• Membrane and Water Treatment
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• 제2권3호
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• pp.175-185
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• 2011

Ultrafiltration is an emerging technology for drinking water treatment because it produces better water quality as compared with conventional treatment systems. More recently, the combination of UF technology with other processes in order to improve its performance has been observed. These associations aim to maximize the contaminants removal and reduce membrane fouling. The operational performance of contaminants removal and water production of two UF pilot plants was compared. The first plant (Guarapiranga) was fed with raw water and the second plant (ABV) with pre-treated water by the coagulation, flocculation and sedimentation processes at Alto da Boa Vista WTP (Sao Paulo, Brazil). Both units operated continuously for approximately 2,500 hours, from September/2009 to January/2010. The results showed that the ABV UF pilot plant was able to operate at higher specific fluxes (6.2 $L.d^{-1}.m^{-2}.kPa^{-1}$ @ $25^{\circ}C$) than Guarapiranga (3.1 $L.d^{-1}.m^{-2}.kPa^{-1}$ @ $25^{\circ}C$). However, the number of chemical cleanings conducted in both pilot units during the considered operation period was the same (4 chemical cleanings for each plant), which shows that the pre-treatment reduced the membrane fouling. The water quality at ABV for all the variables analyzed was better, but the feed water quality was also better due to pretreatment. The rejection values for the different contaminants were higher at Guarapiranga mainly because of a pollution load reduction after pre-treatment at ABV. Even with the better performance of the ABV UF pilot plant, it is necessary to take into consideration the complexity of the complete treatment system, and also the costs involved in the construction and operation of a full-scale treatment unit.

• 한국연소학회지
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• 제15권2호
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• pp.1-11
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• 2010

Power generation systems based on the oxy-coal combustion with carbon dioxide capture and storage (CCS) capability are being proposed and discussed lately. Although a large number of lab scale studies for oxy-coal power plant have been made, studies of pilot scale or commercial scale power plant are not enough. Only a few demonstration projects for oxy-coal power plant are publicized recently. The proposed systems are evolving and various alternatives are to be comparatively evaluated. This paper presents a proposed approach for performance evaluation of a commercial 100 MWe class power plant, which is currently being considered for 'retrofitting' for the demonstration of the concept. The system is configurated based on design and operating conditions with proper assumptions. System components to be included in the discussion are listed. Evaluation criteria in terms of performance are summarized based on the system heat and mass balance and simple performance parameters, such as the fuel to power efficiency and brief introduction of the second law analysis. Also, gas composition is identified for additional analysis to impurities in the system including the purity of oxygen and unwanted gaseous components of nitrogen, argon and oxygen in air separation unit and $CO_2$ processing unit.

• 상하수도학회지
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• 제23권5호
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• pp.539-545
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• 2009

A feasibility of a pilot scale two-phase anaerobic digestion with ultra filtration system treating garbage leachate were evaluated. The treatment system consisted of a thermophilic acidogenic reactor, a mesophilic methanogenic reactor, and an UF membrane. The average COD removal efficiency of the treatment system was 95% up to the OLR of 3.1 g COD/L/d. The higher COD removal efficiency with membrane unit resulted from the removal of some portion of soluble organics by membrane as well as particulate materials. When the membrane unit was in operation, bulk liquid in acidogenic and methanogenic reactors was partially interchanged, which maintained the acidogenic reactor pH over 5.0 without external chemical addition. Also, with the production of methane in the acidogenic reactor, the organic loading rate of the methanogenic reactor reduced. The initial flux of the membrane unit was $50{\sim}60L/m^2/hr$, but decreased to $5 L/m^2/hr$ after 95 days of operation due to clogging caused by particulate materials such as fibrous materials in garbage leachate. To prevent clogging caused by particulate materials, a pretreatment system such as screening is required. With the improvement with membrane unit operation, the two-phase anaerobic digestion with ultra filtration system is expected to have the possibility of treating garbage leachate.

• 한국물환경학회지
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• 제22권2호
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• pp.250-257
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• 2006

The objective of this study is to propose an alternative process for the small sewage treatment plants in rural communities. A biofilter has been used for biological wastewater treatment, which is becoming the alternative to the conventional activated sludge system. The proposed process used in this study, which is packed with floating media (i.e. expanded polystylene), has advantages of biofilter system and alternative flow system and they are incorporated into one process. Pilot and bench scale studies were performed using domestic wastewater. In the results of pilot plant study, it was observed that the stable effluent water quality was achieved and it met the present effluent criteria of suspended solid (SS), organic matters, T-N and T-P. In the study for determination of the cycle of backwashing, it was observed that the cycle of backwashing depended on BOD loading rates of influents. In the BOD loading rates of $0.5kg\;BOD/m^3{\cdot}day$ and $1.0kg\;BOD/m^3{\cdot}day$, the backwashing cycle of 28 hour and 16 hour were needed, respectively. The optimum backwashing time was 120~80 seconds at the media expansion rate of 50%. In the removal of SS, organic matters, T-N and T-P, SS removal was rather achieved by physical filtration than biological mechanism and the removal of organic matters except for SS, T-N and T-P were mainly rather achieved by biological mechanism than physical filtration. In bench-scale study, the effects of recirculation rate was investigated on removal of SS, TCOD, T-N and T-P. It was observed that the recirculation made removal efficiencies of SS, TCOD, T-N and T-P increased. Especially, in T-N removal, the increase of T-N removal efficiency of 40% was observed in the reicirculation rate of 1Q compared with 0Q.

• Environmental Engineering Research
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• 제23권2호
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• pp.195-204
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• 2018

A pilot scale study was conducted on a down-flow hanging sponge (DHS) reactor installed at a sewage treatment plant in Banda Aceh, Indonesia for treatment of desludging septic tank wastewater. Raw wastewater with an average biochemical oxygen demand (BOD) and total suspended solids of 139 mg/L and 191 mg/L, respectively, was pumped into the reactor. Two different hydraulic retention times (HRTs, 3 h and 4 h) were investigated, equivalent to organic loadings of 1.11 and $0.78kg\;BOD/m^3/d$, respectively. The average BOD concentration in the final effluent was 46 and 26 mg/L at HRTs of 3 and 4 h, respectively. The concentration of retained sludge along the reactor height was 10.2-18.7 g VSS/L-sponge, and the sludge activities were 0.24-0.32 and 0.04-0.40 mg/g VSS/h for heterotrophs and nitrification, respectively. Values of water hold-up volume, dispersion coefficient, and number of tank in-series found from tracer studies of clean sponge and biomass-loaded sponge confirmed that growth of retained sludge on the sponge module improved hydraulic performance of the reactor. Adoption of the DHS reactor by this Indonesian sewage treatment plant would enhance the role of the current desludging septic tank wastewater treatment system.

• Carbon letters
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• 제7권3호
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• pp.180-187
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• 2006

The treatment of piggery wastes was carried out at pilot scale using a multilayered metal-activated carbon system followed by carbon bed filtration. The physicochemical properties were obtained from treated samples with aqueous solutions containing metallic ions such as $Ag^+$, $Cu^{2+}$, $Na^+$, $K^+$ and $Mn^{2+}$, which main obsevations are subjected to inspect surface properties, color removal properties by Uv/Vis and EDX. Multilayered metal-activated carbons were contacted with waste water to investigation of the simultaneous catalytic effect for the COD, BOD, T-N and T-P removal. The removal results for the piggery waste using multilayered metal-activated carbon bed was achieved the satisfactory removal performance under permitted values of Ministry of Environment of Korea. The high efficiency of the multilayered metal-activated carbon bed was determined by the performance of this material for trapping, catalytic effect and adsorption of organic solid particles.

• 한국농공학회지
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• 제45권2호
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• pp.107-115
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• 2003

Dairy manure amended with crop and forest residues (moisture 69% wet basis, C/N 22) was composted in a 605 L pilot-scale vessel using continuous air flow (56 L/min) for 19 days. Three pilot-scale sawdust biofilters (moisture 63%, pH 5.0) were built to clean biological waste gas from the composting process. For each methods, two replicated experiments were monitored over a period of three weeks. The system was evaluated to determine the biofilter media depth that would be adequate for compost odour reduction. The compost air cleaning was measured based on ammonia gas concentration before and after passing through the biofilter. Ammonia gas removal efficiency over 3 weeks was 42, 75 and 87% at sawdust biofilter media depth levels of 202, 400 and 600 mm, respectively. Each sawdust biofilter was operated at a moisture content in the range of 60~62% (wb), a temperature from 15 to $25^{\circ}C$, an average pressure drop from 240 to 340 Pa and a detention time from 60 to 180 seconds during the biofiltration process.

• Membrane and Water Treatment
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• 제13권1호
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• pp.1-6
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• 2022

The regulations of the International Maritime Organization (IMO) have been steadily strengthened in ship emissions. Accordingly, there is a growing need for development of related technologies for the removal of contaminants that may occur during the treatment of SOx and NOx using a wet scrubber. However, this system also leads to wastewater production when the exhaust gas is scrubbed. In this research, we evaluated the performance of an ion selective resin process in accordance with scrubber wastewater discharge regulations, specifically nitrate discharge, by the IMO. Accelerated real and synthetic wastewater of wet scrubbers, contained high amounts of TDS with high nitrate, is used as feed water in lab scale systems. Furthermore, a pilot scale dissolved air flotation (DAF) using microbubble generator with ion exchange resin process was combined and developed in order to apply for the treatment of wet scrubber wastewater. The results of the present study revealed that operating conditions, such as resin property, bed volume (BV), and inlet wastewater flow rate, significantly affect the removal performance. Finally, through a pilot test, DAF with ion exchange resin process showed a noticeable improvement of the nitrate removal rate compared to the single DAF process.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.482-488
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• 2017

근래 무기 체계는 IM에 대한 능력을 중요시하고 있다. 화약은 무기체계에 반드시 필요한 에너지 물질이면서 가장 위험한 물질로 IM을 위해 반드시 개선해야 할 주요 부품이라 할 수 있다. RDX는 1930년대부터 사용되어 현재는 가장 널리 사용되는 에너지 물질 중 하나이며 저렴한 가격과 높은 에너지 특성으로 인하여 탄두 화약의 대부분을 그리고 근래에는 화포용 추진제 및 로켓용 추진제에도 많이 사용되고 있는 물질 중 하나이다. 그러나, RDX는 근래에 개발된 NTO나 DADNE등의 둔감 화약에 비해 감도가 민감하다는 단점을 가지고 있어 이를 극복하기 위한 둔감 RDX의 연구 개발이 국내외에서 지속 수행되어 왔다. 본 연구에서는 RDX를 둔감화한 RS-RDX의 연구를 Pilot Scale과 양산 Plant에 적용하여 개발하였으며 그 결과를 Shock 감도를 통해 확인 할 수 있었다.

• 한국콘텐츠학회논문지
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• 제13권6호
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• pp.370-379
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• 2013

본 연구는 환자 및 보호자의 간병부담을 해결하기 위하여 보건복지부에서 수행한 보호자 없는 병원 시범사업에 대한 도입배경, 운영방법, 실시성과, 제한점 등에 대한 사례를 검토하고, 이를 토대로 향후 보호자 없는 병원의 제도 도입 필요성, 운영방법 등 제도화 방안을 도출하고자 수행되었다. 보건복지부 시범사업은 2007년 보호자 없는 병원 시범사업과 2010년 간병제도화 시범사업, 두 차례에 걸쳐 실시되었다. 2007년 시범사업의 결과를 살펴보면, 환자보호자의 간호간병서비스에 대한 만족도는 9.1점(10점 만점)으로 높았고, 재이용 의사 97.8%, 추천의사 98.0%로 높았다. 2007년 시범사업에서 도출된 적정 간호인력(안)은 간호사 1인당 2.3인, 간호보조인력 1인당 4.0인으로 나타났다. 2010년 시범사업 결과는 환자보호자 만족도는 8.0-9.1점(10점 만점)으로 높았고, 재이용, 추천 의향도 높았다. 그러나 2007년 시범사업에 비해 의료기관 유형 및 간호인력 배치 수준이 다양한 점 등 제한적인 측면이 있었다. 결론적으로 보호자 없는 병원을 제도화하기 위해서는 적정 간호인력 배치기준 설정, 간호서비스 제공인력 구성 및 업무 표준화, 간호인력 확보를 위한 재원 마련 및 간호요구도 평가, 질 관리 모니터링 등을 위한 정책 개발이 필요하다.