역삼투막을 이용한 제철폐수 처리 시 실리카 및 철 이온이 막 폐색에 미치는 영향

오희완,이채영 대한토목학회 2018 대한토목학회논문집 Vol.38 No.4

An integrated iron and steel mill uses a large amount of water and produces wastewater which contains various contaminants such asiron, manganese, etc. Especially, in some regions of Southeast Asia, the concentration of silica in iron and steel mill wastewater ishigher than in other countries. Silica is known to be one of the main causes for fouling in the membrane processes for water reuse. Incases of high concentrations of silica in iron and steel mill wastewater, the ferrous silicate tends to be formed. This could lead to higher fouling tendency depositing on the membrane surface. Therefore we conducted a pilot test to investigate the effect of silica and iron on the fouling tendency of reverse osmosis (RO) membrane for treating two types of wastewater from an integrated iron and steel mill. In this case of treated wastewater from iron and steel mill, RO pilot plant was operated with the fluxes 15.9LMH and 18.8LMH for 112 days to investigate the fouling haracteristics. The results found that the fluctuation of flux was much wider than the average flux and the minimum permeability was low at 78%. In the case of treated runoff from an integrated iron and steel mill, the average concentration of iron was lower than in wastewater. RO pilot test was conducted with the flux 18.8LMH for 46 days. The results found that runoff had a lower fouling tendency and pre-treatment using microfiltration (MF) could minimize the fouling problem of RO. 제철공정에서 물 사용량은 조강 생산량 당 4.2m3/톤으로 많으며 폐수의 성상에 있어서 철, 망간 등 물질을 포함하고 있다. 특히 동남아시아의 일부지역은 다른 지역에 비해 실리카의 농도가 높다. 실리카는 물 재이용을 위한 막 처리과정에서 막 폐색의 주된 요인으로 작용하기 때문에 물 재이용에 있어 제한요소이다. 실리카 농도가 높은 제철폐수의 경우 철 이온과 실리카에 의한 규산제일철 형성에 의한 막 폐색 발생우려가 높다. 본 연구는 두 가지 경우에 대하여 파일럿 테스트를 실시하였다. 제철폐수 처리수의 경우 RO 파일럿 테스트는 플럭스 15.9LMH 및 18.8LMH로 112일동안 수행하였다. 실험결과 플럭스의 변동 및 차압(TMP, trans membrane pressure)이 크게 나타났으며, 최소 투과율은 78%로 낮아 막 폐색 가능을 확인할 수 있었다. 오탁수 처리수를 이용한 RO 파일럿 테스트는 플럭스 18.8LMH로 46일 동안 수행하였으며, 철 이온 농도는 0.11mg/l으로 폐수 처리수보다 낮았다. 실험결과 철 이온 등의 농도가 낮은 오탁수 처리수는 플럭스 및 TMP의 변동이 작아 RO 막 폐색현상이 폐수 처리수보다 저감됨을 알 수 있었다. 유입수 조건이 실리카, 철 및 망간 농도가 높은 경우 MF 전처리를 통해 RO 막 폐색현상을 저감시킬 수 있었다.

잔자갈 浸漬濾床法에 의한 酒精廢水의 處理

梁相鉉,吳熙莞 전북대학교 공업기술연구소 1992 工學硏究 Vol.23 No.-

The characteristics of brewery wastewater and its treatability by aerobic submerged biofilter filled with gravels were examined, and following results were ontainde; 1. The BOD_5:N:P ratio of the raw wastewater was 100:6.0:1.8 and it was 100:75:20 of the anaerobic digestion effluent. 2. Deoxygenation Coefficient for raw wastewater and its supernatant was 0.08d^-1 and 0.134d^-1 respectively, and for digested wastewater and its supernatant was 0.023d^-1 and 0.044d^-1 respectively. 3. In the treatment of raw wastewater, above 95% of BOD_5 removal ratio was obtained under the operation of 0.197kg-BOD/kg-MLVSS-d and 6 days retention time. In the treatment of the anaerobic digestion effluent, above 90% of BOD_5 removal ratio was obtained under the operation of 0.074kg-BOD/kg-MLVSS-d and 436 days retention time. 4. The removal ratio of nitrogen and phosphate was 70% and 78% respectively for raw wastewater, and it was 72% and 94% for anaerobic digestion effluent. 5. As the volume of submerged biofilter is enough with 1/7 of activated sludge aeration tank, the treatment by submerged biofilter is a economical process.

서울메트로 1~4호선 고가역(창동역) 고체소음 저감 사례

공선용(Kong Sun-Yong),오희완(Oh Hee-Wan),김상진(Kim Sang-Jin) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-

In the recent railway construction, the concrete slab track is highlighted as the maintenance-free track and the main stream is moving from ballasted track to concrete slab track. However, in spite of many merits of concrete slab track, the higher noise generated from the concrete slab track is a troublesome question to solve and, by this reason, many studies on noise reduction of concrete slab track are carried out. The railway noise can be classified into the reflection noise emitted from wheel/rail contact and the structure-borne noise transmitted through railway structures. In this presentation, we would like to introduce an example of the successful reduction of structure-borne noise at track retrofitting to maintenance-free concrete slab track in elevated Changdong Station which was built with ballasted track on Rahmen structure.

폐타이어 담체를 이용한 유동상 생물막 공법 적용사례 연구

임남재 ( Ihm Nam-jae ),오희완 ( Oh Hee-wan ) 한국환경기술학회 2000 한국환경기술학회지 Vol.1 No.3

전자갈 침지려상법에 의한 주정폐수의 처리

양상현(Sang Hyon yang),오희완(Hee Wan Oh) 전북대학교 공학연구원 (구 전북대학교 공업기술연구소) 1992 工學硏究 Vol.23 No.-

도시철도에서 열차제동하중이 레일표면 열화에 미치는 영향

양태경(Tae-Kyoung Yang),오희완(Hee-Wan Oh),성덕룡(Deok-Yong Sung),최진유(Jin-Yu Choi),박용걸(Yong-Gul Park) 한국철도학회 2011 한국철도학회 학술발표대회논문집 Vol.2011 No.10

The rail surface irregularity is generated severely by train braking effect in the section of station. The braking force increases slip rate and friction factors caused by wheel-rail contact points. It brings rail surface irregularity as well. In this study interactions between wheel and rail were investigated using rolling contact fatigue theory and mechanism of rail degradation through fracture mechanics. For the more the Von-Mises stress occurred on the rail due to the interaction between wheel and rail was analyzed using 3-D finite element method. The amounts of surface irregularity of rail were measured according to accumulated passing tonnage in urban railway in fields. Therefore the maintenance of rail should be separated by running and braking sections to prevent RCF defects.

하수처리장 개조 및 증설 공사의 시운전 기간 방류 수질 보증 방안 - 중동 Y 하수처리장 시공 및 운전 사례를 바탕으로 -

문형준 ( Hyungjun Moon ),곽동근 ( Donggeun Kwak ),오희완 ( Heewan Oh ),고주형 ( Joohyung Ko ),이종명 ( Jongmyong Lee ) 한국물환경학회 2017 한국물환경학회·대한상하수도학회 공동 춘계학술발표회 Vol.2017 No.-

궤도상태별 궤도틀림 진전 분석

신길철(Gil-Cheol Shin),이달재(dal-jae Lee),오희완(Hee-Wan Oh),강윤석(yoon seok Kang),박용걸(yong Geol Park) 한국철도학회 2012 한국철도학회 학술발표대회논문집 Vol.2012 No.10

본 논문에서는 도시철도의 경우 궤도틀림에 대한 유지보수 개소의 선정을 검측된 각 검측항목의 값을 토대로 일정 한계치를 벗어난 구간을 보수대상으로 하거나, 전체적인 검측 값들의 추세를 경험적 측면에 근거하여 주관적으로 판단하여 결정하고 있어, 정기적인 종합검측차의 검측데이터 출력 결과를 이용, 표준편차 관리법에 의한 궤도상태별 궤도 틀림 진행 정도와 표준편차가 시계열에 따라 변화는 진전율을 살펴보고, 국내, 외에서 적용하고 있는 궤도품질기준을 서울메트로 일부 구간의 궤도상태와 비교 분석하였다. This paper is In urban railroad, Selection of track maintenance on track irregularity is aimed at track maintenance subject which get out constant threshold value on the basis of track geometry value, or judge general threshold value subjectively on the basis of empirical side. and subjectively determine the track maintenance by general threshold value on the basis of empirical side. In this paper, The progressing degree and deviation management of the track irregularity classified track structure, radius of curve by standard deviation management using regular outing data of track inspection car check changing a rate of progress depending on time series and analyse part of track condition in Seoul Metro by internal and external track quality criteria.

도상개량에 따른 부족캔트 조정사례 연구

김광은(Kwang-Eun Kim),최삼혁(Sam-Hyeok Choi),오희완(Hee-Wan Oh),강윤석(Yoon-Suk Kang),박용걸(Yong-Gul Park) 한국철도학회 2012 한국철도학회 학술발표대회논문집 Vol.2012 No.10

본 논문의 목적은 도시철도 서울메트로(지하철 1~4호선)의 궤도구조가 건설 당시 기술능력, 건설비, 공사기간 등으로 본선구간 약 81%가 자갈도상으로 건설되었다. 이에 따라 장기사용으로 도상자갈이 마모, 파쇄됨에 따라 마찰력과 충격흡수력 등의 도상기능 저하로 궤도틀림이 발생되어 빈번한 보수작업과 유지보수비용이 많이 소요되어 자갈도상을 콘크리트도상으로 전 구간을 추진하고 있다. 또한 2004년부터 도시철도의 최고속도를 향상시키기 위해 곡선부에 5km/h를 상승시켰다. 따라서 본 논문에서는 도상개량시 실제 현장상태에 적합한 캔트를 조정하기 위하여 선로의 곡선, 운전속도 등을 고려한 부족캔트 조정사례를 통해 레일마모와의 상관관계와 효과를 캔트조정 전, 후의 변화를 분석한 결과 캔트부족량이 레일마모 및 궤도에 미치는 영향이 많은 것을 알 수 있었다. At the time of opening, 81% of mainline tracks of Seoul Metro were built with ballasted tracks due to limited technical capability, construction cost and construction period. All the ballasted tracks have been promoted to replace to slab tracks due to its deterioration of track function resulting from the wear of ballast by abrasion and fragmentation by long-term use and its requirement of higher maintenance cost and more frequent repairs and maintenance. In this study, in order to apply the appropriate cant suitable for real site condition when improving tracks, the relationship and effect of rail wear before and after adjusting cant have been analysed by taking the curves of tracks and driving speed into consideration.