• 멤브레인
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• 제30권2호
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• pp.138-148
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• 2020

본 연구는 (주)퓨어엔비텍에서 제조한 multi-bore 형태의 중공사 막을 이용하여 오염된 원수의 투과 후 오염된 막의 재사용을 위해 화학적 세정효율에 대해 파악하고자 하였으며 이를 위해 제조된 중공사 막의 재료는 내화학성이 좋은 PSf(polysulfone) 소재를 사용하였다. 실험은 소혈청 알부민(BSA)을 이용한 내오염성 평가 및 염기성 용액인 차아염소산나트륨(NaOCl), 산성 용액인 구연산(citric acid)을 이용해 장기 함침하여 내화학성 평가를 진행하였다. 시간에 따른 수투과도와 인장강도를 측정하여 분리막의 기계적 강도와 성능의 감소에 대한 결과를 관찰하였다. 이후 소혈청 알부민으로 오염된 막의 화학적 용액에 따른 역세척 후 회복효율을 파악하였다. PSf 중공사 막은 뛰어난 내화학성을 가졌으며 화학적세척결과 차아염소산나트륨의 효율이 높음을 확인하였다.

• 해양환경안전학회지
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• 제28권6호
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• pp.1078-1085
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• 2022

선박에 부착된 수중생물은 선체에서 성장하면서 선박의 저항을 크게 증가시킬 뿐만 아니라 부착생물이 배와 함께 이동하면서 지역의 해양 생태계 교란을 야기시키기도 한다. 이에 따라 국제해사기구에서는 선체부착생물의 이동을 막기 위해 선체부착생물 제거 및 청소성능 평가 논의를 시작해 오고 있다. 본 연구에서는 소형선박에 사용되는 FRP(Fiber Reinforced Plastic), HDPE((High Density Polyethylene), CFRP(Carbon Fiber Reinforced Plastic) 재료의 시편을 격포항(전락북도)에 약 80일간 양생시킨 후 물 제트 노즐을 이용하여 부착생물 제거실험을 수행하였다. 그 결과 김과 같은 해조류는 노즐과 시편과의 거리가 1.8cm, 100bar 일 때 제거되었지만, 따개비의 경우 200 bar 이상은 되어야 청소가 되는 것을 확인하였다.

• 환경위생공학
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• 제17권2호
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• pp.1-10
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• 2002

Ammonia is used in the manufacture of fertilizers, refrigerants, stabilizers and many household cleaning agents. The wide applications result in ammonia contamination in water. Ammonia can be removed from water by physical, biological, and chemical methods. Especially ozonation is effective in the treatment of water with low concentration of ammonia. Therefore, this study is undertaken to provide kinetic data for the ozonation of ammonia with bromide. The results were as follows; Ammonia oxidized by ozone with bromide catalysis. The denitrification rate of the ammonia increased proportionally to the concentration of bromide, and the overall reaction order was zero. It was also found that the effect of bromide ion concentration on the denitrification can be expressed by Monod type equation and there was no more effect above a proper bromide ion concentration. The reacted ammonia was converted completely to nitrate ion without bromide, but the denitrification of ammonia by ozone was conducted in the presence of bromide.

• 수산해양교육연구
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• 제25권4호
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• pp.819-827
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• 2013

Water quality has been considered to be one of sanitation standard operating procedures (SSOP) for hazard analysis critical control points (HACCP) application in aquaculture farms. This study was conducted to evaluate a hazard caused by water used in aquaculture farm of rainbow trout. The water quality was analyzed to investigate both physiochemical and bacteriological level in water samples collected from aquaculture farm of rainbow trout, Oncorhynchus mykiss. No significant difference were observed on water temperature and pH from season to season. However, the levels of dissolved oxygen were decreased as the outside temperature was increased, even if the levels were adequate for aquaculture. Also, other physiochemical analysis including biochemical oxygen demand (BOD), chemical oxygen demand (COD) and suspended solid (SS) revealed that the waters for aquaculture analyzed in this study was suitable for rainbow trout aquaculture. The bacterial analyses were also revealed that the waters for aquaculture were met to both coliform group (<18 MPN/100mL) and viable cell count (<100 CFU/mL). However, some of waste waters from aquaculture farms showed higher levels of BOD and COD than those of waste water standard (<2 ppm), suggesting that regular cleaning of fish tank and precipitation tank is needed.

• Membrane and Water Treatment
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• 제13권1호
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• pp.39-49
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• 2022

Seawater desalination is doubtlessly a viable option to supply fresh drinking water. Nevertheless, RO (reverse osmosis) desalination plants in specific areas may be intermittently operated to match the imbalance between water demand and supply. Although a handful of works have been done on other membrane systems, few studies have attempted to mitigate fouling in intermittent RO systems. Accordingly, the objectives of this paper were to examine the effect of the intermittent operation on RO fouling; and to compare four intermittent operation modes including feed solution recirculation, membrane storage in the feed solution, deionized water (DI) recirculation, and membrane storage in DI water. Results showed that intermittent operation reduced RO fouling under several conditions. However, the extents of fouling mitigation were different depending on the feed conditions, foulant types, and membrane lay-up methods. When the feed solution was recirculated during the lay-up, the restoration of the flux was less significant than that by the feed solution feed-up. The use of deionized water during the lay-up was effective to restore flux, especially when the feed solution contains scale-forming salts (CaSO₄) and/or colloidal silica.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.952-954
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• 2000

In the cleaning-water treatment process, the flocculation machine is operated by the V.S motor when the coagulation-facility of the coagulation-process is operated. But after the flocculation machine is stopped by an instantaneous power failure, the transient takes place when the coagulation facility is re-started. To improve the transient state, we developed the reinforcement-circuit which had the function of soft-start and adapted to the field. As a result of this study, we reduced the damage of facilities and had the safety in maintaining the quality of water and improved the efficiency in the maintenance and the management.

• Water Engineering Research
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• 제1권1호
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• pp.39-48
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• 2000

This work was completed in partial fulfillment of an on-going research ot descover the effective management of urban nonpoint sources. The current data was obtained from the area of Shingal, Kyunni-do. The investigation was are predominant soures of storm-runoff load and drainage. As a result of the investigation, the road was found to be most seriously contaminated and a significant potential source deteriorating the quality of streams and lakes in the vicinity of the town. Thus, in could be concluded that an effective and systematic cleaning technique must be developed as soon as possible and be frequently applied to the road.

• Membrane and Water Treatment
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• 제1권1호
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• pp.61-74
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• 2010

This paper will integrate models at different levels (from filtration, backwashing to chemical cleaning and membrane lifetime) that can be used to minimize overall operating costs of a dead-end ultra filtration process that is used for the purification of surface water. Integration of the models leads to a multi-level optimization problem (at different levels different objectives should be reached). This problem is solved as a MINLP. Systematic modelling and optimization of membrane systems is not extensively discussed in the scientific literature. In this paper the first steps are taken in the formulation of proper models and the use of systems engineering tools to come to real optimal operating conditions. The optimized variables are used to calculate fouling profiles which can subsequently be used as inputs for a control system that actually enforces the profiles to a real pilot plant.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.362-363
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• 2006

Ozonized DI water was supplied to make alkaline cleaning solutions to replace SCI chemicals in a bath with and without recirculation. With recirculation, low dissolved ozone and low pH cause lower particle removal efficiency (PRE) of 75%. However, direct supply of ozonized water with $NH_4OH$ to a bath without recirculation resulted in higher PRE over 93 %.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1672-1675
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• 2003

In this study, we developed full automation test system for pressure vessel. This pressure vessel containing oxygen, nitrogen and carbon is widely used in industrial field. The test items of pressure vessel are divided into three branches which is weight measurement, water-hydraulic, and leakage test. After leakage test is completed, cleaning and dry progress is carried out. And control system is consist of three controller which is PLC, monitoring system and database system. PLC is control all of system. Monitoring system measures weight, pressure, flow etc and display to all conditions. Database system stores tested data. we design system to control all test modules in communication by a second period with three control modules. Finally, we verified this system by field test.