling is considerably low and moreover, there is no suitable method for the treatment of waste plastics. However, pyrolysis, which is appropriate for the treatment of highly polymerized compounds, such as plastics, has recently gained much interest. In this study, a property of the products from the pyrolysis of mixed waste plastics, with a possible practical use for the recycling oil produced, were assessed. First of all, in order to investigate the pyrolysis characteristic of waste plastics, TGA (Thermogravimetric analysis) and DCS (Differential Scanning Calorimetry) were performed on a number of different plastics, including PP, LDPE, HDPE, PET and PS, as well as others. According to the result, it appeared that PP was the most efficiently pyrolyzed by changing the temperature, followed by LDPE, HDPE, PET, PS and the other plastics, in that order. From the results, the optimum conditions f3r pyrolysis were set up, and the different waste plastics pyrolyzed. The recycling oil produced from the flammable gases generated during the pyrolysis was com-pared with fuel oil by an analysis using the petroleum quality inspection method on KS(Korea industrial Standard). The results of the analysis showed the recycling oil was of a similar standard to fuel oil, with the exception of the ignition point, with a quality somewhere between that of paraffin oil and diesel fuel. With respect to these results, the quality of the recycling oil produced by the pyrolysis of waste plastics was suf-ficient for use as fuel oil.

• Journal of Korean Society of Environmental Engineers
• /
• v.38 no.8
• /
• pp.444-451
• /
• 2016

Most research on membrane fouling models in the past are based on theoretical equations in lab-scale experiments. But these studies are barely suitable for applying on the full-scale spot where there is a sequential process such as filtration, backwash and drain. This study was conducted in submerged membrane system which being on operation auto sequentially and treating wastewater from G-water purification plant in Incheon. TMP had been designated as a fouling indicator in constant flux conditions. Total volume of inflow and SS concentration are independent variables as major operation parameters and time-series analysis and prediction of TMP were conducted. And similarity between simulated values and measured values was assessed. Final prediction model by using genetic algorithm was fully adaptable because simulated values expressed pulse-shape periodicity and increasing trend according to time at the same time. As results of twice validation, correlation coefficients between simulated and measured data were $r^2=0.721$, $r^2=0.928$, respectively. Although this study was conducted limited to data for summer season, the more amount of data, better reliability for prediction model can be obtained. If simulator for short range forecast can be developed and applied, TMP prediction technique will be a great help to energy efficient operation.